Hair Styling Devices

Abstract

A hair styling device is provided, comprising a sensor device configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device indicative of usage of the hair styling device, and a controller configured to receive the sensor output from the sensor device and process the sensor output using a classification algorithm configured to determine, based on the at least one usage characteristic of the hair styling device, whether the hair styling device is being used according to a first styling behavior or a second styling behavior different from the first styling behavior, to obtain classification data, and the controller configured to control the hair styling device to perform an action using the classification data.

Description

[Technical field]

[0001] The present disclosure relates to hair styling devices. In particular, but not exclusively, the present disclosure relates to means, including methods, apparatus and computer programs, for operating hair styling devices. [Background technology]

[0002] Hair styling devices, also called hair styling appliances, are used to shape hair into a desired shape or style, in particular heated hair styling devices use the action of heat, and optionally also mechanical means, to style hair as desired.

[0003] One example of such a hair styling device is a hair straightening device (also called a hair straightener or curling iron). Such a hair styling device typically comprises two articulated arms pivotally attached to one another at one end, with one or more heatable plates attached to the two articulated arms. If both arms have heatable plates, the heatable plates are typically located on the inner surfaces of the opposing arms. The heatable plates have a hair-contactable surface operable to contact and apply heat to hair during use of the hair styling device. The heatable plates (and therefore the hair-contactable surface) can be heated by one or more heating elements. Summary of the Invention [Problem to be solved by the invention]

[0004] However, known hair styling devices have limited flexibility and / or versatility. As a result, known hair styling devices may be limited in their ability to achieve a desired style. For example, known hair styling devices typically emit heat when in contact with a hair strand. This may be relatively inefficient and may even damage the hair. Furthermore, known hair styling devices typically rely on the user to use the hair styling device correctly to achieve the desired style. In some cases, for example, too much or too little heat and / or too much or too little gripping pressure may be applied to the hair. This may cause thermal and / or mechanical damage to the hair and / or may prevent the desired style from being achieved. If the desired style is not achieved using the hair styling device in a first pass, for example due to incorrect or suboptimal use of the hair styling device, the user may repeat the pass on the same portion of hair one or more times. This repetition may involve extended time and / or increased power consumption in addition to increasing the risk of damage to the hair. In some cases, repeated passes may not achieve the desired style.

[0005] It is therefore desirable to provide improved hair styling devices and / or improved methods for operating hair styling devices. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a hair styling device comprising: a sensor device configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device indicative of a current usage of the hair styling device; and a controller configured to receive the sensor output from the sensor device, process the sensor output using a classification algorithm configured to determine whether the hair styling device is being used according to a first styling behavior or a second, different styling behavior based on the at least one usage characteristic of the hair styling device to obtain classification data, and use the classification data to control the hair styling device to perform an action.

[0007] By using the sensor data as input to the classification algorithm, styling behaviors can be recognized without requiring user input. Thus, the hair styling device can autonomously determine how a user is using the hair styling device and adapt accordingly. This allows for more intelligent control of the hair styling device. For example, one or more operational settings of the hair styling device can be controlled depending on the determined behavior. This allows the settings of the hair styling device to more closely correspond to how the user intends to use the hair styling device. This can reduce styling time and / or increase the likelihood of achieving a desired style. Furthermore, this can reduce the likelihood of hair damage, for example, by the user using incorrect and / or suboptimal settings for a given styling behavior.

[0008] In some embodiments, the classification algorithm comprises a trained algorithm that has been trained using training data to determine whether the hair styling device is being used according to a first styling behavior or a second styling behavior. Using such a trained algorithm results in a more accurate and / or reliable classification of the styling behavior than if the trained algorithm were not used. In some embodiments, the classification algorithm comprises a machine learning algorithm. Such a machine learning algorithm may improve with experience and / or training (e.g., may increase the accuracy and / or reliability of the classification).

[0009] In some embodiments, the hair styling device comprises a machine learning agent, which comprises a classification algorithm. Thus, the classification algorithm can be located on the hair styling device. By performing classification of the styling behavior of the hair styling device, the latency is reduced compared to when the classification algorithm is not located on the hair styling device, since the transmission of data to and / or the reception of data from another device is not required. This allows the classification data to be obtained more quickly, which reduces the time it takes to take any corrective action, for example, adjusting one or more operational settings of the hair styling device 100. As a result, the possibility of hair damage, for example due to operational settings not corresponding to the intended use of the hair styling device, can be reduced.

[0010] In embodiments, the first styling behavior includes a hair straightening behavior and the second styling behavior includes a hair curling behavior. Thus, the classification algorithm may be configured to distinguish between hair straightening and hair curling using the sensor data.

[0011] In some embodiments, the first styling behavior includes a full style behavior and the second styling behavior includes a touch-up behavior. Thus, the classification algorithm may be configured to distinguish between a full style and a touch-up using the sensor data.

[0012] In some embodiments, the first styling behavior includes a wet hair styling behavior and the second styling behavior includes a dry hair styling behavior. Thus, the classification algorithm may be configured to distinguish between wet hair styling and dry hair styling using the sensor data.

[0013] In some embodiments, the sensor equipment comprises an inertial measurement unit (IMU). In some such embodiments, the at least one characteristic of use is indicative of a movement of the hairstyling device.

[0014] In some embodiments, the hair styling device comprises a hair contacting member having first and second opposing hair contacting surfaces, the hair contacting member being movable between an open configuration and a closed configuration, In some such embodiments, the at least one use characteristic indicates whether the hair contacting member is in the open configuration or the closed configuration.

[0015] In some embodiments, the sensor device comprises a Hall effect sensor.

[0016] In some embodiments, the controller is configured to use the sensor output to modify the classification algorithm, e.g., the classification algorithm can be trained and / or further trained using the sensor output. Modifying the classification algorithm can improve the accuracy and / or reliability of the classification algorithm with experience and / or use of more training data. That is, the confidence level of the classification data can be increased. Furthermore, modifying the classification algorithm allows the classification algorithm to be tailored to a user. For example, an initial classification algorithm may be provided on the hair styling device, but the initial classification algorithm does not take into account the specific behavior and / or activity of a given user. A user may, for example, move the hair contacting member in a particular manner that differs from other users. By dynamically retraining the classification algorithm using the sensor output as training data, the classification algorithm can more reliably determine which styling behavior the user is intending to use.

[0017] In some embodiments, the hair styling device includes a heating element operable to apply heat to hair. In some such embodiments, the controller is configured to control the heating element based on the classification data. This allows the heat settings of the hair styling device to more closely correspond to the styling behavior that the user intends to employ. Thus, the desired style may be achieved with less potential hair damage and / or less styling time.

[0018] In embodiments, the control unit is configured to provide an output based on the classification data via a user interface, which may prompt the user to take corrective action, e.g., change an operating setting.

[0019] In embodiments, the control unit is configured to store the classification data in memory so that it can be used at a later time, for example during the next use of the hair styling device.

[0020] In embodiments, the controller is configured to output the classification data for transmission to a remote device.

[0021] In some embodiments, the controller is configured to receive training data from the remote device and modify the classification algorithm using the received training data. Modifying the classification algorithm using the training data from the remote device may increase the accuracy and / or reliability of the classification algorithm compared to when such training data is not used.

[0022] In embodiments, the classification algorithm comprises a random forest algorithm.

[0023] In some embodiments, the controller is configured to use one or more contextual features as input to a classification algorithm to obtain the classification data. Using the contextual features as input to the classification algorithm increases the confidence level of the classification data.

[0024] In embodiments, the one or more contextual features are indicative of previous usage of the hair styling device and / or user preferences.

[0025] In embodiments, the hair styling device comprises a hair straightening device and / or a hair curling device.

[0026] According to one aspect of the disclosure, there is provided a method of operating a hair styling device, the hair styling device comprising a sensor device configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device indicative of a current usage of the hair styling device, the method including receiving the sensor output from the sensor device, processing the sensor output using a classification algorithm configured to determine whether the hair styling device is being used according to a first styling behavior or a second, different styling behavior based on the at least one usage characteristic of the hair styling device to obtain classification data, and using the classification data to control the hair styling device to perform an action.

[0027] According to one aspect of the disclosure, there is provided a computer program that, when executed by a computing device, causes the computing device to perform a method of operating a hair styling device, the hair styling device comprising a sensor device configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device indicative of a current usage of the hair styling device, the method including receiving the sensor output from the sensor device, processing the sensor output using a classification algorithm configured to determine whether the hair styling device is being used according to a first styling behavior or a second, different styling behavior based on the at least one usage characteristic of the hair styling device to obtain classification data, and using the classification data to control the hair styling device to perform an action.

[0028] Of course, it will be understood that features described in the context of one aspect of the invention may be incorporated in other aspects of the invention, for example a method of the invention may incorporate any of the features described in the context of an apparatus of the invention, and vice versa.

[0029] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0030] [Figure 1] 1A and 1B are perspective views of a hair styling device according to several embodiments. [Diagram 2] FIG. 1 is a schematic diagram of a hair styling device according to several embodiments. [Diagram 3] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 4] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Diagram 5] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 6] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 7] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 8] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 9] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 10] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 11] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 12] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. [Figure 13] 1 is a flow diagram illustrating a method of operating a hair styling device according to several embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] 1A and 1B show perspective views of a hair styling device 100 according to several embodiments. The hair styling device 100 and / or its components can be used to carry out the methods described herein. In the embodiment shown in Fig. 1A and 1B, the hair styling device 100 comprises a hair straightener.

[0032] The hair styling device 100 comprises a first arm 110 and a second arm 120 joined at one end by a hinge 130. Each arm 110, 120 comprises a heatable plate 115, 125. One or both of the heatable plates 115, 125 can be heated, for example, by a heating element (not shown). In some embodiments, one or both of the heatable plates 115, 125 comprise a resistive plate. Such a resistive plate can be heated directly, for example, without the need for a separate heating element. The heatable plates 115, 125 comprise a hair-contactable surface 116, 126, respectively. The hair-contactable surfaces 116, 126 are arranged opposite one another. The arms 110, 120 are hinged such that they can move between an open position (shown in FIG. 1A) and a closed position (shown in FIG. 1B). In the closed position, the hair-contactable surfaces 116, 126 are brought towards each other so that hair to be styled can be held between the hair-contactable surfaces 116, 126. In some embodiments, the hair-contactable surfaces 116, 126 touch when the arms 110, 120 are in the closed position. In other embodiments, the hair-contactable surfaces 116, 126 do not touch.

[0033] The arms 110, 120 can be moved between the open and closed positions by a user. For example, the user pushes the arms 110, 120 together when using the hair styling device 100 (to style hair between the hair-contactable surface 116 and the hair-contactable surface 126) and releases the arms 110, 120 when styling is complete and / or pulls the arms 110, 120 apart. In some embodiments, the hair styling device 100 comprises a biasing means (not shown), such as one or more springs and / or magnets. The biasing means urges the arms 110, 120 towards the open position, resulting in the arms 110, 120 returning to the open position when the user is no longer pushing the arms 110, 120 together.

[0034] In alternative embodiments, the arms 110, 120 may not pivot about the hinge 130. For example, the arms 110, 120 may be substantially parallel to one another. In either case, a user can press the arms 110, 120 together to style hair.

[0035] 1A and 1B, the hair styling device 100 comprises a cordless hair styling device. For example, the hair styling device 100 may be powered by a rechargeable battery. In alternative embodiments, the hair styling device 100 is externally powered, for example via one or more external power cords (not shown).

[0036] FIG. 2 shows a schematic block diagram of a hair styling device 100 according to several embodiments.

[0037] The hair styling device 100 comprises a controller 210. As described in more detail below, the controller 210 is operable to perform various data processing and / or control functions according to embodiments. The controller 210 may include one or more components. The one or more components may be implemented in hardware and / or software. The one or more components may be co-located in the hair styling device 100 or may be located remotely from each other. The controller 210 may be embodied as one or more software functions and / or hardware modules. In embodiments, the controller 210 comprises one or more processors configured to process instructions and / or data. The operations performed by the one or more processors may be performed by hardware and / or software. The controller 210 may be used to perform the methods described herein. In embodiments, the controller 210 is operable to output control signals for controlling one or more components of the hair styling device 100.

[0038] In embodiments, the hair styling device 100 comprises a heating element 220. The heating element 220 may, for example, be operable to convert electrical energy into heat. The heating element 220 is configured to heat the hair by the hair styling device 100. The controller 210 is operable to control the heating element 220. For example, the controller 210 may be operable to apply energy (e.g., electrical energy) to the heating element 220, for example, via one or more control signals generated by the controller 210.

[0039] In embodiments, the hair styling device comprises a heatable hair contacting member 225. The hair contacting member 225 may be heatable by a heating element 220. In alternative embodiments, the hair contacting member 225 is directly heatable, i.e., heatable without the need for a separate heating element 220. In embodiments, the hair contacting member 225 comprises one or more heatable plates. For example, the hair contacting member 225 may comprise one or more of the heatable plates 115, 125 described above in connection with Figures 1A and 1B. The hair contacting member 225 may comprise one or more hair contactable surfaces, such as the hair contactable surfaces 116, 126 described above. The hair contacting member 225 is operable to apply heat to the hair via the one or more hair contactable surfaces 116, 126. Thus, the control unit 210 controls the heating of the hair contact member 225, for example by controlling the heating element 220, thereby providing heat to hair in contact with one or more hair contactable surfaces 116, 126 of the hair contact member 225.

[0040] In embodiments, the hair contacting member 225 comprises opposing first and second hair contactable surfaces 116, 126. The opposing first and second hair contactable surfaces 116, 126 are arranged to heat a hair inserted between the hair contactable surfaces. In embodiments, the hair contacting member 225 is operable to apply heat to the hair by moving the hair contacting member 225 along the hair bundle, for example, from a first end of the hair bundle toward a second end of the hair bundle. The movement of the hair contacting member 225 along the hair bundle may be referred to as a "pass." In alternative embodiments, the hair contacting member 225 comprises a single hair contactable surface. The hair contacting member 225 may comprise a movable arm, such as the first arm 110 and the second arm 120 described above with reference to FIGS. 1A and 1B.

[0041] In some embodiments, the hair styling device 100 comprises an opening and closing mechanism 227. The opening and closing mechanism 227 may be operable to close and / or open the hair contacting member 225. The opening and closing mechanism 227 may comprise an electromechanical opening and closing mechanism. The opening and closing mechanism 227 is operable to receive a control signal from the controller 210, thereby enabling the controller 210 to control the opening and closing mechanism 227. In embodiments in which the hair contacting member 225 comprises opposing first and second hair contactable surfaces 116, 126, the first and second hair contactable surfaces 116, 126 being positioned to receive hair therebetween, the opening and closing mechanism 227 is operable to adjust the distance between the first hair contactable surface 116 and the second hair contactable surface 126, as will be described in more detail below.

[0042] In some embodiments, the hair styling device 100 comprises a sensor device 230. The sensor device 230 comprises one or more sensors. Examples of such sensors include, but are not limited to, an IMU, a Hall effect sensor, a temperature sensor, a power sensor, a proximity sensor, a motion sensor, a gyroscope, an accelerometer, a magnetometer, etc. In some embodiments, the sensor device 230 comprises one or more processors. The controller 210 is operable to receive a signal (e.g., a sensor output) from the sensor device 230. The sensor output from the sensor device 230 can be used to control the hair styling device 100. In some embodiments, the controller 210 is operable to control the sensor device 230.

[0043] In the embodiment shown in FIG. 2, the sensor device 230 comprises an IMU 235. In such embodiments, the controller 210 is operable to receive a signal from the IMU 235 indicative of movement of the hair styling device 100. In some embodiments, the IMU 235 comprises an accelerometer, a gyroscope, and a magnetometer. Each of the accelerometer, gyroscope, and magnetometer has three axes or degrees of freedom (x, y, z). Thus, the IMU 235 may comprise a nine-axis IMU. In alternative embodiments, the IMU 235 comprises an accelerometer and a gyroscope, but does not comprise a magnetometer. In such embodiments, the IMU 235 comprises a six-axis IMU. A nine-axis IMU may produce more accurate measurements than a six-axis IMU due to the additional degrees of freedom. However, in some circumstances, a six-axis IMU may be preferred over a nine-axis IMU. For example, some hair styling devices may generate and / or be subject to magnetic disturbances during use. This may be a particular consideration for cordless hair styling devices with on-board power supplies and hair styling devices with heating elements. Heating, device magnetism and / or magnetic inductance, and / or other magnetic disturbances may affect the magnetometer behavior. Thus, in some cases, a 6-axis IMU is more reliable and / or more accurate than a 9-axis IMU. The IMU is configured to output data indicative of an accelerometer signal and a gyroscope signal (and in some embodiments, a magnetometer signal). In an alternative embodiment, the IMU 235 may include an accelerometer but not a gyroscope or magnetometer. In such an embodiment, the IMU 235 constitutes a 3-axis IMU.

