Hair styling device

Abstract

A cordless hair styling device is provided. The device includes a heatable hair contact member having a hair-contactable surface, the hair contact member operable to apply heat to a strand of hair of a user via the hair-contactable surface; at least one sensor configured to sense a change in state of the device from a first, stationary state to a second, moving state; and a controller configured to, in response to the change in state from the first state to the second state sensed by the at least one sensor, cause the hair contact member to heat to a predetermined operating temperature within a predetermined time after detecting the change in state. Also provided is a method of operating a cordless hair styling device and a computer program comprising a set of instructions that, when executed by a computerized device, cause the computerized device to perform the method for facilitating use of the cordless hair styling device.

Description

Technical Field

[0001] The present disclosure relates to a hair styling device. In particular, but not exclusively, the present disclosure relates to means for operating a hair styling device, including a method, an apparatus and a computer program. Background Art

[0002] Hair styling devices, also referred to as hair styling appliances, are used to form hair into a desired shape or style. In particular, heated hair styling devices utilize the effect of heat, and optionally also utilize mechanical means, to style hair in a desired manner.

[0003] An example of such a hair styling device is a hair straightening device (also known as a hair straightener or hair styling iron). Such a hair styling device typically includes two articulated arms pivotally attached to one another at one end, with one or more heatable plates attached to the arms. If both arms include heatable plates, the plates are typically located on opposing interior surfaces of the arms. The heatable plates have hair-contactable surfaces that are operable to contact and apply heat to the hair during use of the hair styling device. The heatable plates (and thus the hair-contactable surfaces) can be heated by one or more heating elements. Curling irons or curling tongs are other examples of hair styling devices. Curling irons can include heatable curved plates or barrels. The outer surface of the heatable plates or barrels can be the hair-contactable surface. Curling irons can also include articulated arms for clamping hair against the hair-contactable surfaces.

[0004] Hair styling devices can be mains-powered or cordless. Cordless devices are popular with users because they allow for greater flexibility and versatility in device usage. Cordless hair styling devices typically include an internal rechargeable battery. The rechargeable battery will power the device for a period of time, referred to as runtime, but between uses, it needs to be recharged by connecting the device or battery to a mains power source. This can be problematic for users, for example, if they plan to use the device for extended periods without access to a charging point. Depending on how the user uses the device, the runtime can vary. This can also be problematic for users, as they may not be able to predict when the device will need to be recharged.

[0005] It would therefore be desirable to provide an improved hair styling device, an improved method of operating a hair styling device, and / or an improved run time of a hair styling device between charges. Summary of the Invention

[0006] According to one aspect of the present invention, there is provided a cordless hair styling device comprising: a heatable hair contact member having a hair-contactable surface, the hair contact member operable to apply heat to a strand of a user's hair via the hair-contactable surface; at least one sensor configured to sense a change in state of the device from a first, stationary state to a second, moving state; and a controller configured to, in response to the change in state from the first state to the second state sensed by the at least one sensor, cause the hair contact member to heat to a predetermined operating temperature within a predetermined time after detecting the change in state.

[0007] In an embodiment, heating of the hair contact member begins only when the user moves the device, and by the time the user begins using the device to style their hair, the device will be at the desired operating temperature. Conventional hair styling devices begin to heat up when turned on and release heat when they come into contact with the hair strands. The controlled heating claimed in the present invention is more efficient and less damaging to the hair. In an embodiment, if the device is turned on but not moved, the controller does not heat the hair contact member, thereby conserving battery energy and improving the device's run time. This is more efficient than, for example, immediately heating the hair contact member to the desired operating temperature when the device is turned on. The device may not be at the desired operating temperature until just before the user begins styling their hair. This can improve the device's run time, as keeping the hair contact member at operating temperature for a longer period of time when the device is not being used to style hair can drain the device's battery more quickly.

[0008] In an embodiment, the controller is configured to cause the hair contacting member to initiate heating when the at least one sensor senses a change in state.

[0009] In an embodiment, the controller causes the hair contact member to immediately begin heating when the sensor senses that the user has moved the device, thereby allowing the hair contact member to gradually heat as the user moves the device towards the roots of their hair to begin styling.

[0010] In an embodiment, the controller is configured to cause the hair contacting member to initiate heating after a predetermined time delay.

[0011] In an embodiment, when the sensor senses that the user has moved the device, the hair contact member initially remains at room temperature, but as the hair contact member approaches the roots of the user's hair, the hair contact member rapidly heats to operating temperature. This further improves the operating time of the device because the hair contact member will remain at room temperature for a longer time before heating.

[0012] In an embodiment, the controller is configured to cause the hair contacting member to heat at a predetermined rate.

[0013] In an embodiment, the predetermined rate is set by the manufacturer and may be based on a predicted time it will take a user to move the device to the roots of their hair. By heating the hair contact member at a predetermined rate, the controller can cause the hair contact member to reach the predetermined operating temperature just before the user begins styling their hair. This avoids the need to maintain the hair contact member at a high temperature when the user is not styling their hair, further improving the device's operating time.

[0014] In an embodiment, the predetermined amount of time; the predetermined rate; the predetermined time delay; and the predetermined operating temperature are initially set as default values.

[0015] In an embodiment, at least one of the predetermined amount of time, the predetermined rate, the predetermined time delay, and the predetermined operating temperature is set by the manufacturer based on a predicted expected user value and / or a known safe value. For example, the predetermined operating temperature may be a known suitable temperature for curling and / or straightening hair. This helps ensure that the device performs well, or optimally, from the first time the user uses it.

[0016] In an embodiment, at least one sensor is configured to output a signal based on movement of the hair styling device, and the controller is configured to: receive the output signal from the at least one sensor, identify one or more user operation parameters associated with how the user operates the device; and based on the one or more identified user parameters, adjust at least one of: a predetermined amount of time; a predetermined rate; a predetermined time delay; and a predetermined operating temperature.

