Haircare appliance

Abstract

A haircare appliance comprising a body 104 which hair is wrapped around in use, a sensor arrangement 114 to indicate the presence of hair in one or more regions 108 and a control unit arranged to dete

Description

FIELD OF THE INVENTION The present invention relates to a haircare appliance. 5 BACKGROUND OF THE INVENTION A haircare appliance may comprise a sensor for sensing the proximity of hair to the haircare appliance. It would be desirable for the haircare appliance to obtain further information about the interaction of hair with the haircare appliance. 10 SUMMARY OF THE INVENTION The invention is defined in the attached independent claims to which reference should now be made. Further, optional features may be found in the sub-claims appended thereto. 15 According to a first aspect, there is provided a haircare appliance comprising: a body having an axis around which hair is wrapped in use, the body having one or more regions each having a respective location along the axis; a sensor arrangement configured to output one or more signals, each signal being indicative of a presence of hair at a respective one of the one or more regions; and a control unit configured to determine a number of wraps of hair 20 around the body based on a plurality of changes in the one or more signals. This allows the haircare appliance to determine the number of wraps of hair around the body. For example, in order to curl hair, a user may wrap a hair tress around the body of the haircare appliance. For example, one complete turn or revolution of the hair tress around the 25 body may equate to one wrap of hair around the body. Multiple complete turns or revolutions of the hair around the body may equate to multiple wraps around the body, accordingly. The user may wrap the hair tress around the body once, for example to produce a curl having just one turn. Instead, the user may wrap the hair tress around the body multiple times, for example twice, three times, four times, five times and so on, for example in order to produce 30 a curl having multiple turns. The user may do this depending on the length of the hair and / or the style desired to be achieved. Determining the number of wraps of hair around the body provides information on the way in which the haircare appliance is currently being used. Moreover, determining the number of wraps of hair around the body provides information 18 09 25 of a greater granularity than, for example, merely determining that there is hair wrapped around the body. The number of wraps of hair around the body (that is, the number of times that hair is currently wrapped around the body) is, of itself, useful information about the current interaction of hair with the haircare appliance. Moreover, this information can be 5 used in a number of different ways. For example, this may be used to control an operation of the haircare appliance, such as controlling feedback provided to the user about the number wraps of hair around the body and / or controlling the body to be heated to a particular temperature depending on the number of wraps. Accordingly, an improved haircare appliance is provided. 10 In some examples, each region may extend only part way around the axis. For example, each region may extend less than 180 degrees around the axis, for example less than 90 degrees around the axis. This may help allow for the changes in the one or more signals to be reliably mapped to a number of wraps of the hair around the body. For example, this may allow that, 15 as a hair tress is wrapped around the body, each change (e.g. increase) in a particular signal corresponds to the hair tress becoming present at the region associated with the signal. This may, in turn, allow for the number of changes in each of the one or more signals to be reliably mapped to the number of wraps around the body. For example, in the case of a single region and single signal, a first change (e.g. increase) may be associated with hair becoming present 20 at the region, a second, further, change (e.g. increase) may be associated with a first full wrap of hair around the body, and a third, further, change (e.g. increase) may be associated with a second full wrap of hair around the body (in which case, the number of wraps of hair around the body may be determined as two, for example). Reliable determination of the number of wraps may therefore be provided. 25 In some examples, a first signal of the one or more signals is indicative of a presence of hair at a first region extending along the axis of the body; and the control unit is configured to determine the number of wraps of hair around the body based on a plurality of changes in the first signal. 30 This may allow the number of wraps to be determined by sensing only in one region of the body. This may reduce the cost, size, weight, power consumption and / or number of components of the sensor arrangement. For example, there may be one sensor extending 18 09 25 along the axis of the body. Each time a hair tress completes one turn or revolution around the body, there will be a corresponding change (e.g. increase) in the first signal. By counting the number of these changes in the first signal, the number of wraps of hair around the body may be determined. 5 In some examples, the control unit is configured to determine the number of wraps of hair around the body based on a first change in the first signal indicative of hair being present at the first region and a number of one or more further changes in the first signal, each further change being indicative of further hair being present at the first region. 10 This may provide for efficient determination of the number of wraps. For example, the first change may indicate an initial engagement a hair tress with the body. The further changes may then indicate that respective complete revolutions or turns of the hair tress have been completed. For example, if there are three distinct, successive, changes (e.g. increases) in 15 the first signal, the control unit may infer that hair has completed two full revolutions or turns around the body, and hence that there are two wraps of hair around the around the body. In some examples, the body has a plurality of regions distributed along the axis of the body, 20 and the sensor arrangement is configured to output a plurality of signals, each signal being indicative of a presence of hair at respective one of the plurality of regions; and the control unit is configured to determine the number of wraps of hair around the body based on a change in each of the plurality of signals. 25 This may provide for improved sensitivity in the determination of the number of wraps. For example, having the plurality of regions distributed along the axis of the body may reduce the number of changes in any particular one of the signals for a given number of wraps of hair around the body. Accordingly, the sensitivity and hence reliability with which any particular one of the changes in signal can be detected by the control unit may be improved. 30 In examples, in order to curl hair, a user may wrap a hair tress around and along the body (that is, around and along the axis of the body) so that the hair tress becomes helical in shape. In this case, each complete revolution or turn of hair may occur at a respective different location along the axis of the body. Having the plurality of regions distributed along the axis 18 09 25 of the body may help improve the sensitivity with which the number of wraps can be determined in this case. In examples, there may be one sensor located at each of the plurality of regions distributed along the axis of the body, each sensor configured to output one of the signals. 