[0044] In some embodiments, the hair styling device 100 comprises a user interface 240. The user interface 240 may comprise, for example, an audio and / or a visual interface. In some embodiments, the user interface 240 comprises a display (e.g., a touch screen display). In some embodiments, the user interface 240 comprises an audio output device, such as a speaker. In some embodiments, the user interface 240 comprises a haptic feedback generator configured to provide haptic feedback to a user. The controller 210 is operable to control the user interface 240, e.g., to provide output for a user via the user interface 240. In some embodiments, the controller 210 is operable to receive data based on, for example, a user's input via the user interface 240.

[0045] The hair styling device 100 further comprises a memory 250. The memory 250 is operable to store various data according to multiple embodiments. The memory may comprise at least one volatile memory, at least one non-volatile memory and / or at least one data storage device. The volatile memory, non-volatile memory and / or data storage device may be configured to store computer readable information and / or instructions for use or execution by the control unit 210.

[0046] In alternative embodiments, the hair styling device 100 may include more, fewer, and / or different components. In particular, at least some of the components of the hair styling device 100 shown in Figures 1A, 1B, and / or 2 may be omitted (e.g., may not be required) in some embodiments. For example, in some embodiments, at least one of the heating element 220, the hair contacting member 225, the opening and closing mechanism 227, the sensor device 230, the user interface 240, and the memory 250 may be omitted. In some embodiments, the hair styling device 100 does not include movable (e.g., pivotable) arms 110, 120.

[0047] Figure 3 illustrates a method 300 of operating a hair styling device according to some embodiments. Method 300 can be used to operate the hair styling device 100 described above with reference to Figures 1A, 1B and 2. In the embodiment of Figure 3, the hair styling device 100 comprises a heatable hair contacting member 225 having a hair contactable surface 116, 126. The hair contacting member 225 is operable to apply heat to a strand of a user's hair via the hair contactable surface 116, 126. In some embodiments, method 300 is performed at least in part by the controller 210.

[0048] At step 310, it is determined that the hair contact member 225 is moving along the hair strand from a first end of the hair strand toward a second end of the hair strand.

[0049] In step 320, based on the above determination, the heating element 220 is controlled to change an operating temperature of the hair contact member 225 as the hair contact member 225 moves along the hair bundle from the first end of the hair bundle toward the second end of the hair bundle.

[0050] In some embodiments, the first end constitutes a root end of the hair bundle and the second end constitutes a tip end of the hair bundle. The first end may be located at the root or at a midpoint of the hair bundle. Similarly, the second end may be located at the tip or at a midpoint of the hair bundle. As used herein, the term "root end" refers to the end of the hair bundle closest to the root of the hair. The term "tip" end refers to the end of the hair bundle closest to the tip of the hair (e.g., furthest from the root). In some examples, the hair bundle extends the entire path from the root of the hair (e.g., the user's head) to the tip of the hair. In other examples, however, the hair bundle extends partially from the root of the hair to the tip of the hair. In such examples, the root end of the hair bundle may be located at a location other than the actual root of the hair and / or the tip end of the hair bundle may be located at a location other than the actual tip of the hair.

[0051] Thus, the operating temperature of the hair contacting member 225 changes as it moves along the hair bundle. By adapting and / or adjusting the supply of heat to the hair along the hair bundle, the heat distribution throughout the hair bundle can be controlled. The temperature of the hair may be higher at the root end of the hair bundle compared to the tip end of the hair bundle. However, the hair at the tip end may require more heat to be applied to style (e.g., straighten) as desired than the hair at the root end. The hair at the tip end is older than the hair at the root end, and older hair may require more heat to style as desired. Thus, using a hair contacting member 225 at a constant operating temperature along the hair bundle may cause heat damage to the hair at the root end of the hair bundle (due to too much heat being applied to the root end) and / or may not achieve the desired style (due to too little heat being applied to the tip end). Thus, by providing a heat delivery profile that increases from the root end to the tip end of the hair bundle, the potential for heat damage is reduced (particularly protecting the younger hairs at the root end) while ensuring that a high enough temperature is delivered to the hairs at the tip end to achieve the desired style. Such a heat delivery profile is sometimes referred to as a "root-to-tip" heat delivery profile. In embodiments, the operating temperature of the hair contacting member 225 increases as it moves along the hair bundle. In alternative embodiments, the operating temperature of the hair contacting member 225 decreases as it moves along the hair bundle.

[0052] In some embodiments, the hair styling device 100 includes a sensor device 230 configured to generate a sensor output responsive to movement of the hair contacting member 225. The sensor output is processed to determine that the hair contacting member 225 is moving along the hair bundle. Thus, in some embodiments, the determination that the hair contacting member 225 is moving along the hair bundle may be made without user input and / or intervention. In some embodiments, the sensor device 230 includes an IMU 235. One or more signals from the IMU 235 may be processed to determine that the hair contacting member 225 is moving along the hair bundle. Additionally or alternatively, the sensor device 230 may include a Hall effect sensor. The Hall effect sensor may generate a sensor output responsive to whether the hair contacting member 225 is in an open configuration (e.g., when the arms 110, 120 are open) or a closed configuration (e.g., when the arms 110, 120 are closed). Thus, closure of the hair contacting member 225 can be sensed and used to determine that the hair contacting member 225 is moving along the hair strand. In alternative embodiments, the determination of step 310 is performed without the use of a sensor device. For example, the determination may be made based on user input, such as via a user interface, one or more buttons on the hair styling device 100, or the like.

[0053] In some embodiments, the hair styling device 100 comprises a heating element 220 operable to heat the hair contacting member 225. In some such embodiments, controlling the heating of the hair contacting member 225 comprises controlling the heating element 220.

[0054] In some embodiments, a displacement of the hair contacting member 225 from the first end of the hair bundle is derived based on the sensor output. In some such embodiments, heating of the hair contacting member 225 (e.g., control of the heating element 220) is based on the derived displacement. The displacement may be derived based on signals received from, for example, the IMU 235. In other examples, a start of a path is identified (e.g., when the hair contacting member 225 is at the root end of the hair bundle) and a displacement is derived based on the elapsed time from the start of the path. The start of the path may be identified based on, for example, the closing of the plates of the hair contacting member 225. Controlling the heating of the hair contacting member 225 based on the derived displacement may provide finer control over the heat distribution along the hair bundle.

[0055] In some embodiments, the heating of the hair contacting member 225 is controlled based on a predetermined threshold operating temperature of the hair contacting member 225. The predetermined threshold operating temperature is dependent on the derived displacement of the hair contacting member 225 from the first end (e.g., the root end) of the hair bundle. The heating of the hair contacting member 225 can be controlled, for example, such that the operating temperature of the hair contacting member 225 is greater than a predetermined threshold operating temperature for the hair contacting member 225. In some embodiments, a first predetermined threshold operating temperature is used for the first end of the hair bundle and a second predetermined threshold operating temperature is used for the second end of the hair bundle, the second predetermined threshold operating temperature being greater than the first predetermined threshold operating temperature. In some embodiments, a third predetermined threshold operating temperature is used for a location on the hair bundle between the first end and the second end. The third predetermined threshold operating temperature can be between the first predetermined threshold operating temperature and the second predetermined threshold operating temperature.

[0056] In some embodiments, the speed of the hair contacting member 225 is derived based on the sensor output. For example, the speed may be derived by processing one or more signals from the IMU 235. In such some embodiments, the heating of the hair contacting member 225 is controlled based on the derived speed. In some embodiments, the heating of the hair contacting member 225 is controlled to change (e.g., increase) the operating temperature of the hair contacting member 225 at a rate that depends on the derived speed. In other words, the rate of temperature change of the hair contacting member 225 may depend on the speed at which the hair contacting member 225 is moving. For example, the rate of temperature increase (or "warming up") may be relatively rapid if the hair contacting member 225 is determined to be moving relatively quickly and may be relatively slow if the hair contacting member 225 is determined to be moving relatively slowly. This may allow finer control of heat distribution along the hair strand and / or allow the hair styling device 100 to adapt to the behavior of the user. In some embodiments, the heat delivery profile along the hair strand depends on the derived speed.

[0057] In some embodiments, a velocity and / or position estimation algorithm is used to process the sensor output. In some embodiments, the velocity and / or position estimation algorithm is configured to combine the accelerometer signal and the gyroscope signal from the IMU. For example, determining that the hair contacting member 225 is moving along the hair bundle, deriving the displacement of the hair contacting member 225 from the first end, and / or deriving the velocity of the hair contacting member 225 can be performed by using a velocity and / or position estimation algorithm. In an embodiment where a 9-axis IMU is used, the velocity and / or position estimation algorithm can determine the initial state using signals from a magnetometer in addition to the accelerometer and gyroscope signals. In some embodiments, the velocity and / or position algorithm comprises a Madgwick filter. The velocity and / or position estimation algorithm can be implemented using software or hardware, for example, an application specific integrated circuit (ASIC), or can be implemented using a combination of hardware and software. The velocity and / or position estimation algorithm can be used in various methods described herein.

[0058] IMUs may have noise, bias and / or drift that may cause errors in the resulting calculations unless properly corrected. For example, gyroscope signals may drift over time, accelerometers may be biased by gravity, and both gyroscope and accelerometer signals may be noisy. In some embodiments, filtering, such as high and / or low pass filters and / or median filters, is used to remove at least a portion of the noise in the IMU signals. In some embodiments, a Madgwick filter is used to correct for gyroscope drift by removing the magnitude of the gyroscope measurement error in the direction of the estimated error or in the steepest direction while combining the accelerometer and gyroscope signals. The output of the Madgwick filter is a world reference orientation quaternion or Madgwick quaternion, which provides an orientation to the device. This quaternion is used to rotate the acceleration signal with respect to the Earth reference frame. Once the acceleration is rotated, the proportion of the gravitational pull on each axis is calculated and removed (i.e., gravity is compensated). This gives a linear acceleration, which can be integrated to give velocity, which can then be integrated to give position and / or displacement. Each time these signals are integrated, the residual error due to such bias and / or drift increases. Therefore, such errors can be particularly problematic with respect to velocity and / or position measurements. Compensating for velocity drift before integrating the velocity to give position increases the accuracy of the measurements. The velocity and / or position measurements can comprise separate measurements for all three axes, or the directional components can be combined to give velocity magnitude and / or position magnitude.

[0059] In other embodiments, alternative filters and / or algorithms can be used instead of or in addition to the Madgwick filter. Examples of such filters include complementary filters such as the Kalman filter, the extended Kalman filter, and / or the Mahony filter. However, the Madgwick filter is less computationally intensive than other filters while achieving a comparable or possibly better level of accuracy. This allows the Madgwick filter to be performed on the hair styling device 100 itself without the need for an external processing device. This reduces latency compared to when processing is performed on external processing data, as there is no need to transfer data between devices.

[0060] In some embodiments, the velocity may be derived by processing one or more signals from a three-axis IMU. As described above, in some such embodiments, the heating of the hair contacting member 225 is controlled based on the derived velocity. In some embodiments, the heating of the hair contacting member 225 is controlled to change (e.g., increase) the operating temperature of the hair contacting member 225 at a rate that is responsive to the derived velocity. In other words, the rate of temperature change of the hair contacting member 225 may depend on the speed at which the hair contacting member 225 is moving. For example, the rate of temperature increase (or "warming up") may be relatively rapid if the hair contacting member 225 is determined to be moving relatively quickly and may be relatively slow if the hair contacting member 225 is determined to be moving relatively slowly. This may allow finer control of heat distribution along the hair strand and / or allow the hair styling device 100 to adapt to the behavior of the user. In some embodiments, the heat delivery profile along the hair strand depends on the derived velocity.

[0061] In some embodiments, a velocity and / or position estimation algorithm, such as a machine learning model, is used to process the sensor output. In some embodiments, a 3-axis IMU with an accelerometer is used in combination with a machine learning model. For example, determining that the hair contacting member 225 is moving along the hair bundle, deriving the displacement of the hair contacting member 225 from the first end, and / or deriving the velocity of the hair contacting member 225 may be performed through the use of a machine learning model.

[0062] In embodiments where a three-axis IMU is used, the machine learning model can use signals from the three-axis IMU to determine the initial conditions. In some embodiments, the machine learning model has been trained using a generalized non-linear regression algorithm (such as Gaussian kernel regression and neural networks). The training data for the machine learning model uses three-axis IMU data from past uses of the hair styling device 100 together with target data from a ground truth source, such as a Vicon motion capture system. It will be appreciated that the target data from the ground truth source can be captured using alternative systems. The machine learning model can be implemented using software or hardware, such as an application specific integrated circuit (ASIC), or a combination of hardware and software. The machine learning model can be used in various ways as described herein.

[0063] As noted above, an IMU (such as a 3-axis IMU) may have noise, bias, and / or drift that can cause errors in the resulting calculations unless properly compensated for. For example, an accelerometer may be biased by gravity, and the accelerometer signal may be noisy. In some embodiments, at least a portion of the noise in the accelerometer signal is removed using filtering, such as a high and / or low pass filter and / or a median filter.

[0064] In some embodiments, a low pass filter is applied to each signal output of the 3-axis IMU to remove noise. Each signal is then combined into a single signal output. The ratio of the force on the single signal output due to gravity is then calculated and subtracted from the signal output to obtain the magnitude of acceleration.

[0065] A pre-trained machine learning model is then applied to the acceleration magnitude.

[0066] The machine learning model is used to convert the acceleration magnitude to velocity magnitude by using a machine learning model that has been trained as described above, while simultaneously correcting for noise, bias and drifts such as velocity drift. In embodiments, the machine learning model is trained using motion acceleration magnitude training data provided in past uses of the hair styling device, and velocity magnitude ground truth data from a ground truth source, for example a Vicon motion capture system.

[0067] In embodiments, a sliding window algorithm is used to simultaneously generate input data for the machine learning model, which in preferred embodiments consists of 20 sample points, where the 20th sample point of the calculated velocity is compensated for drift by the machine learning model that takes into account the 20th sample point and the previous 19 sample points of the motion acceleration magnitude input data. However, it will be appreciated that a different number of sample points can be used as input data to the machine learning model. In this regard, the machine learning model can correct and / or compensate for noise, bias and / or drift associated with the 3-axis IMU.

[0068] In an alternative embodiment, a low pass filter is applied to each signal output of the three-axis IMU. Each of the three signal outputs is then processed separately. The ratio of forces in each signal is then calculated and subtracted from each of the signal outputs to obtain three acceleration magnitudes (one acceleration magnitude per axis). The above pre-trained machine learning model is then applied to each of the acceleration magnitudes separately. Similarly, a sliding window algorithm can be applied to generate inputs for the machine learning model. In other words, the machine learning model and the sliding window algorithm can be applied to each axis separately.

[0069] In some embodiments, the velocity is integrated to obtain the position and / or displacement, and since the calculated velocity has been compensated for drift, the position and / or displacement can be derived with greater accuracy.

[0070] Therefore, a machine learning model in combination with a 3-axis IMU can be used to compensate for velocity drift and derive the velocity, position and / or displacement of the hairstyling device.

[0071] In embodiments, changing (e.g., increasing) the operating temperature includes adjusting (e.g., increasing) the amount of energy used to heat the hair contacting member 225 as it moves along the hair bundle from a first end of the hair bundle toward a second end of the hair bundle. For example, the amount of energy applied to the heating element 220 can be adjusted as the hair contacting member 225 moves along the hair bundle. Thus, in such embodiments, both the operating temperature of the hair contacting member 225 and the amount of energy applied to the heating element 220 can be increased as the hair contacting member 225 moves along the hair bundle. In alternative embodiments, the amount of energy used to heat the hair contacting member 225 is not increased as the hair contacting member 225 moves along the hair bundle. For example, the amount of energy used to heat the hair contacting member 225 can be constant.