[0017] In an embodiment, a sensor may output a signal indicating that the user is curling or straightening their hair, and the controller may adjust the operating temperature to suit this action. This improves the device's performance and user experience by ensuring the operating temperature is appropriate for the action being performed. This helps avoid damage to the user's hair by ensuring the device is used at the appropriate operating temperature. In an embodiment, the sensor senses that the user is taking significantly longer or shorter time to move the device to the roots of their hair. The controller may adjust the heating rate or, for example, incorporate / add or eliminate / reduce a time delay. This improves the user experience by ensuring the hair contact member is at the desired operating temperature when the user begins styling their hair, and also improves the device's runtime by preventing the hair contact member from remaining at a high temperature for longer than necessary.

[0018] In an embodiment, the controller is configured to identify one or more user operating parameters specific to a plurality of users and to perform the adapting based on the user-specific operating parameters.

[0019] The device can be used by multiple users at different times. Different users may use the device for different styling actions, which may require different operating temperatures and may take different times to move the device to their hair roots. Therefore, it may be appropriate for the controller to heat the device to different temperatures at different rates for different users to improve the user experience and device efficiency. To facilitate this, the controller can identify different operating parameters for different users.

[0020] In an embodiment, the identified one or more user operation parameters include one or more of a temporal parameter; a spatial parameter; and a thermal parameter.

[0021] In an embodiment, the at least one sensor is configured to sense a change in state of the device from a second motion state to a first stationary state, and the controller is configured to disable heating of the hair contact member in response to the at least one sensor sensing the change in state from the second state to the first state, thereby allowing the hair contact member to cool below a predetermined operating temperature. In an embodiment, the at least one sensor is configured to sense when the hair contact member is not in contact with the hair strand, and the controller is configured to disable heating of the hair contact member in response to the at least one sensor sensing the hair contact member is not in contact with the hair strand, thereby allowing the hair contact member to cool below the predetermined operating temperature.

[0022] In one embodiment, a sensor senses when the user has finished styling their hair and has returned the device to a rest state. In response to receiving a signal from the sensor, the controller can stop heating the hair contact member or disable heating of the hair contact member. This ensures that the hair contact member does not remain at an operating temperature for longer than necessary, thereby increasing the device's operating time. In one embodiment, the controller maintains the hair contact member at a standby temperature until the user turns the device off. This ensures that if the user moves the device and wishes to continue styling their hair, the hair contact member can be effectively heated to operating temperature.

[0023] In an embodiment, the at least one sensor comprises a touch sensor configured to sense when a user has picked up the device, and the controller is configured to prevent the hair contact member from being heated to the predetermined operating temperature in response to the touch sensor sensing that the device is not being held by the user.

[0024] In an embodiment, if the device is being moved but the touch sensor senses that the device is not being held by the user, the controller prevents the hair contact member from heating. This provides a safety check, ensuring that if the device is inadvertently moved, for example, if it is knocked off a surface by the user, the hair contact member will not heat to the predetermined operating temperature. In other words, in an embodiment, the hair contact member will only heat to the predetermined operating temperature when the user is using the device to style their hair.

[0025] In an embodiment, the at least one sensor comprises an inertial measurement unit (IMU) sensor configured to sense when the device is in the second mobile state. In an embodiment, the IMU sensor is configured to sense when the device has returned to the first stationary state.

[0026] In an embodiment, the at least one sensor comprises a proximity sensor configured to sense when styling of the hair tress begins, and / or when styling of the hair tress ends.

[0027] In an embodiment, the device comprises at least one further sensor configured to sense one or more environmental conditions, and the controller is configured to heat the hair contact member to a predetermined operating temperature further based on the sensed environmental conditions. In an embodiment, the environmental conditions comprise the temperature and / or humidity of the room in which the device is operated.

[0028] The humidity and / or temperature of the room in which the device is used may affect the appropriate operating temperature of the device. For example, a higher operating temperature may be required under high humidity levels. According to embodiments, by adjusting the predetermined operating temperature based on the ambient conditions in which the device is used, the user experience is improved, ensuring that the hair contact member is at an optimal operating temperature.

[0029] In an embodiment, the predetermined operating temperature is user configurable.

[0030] For example, if a user intends to use the device for different styling activities, they may wish to override the predetermined operating temperature set by the controller. Similarly, if a user intends to use the device for different styling activities, they may wish to override the predetermined heating rate set by the controller. By allowing this option to control the operating characteristics of the device, the user experience can be improved.

[0031] In an embodiment, the device comprises a hair straightener. In an embodiment, the device comprises a hair curler. A user can use the hair straightener for either curling or straightening operations and can use the device in different ways, requiring different operating temperatures and / or heating rates for these different operations.

[0032] In an embodiment, the apparatus comprises a heating element operable to heat the hair contact member, and the controller is configured to control the heating element so that the heating element heats to a predetermined operating temperature within a predetermined amount of time after the change of state is detected.

[0033] In an embodiment, the hair contact member is operable to apply heat to the hair tress via the hair-contactable surface by movement of the contact member along the hair tress between a root end of the hair tress and a tip end of the hair tress.

[0034] According to one aspect of the present disclosure, a method of operating a cordless hair styling device is provided, the method comprising: in response to a user moving the device from a first, resting state to a second, moving state, generating a sensor signal at a controller, processing the sensor signal to determine that the device is in use, and in response to determining that the device is in use, heating a heatable hair contact member to a predetermined operating temperature within a predetermined amount of time after detecting the change in state.

[0035] According to one aspect of the present disclosure, a computer program product is provided comprising a set of instructions that, when executed by a computerized device, cause the computerized device to perform a method of facilitating use of a cordless hair styling device, the method comprising: generating a sensor signal at a controller in response to a user moving the device from a first, resting state to a second, moving state, processing the sensor signal to determine that the device is in use, and in response to determining that the device is in use, heating a heatable hair contacting member to a predetermined operating temperature within a predetermined amount of time after detecting the change in state.

[0036] It will of course be understood that features described with respect to one aspect of the invention may be incorporated into other aspects of the invention. For example, the method of the invention may be incorporated into any features described with reference to the apparatus of the invention, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0038] Figure 1A is a perspective view of a cordless hair styling device according to an embodiment with the arms in an open position;

[0039] Figure 1B According to the embodiment Figure 1A A perspective view of a cordless hair styling device with the arms in a closed position;

[0040] Figure 2 is a schematic diagram of a hair styling device according to an embodiment; and

[0041] Figure 3 is a flow chart illustrating a method of operating a hair styling device according to an embodiment. DETAILED DESCRIPTION

[0042] Figure 1A and 1B A perspective view of a hair styling device 100 according to an embodiment is shown. The hair styling device 100 and / or its components can be used to implement the methods described herein. Figure 1A and 1B In the illustrated embodiment, hair styling device 100 comprises a hair straightener.