5 In some examples, the control unit is configured to determine the number of wraps of hair around the body based on a change in one of the plurality of signals indicative of hair being present at one of the plurality of regions and a number of one or more changes in a respective one or more others of the plurality of signals, each of the one or more changes being 10 indicative of hair being present at a respective one of the regions. This may provide for efficient determination of the number of wraps of hair around the body. As above, in example, in order to curl hair, a user may wrap a hair tress around and along the body so that the hair tress becomes helical in shape. It is noted that the curl is typically 15 started at an end of the body towards the handle. As an example, there may be three regions distributed long the axis of the body, for example along a length of the body. For example, the first to third regions may be distributed in order from a handle of the haircare appliance. A change (e.g. increase) in signal from the first of these regions (e.g. closest to the handle) may indicate an initial engagement of the hair with the body. A subsequent change (e.g. 20 increase) in signal from the second of these regions (e.g. in between the first and third regions) may indicate a first full revolution or turn of the hair around the body. A subsequent change (e.g. increase) in signal from a third of these regions (e.g. adjacent to the second region and furthest from the handle) may indicate a second full revolution or turn of the hair around the body. Based on these changes in these signals, the control unit may infer that 25 there are two wraps of hair around the body. It will be appreciated that any number of regions and signals may be used. A specific example is six. In some examples, the plurality of regions are arranged in a row extending along the axis of the body. 30 This may help allow for an efficient determination of the number of wraps of hair around the body. For example, when the plurality of regions are arranged in a row, for example a straight line, extending along the axis (for example a length) of the body, subsequent changes 18 09 25 in the signals correspond to whole numbers of wraps of hair around the body. This may provide for simpler processing by the control unit in order to determine the number of wraps from the changes in signals. 5 In some examples, the control unit is configured to determine the number of wraps of hair around the body based on an order in which the plurality of signals change. This may provide for robust and / or reliable determination of the number of wraps of hair around the body. For example, as above, in normal use of the haircare appliance, hair is 10 wrapped around the body starting from the end of the body closest to the handle and moving towards the end of the body furthest from the handle. In the example where there are three regions extending in order along the length of the body from the handle, the signal from the first region should therefore, in normal use, not change after the signal from the second region changes, and the signal from the second region should not change after the signal 15 from the third region changes. Accordingly, in some examples, the determination of the number of wraps of hair around the body may be made responsive to a determination that the changes in the signals have occurred in a certain order. For example, in the above example, the order would be that the third signal does not change before the first or second signal changes and the second signal does not change before the first signal changes. 20 Changes occurring in a different order to this may be indicative that an object other than the hair tress currently being wrapped (e.g. other nearby hair) is present at one of the regions, and hence the determination of the number of wraps based on these changes in signal may not be accurate. In this case, the control unit may restart the determination of the number of wraps of hair based on subsequent changes in signal output by the sensor arrangement. In 25 some examples, the control unit is configured to restart the determination of the number of wraps of hair around the body in response to each of the plurality of signals indicating that hair is not present at the plurality of regions. For example, this may correspond to a situation in which no hair is present at the body, and the control unit may infer that the next change in one of the signals will represent the start of a new wrapping of hair around the body. 30 Robust determination of the direction may therefore be provided. In some examples, the control unit is configured to control an operation of the haircare appliance based on the determined number of wraps of hair around the body. This may allow 18 09 25 the haircare appliance to be operated based on the determined number of wraps of hair around the body. In some examples, the haircare appliance comprises a feedback device configured to provide 5 feedback to a user of the haircare appliance in use, and wherein the control unit is configured to control the feedback device to provide feedback to the user based on the determined number of wraps of hair around the body. This may allow the haircare appliance to guide the use of the haircare appliance by the user. 10 This may assist the user to operate the haircare appliance in an intended manner, or to achieve a particular style, for example. In examples, the feedback device may comprise a display configured to display the feedback to a user, a speaker configured to generate sounds to convey the feedback to the user, and / or a haptic device configured to generate haptic feedback for the user. In examples, the feedback may be indicative of whether the 15 determined number of wraps of hair around the body is in accordance with a particular style. For example, it may be that, according to a selected particular style, hair should be wrapped a particular number of times around the body. If the control unit determines that the number of wraps of hair around the body is fewer or more than the particular number of wraps, or is not within a particular range of the particular number of wraps, the control unit may control 20 the feedback device to convey to the user that the current wrapping of hair is not in accordance with the selected particular style. This may guide the user to continue wrapping the hair tress around the body, or to re-wrap that hair tress with a reduced number of wraps, so as to achieve the selected particular style as appropriate. Other examples are possible. This feedback allows improved interaction of the user and the haircare appliance and helps 25 the user to use the haircare appliance to achieve a particular style. In some examples, the control unit is configured to: compare the determined number of wraps of hair around the body to a predetermined number of wraps; and control the feedback device to provide feedback to the user based on the comparison. 30 This may allow the haircare appliance to guide the use of the haircare appliance by the user to achieve a particular number of curls. For example, the user may input a desired number of curls, or a desired number of curls may be inferred from a selected particular style, for 18 09 25 example. This may be used as the predetermined number of wraps. If the determined number of wraps matches the predetermined number of wraps, or is within a particular range of the predetermined number of wraps, then the control unit may control the feedback device to provide first feedback to the user (such as a particular light, sound, and / or haptic feedback) 5 indicating that the number of wraps matches the predetermined number of wraps. This may prompt the user to cease wrapping that particular hair tress around the body. If the number of wraps is over or under the predetermined number of wraps then the control unit may control the feedback device to provide second feedback to the user (such as a different particular light, sound, and / or haptic feedback) indicating that the number of wraps does not 10 match the predetermined number. This may prompt to the user to either continue wrapping the hair around the body, or to re-wrap the hair around the body but with a reduced number of wraps. This may help the user to achieve a particular curl or style. In some examples, the haircare appliance comprises an input interface configured to receive 