[0072] In some embodiments, the operating temperature of the hair contacting member 225 is increased at a predetermined rate as the hair contacting member 225 moves along the hair bundle from the root end towards the tip end. The predetermined rate of increase may be based on a heat delivery profile along the hair bundle. In some embodiments, the predetermined rate of increase depends on the speed of the hair contacting member 225. The predetermined rate of increase may depend on other factors including, but not limited to, the type of hair being styled, whether the hair is wet or dry, the length of the hair bundle, previous use of the hair styling device, user preferences, etc. In some embodiments, the predetermined rate of increase depends on the condition of the hair bundle, for example as defined by one or more hair damage parameters, as described in more detail below.

[0073] In some embodiments, the heating of the hair contact member 225 is controlled such that the operating temperature of the hair contact member 225 when the hair contact member 225 is at the second end (e.g., the tip end) is 40-80 degrees higher than the operating temperature of the hair contact member 225 when the hair contact member 225 is at the first end (e.g., the root end). For example, the operating temperature when the hair contact member 225 is at the second end can be 50-70 degrees higher, such as 60 degrees higher, than the operating temperature when the hair contact member 225 is at the first end. In some examples, the operating temperature when the hair contact member 225 is at the first end is 120°C and the operating temperature when the hair contact member 225 is at the second end is 180°C. Such a difference between the operating temperature of the first end and the operating temperature of the second end allows the entire hair bundle to be styled (e.g., straightened or curled) as desired, thereby reducing styling time while reducing the potential for heat damage to the hair. The difference between the operating temperature of the first end and the operating temperature of the second end may have other values ​​in other embodiments.

[0074] In some embodiments, the method 300 includes determining whether the hair styling device 100 is being used according to a first styling behavior or a second styling behavior. The heating element 220 is controlled depending on whether the hair styling device 100 is being used according to a first styling behavior or a second styling behavior. In some such embodiments, the heating of the hair contacting member 225 is controlled to vary the operating temperature of the hair contacting member 225 at a rate depending on whether the hair styling device 100 is being used according to a first styling behavior or a second styling behavior. For example, a first predetermined rate of rise can be used for a hair straightening behavior and a second different predetermined rate of rise can be used for a hair curling behavior. Thus, different temperature transfer profiles can be used for different activities. This allows different styles to be achieved with the same hair styling device 100, improving the versatility of the hair styling device 100 while reducing the potential for heat damage and shortening styling time. In some embodiments, the styling behavior is identified using classification algorithms and sensor data, as described in more detail below. In alternative embodiments, the styling behavior is specified based on user input. In alternative embodiments, the exact styling behavior is not specified. For example, the same temperature transfer profile (which may vary along the hair strand) may be used regardless of the styling behavior.

[0075] For example, in alternative embodiments in which the hair styling device 100 does not include a heating element 220, heating of the hair contacting member 225 can be performed, for example, by applying energy directly to the hair contacting member 225 itself. In either case, heating of the hair contacting member 225 is controlled such that the operating temperature of the hair contacting member 225 varies along the hair strand.

[0076] FIG. 4 illustrates a method 400 of operating a hair styling device according to some embodiments. The method 400 can be used to operate the hair styling device 100 described above with reference to FIG. 1A, FIG. 1B and FIG. 2. In the embodiment of FIG. 4, the hair styling device 100 comprises a heatable hair contacting member 225 having a hair contactable surface 116, 126. The hair contacting member 225 is operable to apply heat to the hair strand via the hair contactable surface by movement of the hair contacting member 225 along the hair strand between a first end of the hair strand and a second end of the hair strand. In these embodiments, the hair styling device 100 further comprises a sensor device 230 configured to generate a sensor output indicative of a current use of the hair styling device 100. In some embodiments, the method 400 is at least partially performed by the controller 210.

[0077] In step 410 , a sensor output is received from the sensor device 230 .

[0078] At step 420, it is determined whether the hair contacting member 225 is at the first end of the hair bundle or the second end of the hair bundle based on the sensor output.

[0079] In step 430, the hair styling device 100 is controlled to perform an action based on said determination.

[0080] The start of a path is detected by determining that the hair contacting member 225 is at a first end of the hair bundle (e.g., the root end of the hair bundle). Similarly, the end of a path is detected by determining that the hair contacting member 225 is at a second end of the hair bundle (e.g., the tip end of the hair bundle). Thus, the boundaries of the path (i.e., the start and end) are identified by the hair styling device 100 and used to control the hair styling device 100. This allows for finer and / or more intelligent control of the hair styling device 100 than if the boundaries of the path were not identified.

[0081] The first end may be located at the root or at a midpoint of the hair bundle. Similarly, the second end may be located at the tip or at a midpoint of the hair bundle. In some embodiments, the first end constitutes a root end of the hair bundle and the second end constitutes a tip end of the hair bundle.

[0082] In embodiments, heating of the hair contacting member 225 is controlled based on the determination performed in step 420. For example, if the hair styling device 100 includes a heating element 220, the heating element 220 may be controlled based on the determination performed in step 420. Thus, the method 400 may include controlling the heating element 220 based on a determination that the hair contacting member 225 is at the first end of the hair bundle or the second end of the hair bundle. In alternative embodiments, other components and / or functions of the hair styling device 100 may be controlled based on the determination performed in step 420.

[0083] In some embodiments, in response to determining that the hair contacting member 225 is at a first end (e.g., a root end) of the hair bundle, the amount of energy used to heat the hair contacting member 225 (e.g., the amount of energy applied to the heating element 220) is increased. In response to determining that the hair contacting member 225 is at a second end (e.g., a tip end) of the hair bundle, the amount of energy used to heat the hair contacting member 225 is decreased. Thus, the amount of energy used to heat the hair contacting member 225 can be increased at the beginning of a pass (thereby heating the hair in the hair bundle) and decreased at the end of the pass (when heating of the hair is no longer being performed). This reduces power consumption compared to when a constant amount of energy is used to heat the hair contacting member 225 throughout use of the hair styling device 100. By controlling the heating of the hair contacting member 225 in this manner, a predetermined temperature transfer profile (e.g., increasing temperature) can be applied along the hair bundle. In some embodiments, the amount of energy used to heat the hair contacting member 225 is increased at a predetermined rate as the hair contacting member 225 moves along the hair bundle. In alternative embodiments, the amount of energy used to heat the hair contacting member 225 and / or the operating temperature of the hair contacting member 225 is constant along the hair bundle. In such alternative embodiments, the amount of energy used to heat the hair contacting member 225 is decreased at the end of the pass (when the hair contacting member 225 is determined to be at the second end of the hair bundle), thereby reducing power consumption.

[0084] In embodiments, the sensor output is indicative of a usage characteristic of the hair styling device 100. The usage characteristic is indicative of a current use of the hair styling device 100. The usage characteristic may be a characteristic that changes over time. In embodiments, the usage characteristic is indicative of a movement of the hair contacting member 225. In embodiments, the usage characteristic includes a speed of the hair contacting member 225 (e.g., as the hair contacting member 225 moves along the hair bundle). Thus, a determination that the hair contacting member 225 is at the first end of the hair bundle or the second end of the hair bundle may be based on the speed of the hair contacting member 225. For example, the speed of the hair contacting member 225 may be lower at the end of the hair bundle compared to when the hair contacting member 225 is moving along the hair bundle. In embodiments, the usage characteristic is indicative of whether the hair contacting member 225 is in motion.

[0085] In some embodiments, the use characteristic includes a position of the hair contacting member 225, e.g., a displacement from a first end of the hair bundle. Thus, a determination that the hair contacting member 225 is at the first end of the hair bundle or the second end of the hair bundle may be based on a determined position of the hair contacting member 225, which may be calculated, for example, based on signals received from the IMU 235. The first position may be associated with the first end of the hair bundle and the second position may be associated with the second end. In some embodiments, the position is defined as a coordinate in three-dimensional space. In other embodiments, the position is defined as a one-dimensional value, e.g., a distance from a known or predetermined location.

[0086] In some embodiments, the hair contacting member 225 is movable between an open configuration and a closed configuration. In some such embodiments, the use characteristic indicates whether the hair contacting member 225 is in an open configuration or a closed configuration. In some embodiments, the sensor device 230 comprises a Hall effect sensor. Thus, a determination that the hair contacting member 225 is at a first end of the hair bundle or a second end of the hair bundle may be based on the movement of the hair contacting member 225 between the open configuration and the closed configuration. For example, the hair contacting member 225 may move from an open configuration to a closed configuration when the hair contacting member 225 is at a root end of the hair bundle (e.g., the beginning of a pass) and may move from a closed configuration to an open configuration when the hair contacting member 225 is at a tip end of the hair bundle (e.g., the end of a pass). Thus, the hair styling device 100 may detect the beginning and / or end of a pass without requiring user input.

[0087] In some embodiments, for example where the sensor device 230 comprises an IMU 235, the usage characteristic is indicative of movement of the hair contact member 225. In some such embodiments, a velocity and / or position estimation algorithm (e.g., comprising a Madgwick filter and / or a machine learning model) is used to process the sensor output, as described in more detail above with reference to FIG.

[0088] In some embodiments, the hair contact member 225 is determined to be moving toward the second end of the hair bundle and away from the first end of the hair bundle. Such a determination may be made, for example, based on a signal received from the IMU 235. The heating of the hair contact member 225 may be controlled based on such a determination. For example, the heating of the hair contact member 225 may be controlled to implement a predetermined heat delivery profile as the hair contact member 225 moves along the hair bundle.

[0089] For example, in embodiments in which the hair styling device 100 does not include a heating element 220 , the heating of the hair contacting member 225 can be controlled by applying energy directly to the hair contacting member 225 .

[0090] FIG. 5 illustrates a method 500 of operating a hair styling device according to some embodiments. The method 500 can be used to operate the hair styling device 100 described above with reference to FIG. 1A, FIG. 1B and FIG. 2. In the embodiment of FIG. 5, the hair styling device 100 comprises a heatable hair contacting member 225 having a hair contactable surface 116, 126. The hair contacting member 225 is operable to apply heat to a user's hair via the hair contactable surface. In these embodiments, the hair styling device 100 further comprises an IMU 235. The IMU 235 is configured to output a signal in response to movement of the hair contacting member 225. In some embodiments, the method 500 is performed at least in part by the controller 210.

[0091] At step 510, one or more signals are received from the IMU 235 indicating that the hair contact member 225 is moving along the hair bundle from a first end of the hair bundle to a second end of the hair bundle.

[0092] At step 520, the received signal or signals are processed to derive a displacement of the hair contact member 225 from the first end of the hair bundle.

[0093] In step 530, heating of the hair contact member 225 is controlled based on the derived displacement.

[0094] By controlling the heating of the hair contacting member 225 based on the derived displacement of the hair contacting member 225 from a first end of the hair bundle (e.g., a root end of the hair bundle), the heat delivery and / or heat distribution along the hair bundle can be controlled and / or adapted. Thus, a target heat delivery profile along the hair bundle can be achieved by deriving the displacement of the hair contacting member 225 at a given time and controlling the heating of the hair contacting member 225 accordingly. In alternative embodiments, the received signal or signals are processed to derive the displacement of the hair contacting member 225 from a second end of the hair bundle (e.g., a tip end of the hair bundle).

[0095] In some embodiments, the hair styling device 100 comprises a heating element 220 operable to heat the hair contacting member 225. In some such embodiments, controlling the heating of the hair contacting member 225 comprises controlling the heating element 220.

[0096] In some embodiments, the first end constitutes a root end of the hair bundle and the second end constitutes a tip end of the hair bundle. The first end may be located at the root or at a midpoint of the hair bundle. Similarly, the second end may be located at the tip or at a midpoint of the hair bundle.

[0097] In embodiments, the amount of energy used to heat the hair contacting member 225 (e.g., the amount of energy applied to the heating element 220) is adjusted based on the derived displacement. This allows for a varying heat delivery profile to be achieved along the hair bundle. For example, the amount of energy used to heat the hair contacting member 225 can be increased as the hair contacting member 225 moves along the hair bundle. Thus, the amount of energy used to heat the hair contacting member 225 can be dependent on the displacement of the hair contacting member 225 from the first end of the hair bundle. This allows for a desired style to be achieved while reducing styling time and potential heat damage to the hair.

[0098] In some embodiments, the heating of the hair contacting member 225 is controlled based on a predetermined threshold operating temperature of the hair contacting member 225. For example, the heating of the hair contacting member 225 can be controlled to maintain an operating temperature of the hair contacting member 225 above a predetermined threshold operating temperature. The predetermined threshold operating temperature is dependent on the derived displacement of the hair contacting member 225 from the first end of the hair bundle. For example, the predetermined threshold operating temperature can be lower when the hair contacting member 225 is relatively closer to the root end and higher when the hair contacting member 225 is relatively farther from the root end (or closer to the tip end). Thus, different operating temperatures of the hair contacting member 225 can be used for different displacements. This allows a dynamic or changing heat delivery profile along the hair bundle to be applied to the hair.

[0099] In some embodiments, the signal or signals are processed to derive a length of the hair bundle between the first end and the second end. The derived length can be used to derive a displacement of the hair contacting member 225 from the first end. Using the hair bundle length to derive the displacement can be more accurate than a comparison case in which the hair bundle length is not derived. Furthermore, the hair bundle length can be used to derive a relative displacement in addition to or as an alternative to absolute displacement. For example, it can be determined that at a given time, the hair contacting member 225 is halfway along the hair bundle between the first end and the second end, and heating of the hair contacting member 225 can be controlled accordingly (e.g., applying a predetermined heat to hairs halfway between the first end and the second end). This allows a desired heat delivery profile to be implemented along the hair bundle. In some embodiments, the absolute displacement can be used to implement a heat delivery profile, for example, using a predetermined hair bundle length. This can be easier to implement in practice than measuring the hair bundle length. Sections of a given hair bundle that are longer than the predetermined length may receive the highest temperature of the heat delivery profile. In some embodiments, the position of the hair contact member 225 relative to the user's head is derived and used together with the length of the given hair bundle to derive the displacement from the first end of the hair bundle.

[0100] In some embodiments, a first signal is received from the IMU 235 indicating that the hair contacting member 225 is moving along the hair bundle in a first pass. The first received signal is processed to derive a length of the hair bundle. A second signal is then received from the IMU 235 indicating that the hair contacting member 225 is moving along the hair bundle in a second pass subsequent to the first pass. The second signal is processed using the derived length to derive a displacement of the hair contacting member 225 from the first end. Thus, the length of the hair bundle can be derived from the IMU data in a first pass along the hair bundle, and the derived length is then used together with the IMU data in a second pass to derive a displacement along the hair bundle at a given time. This can provide a more accurate value of the displacement than a comparison case where the length of the hair bundle is not pre-derived. The first and second passes can both be part of the same hair styling session or can be part of different hair styling sessions. For example, the first pass can be from a past hair styling session. In alternative embodiments, both the hair strand length and displacement are derived in the same pass, which involves fewer passes and therefore less time and / or power consumption than deriving the hair strand length and displacement in different passes.

[0101] In some embodiments, the heating of the hair contacting member 225 is controlled to increase the operating temperature of the hair contacting member 225 as it moves along the hair bundle from the root end to the tip end. Providing an increasing heat delivery profile from the root end to the tip end of the hair bundle reduces the potential for heat damage while ensuring that a high enough temperature is distributed to the hair at the tip end to achieve the desired style.

[0102] In some embodiments, a Madgwick filter is used to process the signals received from the IMU 235, as described in more detail above with reference to Figure 3. In some embodiments, a machine learning model is used to process the received signals, as described above.

[0103] For example, in alternative embodiments in which the hair styling device 100 does not include a heating element 220, the heating of the hair contacting member 225 can be controlled by applying energy directly to the hair contacting member 225.

[0104] Figure 6 illustrates a method 600 of operating a hair styling device according to some embodiments. Method 600 can be used to operate the hair styling device 100 described above with reference to Figures 1A, 1B and 2. In the embodiment of Figure 6, the hair styling device 100 includes an IMU 235. The IMU 235 is configured to output a signal in response to movement of the hair styling device 100. In some embodiments, method 600 is performed at least in part by the controller 210.