[0043] The hair styling device 100 comprises a first arm 110 and a second arm 120 connected together at one end by a hinge 130. The hair styling device 100 comprises a heatable hair contacting member. Figure 1A and 1B In the illustrated embodiment, each arm 110, 120 includes a heatable hair contacting member in the form of a heatable plate 115, 125. In an embodiment, one or both of the heatable plates 115, 125 are heatable, for example, by a heating element (not shown). In some embodiments, one or both of the heatable plates 115, 125 include a resistive plate. Such a resistive plate can be heated directly, for example, without the need for a separate heating element. Each heatable plate 115, 125 is operable to apply heat to a strand of hair of a user via a hair contactable surface 116, 126. Hair contactable surfaces 116, 126 are arranged so that they face each other. In an embodiment, the heatable plates 115, 125 include ceramic or metal plates. In an embodiment, the heatable plates 115, 125 include flat hair contactable surfaces 116, 126. In an embodiment, the heatable plates 115, 125 include curved or concave hair contactable surfaces. The arms 110, 120 are hinged so that they can be opened in an open position (e.g., Figure 1A as shown) and closed position (as shown) Figure 1B In the closed position, hair-contactable surfaces 116, 126 are positioned adjacent to each other so that hair to be styled can be held between hair-contactable surfaces 116, 126. In some embodiments, hair-contactable surfaces 116, 126 come into contact when arms 110, 120 are in the closed position. In other embodiments, hair-contactable surfaces 116, 126 do not contact.

[0044] A user can move arms 110, 120 between an open position and a closed position. For example, when using hair styling device 100, the user presses arms 110, 120 together (to style hair between hair-contactable surfaces 116, 126) and, when styling is complete, releases arms 110, 120 and / or pulls arms 110, 120 apart. In an embodiment, hair styling device 100 includes a biasing device (not shown), such as one or more springs and / or magnets. The biasing device urges arms 110, 120 toward the open position, such that when the user stops pressing arms 110, 120 together, arms 110, 120 return to the open position.

[0045] In an alternative embodiment, the arms 110, 120 cannot pivot about the hinge 130. For example, the arms 110, 120 can be substantially parallel to each other. In either case, the user can press the arms 110, 120 together to style the hair.

[0046] In an embodiment, heatable plates 115, 125 are operable to apply heat to the hair strand via hair-contactable surfaces 116, 126 by movement of heatable plates 115, 125 along the hair strand between the root end of the hair strand and the tip end of the hair strand. In an embodiment, the hair strand can be clamped between the two hair-contactable surfaces 116, 126, and the device can be pulled along the length of the hair strand.

[0047] The hair styling device 100 comprises a cordless hair styling device. For example, in an embodiment, the hair styling device 100 may be powered by a rechargeable battery.

[0048] Figure 2 Shown is a schematic block diagram of a hair styling device 100 according to an embodiment.

[0049] Hair styling device 100 includes a controller 210. Controller 210 is operable to perform various data processing and / or control functions according to embodiments, as described in greater detail below. Controller 210 may include one or more components. These one or more components may be implemented in hardware and / or software. These one or more components may be co-located within hair styling device 100 or remotely located from one another. Controller 210 may be implemented as one or more software functions and / or hardware modules. In embodiments, controller 210 includes one or more processors configured to process instructions and / or data. Operations performed by the one or more processors may be performed by hardware and / or software. Controller 210 may be used to implement the methods described herein. In embodiments, controller 210 is operable to output control signals for controlling one or more components of hair styling device 100.

[0050] In an embodiment, heating the hair contact member 225 comprises supplying power to the hair contact member 225. In an embodiment, the power is supplied to the hair contact member by a rechargeable battery. In an embodiment, heating the hair contact member 225 comprises applying a voltage to the hair contact member 225. In an embodiment, the hair contact member 225 comprises a resistive plate.

[0051] In an embodiment, the hair styling device 100 includes a heating element 220. The heating element 220 is operable, for example, to convert electrical energy into heat. The heating element 220 is configured to cause hair to be heated by the hair styling device 100. The controller 210 is operable to control the heating element 220. For example, the controller 210 is 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.

[0052] The hair styling device includes a heatable hair contact member 225. In an embodiment, the hair contact member 225 can be heated by the heating element 220. In an alternative embodiment, the hair contact member 225 can be heated directly, i.e., without a separate heating element 220. In an embodiment, the hair contact member 225 includes one or more heatable plates. For example, the hair contact member 225 can include the hair contact member 225 described above. Figure 1A and 1B The one or more heatable plates 115, 125 described above may be used as a hair contacting member. Hair contacting member 225 may include one or more hair contactable surfaces, such as hair contactable surfaces 116, 126 described above. Hair contacting member 225 is operable to apply heat to the hair via one or more hair contactable surfaces 116, 126. Thus, controller 210 controls the heating of hair contacting member 225, for example, by controlling heating element 220, which causes heat to be transferred to the hair in contact with the one or more hair contactable surfaces 116, 126 of hair contacting member 225.

[0053] In an embodiment, the hair contacting member 225 includes first and second opposing hair contactable surfaces 116, 126. The first and second opposing hair contactable surfaces 116, 126 are arranged to heat the hair engaged therebetween. In an embodiment, the hair contacting member 225 is operable to apply heat to the hair by movement of the hair contacting member 225 along the hair strand (e.g., from a first end of the hair strand toward a second end of the hair strand). Movement of the hair contacting member 225 along the hair strand may be referred to as a "stroke." The hair contacting member 225 may include a movable arm, such as described above with reference to Figure 1A and 1B A first arm 110 and a second arm 120 are depicted.

