Monitoring the use of hair-cutting devices

Abstract

According to one aspect, there is provided a computer-implemented method 100 for monitoring usage of a cutting element of a hair-cutting device comprising receiving (102) pressure data indicative of pressure applied to a surface by a cutting element of the hair-cutting device at intervals during a cutting event; storing (104) the received pressure data in a storage device; estimating (106) a wear level of the cutting element based on the pressure data stored in the storage device associated with the cutting event and pressure data stored in the storage device associated with one or more previous cutting events; and providing (108) an indication of the estimated wear level for presentation to a recipient.

Description

[Technical field]

[0001] The present invention relates to monitoring the use of a hair-cutting device, and more particularly to monitoring the use of a cutting element of a hair-cutting device. [Background technology]

[0002] Personal care devices, such as hair-cutting devices, are used to perform personal care functions such as shaving, cutting or trimming hair. Such devices typically include a body portion that is gripped by a user during use and a cutting element, e.g., including one or more blades, for cutting a subject's hair during use.

[0003] As a hair-cutting device is used, its cutting element or some parts thereof (e.g., blades) wear and therefore become less effective. A worn or dull cutting element will not cut hair as effectively as a new cutting element, and in some cases, a worn cutting element may pose a safety risk to the user, for example if the blades become jagged.

[0004] US Pat. No. 8,122,606 discloses an electric wet razor device having an electronic structure that tracks remaining shaving utility based on expected utility and tracked utility.

[0005] US Patent Application Publication No. 2008 / 0172880 discusses an electric wet shaving razor that provides a usage signal indicative of cartridge usage.

[0006] It can therefore be useful to know when the cutting element of a hair-cutting device is becoming worn. Although visual inspection is one way of determining the extent to which the cutting element is worn, this may not be a reliable method, especially if the cutting element is hidden or obscured from view by another component of the hair-cutting device. Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, there is a need for a method for determining the approximate degree of wear of a cutting element of a hair-cutting device that does not require visual inspection. [Means for solving the problem]

[0008] To ensure that the hair-cutting device operates as intended and / or in the intended manner, it is useful to be able to monitor use of the cutting element of the hair-cutting device so that the cutting element and / or hair-cutting device can be replaced if it is determined that the cutting element has worn through use to such an extent that it is unlikely to function as effectively as intended.

[0009] Various metrics can be monitored to determine wear of the cutting element of a hair-cutting device. The inventors of the present application have recognized that a particularly useful metric that can be monitored is the pressure applied by the cutting element to a surface (e.g., a subject's skin) during use. In general, a cutting element that is applied to a user's skin with a relatively high force or pressure may wear out faster than a cutting element that is applied to a user's skin with a relatively low force or pressure. Thus, a cutting element that is applied with a relatively high force may need to be replaced sooner than a cutting element that is applied with a relatively low force. In the embodiments disclosed herein, the pressure applied by the cutting element to a subject's surface (e.g., a subject's skin) during use is monitored over time and used to estimate the amount of wear of the cutting element. Thus, this is used to estimate when the cutting element should be replaced or disposed of.

[0010] According to a first particular aspect, there is provided a computer-implemented method for monitoring usage of a cutting element of a hair-cutting device, the computer-implemented method comprising receiving pressure data indicative of pressure applied to a surface by a cutting element of the hair-cutting device at intervals during a cutting event, storing the received pressure data in a storage device, estimating a wear level of the cutting element based on the pressure data stored in the storage device in association with the cutting event and pressure data stored in the storage device in association with one or more previous cutting events, and providing an indication of the estimated wear level for presentation to a recipient.

[0011] Estimating the wear level of the cutting element includes determining a total pressure applied by the cutting element to the surface from a defined starting point based on a summation or numerical integration of stored pressure data associated with the cutting event and stored pressure data associated with one or more previous cutting events, and estimating the wear level based on the calculated summation or integration pressure data.

[0012] The method further includes generating an alert signal for delivery to a recipient in response to determining that the estimated wear level meets a defined threshold condition.

[0013] The received data, in some embodiments, includes data obtained from a pressure sensor configured to measure the pressure applied to the surface by a cutting element of the hair-cutting device at intervals during the cutting event.

[0014] In some embodiments, the method further comprises receiving, at intervals during the cutting event, current data indicative of a current across a motor driving a cutting element of the hair-cutting device, wherein estimating a wear level of the cutting element is further based on the received current data.

[0015] The method further includes applying a low pass filter to the received current data.

[0016] In some embodiments, the method further includes determining a total duration that the cutting element was used during the cutting event based on the pressure data stored in the storage device associated with the cutting event and the pressure data stored in the storage device associated with one or more previous cutting events. Estimating a wear level of the cutting element is further based on the determined total duration.