[0105] At step 610, a signal is received from the IMU 235 indicative of movement of the hair styling device 100 along the strand of hair between a first end of the strand of hair and a second end of the strand of hair.

[0106] In step 620, the received signal is processed to derive a length of the hair strand between the first end and the second end.

[0107] At step 630, the hair styling device 100 is controlled to perform an action based on the derived length.

[0108] By deriving the length of the hair strand, more useful information about the user's hair can be obtained and utilized. For example, styling advice and / or feedback can be provided as a function of the length of the hair strand, e.g., via a user interface of the hair styling device 100. Different styling advice may be appropriate for different hair strand lengths. Thus, by deriving the length of the hair strand from the IMU data, the styling advice provided by the hair styling device 100 can be tailored to a particular user. Additionally or alternatively, the derived hair strand length can be used to control one or more operational settings of the hair styling device 100, e.g., operating temperature, thereby enabling tailored adjustment of operational control based on the length of the user's hair strand.

[0109] In some embodiments, the received signal is processed to derive a length between a root end of the hair bundle and a tip end of the hair bundle. The hair styling device 100 can be controlled based on the derived length. The first end can be located at the root or at a midpoint of the hair bundle. Similarly, the second end can be located at the tip or at a midpoint of the hair bundle.

[0110] In some embodiments, the derived length is used to derive a displacement of the hair styling device 100 from the first end of the hair bundle. The hair styling device 100 can be controlled based on the derived displacement. Such derived displacement can be more accurate than in a comparison case where the length of the hair bundle is not used to derive the displacement. By deriving the displacement of the hair styling device 100 from the first end with greater accuracy, the control of the heating profile along the hair bundle can be improved. By deriving the displacement of the hair styling device 100 from the first end of the hair bundle, the heat supply and / or heat distribution along the hair bundle can be controlled and / or adapted. Thus, a target heat supply profile along the hair bundle can be achieved by deriving the displacement of the hair contact member 225 at a given moment and controlling the hair styling device 100 accordingly.

[0111] In embodiments in which the hair styling device 100 includes a heating element 220 operable to apply heat to the user's hair, the heating element 220 can be controlled based on the derived length. In embodiments in which the hair styling device 100 includes a hair contacting member 225, the heating element 220 can be controlled based on a target operating temperature of the hair contacting member 225. The target operating temperature can be dependent on the derived length. Thus, hair strands of different lengths can be heated differently by the hair styling device 100. This allows the hair styling device 100 to be tailored to the user's hair, which can reduce styling time and / or facilitate the desired style compared to when the operating temperature is not dependent on the length of the hair strand.

[0112] In embodiments, the user interface provides an output related to the derived length. In some embodiments, a user interface, such as user interface 240, is provided on the hair styling device 100. In alternative embodiments, the user interface is not provided on the hair styling device 100, for example, the user interface may be provided on an app installed on a charging device for the hair styling device or a mobile phone communication device. The output may include audio and / or visual output. In embodiments, the output includes styling advice and / or feedback in response to the derived length. For example, a first styling advice may be provided if the derived length is less than a predetermined threshold length and a second styling advice different from the first styling advice may be provided if the derived length is greater than the predetermined threshold length. Thus, tailored feedback and / or advice may be provided to the user, thereby assisting the user in using the hair styling device 100 more efficiently and / or optimally.

[0113] In some embodiments, the hair styling device 100 determines the section and / or layer of hair being styled based on the derived length. In such some embodiments, the hair styling device 100 is controlled in response to the determined section and / or layer of hair being styled. For example, specific styling advice and / or feedback may be provided to the user depending on which section and / or layer of hair is being styled. The crown section of the user's hair may have a different strand length compared to the nape section of the user's hair, and by determining which section is being styled, the hair styling device 100 may be controlled differently (e.g., by providing tailored feedback via a user interface and / or controlling heating) for the different sections.

[0114] In embodiments, the derived length is stored in a memory, such as the memory 250 of the hair styling device 100. This allows the derived length to be later retrieved and used, for example, for a subsequent pass and / or subsequent uses of the hair styling device 100. In embodiments, the derived length is derived in a first pass along the hair strand, stored in the memory 250, and then used to derive a displacement of the hair contacting member 225 moving along the hair strand in a second pass. In some embodiments, the derived length is stored for analysis of the user's hair. In embodiments, the derived length is stored to allow one or more settings of the hair styling device 100 to be tailored to the user's hair. For example, a user hair styling profile can be generated for the user based at least in part on the derived hair strand length. Such a user hair styling profile can be used to provide feedback and / or advice to the user and / or to control one or more settings of the hair styling device 100 during subsequent uses of the hair styling device 100 by the user. In some embodiments, the hair styling device 100 is configured to generate and / or store multiple user hair styling profiles for different users, i.e., multiple users, e.g., different users having hair of different lengths, may each use the same hair styling device 100, and the hair styling device 100 may store (locally or remotely) an individually tailored profile for each user to allow the settings of the hair styling device 100 to be adapted to the different users.

[0115] In some embodiments, the received signal is processed using a Madgwick filter, which is described in more detail above with reference to Figure 3. In some embodiments, a machine learning model is used to process the received signal, as described above.

[0116] FIG. 7 illustrates a method 700 of operating a hair styling device according to embodiments. The method 700 can be used to operate the hair styling device 100 described above with reference to FIGS. 1A, 1B and 2. In the embodiments of FIG. 7, the hair styling device 100 comprises a heatable hair contacting member 225. The hair contacting member 225 comprises first and second opposing hair contactable surfaces 116, 126. The hair contacting member 225 is movable between a closed configuration and an open configuration. The hair styling device 100 comprises a sensor device 230 configured to generate a sensor output indicative of whether the hair contacting member 225 is in a closed configuration or an open configuration. In embodiments, the hair styling device 100 comprises a cordless hair styling device. In embodiments, the method 700 is performed at least in part by the controller 210.

[0117] In step 710 , a sensor output is received from the sensor device 230 .

[0118] At step 720, in response to the sensor output indicating the hair contacting member 225 is in the closed configuration, heating of the hair contacting member 225 is controlled based on a first predetermined threshold operating temperature of the hair contacting member 225.

[0119] At step 730, in response to the sensor output indicating the hair contacting member 225 is in the open configuration, controlling heating of the hair contacting member 225 based on a second predetermined threshold operating temperature of the hair contacting member 225. The second predetermined threshold operating temperature is lower than the first predetermined threshold operating temperature.

[0120] Thus, the operating temperature of the hair contacting member 225 will be lower when the hair contacting member 225 is in the open configuration as compared to when the hair contacting member 225 is in the closed configuration, thereby reducing power consumption while maintaining the ability of the hair contacting member 225 to provide a desired amount of heat to the hair.

[0121] The opposing first and second hair contactable surfaces 116, 126 are spaced apart when the hair contacting member 225 is in the open configuration, and the opposing first and second hair contactable surfaces 116, 126 can meet when the hair contacting member 225 is in the closed configuration. In some embodiments, the distance between the first hair contactable surface 116 and the second hair contactable surface 126 is less than a predetermined threshold distance when the hair contacting member 225 is in the closed configuration, and is greater than a predetermined threshold distance when the hair contacting member 225 is in the open configuration. In some cases, the first hair contactable surface 116 and the second hair contactable surface 126 are adjacent when the hair contacting member 225 is in the closed configuration. In other cases, the first hair contactable surface 116 and the second hair contactable surface 126 are not adjacent when the hair contacting member 225 is in the closed configuration.

[0122] When the hair contacting member 225 is in the closed configuration, hair inserted between the opposing first and second hair contactable surfaces 116, 126 is styled, for example, by applying heat and / or mechanical pressure. However, in some embodiments, when the hair contacting member 225 is in the open configuration, no styling of hair occurs. The hair contacting member 225 may be in the open configuration, for example, when no hair is present between the opposing hair contactable surfaces 116, 126. In some embodiments, the hair contacting member 225 is in the open configuration when the hair contacting member 225 is at rest, e.g., not in use. In some embodiments, the hair contacting member 225 is in the open configuration when the hair styling device 100 is between passes. For example, a first pass along the hair strand may be performed (with the hair contacting member 225 in the closed configuration), and then the hair contacting member 225 may be moved to the open configuration before commencing a second pass along the hair strand. Moving the hair contacting member 225 to the open configuration may include releasing a hair inserted between the hair contactable surfaces. Thus, power consumption is reduced by lowering the threshold operating temperature when no hair is inserted between the hair contactable surfaces.

[0123] In some embodiments, the hair styling device 100 comprises a heating element 220 operable to heat the hair contacting member 225. In some such embodiments, controlling the heating of the hair contacting member 225 comprises controlling the heating element 220.

[0124] In some embodiments, in response to a sensor output indicating that the hair contacting member 225 is in a closed configuration, the heating of the hair contacting member 225 is controlled to maintain an operating temperature of the hair contacting member 225 above a first predetermined threshold operating temperature. In response to a sensor output indicating that the hair contacting member 225 is in an open configuration, the heating of the hair contacting member 225 is controlled to maintain an operating temperature of the hair contacting member 225 above a second predetermined threshold operating temperature.

[0125] In some embodiments, in response to a sensor output indicating that the hair contacting member 225 is in the closed configuration, energy is applied to heat the hair contacting member 225 when the operating temperature of the hair contacting member 225 falls below a first predetermined threshold operating temperature. In response to a sensor output indicating that the hair contacting member 225 is in the open configuration, energy is applied to heat the hair contacting member 225 when the operating temperature of the hair contacting member 225 falls below a second predetermined threshold operating temperature.

[0126] In some embodiments, in response to a sensor output indicating that the hair contacting member 225 is in the closed configuration, a first amount of energy is applied (e.g., a first amount of energy is applied to the heating element 220) to heat the hair contacting member 225. In response to a sensor output indicating that the hair contacting member 225 is in the open configuration, a second amount of energy is applied (e.g., a second amount of energy is applied to the heating element 220) to heat the hair contacting member 225. The second amount of energy is lower than the first amount of energy. Thus, less energy is applied to heat the hair contacting member 225 when the hair contacting member 225 is in the open configuration, which can reduce power consumption.

[0127] In some embodiments, the sensor device 230 comprises a Hall effect sensor. In some such embodiments, the hair styling device 100 comprises a magnet coupled to the first hair contactable surface 116, and a Hall effect sensor coupled to the second hair contactable surface 126. A sensor output generated by such a Hall effect sensor can be used to determine whether the hair contacting member 225 is in an open or closed configuration, for example, to determine whether the distance between the first hair contactable surface 116 and the second hair contactable surface 126 is greater than or less than a predetermined threshold distance. In some embodiments, the sensor device 230 comprises an IMU 235. Thus, the determination of whether the hair contacting member 225 is in an open or closed configuration can be based on a sensed movement of the hair contacting member 225.

[0128] In some embodiments, the second predetermined threshold operating temperature is at least 50 degrees lower than the first predetermined threshold operating temperature.

[0129] For example, in embodiments in which the hair styling device 100 does not include a heating element 220 , the heating of the hair contacting member 225 can be controlled by applying energy directly to the hair contacting member 225 .

[0130] Figure 8 illustrates a method 800 of operating a hair styling device according to some embodiments. Method 800 can be used to operate the hair styling device 100 described above with reference to Figures 1A, 1B and 2. In the embodiment of Figure 8, the hair styling device 100 comprises a heatable hair contacting member 225 having a hair contactable surface 116, 126. The hair contacting member 225 is operable to apply heat to the hair via the hair contactable surface 116, 126. In some embodiments, method 800 is performed at least in part by the controller 210.

[0131] At step 810, power consumption associated with heating the hair contacting member 225 while heating the user's hair via the hair contactable surfaces 116, 126 is monitored.

[0132] In step 820, one or more hair damage parameters indicative of damage to the heated hair are calculated based on the monitored power consumption.

[0133] At step 830, the hair styling device 100 is controlled based on the calculated hair damage parameter or parameters.

[0134] In some embodiments, the hair styling device 100 comprises a heating element 220 operable to heat the hair contacting member 225. In such embodiments, the one or more hair damage parameters are calculated based on the monitored power consumed by the heating element 220 to heat the hair contacting member 225. In alternative embodiments, for example, where the hair styling device 100 does not comprise a heating element 220, the one or more hair damage parameters are calculated based on the monitored power consumed by the hair contacting member 225 itself.

[0135] In embodiments, the calculated one or more hair damage parameters are indicative of at least one of physical damage, thermal damage and chemical damage of the heated hair.

[0136] In embodiments, the calculated hair damage parameter or parameters are indicative of existing damage to the heated hair. The hair may have been previously damaged, for example, by overheating (causing thermal damage), chemical treatment (causing chemical damage), applying too high a gripping pressure and / or too many repeated passes (causing mechanical damage), etc. Thus, existing damage to the hair may be taken into account when controlling the hair styling device 100. Controlling the hair styling device 100 to take into account the damage to the hair may include, for example, controlling the heating of the hair and / or providing feedback to the user, as described in more detail below.

[0137] Damaged hair may retain less water than undamaged hair, for example due to changes in the internal structure of the hair. The amount of water retained by the hair will consequently affect the power consumption associated with the hair contacting member 225 when attempting to heat the hair. Thus, an indication of hair damage can be obtained by monitoring the power consumption associated with the hair contacting member 225 to heat the hair (e.g., the power consumed by the heating element 220). For example, the power consumed by the heating element 220 to heat the hair to a given temperature may be relatively high for damaged hair (which retains less water) and relatively low for undamaged hair (which retains more water). Power consumption can be measured using functionality built into the hair styling device, such as a power meter, ammeter, multimeter, etc.

[0138] In some embodiments, the calculated hair damage parameter(s) are indicative of predicted damage resulting from heating of the heated hair. In other words, the power consumption associated with heating the hair contacting member 225 can be used to predict whether and / or how much damage the heating will cause to the hair. Such damage may be in addition to the existing damage. Thus, in some embodiments, the calculated hair damage parameter(s) are indicative of both the existing and predicted damage to the heated hair. For example, if the hair is damaged such that it retains less moisture compared to undamaged hair, the likelihood of further damage to the hair due to heating may increase. By monitoring the power consumption associated with heating the hair contacting member 225 and deriving the hair damage parameter(s), such predicted further hair damage may be avoided. In alternative embodiments, the hair damage parameter(s) are indicative of only predicted damage (and not existing damage).

[0139] In some embodiments, the one or more hair damage parameters indicate a type of damage, for example, chemical damage, thermal damage, or mechanical damage. Such a type of damage can be derived based on the power consumption associated with heating the hair contact member 225. For example, chemically damaged hair may retain less moisture than thermally damaged hair. In some embodiments, the one or more hair damage parameters indicate the degree of damage to the hair. The one or more hair damage parameters may comprise values ​​on an incremental scale, for example ranging from 0: "no damage" to 10: "very damaged".

[0140] In some embodiments, the one or more hair damage parameters are calculated by monitoring the power consumption associated with heating the hair contacting member 225 to keep the operating temperature of the hair contacting member 225 above a predetermined threshold operating temperature. For example, for damaged hair compared to undamaged hair, the heating element 220 may consume more power to keep the operating temperature of the hair contacting member 225 above a predetermined threshold. The power consumed by the heating element 220 is indicative of the power consumption associated with heating the hair contacting member 225 during heating of the hair.

[0141] In embodiments where the hair styling device 100 comprises a sensor apparatus 230 configured to generate a sensor output responsive to movement of the hair contacting member 225, one or more hair damage parameters may be calculated based on the sensor output. The power consumed by the heating element 220 to heat the hair contacting member 225 may depend on the movement of the hair contacting member 225. Thus, by taking into account the movement of the hair contacting member 225, one or more hair damage parameters may be calculated more accurately from the monitored power.