15 a user input, and the control unit is configured to determine the predetermined number of wraps based on the received user input. This allows a user to input a particular curl number or style that they intend to curl the hair in. This may allow the haircare appliance to guide the user’s operation of the haircare 20 appliance so that it is in accordance with a desired result. In examples, the input interface may comprise one or more buttons, and / or a touch screen. Other examples are possible. This may help the user to achieve a desired style. In some examples, the body is removeable, and the feedback is indicative of an instruction 25 to replace the body with a body of a different diameter. This may guide a user in operating the haircare appliance to achieve a desired curl or style. For example, the user may input a desired number of curls, or a desired number of curls may be inferred from a selected particular style, for example. The haircare appliance may 30 comprise a main part, for example including a handle, and a plurality of attachments that are attachable to the main part and each including a body around which the hair is wrapped in use. The control unit may determine that the number of wraps of hair around the body is larger, for example much larger and / or consistently larger, than the desired number of curls. 18 09 25 In this case, the control unit may control the feedback device to provide feedback to the user that they could or should use a body of a larger diameter to achieve the desired number of curls. This may prompt the user to swap the current attachment for another attachment whose body has a larger diameter. Conversely, the control unit may determine that the number of 5 wraps of hair around the body is smaller, for example much smaller and / or consistently smaller, than the desired number of curls. In this case, the control unit may control the feedback device to provide feedback to the user that they could or should use a body of a smaller diameter to achieve the desired number of curls. This may prompt the user to swap the current attachment for another attachment whose body has a smaller diameter. This may 10 guide the user to interact with the appliance to achieve a desired curl or style. In some examples, the control unit is configured to determine a length of a user’s hair based on the determined number of wraps of the hair around the body and a circumference of the body; determine a style to recommend to the user based on the determined length of the 15 user’s hair; and control the feedback device to provide feedback indicative of the determined style. This may allow the haircare appliance to determine a property of the hair with which the appliance is being used, specifically the length of the hair, and recommend a style 20 appropriate for that determined hair length. This may provide for an improved user experience. In examples, the circumference of the body, or a proxy for circumference such as the diameter of the body may, for example, be stored by the control unit, determined by the control unit based on an identity of the body, communicated to the control unit by the body, and / or input by the user. The length of the hair bay be calculated by multiplying the 25 circumference by the determined number of wraps. In an example, if it is determined that the user has long hair, a certain style involving a relatively large number of curls may be recommended to the user. The user may select this style and, as above, the predetermined number of wraps may be set accordingly. Other examples are possible. 30 In some examples, the haircare appliance comprises a heater configured to heat at least a portion of the body, and wherein the control unit is configured to control the heather to heat the at least a portion of the body to a particular temperature based on the particular determined number of wraps of hair around the body. 18 09 25 This may allow for the haircare appliance to set an appropriate temperature to which the body is to be heated based on the number of wraps of hair around the body. For example, ‘newer’ hair, that is, hair that has grown relatively recently, may be more susceptible to 5 damage by high temperatures, whereas ‘older’ hair, that is, hair that has grown a relatively long time ago, is able to withstand higher temperatures without damage. Accordingly, where it is determined that there are a relatively large number of wraps of hair around the body, the control unit may infer (or calculate based on the circumference of the body as described above) that the hair being curled is relatively long. From this, the control unit may infer that 10 at least the part of the hair tress that is located towards the handle of the haircare appliance is relatively ‘older’ hair. In this case, the control unit may control the heater to heat at least the part of the body towards the handle to a relatively higher temperature. As another example, a person may have different lengths of hair, where shorter parts of the hair will be ‘newer’ than the longer parts of the hair. The control unit may be configured to determine 15 that a current number of wraps around the body is less than the number of wraps in an immediately previous one or more instances of wrapping. From this, the control unit may infer that the hair tress currently being wrapped is shorter and hence newer hair, and hence may control the heater to heat the body to a relatively lower temperature in order to avoid damaging the hair. A tailored operation of the haircare appliance may therefore be provided. 20 In some examples, the sensor arrangement comprises one or more sensors, each sensor being configured to output a respective one of the one or more signals. This may provide for a robust way to provide the one or more sensors. For example, each 25 sensor may output a signal independently of the other sensors. This may for example allow a clear and reliable signal as to the presence hair at each region. Moreover, in cases where there are a plurality of sensors, this may allow for the determination to be robust with respect to the failure of one of the sensors. 30 In some examples, one or more of the sensors are non-contact sensors. For example, a non-contact sensor may be configured to output a signal indicative of hair being present at the sensor without the hair necessarily coming into physical contact with 18 09 25 the sensor itself. Examples of non-contact sensors include a capacitance sensor (e.g. either a self-capacitance sensor or a mutual capacitance sensor), a light sensor, and an ultrasonic sensor. In some examples, one or more of the sensors may be a contact sensor, i.e. one which is configured to output a signal indicative of an object being present at the sensor only when 5 an object comes into physical contact with the sensor itself. Examples of contact sensors include touch sensors, force sensors, and pressure sensors. Another example of a contact sensor is an element coupled with a temperature sensor configured to measure the temperature of the element and whereby contact of an object with the element causes a change in the temperature of the element and thereby a change in a signal output by the 10 temperature sensor. Other types of sensor may be used. Non-contact sensors allow for determination the presence of hair even when the hair is not physically touching the sensors. This may allow that the sensors need not necessarily be placed on an external surface of the haircare appliance, which might otherwise interrupt the 15 operation thereof. In some examples, each signal comprises a temporal series of values or the control unit samples each signal as a temporal series of values, and each of the values is indicative of the degree to which hair is present at the respective region at a given time. 20 This may allow for the determination to be readily carried out by a microcontroller or other computer processor, which may provide for a cheap, simple, flexible and / or low weight means by which to determine the direction. This is for example as compared to using hardwired circuit logic, which may nonetheless in some other examples be used. In some 25 examples, the control unit may determine that a change in a given signal has occurred based on a gradient of the temporal series of values being greater than a threshold value. This may allow for a robust determination of the number of wraps, for example by filtering out small and / or slow changes associated with background noise. 