[0017] In some embodiments, estimating the wear level of the cutting element comprises determining a probability that the cutting element will wear to such an extent that the cutting element should be replaced.

[0018] According to a second aspect, there is provided a computer program product comprising a non-transitory computer readable medium having computer readable code embedded therein, the computer readable code being configured, when executed by a suitable computer or processor, to cause the computer or processor to perform the steps of a method disclosed herein.

[0019] According to a third aspect, there is provided a hair cutting device comprising a cutting element configured to cut hair growing from a surface of a subject, a pressure sensor configured to measure pressure applied by the cutting element to the surface of the subject during a hair-cutting event, and a processor, wherein the processor provides data indicative of the pressure for storage in a storage device, estimates a wear level of the cutting element based on pressure data stored in the storage device in association with the cutting event and pressure data stored in the storage device in association with one or more previous cutting events, and provides an indication of the estimated wear level for presentation to a recipient.

[0020] The processor is configured to determine a total pressure applied by the cutting element to the surface from a defined starting point based on a summation or numerical integration of the stored pressure data associated with the cutting event and the stored pressure data associated with one or more previous cutting events, and the processor is configured to estimate a wear level based on the calculated summation or integration pressure data.

[0021] In some embodiments, the hair-cutting device further comprises a current measurement unit configured to measure a current across a motor driving a cutting element of the hair-cutting device, the processor being configured to estimate a wear level of the cutting element further based on current data measured with the current measurement unit.

[0022] In some embodiments, the processor is configured to determine a total duration that the cutting element was used during the cutting event based on the pressure data stored in the storage device associated with the cutting event and the pressure data stored in the storage device associated with one or more previous cutting events, and to estimate a wear level of the cutting element further based on the determined total duration.

[0023] The hair-cutting device in some embodiments further comprises a communications unit, the processor being configured to provide data indicative of the measured pressure for storage in the storage device by transmitting the data to a storage device remote to the hair-cutting device using the communications unit.

[0024] The hair-cutting device further comprises a filter component configured to filter the data indicative of the pressure before the processor estimates the wear level.

[0025] These and other aspects will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0026] Exemplary embodiments will now be described, by way of example only, with reference to the following drawings: [Brief description of the drawings]

[0027] [Figure 1] 1 is a flow chart of an example of a method for monitoring the use of a cutting element. [Diagram 2] 13 is a flow chart of a further example method for monitoring use of a cutting element. [Diagram 3] 1 shows two graphs of exemplary data obtained regarding a hair cutting event. [Figure 4] 1 is a schematic illustration of an example of a processor in communication with a computer-readable medium. [Diagram 5] FIG. 1 is a schematic diagram of an example of a hair-cutting device. [Figure 6] 4 is a schematic illustration of a further example of a hair-cutting device; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Various embodiments disclosed herein provide mechanisms for monitoring the use of a cutting element of a hair-cutting device to enable a determination or estimation of the degree of wear of the cutting element. The embodiments use measurements of the pressure applied by the cutting element of the hair-cutting device to the surface of the subject's skin while the hair-cutting device is in use. As discussed below, the pressure measurements are supplemented with other data in some instances to provide an even more thorough estimation of the wear of the cutting element.

[0029] Some embodiments are described in the context of a hair-cutting device, which is intended to include any personal care device having a cutting element capable of cutting a subject's hair, including, for example, shavers, clippers, hair trimmers, etc. In some embodiments, the cutting element of the hair-cutting device is removable (e.g., separable from a body portion of the hair-cutting device) so that the cutting element can be replaced with a newer, less worn cutting element.

[0030] A first aspect of the present invention provides a method. Referring now to the drawings, FIG. 1 is a flow chart of an example of a method 100. The method 100, including a computer-implemented method, may be considered to be a method of monitoring the use of a cutting element of a hair-cutting device. The method 100 may be performed, for example, using one or more processors. The method 100 comprises, at step 102, receiving pressure data indicative of a pressure applied to a surface by a cutting element of the hair-cutting device at intervals during a cutting event. The hair-cutting device is, for example, held by a user in use, and the cutting element of the hair-cutting device is positioned to contact or engage a surface, such as the user's skin or some surface of a subject. The hair-cutting device may be used to cut, trim, shave or otherwise remove hair from a surface (e.g., skin) of a subject. As such, the cutting element may, in some examples, include one or more blades or other components capable of cutting hair.

[0031] In the context of the present disclosure, a "cutting event" may be considered as a treatment session or cutting session during which a hair-cutting device is used to cut hair over a period of time. For example, a single cutting event may be considered as starting when the hair-cutting device is switched on and ending when the hair-cutting device is switched off. In other examples, a cutting event may be defined differently. For example, a single cutting event may be considered as starting when the cutting element engages the surface and ending when the cutting element is detached from the surface.