[0054] Hair styling device 100 includes at least one sensor 230 configured to sense a change in state of the device from a first, stationary state to a second, moving state. Controller 210 is configured to, in response to the at least one sensor sensing the change in state from the first state to the second state, heat hair contact member 225 to a predetermined operating temperature within a predetermined amount of time after detecting the change in state. In an embodiment, sensing the change in state of the device includes sensing acceleration or displacement of the device.

[0055] In an embodiment, hair styling device 100 includes at least one sensor 230. Examples of such sensors include, but are not limited to, an IMU, a proximity sensor such as a Hall effect sensor, a temperature sensor, a humidity sensor, a power sensor, a proximity sensor, a motion sensor, a gyroscope, an accelerometer, a magnetometer, and the like. Controller 210 is operable to receive a signal (e.g., a sensor output) from at least one sensor 230. The sensor output from at least one sensor 230 can be used to control hair styling device 100. In an embodiment, controller 210 is operable to control at least one sensor 230.

[0056] exist Figure 2 In the illustrated embodiment, at least one sensor 230 includes an IMU 235. In such an embodiment, controller 210 is operable to receive signals from IMU 235 indicative of movement of hair styling device 100. In an embodiment, IMU 235 includes an accelerometer, a gyroscope, and a magnetometer. The accelerometer, gyroscope, and magnetometer each have three axes, or degrees of freedom (x, y, z). Thus, IMU 235 may comprise a 9-axis IMU. In an alternative embodiment, IMU 235 includes an accelerometer and a gyroscope, but no magnetometer. In such an embodiment, IMU 235 comprises a 6-axis IMU. Due to the increased degrees of freedom, a 9-axis IMU may produce more accurate measurements than a 6-axis IMU. However, in certain circumstances, a 6-axis IMU may be superior to a 9-axis IMU. For example, some hair styling devices may induce and / or encounter magnetic interference during use. This may be a particular consideration for wireless hair styling devices that include an onboard power source and hair styling devices that include a heating element. Heating, magnetism and / or magnetic induction and / or other magnetic interference on the device can affect the behavior of the magnetometer. Therefore, 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 indicating accelerometer and gyroscope signals (and in some embodiments, magnetometer signals). In an alternative embodiment, the IMU 235 may include an accelerometer, but not a gyroscope or magnetometer. In such an embodiment, the IMU 235 includes a 3-axis IMU.

[0057] In an embodiment, controller 210 is configured to process the sensor output using a velocity and / or position estimation algorithm. In an embodiment, the velocity / position estimation algorithm incorporates accelerometer / gyroscope signals from an IMU. For example, the velocity and / or position estimation algorithm can be used to determine whether hair contact member 225 has reached the root of a user's hair. In an embodiment using a 9-axis IMU, the velocity and / or position estimation algorithm may also use signals from a magnetometer in addition to the accelerometer / gyroscope signals to determine an initial state. In an embodiment, the velocity and / or position algorithm includes a Madgwick filter. The velocity and / or position estimation algorithm may be implemented using software or hardware (e.g., an application-specific integrated circuit (ASIC)), or a combination of hardware and software. The velocity and / or position estimation algorithm may be used in various methods described herein.

[0058] IMUs can be affected by noise and / or bias and / or drift, which can lead to inaccurate calculations unless properly corrected. For example, gyroscope signals drift over time, and accelerometers may be biased by gravity, both of which are affected by noise. In one embodiment, filters such as high-pass and / or low-pass and / or median filters are used to remove some of the noise from the IMU signals. In one embodiment, 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 the steepest direction, while fusing the accelerometer and gyroscope signals. The output of the Madgwick filter is a world-referenced orientation quaternion, or Madgwick quaternion, which provides the device's orientation. This quaternion is used to rotate the acceleration signal to a world / Earth coordinate system. Once the acceleration is rotated, the gravity ratio on each axis is calculated and removed. This gives a linear / kinematic acceleration, which is integrated to obtain velocity, and the integrated velocity is then used to obtain position. Each time the signal is integrated, the residual error caused by this bias and / or drift increases. Therefore, this error can be particularly problematic for velocity or position measurements. Compensating for velocity drift before integrating velocity to obtain position improves the accuracy of the measurement. Velocity and position measurements can be made individually for all three axes or combined into velocity magnitude and position magnitude.

[0059] In other embodiments, alternative filters may be used in place of or in addition to the Madgwick filter. Examples of such filters include Kalman filters, extended Kalman filters, and / or complementary filters such as Mahony filters. However, the Madgwick filter is computationally less expensive than other filters while achieving comparable, or in some cases, better, levels of accuracy. This allows the Madgwick filter to be run on the hair styling device 100 itself, without the need for external processing. This reduces latency compared to performing processing on externally processed data, as the need to transfer data between devices is avoided.

[0060] In embodiments, speed can be determined by processing one or more signals from a 3-axis IMU. As described above, in such embodiments, heating of hair contact member 225 is controlled based on the determined speed. In embodiments, heating of hair contact member 225 is controlled such that the operating temperature of hair contact member 225 changes (e.g., increases) at a rate that depends on the determined speed. In other words, the rate of change of temperature of hair contact member 225 can depend on the speed at which hair contact member 225 moves. For example, if hair contact member 225 is determined to be moving relatively quickly, the rate of temperature increase (or "temperature slope") can be relatively steep, whereas if hair contact member 225 is determined to be moving relatively slowly, the rate of temperature increase can be relatively gradual. This allows for more refined control over heat distribution along the hair strand and / or enables hair styling device 100 to adapt to the user's behavior. In embodiments, the heat transfer profile along the hair strand depends on the determined speed.

[0061] In an embodiment, the sensor output is processed using a velocity and / or position estimation algorithm, such as a machine learning model. In an embodiment, a 3-axis IMU including an accelerometer is used in conjunction with the machine learning model. For example, determining that the hair contact member 225 is moving along the hair strand, determining the displacement of the hair contact member 225 from the first end, and / or determining the velocity of the hair contact member 225 can be performed using the machine learning model.