30 In some examples, the body has a plurality of regions distributed about the axis; wherein a plurality of signals output by the sensor arrangement are each indicative of a presence of hair at a respective one of the plurality of regions distributed about the axis; and wherein the control unit is configured to determine a direction in which hair is wrapped around the body 18 09 25 based on the plurality of signals each indicative of a presence of hair at a respective one of the plurality of regions distributed about the axis. This allows the direction in which the hair is wrapped around the body to be determined (for 5 example, clockwise or anticlockwise, from a given perspective). This provides further information on the interaction of the hair with the haircare appliance, which is useful information in itself. Moreover, this information may be used in different ways. For example, the control unit may be configured to control an operation of the haircare appliance based on the determined direction in which the hair is wrapped around the body. For 10 example, this may be used to control the feedback device to provide feedback to the user and / or to control a direction around the body in which an airflow is directed. Other examples are possible. This may provide for a yet further improved haircare appliance. According to a second aspect, there is provided a method of determining a number of wraps 15 of hair around a body of a haircare appliance, the body having an axis around which the hair is wrapped, the body having one or more regions each having a respective location along the axis, the method comprising: receiving one or more signals, each signal being indicative of a presence of hair at a respective one of the one or more regions; and determining a number of wraps of hair around the body based on a plurality of changes in the one or more 20 signals. This may allow for similar advantages to as described above for the first aspect. In some examples, the method comprises controlling an operation of the haircare appliance based on the determined number of wraps of hair around the body. This may be the same or similar 25 to as described above for the first aspect. In some examples, the method may be performed by a control unit of a haircare appliance. In some examples the control unit may be the same as described above with reference to the first aspect. In some examples, the control unit may be located in a main part, for example a handle, of a haircare appliance. In some examples, the signals may be received from an attachment, for example an attachment that includes the 30 body, which attachment is attachable to and / or detachable from the main part. This may allow for improved flexibility in the functioning of the haircare appliance. The signals may be received wirelessly or over wires or conductive tracks, for example. In some examples, the method may be performed by a separate entity for example remotely from the haircare 18 09 25 appliance. For example, the signals may be transmitted to and received by a remote processor, and the determination may be made by the remote processor. In some examples, the result of the determination may be transmitted to and received by the haircare appliance, which may in turn, for example, control operation of the haircare appliance on the basis of 5 the determination. BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages will now be described, by way of example only, with reference to the accompanying drawings of which: 10 Figure 1 is a schematic diagram that illustrates a side view of a haircare appliance according to an example; Figure 2 is a schematic diagram that illustrates a cross-sectional view of the haircare appliance of Figure 1; Figure 3 is a graph that illustrates schematically a plot of signal output by a sensor as a 15 function of time, according to an example; Figure 4a is a schematic diagram that illustrates a side view of a haircare appliance according to another example; Figure 4b is a graph that illustrates schematically a plot of signals output by respective sensors as a function of time, according to an example; 20 Figure 5 is a schematic diagram that illustrates a cross-sectional view of a haircare appliance according to another example; Figure 6a is a graph that illustrates schematically a plot of the gradient of two signals output by respective sensors as a function of time according to one example; Figure 6b is a graph that illustrates schematically a plot of the gradient of two signals output 25 by respective sensors as a function of time according to another example; Figure 7 is a schematic diagram that illustrates a cross-sectional view of a haircare appliance according to another example; Figure 8 is a schematic diagram that illustrates a cross-sectional view of a haircare appliance according to another example; 30 Figure 9 is a schematic diagram that illustrates a control unit according to an example; and Figure 10 is a schematic diagram that illustrates a method according to an example. As used herein, like reference numerals denote like features. 18 09 25 DETAILED DESCRIPTION OF THE INVENTION Referring to Figures 1 and 2, there is illustrated a haircare appliance 102 according to an example. 5 The haircare appliance 102 comprises a body 104 having an axis A around which hair is wrapped in use. In this example, the body 104 has a region 108. As is best seen in Figure 2, in this example, the region 108 is elongate along the axis A and extends only part way around the axis A. The haircare appliance 102 comprises a sensor arrangement 112. In this example, the sensor arrangement 112 is configured to output a signal indicative of a presence of hair 10 at the region 108 of the body 104. The haircare appliance 102 comprises a control unit 120. As described in more detail below, the control unit 120 is configured to determine number of wraps of hair around the body based on a plurality of changes in the signal. The haircare appliance 102 is for curling hair. The haircare appliance 102 comprises a main 15 part 106 and the body 104 is provided as an attachment 104 that is attachable and / or detachable from the main part 106. The main part 106 provides a handle for the haircare appliance 102. The body 104 is generally in the form of a cylinder. The body 104 is elongate along the axis A. The body 104 comprises one or more heating elements 121 that are controlled by the control unit 120 to heat up the body 104 or at least an external surface of 20 the body. When hair is wrapped around the body 104, around the axis A, the heat provided by the body may act to set the hair into a curl. Accordingly, a user may use the haircare appliance 102 to style hair. The haircare appliance 102 comprises an input interface 126 configured to receive a user 25 input. For example, the input interface 126 may allow a user to input a particular number of curls or style that they intend to curl the hair in. In examples, the input interface 126 may comprise one or more buttons, and / or a touch screen. Other input interfaces are possible. The haircare appliance 102 comprises a feedback device 124 configured to provide feedback 30 to a user of the haircare appliance 102 in use. In this example, the feedback device 124 comprises a display 125 configured to display the feedback to a user. For example, the display 125 may comprise a LED screen or the like. In examples, the feedback device 124 may alternatively, or additionally comprise a speaker (not shown) configured to generate 18 09 25 sounds to convey the feedback to the user, and / or a haptic device (not shown) configured to generate haptic feedback for the user. Using the