[0032] At intervals during the cutting event, pressure data indicative of the pressure applied by the cutting element to the surface is received. As will be apparent from the discussion below, the pressure data may be obtained in a variety of ways, including through the use of one or more pressure or force sensors. A further indication of the pressure applied by the cutting element to the surface is determined by a measurement of the current across the motor used to drive the cutting element. The amount of pressure data received during the cutting event depends on the number and / or size of the intervals. In other words, the more regularly pressure data measurements are made or obtained, the more pressure data is received. In some examples, pressure data may be obtained at equal intervals, such as every 1 second, 0.5 seconds, 0.1 seconds, etc. (e.g., measurements may be made using a pressure or force sensor). In other examples, pressure data may be obtained continuously during the cutting event.

[0033] At step 104, the method 100 includes storing the received pressure data in a storage device. The storage device includes a storage medium located within the hair-cutting device itself or in a storage medium remote to the hair-cutting device. For example, the pressure data is stored in a storage medium of a computing device such as a smartphone, a tablet computer, a laptop computer, an interactive mirror, and the like. In some examples, the pressure data is stored on a server, for example, in a cloud-based storage medium. In addition to storing pressure data received in association with a recent cutting event (e.g., a current cutting event), the storage device is used to store pressure data received in association with past or previous cutting devices. That is, pressure data obtained in association with a particular cutting element (e.g., for a particular user) is stored in the storage device, thereby creating a record of historical usage data detailing the pressure applied by the cutting element to a surface at intervals during past cutting events and recent cutting events.

[0034] The method 100 comprises, in step 106, estimating a wear level of the cutting element based on pressure data stored in the storage device associated with the cutting event and pressure data stored in the storage device associated with one or more previous cutting events. Due to the correlation between the pressure applied by the cutting element to the surface during the cutting event and the amount of wear the cutting element undergoes, monitoring the pressure data over multiple cutting events allows an estimation to be made regarding the likelihood of wear of the cutting element. In one example, an estimation of the wear level of the cutting element is determined based on the total pressure applied by the cutting element to the surface during the cutting event (e.g., during the most recent cutting event and one or more previous cutting events) from a defined start time or starting point. The defined start time or starting point may, for example, include the start of a first cutting event performed using a new cutting element (e.g., when the hair-cutting device is used for a first time or when a new cutting element is attached to the hair-cutting element to replace an older cutting element). Thus, the pressure data stored in the storage device is associated with a particular cutting element.

[0035] At step 108, the method 100 includes providing an indication of the estimated wear level for presentation to a recipient. The indication of the estimated wear level is, for example, generated by one or more processors performing the method 100 and delivered to a display unit (e.g., a display screen) of the hair-cutting device or another device (e.g., a smartphone or an interactive mirror) for presentation. The recipient of the presented data is, for example, the hair-cutting device and / or a subject whose hair is cut using the hair-cutting device. The indication presented to the recipient can take the form of a text notification, a graphical notification, an audible notification, or any other form of notification capable of indicating to the recipient the wear level of the cutting element. In some examples, the indication is provided as a percentage, with 0% wear indicating a cutting element that has not been used or has not been subjected to pressure sufficient to result in significant wear, and 100% wear indicating a cutting element that has been subjected to a significant amount of use or has been used sufficient to apply significant total pressure to a surface such that the cutting element is estimated to be completely worn or worn to such an extent that the cutting element should be replaced. In the context of this disclosure, "fully worn" is intended to refer to a condition in which a cutting element has worn down to such an extent that it has reached the end of its intended, useful, and / or safe lifespan.

[0036] By providing an indication to the recipient of the indication (e.g., a user of a hair-cutting device) of the extent to which the cutting element may have worn down from use, the user can understand approximately how much effective or useful "life" the cutting element has left. Over time, as the cutting element becomes more worn, the user can determine from the presented information (from the indication that the cutting element is 90% worn) that the cutting element is estimated to be nearing the end of its effective or useful life, and the user can take steps to replace the cutting element with a new cutting element. As discussed above, as a cutting element becomes more worn down from use, its blades become less sharp and less effective at cutting hair. As a result, a user of a worn cutting element may experience a relatively poor cutting experience, which may take longer than a cutting event in which a new cutting element is used. Furthermore, in some cases, the cutting element may even become less safe to use as it deteriorates from excessive wear. Thus, the methods disclosed herein allow a user to be informed of the estimated wear of a cutting element so that they can take steps to replace the cutting element before it reaches a stage where it may become unsafe and potentially harmful to the user.