[0142] In some embodiments, the hair contacting member 225 is operable to apply heat to the user's hair by movement of the hair contacting member 225 along the hair bundle between a root end of the hair bundle and a tip end of the hair bundle. A displacement of the hair contacting member 225 can be derived based on the sensor output. In such some embodiments, one or more hair damage parameters are calculated based on the derived displacement. The power consumption associated with heating the hair contacting member 225 can depend on where the hair contacting member 225 is located within the hair bundle, e.g., relative to the root end or the tip end. This is at least in part due to the fact that hair bundles are generally thicker at the root end and thinner at the tip end. Thus, by taking into account the displacement of the hair contacting member 225 from the root end of the hair bundle, one or more hair damage parameters can be more accurately calculated from the monitored power.

[0143] In some embodiments, the hair contacting member 225 is determined to be in motion based on the sensor output. One or more hair damage parameters can be calculated based on determining whether the hair contacting member 225 is in motion. The power consumption associated with heating the hair contacting member 225 can depend on whether the hair contacting member 225 is in motion. Thus, by taking into account the movement of the hair contacting member 225, one or more hair damage parameters can be more accurately calculated from the monitored power.

[0144] In some embodiments, it is determined whether the heated hair has been previously heated by the hair styling device 100. One or more hair damage parameters can be calculated depending on whether the heated hair has been previously heated by the hair styling device 100. The power consumption associated with heating the hair contacting member 225 may depend on whether the heated hair has been previously heated by the hair styling device 100. Thus, by taking into account the past heating of the hair, one or more hair damage parameters can be more accurately calculated from the monitored power. The past heating of the hair by the hair styling device 100 may include heating during a previous hair styling session and / or heating during a previous pass included in the current hair styling session. Heating previously heated hair may consume less power by the heating element 220 than heating hair that has not been previously heated. Furthermore, heating previously heated hair may increase the likelihood of thermal and / or mechanical damage to the hair.

[0145] In some embodiments, it is determined whether the heated hair has been previously heated during a predetermined period of time. One or more hair damage parameters can be calculated depending on whether the heated hair has been previously heated during a predetermined period of time. The predetermined period of time can correspond, for example, to a current hair styling session. Thus, one or more hair damage parameters can be calculated depending on whether the heated hair has already been heated during the current hair styling session.

[0146] In some embodiments, a section and / or layer of the user's hair being heated via the hair contactable surface is determined. One or more hair damage parameters may be calculated based on the determined section and / or layer of hair. In some embodiments, the section and / or layer being styled is determined using sensor data, e.g., IMU signals, indicative of movement of the hair contacting member 225. The power consumption associated with heating the hair contacting member 225 may depend on which section and / or layer of hair is being styled. Thus, by taking into account the section and / or layer of hair, one or more hair damage parameters may be calculated more accurately from the monitored power.

[0147] Thus, in embodiments, to improve the accuracy of the calculation of the hair damage parameter, one or more factors that may affect the relationship between the power consumption associated with heating the hair contacting member 225 and the hair damage parameter are filtered or taken into account. Such factors include the movement of the hair contacting member 225, the displacement of the hair contacting member 225 along the hair strand, whether and / or when the hair was previously heated, and which section and / or layer of the hair is being styled. In alternative embodiments, other factors may also be determined and taken into account.

[0148] In some embodiments, the user interface provides an output based on the calculated hair damage parameter or parameters. The output may include a notification informing the user that the hair being heated is damaged and / or likely to become damaged. In some embodiments, the notification informs the user of the type of damage to the hair. In some embodiments, the notification informs the user of the location of the damaged hair and / or likely to become damaged. For example, the user may be informed of which section and / or layer of the hair contains damaged hair. In some embodiments, the output includes an alert regarding the hair damage parameter. In some embodiments, the output includes a notification informing the user to take corrective action. For example, the notification may inform the user to cease heating the hair to avoid damaging or further damaging the hair. Alternatively, the notification may inform the user to adjust the operating temperature of the hair contacting member 225100, to adjust the speed at which the user moves the hair contacting member 225, and / or to adjust the gripping pressure applied by the user to the hair.

[0149] The user interface may be provided on the hair styling device 100. For example, the user interface may constitute the user interface 240 described above with reference to FIG. 2. In alternative embodiments, the user interface is not provided on the hair styling device 100. The user interface may be provided on a remote device communicatively coupled (e.g., via wireless communication) to the hair styling device 100. Such a remote device may comprise, for example, a user device or a docking station.

[0150] In embodiments, the heating of the hair contacting member 225 is controlled based on the calculated hair damage parameter(s). For example, if the hair styling device includes a heating element 220, the heating element 220 can be controlled based on the calculated hair damage parameter(s). In embodiments, the amount of energy applied to the heating element 220 is adjusted based on the calculated hair damage parameter(s). This can reduce and / or avoid damage and / or further damage to the hair. In embodiments, if it is determined that the hair is damaged, the operating temperature of the hair contacting member 225 is decreased. In alternative embodiments, if it is determined that the hair is damaged, the operating temperature of the hair contacting member 225 is increased. Damaged hair may, for example, require more heat to be styled as desired. In embodiments, the extent and / or type of damage to the hair may be determined such that the likelihood and / or impact of further damage is negligible. In some embodiments, heating of the hair contacting member 225 (e.g., by the heating element 220) is stopped based on the calculated one or more hair damage parameters. Thus, heating of the hair by the hair contacting member 225 is discontinued, which may reduce and / or avoid damage and / or further damage to the hair.

[0151] For example, in alternative embodiments in which the hair styling device 100 does not include a heating element 220, the heating of the hair contacting member 225 may be controlled by applying energy directly to the hair contacting member 225. In such embodiments, the power consumption associated with heating the hair contacting member 225 may be monitored directly (rather than by monitoring the power consumed by the heating element 220 to heat the hair contacting member 225) and used to calculate one or more hair damage parameters.

[0152] Figure 9 illustrates a method 900 of operating a hair styling device according to embodiments. Method 900 can be used to operate the hair styling device 100 described above with reference to Figures 1A, 1B and 2. In the embodiment of Figure 9, the hair styling device 100 comprises a sensor device 230 configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device 100. The at least one usage characteristic is indicative of a current usage of the hair styling device 100. In embodiments, method 900 is at least partially performed by the controller 210.

[0153] In step 910 , a sensor output is received from the sensor device 230 .

[0154] At step 920, the sensor output is processed using a classification algorithm to obtain classification data. The classification algorithm is configured to determine whether the hair styling device 100 is being used according to a first styling behavior or a second, different styling behavior based on at least one usage characteristic of the hair styling device 100.

[0155] At step 930, the classification data is used to control the hairstyling device 100 to perform an action.

[0156] Thus, the hair styling device 100 can determine the styling behavior currently being used based on the sensor data. By using the sensor data as input to a classification algorithm, the styling behavior can be recognized without requiring user input. Thus, the hair styling device 100 can autonomously determine how the user is using the hair styling device 100 and adapt accordingly. This allows for a more intelligent control of the hair styling device 100. For example, one or more operational settings of the hair styling device 100 can be controlled depending on the determined behavior. This allows the settings of the hair styling device 100 to more closely correspond to how the user intends to use the hair styling device 100. This can reduce styling time and / or increase the likelihood of achieving a desired style. Furthermore, this can reduce the likelihood of hair damage caused by, for example, the user using incorrect and / or suboptimal settings for a given styling behavior.

[0157] In some embodiments, the first styling behavior includes a hair straightening behavior, and the second styling behavior includes a non-hair straightening behavior, e.g., a hair curling behavior. In the case of hair straightening, at least one usage characteristic may be different compared to hair curling. For example, a user may move the hair styling device 100 differently depending on whether the user is trying to straighten or curl hair. Hair curling involves a larger amount of rotation of the hair styling device 100 compared to, e.g., hair straightening. Thus, the classification algorithm may be configured to distinguish between hair straightening and hair curling using the sensor data. In some embodiments, it is determined that the hair styling device 100 is not being used to straighten hair, and such a determination is used to infer that the hair styling device 100 is being used to curl hair or vice versa. In some embodiments, different operating settings of the hair styling device 100 can be used depending on whether the hair styling device 100 is being used for hair straightening or for other purposes, such as hair curling. For example, in the case of hair curling, it may be desired to use a lower operating temperature compared to hair straightening in order to achieve a desired style while reducing the possibility of hair damage. This may be due to the pass duration for hair curling being longer than that for hair straightening and / or the pass speed for hair curling being slower than that for hair straightening. In some embodiments, different heat delivery profiles can be determined and / or used depending on whether the hair styling device 100 is being used for hair straightening or hair curling.

[0158] In embodiments, the first styling behavior includes a full style behavior and the second styling behavior includes a touch-up behavior. A full style may have at least one different usage characteristic compared to a touch-up. For example, a user may move the hair styling device 100 differently depending on whether the user is performing a full style or a touch-up. A full style may involve styling along the entire length of the hair bundle, whereas a touch-up may involve styling only a portion of the length of the hair bundle (e.g., the tip of the hair bundle). Additionally or alternatively, a full style may involve styling the hair from a pristine state (e.g., the hair has not been previously styled or has not been previously styled within a period of time), whereas a touch-up may involve modifying or restoring an existing style. Thus, a classification algorithm may be configured to distinguish between a full style and a touch-up using sensor data. In embodiments, different operational settings of the hair styling device 100 may be used depending on whether the hair styling device 100 is being used for a full style or a touch-up. For example, it may be desirable to use a higher operating temperature for a touch-up compared to a full style. In embodiments, different heat delivery profiles may be determined and / or used depending on whether the hair styling device 100 is being used for a full style or a touch-up. For example, a constant heat delivery profile may be used for a touch-up, while a varying heat delivery profile may be used for a full style.

[0159] In some embodiments, the first styling behavior includes a wet hair styling behavior and the second styling behavior includes a dry hair styling behavior. At least one use characteristic may be different for wet hair compared to dry hair. For example, power consumption by the hair styling device 100 during use may depend on whether the hair is wet or dry. Whether the hair is wet or dry may be determined, for example, using a capacitive sensor, using a moisture sensor, and / or by monitoring power consumption during heating of the hair. Thus, a classification algorithm may be configured to distinguish between wet hair styling and dry hair styling using sensor data. In some embodiments, different operating settings of the hair styling device 100 may be used depending on whether the hair styling device 100 is being used on wet hair or dry hair. In some cases, using the hair styling device 100 on wet hair may increase the risk of hair damage compared to using the hair styling device 100 on dry hair. In some such examples, the user interface may provide an output advising the user not to use the hair styling device 100 on wet hair to avoid damaging the hair. In other examples, one or more operational settings of the hair styling device 100 may be adjusted depending on whether the hair styling device 100 is being used for wet or dry hair.

[0160] In alternative embodiments, other styling behaviors can be identified by the classification algorithm. For example, the classification algorithm may be configured to determine which section and / or layer of hair is being styled. In some examples, the classification algorithm is configured to determine whether the hair styling device 100 is currently being used, is stationary (e.g., at rest) because it is charging, or is stationary because the user is moving between sections and / or layers of hair.

[0161] In some embodiments, the classification algorithm comprises a trained algorithm. The classification algorithm is trained using training data to determine whether the hair styling device 100 is being used according to a first styling behavior or a second styling behavior. Use of such a trained algorithm results in a more accurate and / or reliable classification of styling behaviors than if the trained algorithm was not used.

[0162] In some embodiments, the classification algorithm comprises a machine learning algorithm. Such machine learning algorithms may improve with experience and / or training (e.g., may increase classification accuracy and / or reliability). In some embodiments, the classification algorithm comprises a random forest algorithm. Such algorithms may use multiple decision trees. Classification data may be obtained based on an average of the output classes of the individual trees. In alternative embodiments, other types of classification algorithms may be used. In some embodiments, the classification algorithm includes a first step of performing feature extraction on the sensor output and a second step of performing behavior classification using the extracted features. In some embodiments, the machine learning algorithm includes one or more artificial neural networks.

[0163] In some embodiments, the hair styling device 100 comprises a machine learning agent (not shown). The machine learning agent may be, for example, comprised in the control unit 210. In some such embodiments, the machine learning agent comprises a classification algorithm. Thus, the classification algorithm may be located in the hair styling device 100. By performing a classification of the styling behavior of the hair styling device 100, the latency is reduced compared to when the classification algorithm is not located in the hair styling device 100, since no transmission of data to and / or reception of data from another device is required. This allows the classification data to be obtained more quickly, which reduces the time it takes for any corrective action to be taken, for example, adjusting one or more operational settings of the hair styling device 100. As a result, the possibility of hair damage due to, for example, operational settings not corresponding to the intended use of the hair styling device 100, may be reduced.

[0164] In some embodiments, for example, when the sensor device 230 comprises an IMU 235, the at least one use characteristic is indicative of a movement of the hair styling device 100. Thus, the styling behavior can be determined based on how the hair styling device 100 is moving. In an embodiment in which the hair styling device 100 comprises a hair contacting member 225, the hair contacting member 225 comprises opposing first and second hair contactable surfaces 116, 126 and is movable between an open configuration and a closed configuration, the at least one use characteristic can be indicative of whether the hair contacting member 225 is in an open configuration or a closed configuration. The sensor device 230 can comprise, for example, a Hall effect sensor operable to sense whether the hair contacting member 225 is in an open configuration or a closed configuration. Thus, the styling behavior can be determined based on whether the hair contacting member 225 is in an open configuration or a closed configuration and / or when the hair contacting member 225 is in an open configuration or a closed configuration.

[0165] In some embodiments, the classification algorithm is modified using the sensor output. Thus, the classification algorithm can be trained and / or further trained using the sensor output. Modifying the classification algorithm can improve the accuracy and / or reliability of the classification algorithm with experience and / or use of more training data. That is, the confidence level of the classification data can be increased. Furthermore, modifying the classification algorithm allows the classification algorithm to be tailored to a user. For example, an initial classification algorithm may be provided on the hair styling device 100, but the initial classification algorithm does not take into account the particular behavior and / or activity of a given user. A user may, for example, move the hair contact member 225 in a particular manner that differs from other users. By dynamically retraining the classification algorithm using the sensor output as training data, the classification algorithm can more reliably determine which styling behavior the user is intending to use.

[0166] In embodiments where the hair styling device 100 comprises a heating element 220 operable to apply heat to the hair, the heating element 220 can be controlled based on the classification data. Thus, the heating element 220 can be controlled depending on whether the hair styling device 100 is being used according to a first styling behavior or a second styling behavior. In some embodiments, the heating element 220 is controlled to apply a predetermined heat delivery profile along the hair strand. The predetermined heat delivery profile depends on whether the hair styling device 100 is being used according to a first styling behavior or a second styling behavior. In some embodiments, controlling the heating element 220 includes adjusting the amount of energy applied to the heating element 220 and / or adjusting the operating temperature of the hair styling device 100. This allows the heat settings of the hair styling device 100 to more closely correspond to the styling behavior that the user intends to use. Thus, the desired style can be achieved with less potential hair damage and / or less styling time.

[0167] In some embodiments, the user interface provides an output based on the classification data. The output may include, for example, a notification informing the user that the current operational settings of the hair styling device 100 do not correspond to the identified styling behavior, which may prompt the user to take corrective action, e.g., change the operational settings. In some embodiments, the output includes a warning against improper and / or unsafe use of the hair styling device 100. In some embodiments, the output includes requesting the user to confirm that the identified styling behavior is correct.

[0168] In some embodiments, the classification data is obtained using one or more contextual features as input to a classification algorithm. Thus, the classification algorithm can take both the sensor output and the one or more contextual features as input. In some embodiments, the one or more contextual features are indicative of a past use of the hair styling device. For example, it may be determined and / or known that the hair styling device 100 has been used by a user in the past for hair straightening. This information influences the behavior classification for subsequent uses. For example, knowing the past behavior may increase the probability of determining that the hair styling device 100 is currently being used for hair straightening rather than hair curling. In some embodiments, the past use includes hair strands that have been previously styled in the same hair styling session. For example, it may be determined and / or known that the hair styling device 100 was used to straighten a first hair strand. This information increases the probability of determining that a second hair strand will be straightened as well. In some embodiments, the one or more contextual features are indicative of a user's preference. Using the contextual features as input to the classification algorithm increases the confidence level of the classification data.