[0062] In embodiments using a 3-axis IMU, the machine learning model can use signals from the 3-axis IMU to determine an initial state. In embodiments, the machine learning model has been trained using a generalized nonlinear regression algorithm (e.g., Gaussian kernel regression and a neural network). The training data for the machine learning model uses previously used 3-axis IMU data from the hair styling device 100, as well as target data from a ground truth source (e.g., a Vicon motion capture system). It should be understood that alternative systems can be used to capture target data from the ground truth source. The machine learning model can be implemented using software or hardware (e.g., an application specific integrated circuit (ASIC)), or a combination of hardware and software. The machine learning model can be used in various methods described herein.

[0063] As described above, an IMU (e.g., a 3-axis IMU) may be subject to noise, bias, and / or drift, which may result in inaccurate calculations unless properly corrected. For example, an accelerometer may be biased by gravity, and the accelerometer signal may be affected by noise. In embodiments, filtering (e.g., a high-pass and / or low-pass and / or median filter) is used to remove at least some of the noise from the accelerometer signal.

[0064] In an embodiment, 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 of gravity on the single signal output is then calculated and subtracted from the signal output to give the acceleration magnitude.

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

[0066] The machine learning model described above is used to correct for noise, bias, and drift, such as velocity drift, by simultaneously converting acceleration magnitudes to velocity magnitudes using the machine learning model trained as described above. In an embodiment, the machine learning model is trained using velocity magnitude ground truth data and motion acceleration magnitude training data from previous uses of the hair styling device and from a ground truth source, such as a Vicon motion capture system.

[0067] In an embodiment, a sliding window algorithm is used to generate input data for the machine learning model, and in a preferred embodiment, the input data consists of twenty sample points at a time. In doing so, the machine learning model compensates for drift in the 20th sample point of the calculated velocity, having considered that sample point and the first 19 sample points of the motion acceleration magnitude input data. However, it should be understood that a different number of sample points can be used as input data for 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 3-axis IMU. The three signal outputs are then processed separately. The ratio of the force on each signal is then calculated and subtracted from each signal output to give three acceleration values (acceleration values for each axis). The previously trained machine learning model as described above is then applied separately to each acceleration magnitude. Similarly, a sliding window algorithm can be applied to generate the input to the machine learning model. In other words, the machine learning model and the sliding window algorithm can be applied separately to each axis.

[0069] In an embodiment, the velocity is integrated to obtain the position and / or displacement. Since the drift is already compensated in the calculated velocity, the position and / or displacement can be determined more accurately.

[0070] Therefore, a machine learning model combined with a 3-axis IMU can be used to compensate for velocity drift and determine the velocity, position and / or displacement of the hair styling device.

[0071] In embodiments, hair styling device 100 includes a user interface 240 to facilitate efficient and easy user interaction with device 100. For example, user interface 240 may include an audio and / or visual interface. In embodiments, user interface 240 includes a display (e.g., a touch screen display). In embodiments, user interface 240 includes an audio output device, such as a speaker. Controller 210 is operable to control user interface 240, e.g., causing user interface 240 to provide output to the user. In some embodiments, controller 210 is operable to receive data via user interface 240, e.g., based on user input.

[0072] In an embodiment, hair styling device 100 further includes memory 250. Depending on the embodiment, memory 250 is operable to store various data. The memory may include at least one volatile memory, at least one non-volatile memory, and / or at least one data storage unit. The volatile memory, non-volatile memory, and / or data storage unit may be configured to store computer-readable information and / or instructions for use / execution by controller 210. Memory 250 may store data specific to a single user, or data for multiple different users, thereby improving the user experience when using device 100.

[0073] In alternative embodiments, hair styling device 100 may include more, fewer, and / or different components. In particular, in some embodiments, Figure 1A 、 1B and / or Figure 2At least some components of the illustrated hair styling device 100 may be omitted (e.g., may not be required). For example, in some embodiments, at least one of the heating element 220, the closing mechanism 227, 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.

[0074] In an embodiment, controller 210 is configured to cause hair contact member 225 to begin heating when at least one sensor 225 senses a change in state. In an embodiment, hair contact member 225 begins heating immediately when at least one sensor 230 senses a change in state. In an embodiment, controller 210 is configured to cause hair contact member 225 to begin heating after a predetermined time delay. In an embodiment, the time delay is up to about 2 seconds, for example, about 0.5 seconds.

[0075] In an embodiment, controller 210 is configured to heat hair contact member 225 at a predetermined rate. In an embodiment, the predetermined rate is between approximately 10°C / s and 40°C / s, for example, approximately 20°C / s. In an embodiment, hair contact member 225 is heated to a predetermined operating temperature between approximately 160°C and 210°C, for example, approximately 185°C.

[0076] In an embodiment, the predetermined amount of time; the predetermined rate; the predetermined time delay; and the predetermined operating temperature are initially set to default values. In an embodiment, at least one of the predetermined rate, the predetermined time delay, or the predetermined operating temperature is initially set by the manufacturer. In an embodiment, at least one of the predetermined rate, the predetermined time delay, or the predetermined operating temperature is user-configurable. In an embodiment, for example, if a user wishes to override the default value set by the manufacturer, they may use a user interface to input and adjust the predetermined rate, the predetermined time delay, or the predetermined operating temperature.

[0077] In an embodiment, at least one sensor 230 is configured to output a signal based on the movement of hair styling device 100, and controller 210 is configured to: receive the output signal from the at least one sensor 230, identify one or more user operating parameters associated with how the user operates the device; and, based on the one or more identified user parameters, adjust at least one of the following: a predetermined amount of time; a predetermined rate; a predetermined time delay; and a predetermined operating temperature. This improves the user's experience by, for example, ensuring that device 100 has reached the appropriate operating temperature when they begin styling their hair, and ensuring that the operating temperature is appropriate for the styling action they are performing. This can also improve the run time of device 100 by preventing device 100 from remaining at operating temperature for longer than necessary.