[0037] 2 is a flow chart of a further example of a method 200. The method 200, which may be a computer-implemented method of monitoring the use of a cutting element of a hair-cutting device, includes one or more steps of the method 100 described above. In some embodiments, estimating the wear level of the cutting element (step 106) includes determining a total pressure applied by the cutting element to the surface from a defined starting point based on a summation or numerical integration of stored pressure data associated with the cutting event and stored pressure data associated with one or more previous cutting events. In other words, pressure data associated with a cutting event (e.g., a recent or current cutting event) and pressure data stored in the storage device associated with previous cutting events are summed or numerically integrated over time to determine a total pressure (e.g., cumulative pressure) applied by the cutting element to the surface from a defined starting point. The defined starting point includes, for example, a time when the cutting element is first used. The starting point is automatically detected in some examples, for example, when the cutting element is attached to the hair-cutting device. In other examples, the starting point may be indicated manually, for example, through a user input. A new starting point (eg, the starting point from which pressure data begins to be recorded) is assigned or set each time a cutting element is replaced.

[0038] The estimating step (step 106) may further include estimating a wear level based on the calculated summed or integrated pressure data. For example, various pressure thresholds may correspond to the estimated wear levels, such that when the accumulated pressure (e.g., summed or integrated pressure) reaches a first threshold, it is estimated that the cutting element has worn down to 50% of its useful life, and when the accumulated pressure reaches a second threshold, it is estimated that the cutting element is completely worn (e.g., 100%) and has reached the end of its useful life.

[0039] FIG. 3 shows two graphs 300 and 310 of exemplary data required for two different individuals, individual A and individual B, during a single cutting event (e.g., over a single shaving session). In this example, the graphs show the force applied to the surface by the cutting element. In graph 300, measured force data (which may be converted to pressure data) for individual A is shown by line 302, and measured data for individual B is shown by line 304. The data represented by line 302 shows that individual A spent approximately 500 seconds (i.e., 8 minutes and 20 seconds) using the cutting element and applied an average force of approximately 4 N during the current event. The data represented by line 304 shows that individual B spent approximately 180 seconds (i.e., 3 minutes) using the cutting element and applied an average force of approximately 1-2 N during the cutting event. Graph 310 shows that the force data from graph 300 has a cumulative signal for each of individual A and individual B. Thus, line 312 represents the cumulative signal (e.g., summed or numerically integrated data) for individual A, and line 314 represents the cumulative signal (e.g., summed or numerically integrated data) for individual B. It is clear that the total / cumulative force applied to individual A is much greater than the total / cumulative force applied by individual B due to the greater average force applied by individual A during the cutting event. Because the cutting element is new, it is possible to determine the total / cumulative force for a given cutting element by adding the data required for previous cutting events, e.g., all cutting events performed using the cutting element.

[0040] Referring again to FIG. 2, the method 200 further comprises, in step 202, generating a warning signal for delivery to a recipient in response to determining that the estimated wear level meets a defined threshold condition. Thus, the wear level of the cutting device is estimated throughout the life of the cutting element and provided for presentation to the user, while the warning signal is generated when one or more defined threshold conditions are met. For example, if the wear level is estimated to meet or exceed a threshold corresponding to 50% of the useful or useful life of the cutting element, a warning signal is generated that can be used to inform the user that the cutting element is approximately midway through its useful life. Similarly, if the wear level is estimated to meet or exceed a threshold corresponding to, for example, 95% of the intended useful or useful life of the cutting element, a warning signal is generated that can be used to inform the user that the cutting element is reaching the end of its useful life. This allows the user to replace the cutting element with a new / unused cutting element, which should result in an improved hair cutting experience. Other threshold conditions may be defined and a warning signal may be generated when the threshold conditions are met. For example, a warning signal may be generated if a particular threshold (e.g., corresponding to 30% wear) is determined to be reached within a specified duration of use, indicating, for example, that a user of the cutting element is exerting excessive force or pressure during use.

[0041] As indicated above and discussed in more detail below, the received data in some embodiments includes data obtained from a pressure sensor configured to measure the pressure applied to the surface by the cutting element of the hair-cutting device at intervals during the cutting event. In other embodiments, the received data includes data obtained from a force sensor configured to measure the force applied to the surface by the cutting element of the hair-cutting device at intervals during the cutting event. By knowing the cutting area, in particular the amount of surface area of ​​the cutting element that contacts the subject's surface during use, the pressure can be calculated from the force measurements. The one or more processors performing the methods 100, 200 are, for example, in communication with a force or pressure sensor, so that the force or pressure measurements can be received from the force or pressure sensor in real-time use or at the end of the cutting event, for example when the user has finished cutting their hair and removes the hair-cutting device from their skin or switches the hair-cutting device off.