[0169] In some embodiments, the classification data is stored in a memory, for example, memory 250 of the hair styling device 100. Thus, the classification data can be used at a later time, for example, during the next use of the hair styling device 100. In some embodiments, the classification data is stored for use as a contextual feature during the next use of the hair styling device 100. This can increase the confidence level of future classifications performed by the classification algorithm. In some embodiments, the classification data is output for transmission to a remote device. For example, the classification data can be output for transmission to a user device. In some embodiments, the classification data is used to generate a user hair styling profile for the user. The user hair styling profile can be used, for example, to provide the user with tailored styling advice. The user hair styling profile can be modified and / or updated as new classification data is obtained.

[0170] In some embodiments, training data is received from a remote device. In some such embodiments, the received training data is used to modify the classification algorithm. The training data may be received from a network, e.g., the "cloud." Such training data may include sensor data and / or classification data associated with other users. Such training data may include, for example, crowdsourced data. In some embodiments, such training data is more voluminous than the sensor data and / or classification data obtained directly from using the hair styling device 100. Using training data from a remote device to modify the classification algorithm may increase the accuracy and / or reliability of the classification algorithm compared to when such training data is not used.

[0171] FIG. 10 illustrates a method 1000 of operating a hair styling device according to embodiments. The method 1000 can be used to operate the hair styling device 100 described above with reference to FIGS. 1A, 1B, and 2. In the embodiments of FIG. 10, the hair styling device comprises a heatable hair contacting member 225. The hair contacting member 225 comprises opposing first and second hair contactable surfaces 116, 126. The hair contacting member 225 is operable to apply heat to the hair via at least one of the first hair contactable surface 116 and the second hair contactable surface 126. The hair styling device 100 further comprises an opening and closing mechanism 227 operable to move the first hair contactable surface 116 relative to the second hair contactable surface 126. In embodiments, the method 1000 is performed at least in part by the controller 210.

[0172] In step 1010 , a control signal is output to the opening and closing mechanism 227 .

[0173] At step 1020, in response to receiving the control signal, the opening and closing mechanism 227 adjusts the distance between the first hair-contactable surface 116 and the second hair-contactable surface 126.

[0174] Thus, the opening and closing mechanism 227 is immediately responsive to a control signal, for example, from the control unit 210. Thus, in some embodiments, the control of the distance between the first hair-contactable surface 116 and the second hair-contactable surface 126 is not relied upon by the user. This allows the gripping of the hair between the hair-contactable surface 116 and the hair-contactable surface 126 to be performed in a more controlled and intelligent manner. If the gripping of the hair is relied upon by the user manually, too much or too little pressure may be applied to the hair. For example, at the root end of the hair strand where the hair strand is relatively thick between the hair-contactable surface 116 and the hair-contactable surface 126, the user may apply too much gripping pressure, which may cause a risk of damage to the hair. However, at the tip end of the hair strand where the hair strand is relatively thin between the hair-contactable surface 116 and the hair-contactable surface 126, the user may not be able to apply enough gripping pressure to style the hair as desired. Therefore, pinching the hair only by manual gripping force applied by the user may damage the hair, prevent a desired style from being achieved, and / or extend the styling time. Therefore, automatically controlling the opening and closing mechanism 227 by a control signal from the control unit 210 reduces the possibility of hair damage, increases the possibility of a desired style being achieved, and / or shortens the styling time.

[0175] In some embodiments, the hair contacting member 225 comprises a first arm 110 and a second arm 120 movably coupled to the first arm 110, as described above in connection with Figures 1A and 1B. The first arm 110 comprises a first hair-contactable surface 116, and the second arm 120 comprises a second hair-contactable surface 126. In some such embodiments, the opening and closing mechanism 227 is configured to move the first hair-contactable surface 116 relative to the first arm 110 in response to receiving a control signal. Thus, the first arm 110 can move relative to the second arm 120, and the first hair-contactable surface 116 can further move relative to the first arm 110. In some such embodiments, closing of the hair styling device 100 comprises two stages. In a first manual phase, the user moves the first arm 110 relative to the second arm 120, i.e., from an open configuration of the arms 110, 120 to a closed configuration of the arms 110, 120. In a second automated phase, the control unit 210 moves the first hair-contactable surface 116 relative to the first arm 110 via the opening and closing mechanism 227, thereby adjusting the distance between the first hair-contactable surface 116 and the second hair-contactable surface 126. In some embodiments, the opening and closing mechanism 227 is configured to move the first arm 110 relative to the second arm 120 in response to receiving a control signal.

[0176] In some embodiments, the opening and closing mechanism 227 is operable to move the second hair contactable surface 126 in addition to the first hair contactable surface 116. This allows for a finer level of control than if the opening and closing mechanism 227 was operable to move only one of the hair contactable surfaces 116, 126.

[0177] In some embodiments, a target distance is determined between the first hair contactable surface 116 and the second hair contactable surface 126. In some such embodiments, a control signal is output to the opening and closing mechanism 227 based on the target distance. The target distance can be determined based on several factors, which are described below.

[0178] In some embodiments, a target gripping pressure to be applied to the hair between the first hair-contactable surface 116 and the second hair-contactable surface 126. In some such embodiments, a control signal is output to the opening and closing mechanism 227 based on the target gripping pressure. For example, the control signal may cause the opening and closing mechanism 227 to apply a target gripping pressure to the hair between the first hair-contactable surface 116 and the second hair-contactable surface 126. The target gripping pressure may be determined based on several factors, which are described below.

[0179] In some embodiments, the opening and closing mechanism 227 is at least partially electromechanical. For example, the opening and closing mechanism 227 can receive electrical control signals and convert such control signals into mechanical movement. In some embodiments, the opening and closing mechanism 227 comprises one or more stepper motors. In some such embodiments, the opening and closing mechanism 227 is configured to, in response to receiving the control signals, drive the one or more stepper motors to move the first hair-contactable surface 116 relative to the second hair-contactable surface 126.

[0180] In some embodiments, the opening and closing mechanism 227 comprises one or more inflatable airbags adjacent the first hair-accessible surface 116. In some such embodiments, the opening and closing mechanism 227 is configured to control the inflation of the one or more inflatable airbags to move the first hair-accessible surface 116 relative to the second hair-accessible surface 126 in response to receiving a control signal. Such airbags can be used to provide a "floating" plate 115 that defines the first hair-accessible surface 116, which can move relative to the first arm 110. Such airbags may be located behind the first hair-accessible surface 116, i.e., within the first arm 110. The opening and closing mechanism 227 is configured to control the inflation of the one or more airbags to a desired pressure. In some embodiments, air is provided from a reservoir (e.g., a canister) under the control of the controller 210. The desired pressure depends on the target distance between the first hair-accessible surface 116 and the second hair-accessible surface 126 and / or the target pressure to be applied to the hair between the first hair-accessible surface and the second hair-accessible surface. The opening and closing mechanism 227 can include a valve to prevent the desired pressure from being exceeded and / or to reduce pressure in the airbag or airbags. In some embodiments, the opening and closing mechanism 227 further includes one or more inflatable airbags adjacent the second hair-accessible surface 126, and the one or more inflatable airbags can be controlled in a similar manner.

[0181] In some embodiments, it is determined that the hair contacting member 225 is moving along the hair bundle from a root end of the hair bundle toward a tip end of the hair bundle. For example, a signal may be received from the IMU 235 indicating that the hair contacting member 225 is moving along the hair bundle. In some such embodiments, in response to determining that the hair contacting member 225 is moving along the hair bundle, a control signal is output to the opening and closing mechanism 227. A target distance between the first hair contactable plate 116 and the second hair contactable plate 126 and / or a target pressure to be applied to the hair between the first hair contactable plate 116 and the second hair contactable plate 126 may depend on the movement of the hair contacting member 225 along the hair bundle.

[0182] In some embodiments, a control signal is output to the opening and closing mechanism based on the derived speed of the hair contact member 225 moving along the hair strand. For example, if the derived speed is higher than a predetermined threshold, the gripping pressure may be reduced to reduce the possibility of mechanical damage to the hair.

[0183] In some embodiments, the displacement of the hair contacting member 225 from the root end of the hair bundle is derived. In some such embodiments, a control signal is output to the opening and closing mechanism 227 based on the derived displacement. The displacement may be derived, for example, using a signal from the IMU 235. In some embodiments, the displacement of the hair contacting member 225 from the root end is used to calculate a target distance between the first hair contactable plate 116 and the second hair contactable plate 126 and / or a target pressure to be applied to the hair between the first hair contactable plate 116 and the second hair contactable plate 126. Thus, the gripping pressure applied to the hair may be more intelligently controlled.

[0184] In some embodiments, as the hair contacting member 225 moves along the hair bundle from the root end of the hair bundle towards the tip end of the hair bundle, a control signal is output to the opening and closing mechanism 227 to decrease the distance between the first hair contactable surface 116 and the second hair contactable surface 126. Because hair is typically thicker at the root end and thinner (and / or less healthy) at the tip end, decreasing the distance between the hair contactable surface 116 and the hair contactable surface 126 along the hair bundle reduces the potential for damage to hair at the root end while ensuring that hair at the tip end of the hair bundle is styled as desired.

[0185] In embodiments, as the hair contacting member 225 moves along the hair bundle from the root end of the hair bundle toward the tip end of the hair bundle, a control signal is output to the opening and closing mechanism 227 to increase the gripping pressure applied to the hair between the first hair-contactable surface 116 and the second hair-contactable surface 126. Thus, an increased pressure can be applied to the hair bundle. Such increased pressure reduces the possibility of damage to hair at the root end of the hair bundle while ensuring that hair at the tip end of the hair bundle is styled as desired. In embodiments, the increased pressure (or "pressure profile") is tailored to the user. For example, the increased pressure can be determined based on one or more of the user's preferences, the hairstyling device 100, sensor data indicative of current use of the hairstyling device 100, and the like.

[0186] In some embodiments, a thickness of the hair between the first hair contactable surface 116 and the second hair contactable surface 126 is derived. In some such embodiments, a control signal is output to the opening and closing mechanism 227 based on the derived thickness of the hair. The thickness can be derived, for example, by measuring the distance between the first hair contactable surface 116 and the second hair contactable surface 126. In other examples, the thickness of the hair is derived by measuring the power consumed by the hair contact member 225 during heating. For example, if the hair styling device 100 includes a heating element 220 configured to heat the hair, the thickness of the hair can be derived by measuring the power consumed by the heating element 220 during heating. In some embodiments, the thickness is derived based on the displacement of the hair styling device 100 from the root end of the hair bundle. In some embodiments, the derived thickness is used to calculate a target distance between the first hair-contactable plate 116 and the second hair-contactable plate 126 and / or a target pressure to be applied to the hair between the first hair-contactable plate 116 and the second hair-contactable plate 126. In some embodiments, the thickness of the hair between the first hair-contactable plate 116 and the second hair-contactable plate indicates the amount of hair between the first hair-contactable plate 116 and the second hair-contactable plate 126.

[0187] In some embodiments, a distance between the first hair contactable surface 116 and the second hair contactable surface 126 is derived. In some such embodiments, a control signal is output to the opening and closing mechanism 227 based on the measured distance. The distance between the first hair contactable surface 116 and the second hair contactable surface 126 can be measured using, for example, a Hall effect sensor. A target distance between the first hair contactable plate 116 and the second hair contactable plate 126 and / or a target pressure to be applied to the hair between the first hair contactable plate 116 and the second hair contactable plate 126 can depend on the measured distance.

[0188] In some embodiments, the power consumption associated with the heating of the hair contacting member 225 can be monitored during heating of the hair via at least one of the first hair-contactable surface 116 and the second hair-contactable surface 126. The power consumption can be monitored using a sensor device, for example a power meter. In examples where the hair styling device 100 includes a heating element 220, monitoring the power consumption can include monitoring the power consumed by the heating element 220 during heating of the hair. Based on the monitored power consumption, one or more hair damage parameters indicative of damage to the heated hair are calculated. In such some embodiments, a control signal is output to the opening and closing mechanism 227 based on the calculated one or more hair damage parameters. A target distance between the first hair-contactable plate 116 and the second hair-contactable plate 126 and / or a target pressure to be applied to the hair between the first hair-contactable plate 116 and the second hair-contactable plate 126 can depend on the calculated one or more hair damage parameters. For example, the control signal may decrease the gripping pressure if the calculated hair damage parameter or parameters indicate that damage to the hair is likely to occur (e.g., due to excessive gripping pressure). In some cases, the control signal may increase the gripping pressure if the calculated hair damage parameter or parameters indicate that the hair is already damaged. This increased gripping pressure may facilitate styling of the damaged hair.

[0189] In embodiments, the hair styling device 100 is determined to be used according to a first styling behavior (e.g., a hair straightening behavior) or a second styling behavior different from the first styling behavior (e.g., a hair curling behavior). Such a determination may be made without user input, for example using a classification algorithm as described above in connection with FIG. 9. In alternative embodiments, such a determination is made based on user input. In embodiments, a control signal is output to the opening and closing mechanism 227 depending on whether the hair styling device 100 is used according to the first styling behavior or the second styling behavior. A target distance between the first hair-contactable plate 116 and the second hair-contactable plate 126 and / or a target pressure to be applied to the hair between the first hair-contactable plate 116 and the second hair-contactable plate 126 may depend on the determined styling behavior. For example, the control signal may cause a gripping pressure for hair straightening to be different from a gripping pressure for hair curling. This allows different styles to be achieved while reducing styling time and / or potential damage to the hair.

[0190] In some embodiments, the hair styling device 100 is configured to prevent an external gripping force applied by a user from reducing the distance between the first hair contactable surface 116 and the second hair contactable surface 126 below a first predetermined threshold distance. In some such embodiments, the control signal can reduce the distance between the first hair contactable surface 116 and the second hair contactable surface 126 below the first predetermined threshold distance, but the external gripping force applied by the user cannot reduce the distance between the first hair contactable surface 116 and the second hair contactable surface 126 in this manner. If the distance between the first hair contactable surface 116 and the second hair contactable surface 126 is less than the first predetermined threshold distance, this distance can be further reduced by the control signal rather than the external gripping force. Thus, control of the distance between the hair contactable surface 116 and the hair contactable surface 126 can be performed by the user when the hair contactable surfaces 116, 126 are relatively far apart (e.g., by moving the first arm 110 relative to the second arm 120), but can be performed only by the control unit 210 when the hair contactable surfaces 116, 126 are relatively close to each other (e.g., by moving the first hair contactable surface 116 relative to the first arm 110). This prevents external forces applied by the user from overriding the action of the control signal. In some embodiments, the first predetermined threshold distance is about 2 meters.

[0191] In some embodiments, the distance between the first hair contactable surface 116 and the second hair contactable surface 126 is determined to be less than a second predetermined threshold distance. The second predetermined threshold distance may be the same as or different from the first predetermined threshold distance. In response to determining that the distance between the first hair contactable surface 116 and the second hair contactable surface 126 is less than the second predetermined threshold distance, a control signal is output to the opening and closing mechanism 227. Thus, the control of the opening and closing mechanism 227 by the control signal is performed when the first hair contactable surface 116 and the second hair contactable surface 126 are relatively close to each other. This ensures that the control of the opening and closing mechanism 227 by the control signal is performed appropriately, i.e., when hair is being styled by the hair styling device 100. In embodiments in which the arms 110, 120 are movable between an open configuration and a closed configuration, the control signal is output to the opening and closing mechanism 227 in response to determining that the arms 110, 120 are in the closed configuration. In some embodiments, when the arms 110, 120 are in a closed configuration but the hair styling device is not actively being used (e.g., when it is being held by a user and / or when styling hair), automatic control of the opening and closing mechanism 227 is not performed.

[0192] In some embodiments, when the arms 110, 120 are in the closed configuration, the distance between the hair contactable surface 116 and the hair contactable surface 126 after the opening and closing mechanism 227 has moved the first hair contactable surface 116 is less than the distance between the hair contactable surface 116 and the hair contactable surface 126 before the opening and closing mechanism 227 has moved the first hair contactable surface 116 when the arms 110, 120 are in the closed configuration. In other words, a "manual closed position" is provided in which the arms 110, 120 are in the closed position, and a separate "automatic closed position" is provided in which the arms 110, 120 are in the closed position and, in response to a control signal, the opening and closing mechanism 227 decreases the distance between the hair contactable surface 116 and the hair contactable surface 126. Thus, in some embodiments, the automatic closed position is "more closed" compared to the manual closed position.