[0078] In an embodiment, the output signal provides an indication of whether the device 100 is being used to curl or straighten hair. In an embodiment, a user operating parameter provides an indication of the type of styling being performed. In an embodiment, the controller 210 adapts the operating temperature based on the type of styling being performed by heating or cooling the hair contact member 225 to different temperatures. This can prevent users from damaging their hair due to using inappropriate operating temperatures and can help improve device performance. In an embodiment, the output signal provides an indication of the length of time the user spends styling a hair strand. In an embodiment, the output signal provides an indication of the time between the user picking up the device 100 and beginning to style the hair strand. In an embodiment, the controller 210 identifies a time parameter indicating the time between the user picking up the device and beginning to style the hair strand. In an embodiment, the controller 210 stores the time parameter for future use. In an embodiment, the controller adapts the predetermined speed and / or predetermined operating temperature based on the time between the user picking up the device and beginning to style the hair strand. In an embodiment, the output signal provides an indication of the length of time the hair contact member 225 is in contact with the hair strand and / or the speed at which the hair contact member 225 moves along the hair strand. In an embodiment, controller 210 adapts the predetermined operating temperature based on the length of time hair contact member 225 is in contact with the hair strand and / or the speed at which hair contact member 225 is moved along the hair strand.

[0079] In an embodiment, the controller 210 is configured to identify one or more user operating parameters specific to multiple users and perform adaptation based on the user-specific operating parameters. This allows multiple different users to use the device 100 while ensuring that the device will operate effectively for each of them. In an embodiment, the device 100 receives input from a user indicating their identity. In an embodiment, at least one sensor 230 outputs a signal indicating the user's identity. In an embodiment, the controller 210 receives a signal indicating the user's identity from the at least one sensor 230 and identifies parameters associated with the user. In an embodiment, the controller 210 identifies a user-specific time parameter indicating the time between the user picking up the device 100 and starting styling. In an embodiment, the controller 210 stores the user-specific time parameter for future use.

[0080] In an embodiment, the user interface 240 enables a user to input their identity. In response thereto, in an embodiment, the controller 210 adjusts the operating temperature and / or heating rate based on known user-specific time parameters associated with that user.

[0081] In an embodiment, device 100 is wirelessly connected to a user's electronic device, and device 100 may receive input from the user via the electronic device indicating their identity.

[0082] In an embodiment, the identified one or more user operation parameters include one or more of a temporal parameter; a spatial parameter; and a thermal parameter.

[0083] In an embodiment, at least one sensor 230 is configured to sense a change in state of the device 100 from the second, mobile state to the first, stationary state, and the controller 210 is configured to disable heating of the hair contact member 225 in response to the at least one sensor 230 sensing the change in state from the second state to the first state, thereby allowing the hair contact member 225 to cool below a predetermined operating temperature.

[0084] In an embodiment, disabling heating of the hair contact member 225 includes preventing power from being supplied to the hair contact member 225. In an embodiment, disabling heating of the hair contact member 225 includes preventing power from being supplied to the heating element. In an embodiment, the hair contact member 225 cools to a standby temperature. In an embodiment, the controller maintains the hair contact member 225 at the standby temperature. The standby temperature may be between approximately 50°C and 150°C. In an embodiment, the hair contact member 225 may cool to room temperature.

[0085] exist Figure 2 In the illustrated embodiment, the at least one sensor 230 includes a touch sensor 237 configured to sense when a user picks up the device, and the controller 210 is configured to prevent the hair contact member from being heated to a predetermined operating temperature in response to the touch sensor 237 sensing that the device is not being held by the user. Figure 2 In the illustrated embodiment, the at least one sensor includes a proximity sensor 236 that is configured to sense when a trip begins and ends.

[0086] In an embodiment, the device 100 includes at least one other sensor configured to sense one or more environmental conditions, and the controller 210 is configured to heat the hair contact member 225 to a predetermined operating temperature further based on the sensed environmental conditions. In an embodiment, the controller 210 receives a signal from the at least one other sensor 239 that provides an indication of the one or more environmental conditions. In an embodiment, the controller 210 adapts the predetermined operating temperature and / or the predetermined heating rate based on the one or more environmental conditions. Figure 2 In the illustrated embodiment, the apparatus 100 includes a temperature sensor 239, and the temperature sensor 239 outputs a signal that provides an indication of the temperature in the room in which the apparatus 100 is operating. In an embodiment, the controller 210 receives the signal that provides an indication of the temperature of the room in which the apparatus 100 is operating and adapts the predetermined operating temperature and / or the predetermined rate based on the room temperature.

[0087] In an embodiment, the device 100 includes a humidity sensor, and the humidity sensor outputs a signal that provides an indication of the humidity level of the room in which the device is operating. In an embodiment, the controller 210 receives the signal that provides an indication of the humidity level of the room in which the device is operating and adapts the predetermined operating temperature and / or the predetermined rate based on the humidity level.

[0088] In embodiments, device 100 is configured to receive input from a user. In embodiments, a user may input a desired operating temperature using user interface 240 or using an electronic device wirelessly connected to hair styling device 100. In embodiments, a user may input a desired heating rate. In embodiments, a user may input a desired styling action, and in response to the input, controller 210 may change the operating temperature and / or heating rate. In embodiments, the user input may override the predetermined operating temperature and / or heating rate.

[0089] In an embodiment, a user may input an indication of their identity using the user interface 240 or a wirelessly connected electronic device, and in response to the indication, the controller 210 may adjust the operating temperature and / or heating rate based on known parameters associated with the user.

[0090] In an embodiment, the device 100 may receive input from the user indicating their identity via the user interface 240 or a wirelessly connected electronic device. In an embodiment, the controller 210 associates the user's identity with stored parameters related to the user and the controller may change the operating temperature and / or heating rate.

[0091] In one embodiment, device 100 comprises a hair curler. In other embodiments, the hair curler comprises a curved plate or barrel. The hair curler may include a hair-contacting member in the form of a heatable barrel or curved plate, the member comprising a hair-contacting surface. The hair-contacting surface may be a curved surface of ceramic or metal. The hair-contacting surface may be the outer surface of the heatable barrel or curved plate. In one embodiment, the hair curler comprises an articulated arm for clamping a hair bundle to the hair-contacting surface. In one embodiment, the hair bundle may be wrapped around the hair-contacting surface.

[0092] Figure 3 A method 300 of operating a hair styling device according to an embodiment is shown. The method 300 may be used to operate the hair styling device described above with reference to Figure 1A 、 1B and Figure 2 The hair styling device 100 is described. Figure 3In an embodiment, hair styling device 100 includes a heatable hair contacting member 225 having hair-contactable surfaces 116, 126. Hair contacting member 225 is operable to apply heat to a user's hair strand via hair-contactable surfaces 116, 126. In an embodiment, method 300 is performed at least in part by controller 210.