[0042] The force or pressure sensor provides a reliable and accurate means of obtaining an indication of the force or pressure applied by the cutting element to the surface during a cutting event. However, in some embodiments, the data obtained using the pressure sensor is supplemented with other data to provide an even more accurate estimate of the wear of the cutting element. In some examples, the hair-cutting device includes a motor configured to drive the cutting element in use. For example, such a motor causes a reciprocating or circular motion of one or more blades of the cutting element to perform hair cutting when brought into contact with a hair. In use, a force is applied that urges the cutting element against the surface to be treated, which changes the torque of the motor. The current across the motor changes as a function of the motor torque, and therefore the change in torque resulting from the force applied by the cutting element to the surface is evident in the current measurement. Thus, by monitoring the current across the motor during a cutting event, it is possible to determine an indication of the pressure or force applied by the cutting element to the surface, which can be used to determine an estimate of the wear level of the cutting element. The estimated wear level determined using the current across the motor is combined with the estimated wear level determined using pressure data obtained from the sensor to achieve an even more accurate estimate.

[0043] Thus, the method 200 comprises receiving, at intervals during a cutting event, current data indicative of the current across a motor driving a cutting element of a hair-cutting device, at step 204. The step of estimating the wear level of the cutting element (step 106) is further based on the received current data. The method in some embodiments further comprises storing the received current data in a storage device, which may be the same storage device used to store the received pressure data. The current data is received and stored in relation to a current / present cutting event and the current data is stored in relation to a previous / past cutting event. For example, the storage device stores current data associated with the same cutting event for which pressure data is available. With respect to the pressure data, the changes in current are summed or numerically integrated to determine the total cumulative effect on the current from a defined starting point and across multiple cutting events.

[0044] In some embodiments, determining the wear level of the cutting element based on the pressure data and the received current data is accomplished using a look-up table. For example, a particular total or cumulative pressure corresponds to a particular estimated wear level of the cutting element, and a particular total or cumulative measurement of change in current corresponds to a particular estimated wear level of the cutting element. The estimated wear level based on the pressure data and the estimated wear level based on the current measurements may be combined (e.g., averaged) in some manner to determine a more accurate estimate of the wear level of the cutting element.

[0045] During use, other forces acting on the cutting element may also affect the torque of the motor, resulting in disturbances in the current measurement signal when measuring the current across the motor. Therefore, in some embodiments, one or more filters are used to filter out those disturbances in the measurement signal that are not due to the pressure applied to the surface by the cutting element. Thus, the method 200 includes applying a low pass filter to the received current data in step 206. In this way, the received current data that is taken into account when estimating the wear level of the cutting element is the current data that is indicative of the pressure applied to the surface by the cutting element.

[0046] One or more filters are also applied to the received pressure data. For example, a low pass filter is applied to the pressure data to filter out high frequency noise or disturbances that are not related to the hair cutting function but may affect decisions made using the data. In some embodiments, a notch filter is used to filter out certain electromechanical characteristics of the motor, such as commutation spikes. Filtering is accomplished using hardware components and / or a processor.

[0047] In addition to the received pressure data, or in addition to the received pressure data and the received current data, the estimation of the wear level of the cutting element is based on further data including, for example, the total duration the cutting element was used. Whereas the duration of use of the cutting element does not by itself provide an accurate indication of the wear level of the cutting element, such estimation is improved when the duration of use is combined with the pressure data and / or the current data. Thus, the method 200 comprises, in step 208, determining the total duration the cutting element was used during the cutting event based on the pressure data stored in the storage device in association with the cutting event and the pressure data stored in the storage device in association with one or more previous cutting events. As shown in FIG. 3, the stored pressure data includes an indication of the duration of each cutting event, which can be used to determine, for example, the total duration the cutting element was used from a defined starting point (e.g., when the cutting element was first used). Estimating the wear level of the cutting element (step 106) may be further based on the determined total duration. For example, a particular total duration of use of the cutting element corresponds to a particular estimated wear level, with 0 minutes of use corresponding to 0% estimated wear of the cutting element, and 160 minutes of use corresponding to 100% estimated wear of the cutting element. A look-up table can be used to determine the correspondence. As explained above for the current data, to determine the overall estimated wear level of the cutting element, an estimated wear level is determined based on the total duration of the cutting element, which is combined with the estimated wear level determined based on the pressure data and / or current data (e.g., by averaging the estimated wear levels). In another example, a conditional probability method is applied to combine the various estimated wear levels. For example, one probability is determined corresponding to each of the estimated wear levels, and the multiple probabilities are multiplied together to obtain an overall probability that the cutting element has worn to a level at which it should be replaced.

[0048] In some embodiments, estimating the wear level of the cutting element comprises determining a probability that the cutting element will wear to such an extent that it will be replaced. For example, any of the metrics used to estimate the wear level may correspond to a probability that the cutting element will wear a particular amount. In other words, it may not be known with certainty that if the cutting element is applied to the subject's skin with a particular threshold cumulative pressure that will wear beyond its useful life, then it is likely or likely that after such use the cutting element will be considered likely to wear and be due for replacement. Thus, in some embodiments, a particular value in the received data (e.g., a particular cumulative pressure, a particular duration of use and / or a particular cumulative measurement based on current data) corresponds to a particular probability that the cutting element has worn a given amount.