feedback device 124, the haircare appliance 102 may provide feedback to the user during use of the haircare appliance 102, so as to guide the user’s operation of the haircare appliance 102. In some examples, the input interface 126 5 and the feedback device 124 may be provided by the same device, such as a touch screen display. As mentioned, the haircare appliance 102 comprises a sensor arrangement 112 configured to output a signal indicative of a presence of hair at the region 108 of the body 104. In this 10 example, the sensor arrangement 112 comprises a sensor 114 located at the region 108 and configured to output the signal. In this example, the sensor 114 is elongate along the axis A and extends only part way round the axis A. The sensor 114 is positioned so as to sense radially outwardly from the body 104 (i.e. radially outwardly of the region 108 to which the sensor corresponds). In some examples, the sensor 114 may be a non-contact sensor. For 15 example, a non-contact sensor may be configured to output a signal indicative of hair 230 being present at the sensor 114 without hair 230 necessarily coming into physical contact with the sensor 114. Examples of non-contact sensors include a capacitance sensor (e.g. either a self-capacitance sensor or a mutual capacitance sensor), a light sensor, and an ultrasonic sensor. In other examples, the sensor 114 may be a contact sensor, i.e. one which 20 is configured to output a signal indicative of hair 230 being present at the sensor 114 only when hair comes into physical contact with the sensor itself. Examples of contact sensors include touch sensors (e.g. capacitance sensors or resistance sensors), force sensors, and pressure sensors. Another example of a contact sensor is an element coupled with a temperature sensor configured to measure the temperature of the element and whereby 25 contact of an object with the element causes a change in the temperature of the element and thereby a change in a signal output by the temperature sensor. Other types of sensor may be used. In some examples, the sensor 114 may be any sensor whose output is affected by the presence of hair. For example, where the region 114 is heated, a sensor resistant to high temperature may be chosen (such as the heated element coupled with a temperature sensor 30 described above). In some examples, the signal may be non-binary, for example have a range or continuum of values. For example, the magnitude or amplitude of each signal may indicate the proximity 18 09 25 of hair 230 to the region 108 or otherwise a degree to which hair 230 is present at the region 108. In some examples, the signal comprises a temporal series of values or the control unit 120 may sample each signal as a temporal series of values, and each of the values is indicative of the degree to which hair 230 is present at the region 108 at a given time. In 5 some examples, hair being present at the region 108 may correspond to hair 230 being near or proximate to the region 108. In other examples, hair 230 being present at the region may correspond to the hair 230 being in contact with the region 108. The sensor arrangement 112 may be connected to the control unit 120 by wired or wireless 10 means, in order to provide the signal to the control unit 120. In examples where the body 104 is provided by an attachment and the control unit 120 is in the main part 106, the body 104 and the main part 106 may form a connection, which may be wired or wireless, over which the signals may be transmitted from the sensor arrangement 112 to the control unit 120. In some examples, the sensor arrangement 112 may comprise the sensor 114 and the 15 signal output by the sensor may be provided directly to the control unit 120. In other examples, the sensor arrangement 112 may comprise the sensor 114 and a multichannel reader (not shown), and the signal may be provided to the control unit 120 by the multichannel reader (not shown). For example, the multichannel reader may sample the signal output by the sensor (as well as the output of other sensors, not shown in Figure 1) as 20 a temporal series of values and provide these temporal series of values to the control unit 120. In any case, the sensor arrangement 112 is configured to output the signal indicative of a presence of hair at the respective region 108 of the body 104. The control unit 120 is configured to determine a number of wraps of hair 230 around the 25 body 104 based on a plurality of changes in the signals. For example, one complete turn or revolution of a hair tress 230 around the body 104 may equate to one wrap of hair around the body 104. Multiple complete turns or revolutions of the hair around the body 104may equate to multiple wraps around the body 104, accordingly. The user may wrap the hair tress around the body once, for example to produce a curl having just one turn. Instead, the user 30 may wrap the hair tress around the body 104 multiple times, for example twice, three times, four times, five times and so on, for example in order to produce a curl having multiple turns. 18 09 25 Referring to Figure 3, there is illustrated a plot of the signal 330 indicative of a presence of hair at the first region 108 as a function of time. Specifically, Figure 3 illustrates a plot of the signal 330 output by the sensor 114 as a function of time, according to an example where a user is wrapping hair around the body 104. Before a first time, tl, hair is not present at the 5 first region 108. Accordingly, before tl, the signal 330 has a relatively low value, RI, indicating that hair is not present at the first region 108. At tl, a user begins to wrap a hair tress around the body 104 and hair becomes present at the first region 108. Accordingly, at tl, there is a first change, ARI, specifically an increase, in the signal 330, from RI to a higher value, R2. This indicates that hair is present at the first region 108. The user continues 10 to wrap the hair tress around the body 104 and at a second time, t2, the hair tress has completed one complete turn around the body 104. Accordingly, at t2, there is a second, further change, AR2, specifically a further increase, in the signal 330 from R2 to a yet higher value, R3. This indicates that further hair is present at the first region 108 and hence that the hair tress has completed one complete turn around the body 104. The control unit 120 15 analyses the signal 330 to detect the plurality of changes ARI, AR2 and determines the number of wraps of hair around the body 104 based on the detected number of changes. In this example, based on the two changes in the signal, the control unit 120 determines that the number of wraps of hair around the body 104 is one. 20 More generally, in examples, the control unit 120 may be configured to determine the number of wraps of hair around the body 104 based on a first change in the signal indicative of hair being present at the first region 108 and a number of one or more further changes in the signal, each further change being indicative of further hair being present at the first region 108. For example, the first change may indicate an initial engagement a hair tress 25 with the body 104. The further, additional, changes may then indicate that respective complete revolutions or turns of the hair tress have been completed. For example, if there are three distinct, successive, cumulative, changes (e.g. increases) in the first signal, the control unit may infer that hair has completed two full revolutions or turns around the body 104, and hence that there are two wraps of hair around the around the body 104. More 30 generally, the control unit 120 may determine that if there are n such changes, the number of wraps around the body is n-1. As above, in this example, the region extends only part way around the axis A (such as less than 180 degrees or less than 90 degrees around the axis A). This may help allow for the changes in the signal to be reliably mapped to a number of 18 09 25 wraps of the hair around the body 104. In some examples, the control unit may determine that a change ARI, AR2 in the signal has occurred based on a gradient of the signal (e.g. made up of a temporal series of values) being greater than a threshold value. This may act to filter out small and / or slow changes in the signal associated with background noise. 