[0093] In response to a user moving the device from a first, resting state to a second, moving state, a sensor 230 signal is generated in step 310. In step 320, at controller 210, the sensor 230 signal is processed to determine that device 100 is in use. In step 330, in response to determining that the device is in use, the heatable hair contacting member 225 is heated to a predetermined operating temperature within a predetermined amount of time after the change in state is detected.

[0094] In an embodiment, the predetermined operating temperature and the predetermined amount of time are default settings set by the manufacturer upon first use of the device. In an embodiment, when a user uses the device 100 to style their hair, the controller 210 receives a signal from the IMU sensor 235 indicating a time parameter associated with the user. In an embodiment, for a given user, the time parameter indicates the time or average time between the user moving the device 100 and beginning to style their hair. In an embodiment, the controller 210 adapts the predetermined amount of time or heating rate based on this parameter.

[0095] In an embodiment, the controller 210 receives a sensor signal from the IMU 235 sensor indicating that the device 100 is moving. In an embodiment, the controller 210 also receives a signal from the touch sensor 237 indicating that the device 100 is being held by a user. In an embodiment, if the controller 210 receives a signal from the IMU sensor 235 indicating that the device 100 is moving, but the touch sensor 235 indicates that the device 100 is not being held by a user, the heatable hair contacting member 225 is not heated.

[0096] In an embodiment, when a user begins styling their hair using device 100, the IMU 235 sensor outputs a signal indicating that the user is using device 100 and indicating a styling action. Controller 210 receives the sensor signal from the IMU 235 sensor and supplies power to the heatable hair contact member 225. In an embodiment, the heatable hair contact member is heated to a temperature suitable for the styling action. In an embodiment, the IMU sensor 235 also outputs a second signal indicating the time between the user moving the device and the start of styling. In an embodiment, the proximity sensor 236 outputs a third signal indicating that a stroke has begun. In an embodiment, controller 210 receives the second signal and identifies the user's time parameter. In an embodiment, the controller receives the third signal and uses it to identify the user's time parameter. In an embodiment, controller 210 stores the time parameter for future reference. In an embodiment, controller 210 adapts the heating rate of the heating element in response to the time parameter.

[0097] In an embodiment, when a stroke is completed, the controller 210 receives a signal from the proximity sensor 236 indicating that the hair contact member 225 is no longer in contact with the hair strand. In an embodiment, when the user finishes styling their hair and sets the device down, the IMU sensor 235 senses that the hair straightener 100 has returned to the first resting state. The controller 210 receives a signal from the IMU sensor 235 indicating that the hair straightener 100 has returned to the resting state. In an embodiment, in response to receiving the signal from the IMU sensor 235, the controller 210 stops supplying power to the heated hair contact member 225, and the heated hair contact member 225 cools down. In an embodiment, in response to receiving the signal from the proximity sensor 236, the controller 210 stops supplying power to the heated hair contact member 225, and the heated hair contact member 225 cools down. In an embodiment, the heated hair contact member 225 cools down to room temperature.

[0098] In an embodiment, the controller 210 also receives a signal from the temperature sensor 239 indicating the current temperature of the room in which the device 100 is used. In an embodiment, the controller 100 also receives a signal from the humidity sensor indicating the humidity level of the room. In an embodiment, the controller 210 adapts the operating temperature and heating rate based on the indoor temperature and / or humidity level.

[0099] In an embodiment, the next time the user begins styling their hair using device 100, controller 210 uses the stored time parameters to cause the heatable hair contact element 255 to heat at a rate appropriate for the user, rather than the default rate. In an embodiment, if IMU sensor 235 senses that the user is using the device to perform a different styling action (e.g., curling rather than heating), controller 210 receives a signal from IMU sensor 235 and causes the heatable hair contact element 225 to heat or cool to a different operating temperature appropriate for the styling action. In an embodiment, IMU sensor 235 senses the time between the user moving device 100 and beginning to style their hair using a new styling action. In an embodiment, IMU sensor 235 outputs a new signal to controller 210. In an embodiment, if controller 210 determines that the user spent a different amount of time between picking up device 100 and beginning to style their hair using a different styling action, controller 210 identifies a second parameter associated with the user when the user uses the different styling action. In an embodiment, this second parameter is stored by controller 210 for future use.

[0100] In an embodiment, before starting to style hair using device 100, the user enters their identity using user interface 240. In an embodiment, while the user uses device 100 to style their hair, controller 210 receives a signal from IMU sensor 235 indicating the time or average time between the user moving device 100 and starting to style their hair. In an embodiment, controller 210 identifies the time parameters of the identified user. In an embodiment, controller 210 stores the parameters for future use.

[0101] In an embodiment, if a second, different user will use device 100 to style their hair, they enter their identity using user interface 240 before beginning styling. In an embodiment, if IMU sensor 235 senses that the second user spent a different amount of time between moving the device and beginning to style their hair, IMU sensor 235 outputs a second signal to the controller. In an embodiment, the controller identifies a different, second time parameter associated with the second user. In an embodiment, this second parameter is stored for future use.

[0102] In an embodiment, if either the first or second user uses the device 100 to style their hair on a future occasion, before beginning styling, they may input their identity into the device 100 using the user interface 240. In an embodiment, if the controller 210 recognizes that the user is a known user, and if the controller 210 has stored parameters associated with the user, the controller 210 uses the identified time parameters associated with the user to adjust the heating rate of the heatable plates to suit the user.

[0103] In embodiments of the present disclosure, hair styling device 100 includes a controller 210. Controller 210 is configured to perform the various methods described herein. In embodiments, the controller includes a processing system. Such a processing system may include one or more processors and / or memory. Each device, component, or functionality described with respect to any of the examples described herein, such as at least one sensor 230 or user interface 240, may similarly include a processor or may be included in a device that includes a processor. One or more aspects of the embodiments described herein include processes performed by a device. In some examples, the device includes one or more processors configured to perform these processes. In this regard, embodiments may be implemented at least in part by computer software stored in (non-transitory) memory and executable by a processor, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware). Embodiments also extend to computer programs, particularly computer programs on or in a carrier, suitable for implementing the above-described embodiments. 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 processes according to the embodiments. The carrier may be any entity or device capable of carrying the program, such as RAM, ROM, or optical storage devices.