[0049] As discussed above, using a cutting element that has worn beyond a certain level may be unsafe for a user, for example, and the blades of the cutting element may become dull or jagged over time with use, especially if the cutting element is pressed against a subject's skin with significant force or pressure. Thus, in some embodiments, steps are taken to reduce the risk of injury when a cutting element is likely to be damaged in this manner. Steps may include, for example, notifying a user that the cutting element should be replaced.

[0050] A further aspect of the present invention provides a computer program product. Figure 4 is a schematic diagram of an example of a processor 402 in communication with a computer readable medium 404. According to various embodiments, the computer program product includes a non-transitory computer readable medium 404 having computer readable code embedded therein, which, when executed by a suitable computer or processor 402, is configured to cause the computer or processor to perform the steps of the methods 100, 200 disclosed herein. The processor 402 includes a processor of a hair cutting device or a processor of a different electronic device, such as a smartphone. Alternatively, the processor 402 includes a remote processor, such as a cloud-based processing device.

[0051] A further aspect of the present invention provides a hair-cutting device. Figure 5 is a schematic diagram of an example of a hair-cutting device 500. The hair-cutting device 500 comprises a processor 502, a cutting element 504, and a pressure sensor 506. The cutting element 504 is configured to cut hair growing from a surface of a subject. For example, the cutting element includes one or more blades configured to trim or shave hair on the head, body, or face of an individual. The pressure sensor 506 is configured to measure the pressure applied by the cutting element 504 to the surface of the subject during a hair-cutting event. As mentioned above, a hair-cutting event can be considered as a treatment session, during which a user cuts his or her own hair using the hair-cutting device 500. Such a treatment session or hair-cutting event is configured to start when the user switches on the hair-cutting device 500 and end when the user switches off the hair-cutting device.

[0052] The processor 502 is configured to provide data representative of the pressure for storage in a storage device. The data indicative of the pressure includes a continuous pressure measurement signal over the duration of the cutting event or multiple pressure measurements taken at intervals during the cutting event. The storage device is located in the hair-cutting device 500 and the processor 502 is configured to provide the data to the storage device via a wired connection. In another example, the storage device is remote with respect to the hair-cutting device 500 and the processor 502 is configured to provide the data to the storage device via a wireless connection. The storage device includes pressure data obtained during previous cutting events performed using the same cutting element.

[0053] The processor 502 is also configured to estimate a wear level of the cutting element based on the pressure data stored in the storage device associated with the cutting event and the pressure data stored in the storage device associated with one or more previous cutting events. Thus, the processor 502 determines an estimate of the wear level of the cutting element based on, for example, the cumulative pressure applied by the cutting element to the subject's surface (e.g., calculated by summing or numerically integrating the pressure data over the duration of the cutting event). This function of the processor 502 may be considered to correspond to step 106 of the methods 100, 200.

[0054] The processor 502 is also configured to provide an indication of the estimated wear level for display to a recipient. In this regard, the hair-cutting device 500 further includes a presentation interface, such as a display, a touch screen, a speaker, a tactile element, etc., capable of presenting the estimated wear level to a user of the hair-cutting device and / or a recipient, who is the subject whose hair is to be cut. The indication of the estimated wear level may be presented in the form of a percentage that is displayed numerically or audibly, or in the form of a number of lighting elements, whereby the proportion or number of lighting elements that are illuminated depends on the estimated wear level of the cutting element.

[0055] In some embodiments, the processor is configured to determine a total pressure exerted by the cutting element on the surface from a defined starting point based on a summation or numerical integration of stored pressure data associated with the cutting event and stored pressure data associated with one or more previous cutting events. The estimation of the wear level by the processor 502 is based on the calculated summation or integration pressure data.

[0056] Figure 6 is a schematic diagram of a further example of a hair-cutting device 500. The hair-cutting device 500 shown in Figure 6 comprises the features of the hair-cutting device shown in Figure 5 and comprises a number of further optional features.

[0057] The hair-cutting device 500 includes a motor 508 configured to drive the cutting element 504 in use. In some embodiments, the hair-cutting device 500 further comprises a current measurement unit 510 configured to measure a current across the motor 508 that drives the cutting element 504 of the hair-cutting device 500. The processor 502 is configured to estimate a wear level of the cutting element 504 further based on the current data measured using the current measurement unit 510. The estimation of the wear level based on the current data is performed as described in step 204 above.