[0193] In embodiments, the hair styling device 100 is configured to prevent an external gripping force applied by a user from bringing the first hair contactable surface 116 and the second hair contactable surface 126 into contact. For example, when the arms 110, 120 are in a closed configuration, the first hair contactable surface 116 and the second hair contactable surface 126 can be spaced apart. In such embodiments, the control signal output to the opening and closing mechanism 227 can bring the first hair contactable surface 116 and the second hair contactable surface 126 into contact. Thus, an external force applied by a user is prevented from overriding the action of the control signal when controlling the opening and closing mechanism 227.

[0194] In some embodiments, a gripping force applied by a user acting on the first arm 110 toward the second arm 120 is derived, e.g., measured. Such gripping force may be derived using sensor output from a sensor device (e.g., a force sensor and / or a pressure sensor). That is, the gripping force may be measured by one or more sensors. The gripping force is applied by the user to act on the first hair contactable surface 116 toward the second hair contactable surface 126. In some embodiments, a control signal is output to the opening and closing mechanism 227 based on the derived gripping force. Thus, control of the opening and closing mechanism 227, and thus the distance between the hair contactable surface 116 and the hair contactable surface 126, may depend on the gripping force applied by the user. Therefore, the external gripping force applied by the user does not directly bring the first hair-contactable surface 116 and the second hair-contactable surface 126 together, but can affect the control of the opening and closing mechanism 227 via a control signal generated by the control unit 210.

[0195] In some embodiments, in response to the measured external gripping force exceeding a predetermined threshold, a control signal is output to the opening and closing mechanism 227. Thus, the opening and closing mechanism 227 can be controlled by the controller 210 when the user attempts to act on the hair contactable surfaces 116, 126 together. In some embodiments, the target gripping pressure to be applied by the opening and closing mechanism 227 to the hair between the hair contactable surfaces 116, 126 depends on the measured external gripping force applied by the user. In other words, when the user attempts to increase the gripping pressure (by increasing the force exerted on the arms 110, 120), such increase in gripping pressure is determined by the controller 210, resulting in an increase in the target gripping pressure applied by the opening and closing mechanism 227.

[0196] In some embodiments, the measured external gripping force is used to estimate the displacement of the hair contacting member 225 along the hair bundle. For example, the user may attempt to apply less force at the root end of the hair bundle and more force towards the tip end of the hair bundle, which may be determined by the control unit 210. In some examples, the measured external gripping force is used to derive the thickness of the hair between the first hair contactable surface 116 and the second hair contactable surface 126. For example, the user may attempt to apply more force if there are fewer and / or thinner hairs between the hair contactable surface 116 and the hair contactable surface 126.

[0197] In embodiments where the hair styling device 100 comprises a sensor device 230 configured to generate a sensor output indicative of a current use of the hair styling device 100, a control signal can be output based on the sensor output. The sensor device 230 can comprise, for example, an IMU 235 and / or a Hall effect sensor. Thus, the opening and closing mechanism 227 can be controlled based on a sensor output indicative of a current use of the hair styling device 100, for example, a sensor output indicative of how a user is moving the hair styling device 100. In embodiments, the sensor output is processed to do one or more of: derive the velocity of the hair contacting member 225, derive the displacement of the hair contacting member 225 from the root end of the hair bundle, derive the power consumption associated with heating the hair contacting member 225, determine whether the arms 110, 120 are in an open or closed configuration, derive the magnitude of the gripping force applied by the user, determine the styling behavior being used, derive the distance between the first hair contactable surface 116 and the second hair contactable surface 126, and derive the thickness of the hair between the first hair contactable surface 116 and the second hair contactable surface 126. This allows the opening and closing mechanism 227 to be controlled in a more intelligent and flexible manner.

[0198] FIG. 11 illustrates a method 1100 of operating a hair styling device according to embodiments. Method 1100 can be used to operate the hair styling device 100 described above with reference to FIGS. 1A, 1B and 2. In the embodiment of FIG. 11, the hair styling device 100 comprises a heatable hair contacting member 225 having a hair contactable surface 116, 126. The hair contacting member 225 is operable to apply heat to the hair via the hair contactable surface 116, 126. The hair styling device 100 further comprises an IMU 235. The IMU 235 is configured to output a signal in response to movement of the hair contacting member 225. In embodiments, the method 1100 is at least partially performed by the controller 210.

[0199] At step 1110, a signal is received from the IMU 235 indicative of a movement of the hair contact member 225 along the hair bundle between a first end of the hair bundle and a second end of the hair bundle.

[0200] In step 1120 , the received signal is processed to derive the velocity of the hair contacting member 225 .

[0201] In step 1130, the heating of the hair contacting member 225 is controlled based on the derived rate.

[0202] By controlling the heating of the hair contacting member 225 based on the derived speed of the hair contacting member 225, the heat supply and / or heat distribution along the hair bundle can be more intelligently controlled and / or adapted. Furthermore, the derived speed can be used to predict whether damage to the hair may occur, for example, due to heat and / or mechanical pressure being applied to the hair. For example, if it is determined that the hair contacting member 225 is moving relatively slowly along the hair bundle, the likelihood of heat damage to the hair increases. The heating of the hair contacting member 225 can be controlled to reduce and / or avoid such damage. For example, the heating of the hair contacting member 225 can be controlled to reduce the amount of heat applied to the hair.

[0203] In some embodiments, the first end of the hair bundle constitutes a root end of the hair bundle and the second end of the hair bundle constitutes a tip end of the hair bundle. In such some embodiments, the velocity of the hair contact member 225 moving between the root end and the tip end is derived and used according to the described method. The first end may be located at the root or at the midpoint of the hair bundle. The second end may be located at the tip or at the midpoint of the hair bundle.

[0204] In some embodiments, the hair styling device 100 comprises a heating element 220 operable to heat the hair contacting member 225. In some such embodiments, controlling the heating of the hair contacting member 225 comprises controlling the heating element 220. Thus, the heating element 220 can be controlled based on the derived rate.

[0205] In some embodiments, the derived speed is used to determine a target heat delivery profile along the hair bundle. In such some embodiments, the heating of the hair contacting member 225 is controlled based on the target heat delivery profile. Thus, a target heat delivery profile tailored to the user can be determined based on how quickly the user moves the hair contacting member 225 along the hair bundle. Different target heat delivery profiles can be used for different speeds of the hair contacting member 225. In some embodiments, the target heat delivery profile constitutes a heat delivery profile that varies along the hair bundle. For example, the target heat delivery profile can include a temperature rise along the hair bundle. The rapidity of the temperature rise (i.e., the rate of temperature rise) along the hair bundle can depend on the derived speed of the hair contacting member 225. This allows for more intelligent control of heat distribution along the hair bundle. In some embodiments, a first target heat delivery profile is used by the hair styling device 100 initially. However, a second, different target heat delivery profile is determined based on the derived speed of the hair contacting member 225. The second target heat delivery profile may be capable of achieving a desired style more quickly and / or with a reduced risk of damaging the hair as compared to the first target heat delivery profile.

[0206] In some embodiments, the amount of energy used to heat the hair contacting member 225 (e.g., the amount of energy applied to the heating element 220) is adjusted based on the derived speed. For example, if the speed of the hair contacting member 225 is determined to be below a predetermined threshold speed, the amount of energy used to heat the hair contacting member 225 may be reduced, thereby reducing the possibility of thermal damage to the hair due to overheating. If the speed is determined to be above the predetermined threshold speed, the amount of energy used to heat the hair contacting member 225 may be increased, thereby ensuring that sufficient heat is applied to the hair to achieve the desired style.

[0207] In some embodiments, the heating of the hair contacting member 225 is controlled based on a target operating temperature of the hair contacting member 225. The target operating temperature depends on the derived speed. For example, a relatively low target operating temperature may be used when the hair contacting member 225 is moving relatively slowly (thereby reducing the possibility of heat damage), while a relatively high target operating temperature may be used when the hair contacting member 225 is moving relatively quickly (thereby transferring enough heat to the hair to achieve the desired style).

[0208] In some embodiments, a displacement of the hair contacting member 225 from a first end (e.g., a root end) of the hair bundle is derived based on the derived velocity. In such some embodiments, heating of the hair contacting member 225 is controlled based on the derived displacement from the first end. In some embodiments, the displacement of the hair contacting member 225 is derived using both a measurement of the length of the hair bundle and the derived velocity of the hair contacting member 225. Such a determination may be more accurate than a comparison case in which the length and / or velocity of the hair bundle is not used to derive the displacement from the first end. By controlling the heating of the hair contacting member 225 based on the derived displacement, finer control of heat distribution along the hair bundle can be achieved. For example, an operating temperature of the hair contacting member 225 can be increased as the hair contacting member 225 moves toward the tip end. Providing a heat delivery profile that increases from the root end toward the tip end of the hair bundle reduces the potential for heat damage while ensuring that a sufficiently high temperature is transferred to the hair at the tip end to achieve a desired style.

[0209] In some embodiments, a user interface (e.g., the user interface 240 of the hair styling device 100) provides an output based on the derived speed. In some embodiments, the output includes a notification informing the user that the operating temperature of the hair styling device 100 has been adjusted by the speed of the hair contacting member 225. In some embodiments, the output includes a notification advising the user to adjust the speed of the hair contacting member 225.

[0210] In some embodiments, signals received from the IMU 235 are processed using a velocity and / or position estimation algorithm (e.g., comprising a Madgwick filter), as described in more detail above with reference to Figure 3. In some embodiments, machine learning models are used to process the received signals, as described above.

[0211] For example, in embodiments in which the hair styling device 100 does not include a heating element 220, the heating of the hair contacting member 225 can be controlled by applying energy directly to the hair contacting member 225. In either case, the heating of the hair contacting member 225 is controlled based on the derived rate.

[0212] FIG 12 illustrates a method 1200 of operating a hair styling device according to embodiments. Method 1200 can be used to operate the hair styling device 100 described above with reference to FIG 1A, FIG 1B and FIG 2. In the embodiment of FIG 12, the hair styling device 100 comprises a heatable hair contacting member 225 having a hair contactable surface 116, 126. The hair contacting member 225 is operable to apply heat to the hair via the hair contactable surface 116, 126. The hair styling device 100 further comprises an IMU 235. The IMU 235 is configured to output a signal in response to movement of the hair contacting member 225. In embodiments, the method 1200 is at least partially performed by the controller 210.

[0213] At step 1210, a signal is received from the IMU 235 indicative of movement of the hair contact member 225 along the user's hair strand between a first end of the hair strand and a second end of the hair strand.

[0214] In step 1220 , the received signal is processed to derive the velocity of the hair contacting member 225 .

[0215] In step 1230, the difference between the heat delivery profile achievable by the hair contact member 225 moving at the derived speed along the hair strand and the target heat delivery profile along the hair strand is derived.

[0216] At step 1240, a user interface provides an output related to the derived velocity of the hair contacting member 225 based on the derived difference.

[0217] Based on the difference between the heat delivery profile achievable by the hair contacting member 225 moving at the derived speed and the target heat delivery profile, an output may be provided in the user interface to notify the user that such a difference exists, i.e., the user may be notified that the target heat delivery profile cannot be achieved due to the speed of the hair contacting member 225.

[0218] In some embodiments, the output provided by the user interface includes a notification informing the user to adjust the speed of the hair contacting member 225. For example, the user may be prompted to speed up or slow down. By prompting the user to adjust the speed of the hair contacting member 225, the hair styling device 100 may achieve a target heat delivery profile, thereby reducing styling time and / or increasing the likelihood of achieving a desired style while reducing the likelihood of hair damage.

[0219] In some embodiments, the target heat delivery profile comprises a heat delivery profile that varies along the hair bundle. That is, the target operating temperature of the hair contacting member 225 may vary along the hair bundle. For example, the target heat delivery profile may comprise a heat delivery profile that increases along the hair bundle from the root end to the tip end. Achieving such a target heat delivery profile reduces the likelihood of damage to hairs at the root end of the hair bundle while ensuring that sufficient heat is applied to hairs at the tip end of the hair bundle to achieve a desired style.

[0220] In some embodiments, the speed of the hair contacting member 225 is identified as being outside of a target speed range. The target speed range defines a speed at which the hair contacting member 225 can achieve a target heat delivery profile along the hair strand. For example, the speed of the hair contacting member 225 can be lower (i.e., too slow) or higher (i.e., too fast) than the target speed range. If it is determined that the hair contacting member 225 is moving too slowly and / or too quickly to achieve the target heat delivery profile, the user is notified via the user interface. The user may be prompted to adjust the speed of the hair contacting member 225 so that the speed of the hair contacting member 225 falls within the target speed range. In some embodiments, a target speed range is identified. Different target speed ranges may be associated with different target heat delivery profiles.

[0221] In some embodiments, it is determined whether the hair styling device 100 is being used according to a first styling behavior or a second styling behavior different from the first styling behavior. In such some embodiments, the target heat delivery profile depends on whether the hair styling device 100 is being used according to the first styling behavior or the second styling behavior. For example, if the hair styling device 100 is being used for hair straightening, a first target heat delivery profile can be used, and if the hair styling device 100 is being used for hair curling, a second target heat delivery profile can be used. In some embodiments, the styling behavior is determined using a classification algorithm, as described above. In alternative embodiments, the target heat delivery profile does not depend on the styling behavior being used.

[0222] In embodiments, determining whether the hair styling device 100 is being used according to the first styling behavior or the second styling behavior is based on signals received from the IMU 235. Thus, the movement of the hair contacting member 225 is used to identify the current styling behavior of the hair styling device 100. For example, hair curling may involve a greater amount of rotation of the hair contacting member 225 compared to hair straightening. Such movement can be analyzed using data from the IMU 235.

[0223] In some embodiments, signals received from the IMU 235 are processed using a velocity and / or position estimation algorithm (e.g., comprising a Madgwick filter), as described in more detail above with reference to Figure 3. In some embodiments, machine learning models are used to process the received signals, as described above.

[0224] In some embodiments, the hair styling device 100 includes a user interface. For example, an output regarding the derived speed of the hair contacting member 225 may be provided via the user interface 240 of the hair styling device 100. This may increase the likelihood that the user will receive the output quickly, as compared to when a user interface is not included in the hair styling device 100. The output may include an audio output, a visual output, and / or a tactile output.

[0225] In some embodiments, the user interface is provided on a remote device, such as a mobile device or a docking station, communicatively coupled to the hair styling device 100. In such embodiments, a signal is output to the remote device to provide an output via the user interface. The user interface of such a remote device may be more versatile than the user interface of the hair styling device 100 itself. For example, a larger display may be provided on the remote device than can be accommodated on the hair styling device 100. Because the hair styling device 100 is generally handheld and has various other components, such as a heating element and a hair-contactable surface, the amount of physical space on the hair styling device 100 available for a user interface may be limited.

[0226] In embodiments, the method 1200 includes determining a heat delivery profile achievable by the hair contacting member 225 moving at the derived speed. In alternative embodiments, the method 1200 does not determine a heat delivery profile achievable by the hair contacting member 225. Thus, the derivation performed in step 1230 may include quantifying a difference between the achievable heat delivery profile and the target heat delivery profile, but may alternatively include simply asserting that a difference exists, i.e., that the target heat delivery profile cannot be achieved at the current speed.

[0227] In some embodiments, the first end comprises a root end of the hair bundle and the second end comprises a tip end of the hair bundle. Thus, in some embodiments, the signal received from the IMU 235 is indicative of movement of the hair contact member 225 between the root end of the hair bundle and the tip end of the hair bundle. In such embodiments, the velocity of the hair contact member 225 moving between the root end of the hair bundle and the tip end of the hair bundle is derived and used by the methods described.

[0228] Figure 13 illustrates a method 1300 of operating a hair styling device according to embodiments. Method 1300 can be used to operate the hair styling device 100 described above with reference to Figures 1A, 1B and 2. In the embodiment of Figure 13, the hair styling device 100 comprises a sensor device 230 configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device 100 indicative of a current usage of the hair styling device 100. In embodiments, method 1300 is at least partially performed by the controller 210.

[0229] In step 1310 , a sensor output is received from the sensor device 230 .

[0230] At step 1320, the sensor output is processed to derive one or more hair damage parameters. The one or more hair damage parameters are indicative of damage to the hair being heated by the hair styling device 100.