[0104] The one or more processors of the processing system may include a central processing unit (CPU). The one or more processors may include a graphics processing unit (GPU). The one or more processors may include 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 include 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 include multiple co-located processors or multiple differently located processors. The operations performed by the one or more processors may be performed by one or more of hardware, firmware, and software. It should be understood that the processing system may include more, fewer, and / or different components than described.

[0105] The techniques described herein can be implemented in software or hardware, or can be implemented using a combination of software and hardware. They can include configuration devices to perform and / or support any or all of the techniques described herein. Although at least some aspects of the examples described herein with reference to the accompanying drawings include computer processes executed in a processing system or processor, the examples described herein also extend to computer programs, such as computer programs on or in a carrier, which are suitable for putting the examples into practice. The carrier can be any entity or device capable of carrying a program. The carrier can include a computer-readable storage medium. Examples of tangible computer-readable 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.

[0106] Where in the foregoing description, reference is made to integers or elements that have known, obvious or foreseeable equivalents, such equivalents are incorporated herein as if individually set forth. Reference should be made to the claims to determine the true scope of the present disclosure, which should be interpreted as encompassing any such equivalents. The reader will also understand that integers or features of the present disclosure that are described as preferred, advantageous, convenient, etc. are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that such optional integers or features, while potentially beneficial in some embodiments of the present disclosure, may be undesirable in other embodiments and, therefore, may not be present.

Claims

1. A cordless hair styling device, comprising: a heatable hair contacting member having a hair contactable surface, the hair contacting member being operable to apply heat to a hair strand of a user via the hair contactable surface; at least one sensor configured to sense a change in state of the device from a first stationary state to a second moving state; and A controller is configured to, in response to the at least one sensor sensing a change in state from a first state to a second state, heat the hair contacting member to a predetermined operating temperature within a predetermined amount of time after detecting the change in state.

2. The cordless hair styling device of claim 1, wherein The controller is configured to cause the hair contacting member to initiate heating when the at least one sensor senses the change in state.

3. The cordless hair styling device of claim 1 , wherein: The controller is configured to cause the hair contacting member to initiate heating after a predetermined time delay.

4. A cordless hair styling appliance according to any one of the preceding claims, wherein The controller is configured to cause the hair contacting member to heat at a predetermined rate.

5. A cordless hair styling appliance according to any one of the preceding claims, wherein At least one of the following: the amount of time scheduled; Predetermined rate; Delays in scheduled times; and Expected operating temperature Initially set to the default value.

6. A cordless hair styling appliance according to any one of the preceding claims, wherein The at least one sensor is configured to output a signal based on movement of the hair styling device, wherein the controller is configured to: receiving an output signal from the at least one sensor, identifying one or more user operation parameters associated with how the user operates the device; and Based on one or more identified user operation parameters, adapt at least one of the following: the amount of time scheduled; Predetermined rate; Delays in scheduled times; and Intended operating temperature.

7. The cordless hair styling device of claim 6, wherein: The controller is configured to identify one or more user operating parameters specific to a plurality of users, and wherein the adapting is performed based on the user-specific operating parameters.

8. A cordless hair styling device according to claim 6 or 7, wherein The one or more user operation parameters identified include one or more of the following: Time parameters; spatial parameters; and Thermal parameters.

9. A cordless hair styling appliance according to any preceding claim, wherein: The at least one sensor is configured to sense a change in state of the device from a second moving state to a first stationary state, and wherein The controller is configured to disable heating of the hair contacting member in response to the at least one sensor sensing a change in state from the second state to the first state, thereby allowing the heating element to cool below a predetermined operating temperature.

10. A cordless hair styling appliance according to any preceding claim, wherein The at least one sensor includes a touch sensor configured to sense when a user picks up the device, wherein the controller is configured to prevent the hair contact member from heating to a predetermined operating temperature in response to the touch sensor sensing that the device is not being held by the user.

11. A cordless hair styling appliance according to any one of the preceding claims, wherein The at least one sensor includes an inertial measurement unit (IMU) sensor configured to sense when the device is in a second movement state.

12. A cordless hair styling appliance according to any preceding claim, comprising at least one further sensor configured to sense one or more environmental conditions, and wherein The controller is configured to heat the hair contacting member to a predetermined operating temperature further based on the sensed environmental condition.

13. The cordless hair styling device of claim 12, wherein The environmental conditions include the temperature and / or humidity of the room in which the device is operated.

14. A cordless hair styling appliance according to any preceding claim, wherein The predetermined operating temperature is user configurable.

15. A cordless hair styling appliance according to any preceding claim, wherein The device comprises a hair straightener.

16. A cordless hair styling appliance according to any preceding claim, wherein The device comprises a hair curler.

17. A hair styling device according to any one of the preceding claims, in, The hair styling device comprises a heating element operable to heat the hair contacting member, and Wherein the controller is configured to control the heating element so that the heating element is heated to a predetermined operating temperature within a predetermined amount of time after the change in state is detected.

18. A cordless hair styling appliance according to any preceding claim, wherein The hair contacting member is operable to apply heat to the hair strand via the hair-contactable surface by movement of the contacting member along the hair strand between a root end of the hair strand and a tip end of the hair strand.

19. A method of operating a cordless hair styling appliance, the method comprising: generating a sensor signal in response to a user moving the device from a first stationary state to a second moving state; At the controller, processing the sensor signal to determine that the device is in use, and In response to determining that the device is in use, the heatable hair contacting member is heated to a predetermined operating temperature within a predetermined amount of time after detecting the change in state.

20. A computer program comprising a set of instructions which, when executed by a computerized device, cause the computerized device to perform a method of facilitating use of a cordless hair styling device, the method comprising: generating a sensor signal in response to a user moving the device from a first stationary state to a second moving state; processing, at a controller, the sensor signal to determine that the device is in use; and In response to determining that the device is in use, the heatable hair contacting member is heated to a predetermined operating temperature within a predetermined amount of time after detecting the change in state.

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