5 In the example described above with reference to Figures 1 to 3, the number of wraps is determined based on a plurality of changes in the signal indicative of a presence of hair at the region 108 / sensor 114. In that example, the region 108 / sensor 114 has one location along the axis, and extends along the elongate body 104. However, in other examples, the body 10 may have a plurality of regions distributed along the axis A of the body, as described in more detail hereinafter. Referring to Figure 4a, there is illustrated a haircare appliance 402 according to another example. The haircare appliance 402 may be the same as or similar to the haircare appliance 15 102 described above with reference to Figures 1 to 3 (that is, it may have at least some or all of the same or similar components or functionality), except that the body 404 of the haircare appliance 402 has a plurality of regions 408, 410, 412 distributed along the axis A of the body 404. Each region 408, 410, 412 of the body has a respective location along the axis A. Specifically, the first region 408 is closest to the main unit 406, the second region is in 20 between the first region 408 and the third region 412, and the third region 412 is furthest from the main unit 306. In this example, as above, each region 408, 410, 412 extends only part way round the axis A. In this example, the plurality of regions 408, 410, 412 are arranged in a linear row along the axis A. 25 In this example, the sensor arrangement 412 is configured to output a plurality of signals, each signal being indicative of a presence of hair at respective one of the plurality of regions 408, 410, 412. Specifically, in this example, the sensor arrangement 412 comprises three sensors 414, 416, 418 arranged in a row along the axis A of the body 404. A first sensor 414 is located in the first region 408, a second sensor 416 is located in the second region 410, 30 and a third sensor 418 is located in the third region 412. In this example, the control unit 102 is configured to determine the number of wraps of hair around the body 404 based on a change in each the plurality of signals. This may provide for improved sensitivity in the determination of the number of wraps. For example, having the plurality of regions 18 09 25 distributed along the axis A of the body 404 may reduce the number of changes in any particular one of the signals for a given number of wraps of hair around the body 404. Accordingly, the sensitivity and hence reliability with which any particular one of the changes in signal can be detected by the control unit 120 may be improved. 5 In examples, in order to curl hair, a user may wrap a hair tress 430 around and along the body (that is, around and along the axis A of the body 404) so that the hair tress becomes helical in shape (as in Figure 4). In this case, each complete revolution or turn of hair may occur at a respective different location along the axis A of the body 404. Having the plurality 10 of regions distributed along the axis A of the body 404 may help improve the sensitivity with which the number of wraps can be determined in this case. In this example, the control unit 120 may be configured to determine the number of wraps of hair around the body 404 based on a change in one of the plurality of signals indicative 15 of hair being present at one of the plurality of regions 408 and a number of one or more changes in a respective one or more others of the plurality of signals, each of the one or more changes being indicative of hair being present at a respective one of the regions 410, 412. As above, in examples, in order to curl hair, a user may wrap a hair tress around and along the body so that the hair tress becomes helical in shape. It is noted that the curl is typically 20 started at an end of the body towards the main unit or handle 406. Referring to Figure 4b there is illustrated a plot of the signals associated with each of the plurality of regions 408, 410, 412 of the body 404 of Figure 4a. Specifically, a first signal 440 is indicative of a presence of hair at the first region 408, a second signal 442 is indicative of a presence of hair at the second region 410, and a third signal 444 is indicative of a presence of hair at the third 25 region 412. A first change (specifically the increase), ARI’, in the first signal 880 at a first time, tl’, indicates an initial engagement of the hair tress 430 with the body 404. There is also a small increase in the second signal 482 at tl’ as the hair tress 430 partially overlaps the second region 410. A subsequent change (specifically the subsequent increase), AR2’, in the second signal 442 at a second time, t2’, indicates a first full revolution or turn of the 30 hair 430 around the body 404. A subsequent change (specifically the subsequent increase), AR3’, in the third signal 444 at a third time, t3’, indicates a second full revolution or turn of the hair 430 around the body 404. The control unit 120 may count the number of changes ARI’, AR2’, AR3’ across the plurality of signals to determine the number of wraps of hair 18 09 25 430 around the body 404. For example, based on the three successive increases ARI’, AR2’, AR3’ in the signals as in the present example, the control unit 120 may infers that there are two wraps of hair around the body 804. More generally, where there are n changes detected, the control unit may determine that there are n-1 wraps of hair around the body 404. It will 5 be appreciated that any number of regions and signals may be used. A specific example is six regions and respective signals. As above, the control unit 120 may determine that a change ARI’, AR2’, AR3’ in the signals has occurred (and hence should be counted) based on a gradient of the signal being greater than a threshold value. This may act to filter out small and / or slow changes in the signal associated with background noise. 10 In some examples, the control unit 120 may determine the number of wraps of hair around the body 404 based on an order in which the plurality of signals change. For example, as above, in normal use of the haircare appliance, hair is wrapped around the body 404 starting from the end of the body closest to the main unit or handle 406 and moving towards the end 15 of the body 404 furthest from the main unit or handle 406. In the examples of Figures 4a and 4b therefore, the first signal 440 should not, in normal use, change after the second signal 442 changes, and the second signal 442 should not change after the third signal 444 changes. Accordingly, in some examples, the determination of the number of wraps of hair around the body 404 may be made responsive to a determination that the changes in the 20 signals have occurred in a certain order. For example, in the above example, the order would be that the third signal 444 does not change before the first signal 440 or second signal 442 changes and the second signal 552 does not change before the first signal 440 changes. Changes occurring in a different order to this may be indicative that an object other than the hair tress currently being wrapped (e.g. other nearby hair) is present at one of the regions 25 408, 410, 412, and hence the determination of the number of wraps based on these changes in signal may not be accurate. In this case, the control unit 120 may restart the determination of the number of wraps of hair based on subsequent changes in signal output by the sensor arrangement 408. 