[0231] At step 1330, while the hair styling device 100 is heating the hair, the user interface provides an output responsive to one or more hair damage parameters.

[0232] The user interface can provide feedback in substantially real-time by providing an output while the hair is being heated, rather than after the completion of the hair styling session. This can inform the user that the currently heated hair has been or may become damaged. Thus, more meaningful information can be conveyed to the user more quickly than in other methods. Furthermore, such feedback can prompt the user to take corrective action, e.g., modify the speed and / or operating temperature of the hair styling device 100, to reduce the damage and / or the likelihood of further damage to the heated hair.

[0233] In some embodiments, the one or more hair damage parameters are indicative of existing damage to the hair. In some embodiments, the one or more hair damage parameters are indicative of predicted damage resulting from heating of the hair by the hair styling device 100. In some embodiments, the one or more hair damage parameters are indicative of both existing and predicted damage. In some embodiments, the one or more hair damage parameters are indicative of at least one of physical, thermal and chemical damage to the hair.

[0234] In some embodiments, the output provided by the user interface includes audio output, visual output, and / or tactile output. For example, the output may be provided via a display, a speaker, and / or a haptic actuator.

[0235] In some embodiments, the user interface is provided on a remote device. Such a remote device's user interface may be more versatile than the user interface of the hair styling device 100 itself. For example, a larger display may be provided on the remote device than can be accommodated on the hair styling device 100. Because the hair styling device 100 is typically handheld and may have various other components, such as a heating element and a hair-contactable surface, the amount of space on the hair styling device 100 available for the user interface may be limited. In such embodiments, a signal is output to the remote device to provide an output by the user interface. Such a signal may be transmitted wirelessly to the remote device, for example, via Bluetooth™ technology.

[0236] In alternative embodiments, the hair styling device 100 includes a user interface. By providing a user interface on the hair styling device 100, the need for communication between different devices is eliminated, allowing output to be generated and received by the user more quickly than if the user interface were not provided on the hair styling device 100. Additionally, by providing a user interface on the hair styling device 100, the user may be more likely to receive feedback quickly. For example, the user may not be in the same location as the remote device while using the hair styling device 100, and therefore the user may not be able to quickly see or hear notifications on the remote device.

[0237] In some embodiments, the output provided by the user interface includes a notification informing the user that a feedback message is available on the remote device. In some such embodiments, both the hair styling device 100 and the remote device include a user interface. However, the user interface of the remote device may be more versatile, more complex, and / or larger than the user interface of the hair styling device 100. Informing the user that a feedback message is available on the remote device prompts the user to look at the remote device (which may in some cases be in a different location than the user) to receive the feedback. The output provided to the hair styling device 100 may include, for example, a flashing light, an audio tone, and / or a vibration. The feedback message on the remote device may include a text message, an emoji message, a voice message, etc. In some embodiments, the control unit 210 of the hair styling device 100 provides the feedback message via the remote device.

[0238] In some embodiments, the output provided by the user interface includes an alert regarding one or more hair damage parameters. Such an alert may, for example, indicate that the portion of hair currently being heated has already been damaged by heating or is likely to become damaged by heating. In some embodiments, the alert indicates the type of damage to the hair, for example chemical damage, thermal damage, or mechanical damage.

[0239] In some embodiments, the output provided by the user interface includes a notification informing the user to take corrective action. Such a notification may, for example, advise the user to adjust the speed of the hair styling device 100 and / or the operating temperature of the hair styling device 100. In some embodiments, the notification includes a recommended operating temperature. By notifying the user in substantially real-time to take corrective action, damage and / or further damage to the heated hair may be prevented.

[0240] In some embodiments, one or more settings of the hair styling device 100 are altered based on one or more hair damage parameters. The one or more settings are altered by the hair styling device 100 itself, for example, by the control unit 210. The one or more settings are altered to prevent damage and / or further damage to the heated hair. In some such embodiments, the output provided by the user interface includes a notification informing the user that one or more settings have been altered. Thus, the hair styling device 100 may autonomously alter its settings based on the one or more hair damage parameters and then notify the user that such alteration has been made. This may be faster than relying on the user to alter the settings of the hair styling device 100, thereby reducing the possibility of further damage to the hair. In some embodiments, the one or more settings include the operating temperature of the hair styling device 100. For example, the operating temperature may be reduced to prevent damage and / or further damage to the heated hair.

[0241] In some embodiments, for example when the hair styling device 100 includes an IMU 235, the at least one usage characteristic is indicative of a movement of the hair styling device 100. For example, the at least one usage characteristic may be indicative of a speed of the hair styling device 100. Thus, one or more hair damage parameters may be derived based on the speed of the hair styling device 100. For example, if the speed of the hair styling device 100 is determined to be lower than a predetermined threshold speed (i.e., moving too fast), the one or more hair damage parameters may indicate a relatively high likelihood of mechanical damage to the hair. If the speed of the hair styling device 100 is determined to be lower than a predetermined threshold speed (i.e., moving too slowly), the one or more hair damage parameters may indicate a relatively high likelihood of thermal damage to the hair. In some embodiments, the at least one usage characteristic is indicative of a displacement of the hair styling device 100 along the hair bundle from the root end of the hair bundle. Thus, one or more hair damage parameters may be derived based on such displacement.

[0242] In embodiments in which the hair styling device 100 comprises a hair contacting member 225, the hair contacting member 225 comprising opposing first and second hair contactable surfaces and movable between an open configuration and a closed configuration, the at least one use characteristic may be indicative of whether the hair contacting member 225 is in the open configuration or the closed configuration. Accordingly, one or more hair damage parameters may be derived based on whether the hair contacting member 225 is in the open configuration or the closed configuration. For example, the likelihood of mechanical and / or thermal damage to hair may be increased when the hair contacting member 225 is in the closed configuration for an extended period of time.

[0243] In some embodiments, the sensor device 230 comprises a temperature sensor configured to sense an operating temperature of the hair styling device 100 (e.g., an operating temperature of the hair contacting member 225). In some such embodiments, the at least one usage characteristic includes an operating temperature of the hair styling device 100. Accordingly, one or more hair damage parameters may be derived based on the operating temperature of the hair styling device 100. For example, if the operating temperature of the hair styling device 100 is determined to be higher than a predetermined threshold (i.e., too hot), there may be an increased likelihood of thermal damage to the hair.

[0244] In embodiments in which the hair styling device comprises a heating element 220, the sensor device 230 comprises a power sensor configured to sense the power consumed by the heating element 220 during heating of the hair. In such embodiments, the at least one usage characteristic includes the power consumed by the heating element 220. Thus, one or more hair damage parameters can be derived based on the power consumed by the heating element 220 during heating of the hair. As described above in connection with FIG. 8, since the moisture retention characteristics of damaged hair differ from the moisture retention characteristics of undamaged hair, an indication of the damage of the hair can be obtained by monitoring the power consumption (e.g., the power consumed by the heating element 220) associated with heating the hair contacting member 225 to heat the hair. For example, the power consumed by the heating element 220 to heat the hair to a given temperature can be relatively high for damaged hair (which retains less moisture) and relatively low for undamaged hair (which retains more moisture). For example, in alternative embodiments in which the hair styling device 100 does not include a heating element 220, the power sensor may sense the power consumed by the hair contacting member 225 itself during heating of the hair.

[0245] The at least one usage characteristic may include a combination of one or more of the above factors. For example, one or more hair damage parameters may be derived based on a combination of the operating temperature and the speed of the hair styling device 100.

[0246] It should be understood that any feature described in connection with any one of the embodiments and / or aspects may be used alone or in combination with other features described, and may also be used in combination with one or more features of any other embodiment and / or aspect, or with any combination of any other embodiment and / or aspect. For example, it will be understood that features and / or steps described in connection with a given one of the methods 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300 may be included instead of or in addition to features and / or steps described in connection with any other one of the methods 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300.

[0247] In embodiments of the present disclosure, the hair styling device 100 comprises a controller 210. The controller 210 is configured to execute the various methods described herein. In embodiments, the controller comprises a processing system. Such a processing system may comprise one or more processors and / or memory. Each device, component or function described in connection with any of the examples described herein, such as the sensor device 230, the user interface 240 and / or the machine learning agent, may also comprise a processor or be comprised in an apparatus that comprises a processor. One or more aspects of the embodiments described herein include processes performed by the apparatus. In some examples, the apparatus comprises one or more processors configured to execute these processes. In this regard, the embodiments may be implemented at least in part by computer software stored in a (non-transitory) memory and executable by a processor, or by hardware, or by a combination of software and hardware (and firmware stored in a tangible object) stored in a tangible object. The embodiments also extend to computer programs adapted for practicing the above embodiments, in particular computer programs on or in a carrier. The program may be in the form of non-transitory source code, object code, or any other non-transitory form suitable for use in implementing the processes according to the embodiments. The carrier may be any entity or device capable of carrying a program, such as a RAM, ROM, or optical memory device.

[0248] The one or more processors of the processing system may comprise a central processing unit (CPU). The one or more processors may comprise a graphics processing unit (GPU). The one or more processors may comprise one or more of a field programmable gate array (FPGA), a programmable logic device (PLD), or a complex programmable logic device (CPLD). The one or more processors may comprise an application specific integrated circuit (ASIC). Those skilled in the art will appreciate that in addition to the examples provided, many other types of devices may be used to provide the one or more processors. The one or more processors may comprise multiple co-located processors or multiple processors located at different locations. The operations performed by the one or more processors may be implemented by one or more of hardware, firmware, and software. It will be appreciated that the processing system may comprise more, fewer, and / or different components than those described.

[0249] The techniques described herein may be implemented in software or hardware, or may be implemented using a combination of software and hardware. The techniques described herein may include configuring an apparatus for performing and / or assisting any or all of the techniques described herein. Although at least some aspects of the examples described herein with reference to the drawings include computer processes executed in a processing system or processor, the examples described herein also extend to computer programs adapted to practice these examples, such as computer programs on or within a carrier. A carrier may be any entity or device capable of executing a program. A carrier may comprise a computer readable storage medium. Examples of computer readable tangible storage media include, but are not limited to, optical media (e.g., CD-ROM, DVD-ROM, or Blu-ray), flash memory cards, floppy disks, or hard disks, or any other medium capable of storing computer readable instructions, such as firmware or microcode, in at least one ROM or RAM or programmable ROM (PROM) chip.

[0250] In the above description, where integers or elements having known, obvious or foreseeable equivalents are referred to, such equivalents are incorporated herein exactly as if they were set forth separately. Reference to the claims should be made for the purpose of determining the true scope of the present disclosure, which should be interpreted to encompass all such equivalents. The reader will also understand that integers or features of the present disclosure described as preferred, advantageous, convenient, etc. are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that the aforementioned optional integers or features may be beneficial in some embodiments of the present disclosure, but may not be desirable and therefore may not be present in other embodiments.

Claims

1. 1. A hair styling device comprising: a hair contacting member having first and second opposing hair contactable surfaces, the hair contacting member movable between an open configuration and a closed configuration; a sensor device configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device indicative of a current usage of the hair styling device, the at least one usage characteristic indicative of one or a combination of the following: movement of the hair contacting member and whether the hair contacting member is in the open configuration or the closed configuration; a heating element operable to apply heat to the hair; A control unit, receiving the sensor output from the sensor device; processing the sensor output using a classification algorithm configured to determine whether the hair styling device is being used according to a first styling behavior or a second, different styling behavior based on the at least one usage characteristic of the hair styling device to obtain classification data; Controlling the heating elements based on the classification data to apply a predetermined heat delivery profile along the hair strand. A control unit configured as above, Equipped with A hair styling device, wherein the predetermined heat delivery profile depends on whether the hair styling device is being used according to the first styling behavior or the second styling behavior.

2. 2. A hair styling device according to claim 1, the classification algorithm comprises a trained algorithm that has been trained using training data to determine whether the hair styling device is being used according to the first styling behavior or the second styling behavior. Hair styling device.

3. A hair styling device according to claim 1 or 2, the classification algorithm comprises a machine learning algorithm; Hair styling device.

4. A hair styling device according to any one of claims 1 to 3, the hair styling device comprising a machine learning agent, the machine learning agent comprising the classification algorithm; Hair styling device.

5. A hair styling device according to any one of claims 1 to 4, The first styling behavior includes a hair straightening behavior, and the second styling behavior includes a hair curling behavior. Hair styling device.

6. A hair styling device according to any one of claims 1 to 4, the first styling behavior comprises a full style behavior, and the second styling behavior comprises a touch-up behavior; Hair styling device.

7. A hair styling device according to any one of claims 1 to 4, The first styling behavior comprises a wet hair styling behavior and the second styling behavior comprises a dry hair styling behavior. Hair styling device.

8. A hair styling device according to any one of claims 1 to 7, the sensor equipment comprises an inertial measurement unit (IMU) and the at least one usage characteristic is indicative of a movement of the hair styling device; Hair styling device.

9. A hair styling device according to any one of claims 1 to 8, the at least one use characteristic indicating whether the hair contact member is in the open configuration or the closed configuration; Hair styling device.

10. A hair styling device according to any one of claims 1 to 9, the sensor device comprises a Hall effect sensor; Hair styling device.

11. A hair styling device according to any one of claims 1 to 10, the controller is configured to use the sensor output to modify the classification algorithm. Hair styling device.

12. A hair styling device according to any one of claims 1 to 11, the control unit is configured to provide, via a user interface, an output based on the classification data. Hair styling device.

13. A hair styling device according to any one of claims 1 to 12, The control unit is configured to store the classification data in a memory. Hair styling device.

14. A hair styling device according to any one of claims 1 to 13, the control unit is configured to output the classification data for transmission to a remote device. Hair styling device.

15. A hair styling device according to any one of claims 1 to 14, The control unit: receiving training data from a remote device; modifying the classification algorithm using the received training data; It is configured as follows: Hair styling device.

16. A hair styling device according to any one of claims 1 to 15, The classification algorithm comprises a random forest algorithm. Hair styling device.

17. A hair styling device according to any one of claims 1 to 16, the control unit is configured to obtain the classification data using one or more contextual features as input to the classification algorithm. Hair styling device.

18. 18. A hair styling device according to claim 17, comprising: the one or more contextual features being indicative of past usage and / or user preferences of the hair styling device; Hair styling device.

19. A hair styling device according to any one of claims 1 to 18, Hair straightening device and / or hair curling device 1. A hair styling device comprising:

20. 1. A method of operating a hair styling device, comprising: The hair styling device comprises: a hair contacting member having first and second opposing hair contactable surfaces, the hair contacting member movable between an open configuration and a closed configuration; a sensor device configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device indicative of a current usage of the hair styling device, the at least one usage characteristic indicative of one or a combination of the following: movement of the hair contacting member and whether the hair contacting member is in the open configuration or the closed configuration; Equipped with The method comprises: receiving the sensor output from the sensor device; processing the sensor output using a classification algorithm configured to determine whether the hair styling device is being used according to a first styling behavior or a second, different styling behavior based on the at least one usage characteristic of the hair styling device to obtain classification data; controlling the heating elements based on said classification data to apply a predetermined heat delivery profile along the hair strand; Including, A method, wherein the predetermined heat delivery profile depends on whether the hair styling device is being used according to the first styling behavior or the second styling behavior.

21. 1. A computer program comprising a set of instructions that, when executed by a computing device, causes the computing device to perform a method of operating a hair styling device, the computer program comprising: The hair styling device comprises: a hair contacting member having first and second opposing hair contactable surfaces, the hair contacting member movable between an open configuration and a closed configuration; a sensor device configured to generate a sensor output responsive to at least one usage characteristic of the hair styling device indicative of a current usage of the hair styling device, the at least one usage characteristic indicative of one or a combination of the following: movement of the hair contact member and whether the hair contact member is in the open configuration or the closed configuration; The method further comprising: receiving the sensor output from the sensor device; processing the sensor output using a classification algorithm configured to determine whether the hair styling device is being used according to a first styling behavior or a second, different styling behavior based on the at least one usage characteristic of the hair styling device to obtain classification data; controlling the heating elements based on said classification data to apply a predetermined heat delivery profile along the hair strand; Including, The predetermined heat delivery profile depends on whether the hair styling device is being used according to the first styling behavior or the second styling behavior.

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