[0058] Similarly, in accordance with the description of step 208 above, the processor 502 further considers the total duration of use of the cutting element 504 in estimating the wear level of the cutting element. Thus, the processor 502 is configured in some embodiments to determine the total duration that the cutting element was used during the cutting event based on the pressure data stored in the storage device associated with the cutting event and the pressure data stored in the storage device associated with one or more previous cutting events. The processor 502 is further configured to estimate the wear level of the cutting element 504 further based on the determined total duration.

[0059] In some embodiments, the hair-cutting device 500 further comprises a storage device 512 configured to store data (e.g. pressure data and / or current data) acquired and / or received using components of the hair-cutting device. In other embodiments, the hair-cutting device 500 may not include a storage device 512 for storing data, rather the received data may be stored in a storage device remote to the hair-cutting device.

[0060] In some embodiments, the processor 502 is configured to generate a warning signal in response to determining that the data stored in the storage device meets a defined threshold condition. For example, the warning signal is generated if the total or cumulative pressure or force exceeds a defined threshold. The processor 502 provides the warning signal for delivery to a recipient, such as a user of the device and / or a subject whose hair is to be cut.

[0061] The cutting element 504 is intended to be replaced when the cutting element is presumed to have reached the end of its useful life, for example by comprising a replaceable cutting element configured to have a limited useful life. The warning signal includes an indication to the recipient that the cutting element should be replaced. For example, a message is presented to the user of the hair-cutting device 500 requesting that the user "replace blade now."

[0062] The hair-cutting device 500 further comprises, in some embodiments, a communication unit 514. For example, the communication unit 514 allows data to be transmitted via a wireless communication protocol to a remote processing device. In embodiments where the storage device is remote, the processor 502 is configured to provide data indicative of the measured pressure to a storage device remote to the hair-cutting device 500 by transmitting the data using the communication unit 514 for storage in the storage device.

[0063] In some embodiments, the hair-cutting device 500 further comprises a filter component 516 configured to filter the data indicative of the pressure before the processor 502 estimates the wear level. In other embodiments, multiple filter components are provided. The one or more filter components include a low pass filter or a notch filter. As mentioned above, the one or more filters are provided for filtering out some portions of the obtained data (e.g. some portions of the measured signal) that are not related to applying pressure to the cutting element 504.

[0064] The embodiments disclosed herein provide a mechanism by which the wear level of a cutting element of a hair-cutting device is estimated based on the amount of pressure or force the cutting element experiences as a result of contacting a surface (e.g., a subject's skin) during use. Although an accurate determination of the amount of wear on the cutting element blade requires examination, e.g., with a microscope, the techniques disclosed herein, combined with empirical data from a representative group of users, can be used to make a level estimate that can provide a user with an indication of when the cutting element should be replaced. Monitoring the wear of the cutting element and informing the user in advance that the cutting element is reaching the end of its useful life can help reduce the likelihood of an accident occurring, which could result in injury from use, for example, if the cutting element blade becomes jagged and unsafe.

[0065] The processor 402, 502 may include one or more processors, processing units, multi-core processors or modules configured or programmed to control the hair-cutting device 500 in the manner described herein. In certain embodiments, the processor 402, 502 may include multiple software and / or hardware modules each configured or intended to perform individual or multiple steps of the methods described herein.

[0066] The term "module" as used herein is intended to include a hardware component, such as a processor or a component of a processor configured to perform a particular function, or a software component, such as a set of instruction data that has a particular function when executed by a processor.

[0067] It will be understood that the embodiments of the present invention also apply to computer programs adapted to carry out the invention, in particular computer programs on or in a carrier. The programs are in the form of source code, object code, source and object intermediate code, such as partially compiled form, or any other form suitable for use in carrying out the methods according to the embodiments of the present invention. It will also be understood that such programs may have many different architectural designs. For example, the program code implementing the functions of the method or system according to the present invention is subdivided into one or more subroutines. Many different ways of distributing functionality among these subroutines will be apparent to those skilled in the art. The subroutines are stored together in one executable file to form a self-contained program. Such an executable file comprises computer executable instructions, such as processor instructions and / or interpreter instructions (e.g. Java interpreter instructions). Alternatively, one or more or all of the subroutines may be stored in at least one external library file and linked with the main program, for example statically or dynamically, at run-time. The main program comprises at least one call to at least one of the subroutines. The subroutines may also comprise function calls to each other. An embodiment of a computer program product includes computer-executable instructions corresponding to each processing step of at least one of the methods described herein. These instructions may be subdivided into subroutines and / or stored in one or more files that may be statically or dynamically linked. Another embodiment of a computer program product includes computer-executable instructions corresponding to each means of at least one of the systems and / or products described herein. These instructions may be subdivided into subroutines and / or stored in one or more files that may be statically or dynamically linked.