30 In examples, the control unit 120 may restart the determination of the number of wraps of hair around the body 104, 404 in response to each of the signals indicating that hair is not present at the one or more regions 108, 408, 410, 412. For example, this may correspond to a situation in which no hair is present at the body 104, 404 and the control unit 120 may 18 09 25 infer that the next change in one of the signals will represent a new wrapping of hair around the body 104, 404. In some examples, the control unit 120 may be configured to control an operation of the 5 haircare appliance 102, 402 based on the determined number of wraps of hair around the body. As one example, the control unit 120 may be configured to control the feedback device 124 to provide feedback to the user based on the determined number of wraps of hair around the 10 body 104, 404. For example, the control unit 120 may compare the determined number of wraps of hair around the body 104, 404 to a predetermined number of wraps, and control the feedback device 124 to provide feedback to the user based on the comparison. For example, if the control unit 120 determines that the number of wraps of hair around the body 104, 404 is fewer or more than the predetermined number of wraps, or is not within a 15 particular range of the predetermined number of wraps, the control unit 120 may control the feedback device 124 to convey to the user that the current wrapping of hair is not in accordance with predetermined number of wraps. For example, if the determined number of wraps is over or under the predetermined number of wraps or is not within a particular range of the predetermined number of wraps, then the control unit 120 may control the feedback 20 device 124 to provide first feedback to the user (for example a first particular light on the display device 125) indicating that the number of wraps does not match the predetermined number. However, if the determined number of wraps matches the predetermined number of wraps, or is within the particular range of the predetermined number of wraps, then the control unit 120 may control the feedback device 124 to provide second feedback (e.g. a 25 second particular light on the display screen) to the user indicating that the number of wraps matches the predetermined number of wraps. This may prompt the user to cease wrapping that particular hair tress around the body 104, 404. In examples, the predetermined number of wraps may be input by the user into the user 30 interface 126, and the control unit 120 may set the predetermined number of wraps accordingly. In examples, the control unit 120 may determine the predetermined number of wraps based on a particular style, for example selected or otherwise input to the input interface 126 by the user. For example, it may be that according to particular style, hair 18 09 25 should be wrapped a particular number of times around the body 104, 404. The control unit 120 may accordingly set the predetermined number of wraps as the particular number of wraps according to the selected style. 5 In some examples, the body 102, 404 may be removeable from the main unit 106, 406, and the feedback may be indicative of an instruction to replace the body 104, 404 with a body of a different diameter. For example, the haircare appliance may comprise the main part 106, 406 and a plurality of attachments that are attachable to the main part and each including a body 104, 404 around which the hair is wrapped in use. The control unit 120 may determine 10 that the number of wraps of hair around a currently attached body 104, 404 is larger, for example much larger and / or consistently larger, than the predetermined number of curls. In this case, the control unit 120 may control the feedback device 124 to provide feedback to the user that they could or should use a different body of a larger diameter to achieve the desired number of curls. This may prompt the user to swap the current attachment for another 15 attachment whose body 104, 404 has a larger diameter. Conversely, the control unit 120 may determine that the number of wraps of hair around the currently attached body 104, 404 is smaller, for example much smaller and / or consistently smaller, than the predetermined number of curls. In this case, the control unit 120 may control the feedback device 124 to provide feedback to the user that they could or should use a body 104, 404 of a smaller 20 diameter to achieve the desired number of curls. This may prompt the user to swap the current attachment for another attachment whose body 104, 404 has a smaller diameter. This may guide the user to interact with the appliance to achieve a desired number of curls or style. 25 In some examples, the control unit 120 may be configured to determine a length of a user’s hair based on the determined number of wraps of the hair around the body 104, 404 and a circumference of the body 104, 404. In examples, the circumference of the body 104, 404 or a proxy for circumference such as the diameter of the body 104, 404 may, for example, be stored by the control unit 120, determined by the control unit 120 based on an identity of 30 the body 104, 404, communicated to the control unit 120 by the body 104, 404, and / or input by the user using the input interface 126. The length of the hair may be calculated by multiplying the circumference of the body 104, 404 by the determined number of wraps. In examples, the control unit 120 may be configured to determine a style to recommend to the 18 09 25 user based on the determined length of the user’s hair, and control the feedback device 124 to provide feedback indicative of the determined style. For example, if it is determined that the user has long hair, a certain style involving a relatively large number of curls may be recommended to the user. The user may select this style and, as above, the predetermined 5 number of wraps may be set accordingly. Other examples are possible. As another example, the control unit 120 may be configured to control the heater 121 to heat the at least a portion of the body 104, 404 to a particular temperature based on the particular determined number of wraps of hair around the body 104, 404. For example, ‘newer’ hair, 10 that is, hair that has grown relatively recently, may be more susceptible to damage by high temperatures, whereas ‘older’ hair, that is, hair that has grown a relatively long time ago, may be able to withstand higher temperatures without damage. Accordingly, where it is determined that there are a relatively large number of wraps of hair around the body 104, 404, the control unit 120 may infer (or calculate based on the circumference of the body 104, 15 804 as described above) that the hair being curled is relatively long. From this, the control unit may infer that at least the part of the hair tress 230, 430 that is located towards the main unit or handle 106, 406 of the haircare appliance 102, 402 is relatively ‘older’ hair. In this case, the control unit 120 may control the heater 121 to heat at least the part of the body 104, 404 towards the main unit or handle 106, 406 to a relatively higher temperature. As another 20 example, a person may have different lengths of hair, where shorter parts of the hair will be ‘newer’ than the longer parts of the hair. The control unit 120 may be configured to determine that a current number of wraps around the body 104, 404 is less than the number of wraps in an immediately previous one or more instances of wrapping. From this, the control unit 120 may infer that the hair tress 230, 430 currently being wrapped is shorter and 25 hence newer hair, and hence may control the heater 121 to heat the body 104, 504 to a relatively lower temperature in order to avoid damaging the newer hair. Other examples are possible. In the examples described above with reference to Figures 1 to 4b, body 104, 404 has an 30 axis A around which hair is wrapped in use, and has one or more regions 108, 408, 410, 412 each having a respective location along the axis A. The sensor arrangement 112, 412 is configured to output one or more signals 330, 440, 442, 444, each signal being indicative of a presence of hair 230, 430 at a respective one of the one or more regions 108, 408, 410, 18 09 25 412. In these examples, the control unit 120 is configured to determine a number of wraps of hair 230, 430 around the body 104, 404 based on a plurality of changes ARI, AR2, ARI’, AR2’, AR3’ in the one or more signals 330, 440, 442, 444. 