[0068] The carrier of a computer program may be any entity or device capable of carrying the program. For example, the carrier comprises a data storage unit such as a ROM, for example a CD ROM or a semiconductor ROM, or a magnetic recording medium, for example a hard disk. Furthermore, the carrier may be a transmissible carrier, such as an electric or optical signal, which may be conveyed via an electric or optical cable or by radio or other means. When the program is embodied in such a signal, the carrier may be constituted by such a cable or other device or means. Alternatively, the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being adapted for or used for performing the relevant method.

[0069] Variations to the disclosed embodiments can be understood and effected by those skilled in the art practicing the principles and techniques described herein, from an examination of the drawings, the disclosure and the appended claims. In the claims, the word "comprises" does not exclude other elements or steps, and the singular form "a" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain means are recited in mutually different dependent claims does not indicate that a combination of these means cannot be used to advantage. A computer program can be stored or distributed in a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, as well as distributed in other forms, such as via the Internet or other wired or wireless communication systems. Reference signs in the claims should not be interpreted as limiting the scope thereof.

Claims

Claim 1 A computer-implemented method for monitoring the use of a cutting element of a hair cutting device, comprising: Receiving pressure data indicative of the pressure applied to the surface by the cutting element of the hair cutting device at intervals during a cutting event; Storing the received pressure data in a storage device; Estimating the wear level of the cutting element based on the pressure data stored in the storage device in relation to the cutting event and the pressure data stored in the storage device in relation to one or more previous cutting events, Determining the total pressure applied to the surface by the cutting element from a defined starting point based on the sum or numerical integration of the stored pressure data related to the cutting event and the stored pressure data related to the one or more previous cutting events, and Estimating the wear level based on the calculated sum or integrated pressure data; and Providing a display of the estimated wear level for presentation to a recipient. Claim 2 The computer-implemented method according to claim 1, further comprising generating a warning signal for delivery to the recipient in response to a determination that the estimated wear level meets a defined threshold condition. Claim 3 The computer-implemented method according to claim 1 or 2, wherein the received pressure data includes data obtained from a pressure sensor that measures the pressure applied to the surface by the cutting element of the hair cutting device at intervals during the cutting event. Claim 4 The method further comprising receiving current data indicative of the current at both ends of a motor that drives the cutting element of the hair cutting device at intervals during the cutting event, wherein the step of estimating the wear level of the cutting element is further based on the received current data. Claim 5 The computer-implemented method according to claim 4, further comprising applying a low-pass filter to the received current data. Claim 6 Based on the pressure data stored in the memory device in relation to the cutting event and the pressure data stored in the memory device in relation to one or more previous cutting events, further comprising the step of determining the total duration for which the cutting element was used during the cutting event, The step of estimating the wear level of the cutting element is based further on the determined total duration, the computer-implemented method according to any one of claims 1 to 5. **Claim 7** The step of estimating the wear level of the cutting element comprises determining the probability that the cutting element wears to such an extent that it should be replaced, the computer-implemented method according to any one of claims 1 to 6. **Claim 8** A non-transitory computer-readable medium embedded with computer-readable code, wherein the computer-readable code causes the computer or the processor to perform the method according to any one of claims 1 to 7 when executed by a suitable computer or processor. **Claim 9** A cutting element for cutting hair extending from the surface of a subject, A pressure sensor for measuring the pressure applied to the surface of the subject by the cutting element during a hair cutting event, A hair cutting device comprising a processor, The processor, Provides data indicating the pressure for storage in a memory device, Determines the total pressure applied to the surface by the cutting element from a defined starting point based on the sum or numerical integration of the stored pressure data related to the cutting event and the stored pressure data related to one or more previous cutting events, Estimates the wear level of the cutting element based on the pressure data stored in the memory device in relation to the cutting event and the pressure data stored in the memory device in relation to one or more previous cutting events, Estimates the wear level based on the calculated sum or integrated pressure data, A hair cutting device that provides a display of the estimated wear level for presentation to a recipient. **Claim 10** The hair cutting device further comprises a current measurement unit for measuring the current at both ends of a motor that drives the cutting element of the hair cutting device, The processor, The hair cutting device according to claim 9, further estimating the wear level of the cutting element based on the current data measured using the current measurement unit. **Claim 11** The processor determines the total duration for which the cutting element was used during a cutting event based on the pressure data stored in the memory device in relation to the cutting event and the pressure data stored in the memory device in relation to one or more previous cutting events, and the hair cutting device according to claim 9 or 10, further estimating the wear level of the cutting element based on the determined total duration. **Claim 12** The hair cutting device further comprises a communication unit, and the processor provides data indicating the measured pressure for storage in the memory device by transmitting the data to the memory device remote from the hair cutting device using the communication unit. The hair cutting device according to claim 9 or 10. **Claim 13** The hair cutting device according to any one of claims 9 to 12, further comprising a filter component that filters the data indicating the pressure before the processor estimates the wear level.

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