5 However, in some examples, the control unit 120 may additionally be configured to determine a direction in which hair is wrapped around the axis A, as described in more detail below. Determining the direction in which the hair is wrapped around the body provides information of a greater granularity on the way in which the haircare appliance is currently being used. The direction in which hair is currently wrapped around the body is, of itself, 10 useful information about the current interaction of hair with the haircare appliance. Moreover, this information can be used in a number of different ways. For example, this may be used to control an operation of the haircare appliance, such as controlling feedback provided to the user about the direction in which the hair is wrapped and / or controlling an airflow to be provided in a certain direction around the body, as described in more detail 15 below. Referring to Figure 5, there is illustrated a haircare appliance 502 according to another example. The haircare appliance 502 may be the same as or similar to the haircare appliance 102, 402 of any of the examples described above with reference to Figures 1 to 4b (that is, 20 it may have at least some or all of the same or similar components or functionality), except that the haircare appliance 502 of the example of Figure 5 has a plurality of regions 508, 510 distributed around the axis A (referred to hereinafter as the second plurality of regions 508, 510). In examples, one or more of the one or more regions 108, 408, 410, 410 located along the axis A described above with reference to Figures 1 to 4b may be included in the second 25 plurality of regions 508, 510. In this example, the sensor arrangement 512 is configured to output a plurality of signals, each signal being indicative of a presence of hair at a respective one of the second plurality of regions 508, 510 of the body 504 (referred to hereinafter as the second plurality of signals). In this example, the control unit (not shown in Figure 5) is additionally configured to determine a direction in which hair is wrapped around the body 30 104 based on the second plurality of signals. In the example of Figure 5, the second plurality of regions 508, 510 distributed around the axis A comprises a first region 508 and a second region 510. Each region of the second 18 09 25 plurality of regions 508, 510 extends only part way round the axis A. The sensor arrangement 512 is configured to output a first signal indicative of a presence of hair at the first region 508, and a second signal indicative of a presence of hair at the second region 510. The sensor arrangement 512 comprises a plurality of sensors 514, 516 each sensor 514, 5 516 being located at a respective region 114, 116 of the body 104 and being configured to output one of the second plurality of signals. The sensors 514, 516 and signals may themselves be the same or similar to those described above with reference to Figures 1 to 4b. Further, in this example, the first region 508 and the second region 510 are spaced about the axis A by less than 180 degrees (specifically by an angle in the range 45 to 135 degrees, 10 specifically 90 degrees). As a result, the distance around the circumference of the body 504 in a clockwise direction, in the sense of Figure 5, between the first region 108 and the second region 110 is less than that between the second region 110 and the first region 108. In this example, the control unit 120 is configured to determine the direction in which hair 15 is wrapped around the body 504 based on a timing of one or more changes in each of the first signal and the second signal of the second plurality of signals. Specifically, referring to Figures 6a and 6b, there are illustrated plots of the gradient of the signal output by each of the first sensor 514 and the second sensor 516 as a function of time. It will be understood that a positive spike or peak in the gradient of the signal corresponds to a change, specifically 20 an increase, in the signal, and hence is indicative of hair being present at the region 508, 510 associated with the signal. Figure 6a illustrates the case where hair is being wrapped clockwise (in the sense of Figure 5) around the body 504. Figure 6b illustrates the case where hair is being wrapped anticlockwise (in the sense of Figure 5) around the body 504. In each of Figures 6a and 6b, the solid bars represent a peak in the gradient of the signal 25 associated with the first region 508 / first sensor 514, and the hollow bars represent a positive spike or peak in the gradient of the signal associated with the second region 510 / second sensor 516. Referring first to Figure 6a, at a first time, Tl, there is a first change in the first signal 30 indicative of hair being present at the first region 508. This is represented by the first peak associated with the first region 508 at Tl. Following this, at a second time, T2, there is a first change in the second signal indicative of hair being present at the second region 510. This is represented by the first peak associated with the second region 510 at T2. Following 18 09 25 this, at a third time, T3, there is a second change in the first signal indicative of further hair being present at the first region 508. This is represented by the second peak associated with the first region 508 at T3. Following this, at a fourth time, T4, there is a second change in the second signal indicative of further hair being present at the second region 510. This is 5 represented by the second peak associated with the second region 510 at T4. In the example of Figure 6a, a first time difference, Atl, between the first change in the first signal at T1 and the first change in the second signal at T2 is less than a second time difference, At2, between the first change in the second signal at T2 and the second change in the first signal at T3. Given that the distance around the circumference of the body 504 in a clockwise 10 direction, in the sense of Figure 5, between the first region 508 / first sensor 514 and the second region 510 / second sensor 516 is less than that between the second region 510 / second sensor 516 and the first region 508 / first sensor 514, the control unit 120 infers that hair is being wrapped clockwise (in the sense of Figure 5) around the body 504. In examples, the control unit 120 may be configured to determine that, where Atl <At2, hair is wrapped in a 15 clockwise direction (in the sense of Figure 5) around the body 504. Referring to Figure 6b, at a first time, Tl’, there is a first change in the first signal indicative of hair being present at the first region 508. This is represented by the first peak associated with the first region 508 at Tl’. Following this, at a second time, T2’, there is a first change 20 in the second signal indicative of hair being present at the second region 510. This is represented by the first peak associated with the second region 510 at T2’. Following this, at a third time, T3 ’, there is a second change in the first signal indicative of further hair being present at the first region 508. This is represented by the second peak associated with the first region 508 at T3’. Following this, at a fourth time, T4’, there is a second change in the 25 second signal indicative of further hair being present at the second region 510. This is represented by the second peak associated with the second region 510 at T4’. In the example of Figure 6b, a first time difference, Atl’, between the first change in the first signal at Tl’ and the first change in the second signal at T2’ is more than the a second time difference, At2’, between the first change in the second signal at T2’ and the second change in the first 30 signal at T3’. In this case, the control unit 120 infers that hair is being wrapped anticlockwise (in the sense of Figure 5) around the body 504. In examples, the control unit 120 may be configured to determine that, where Atl >At2, hair is wrapped in an anti-clockwise direction (in the sense of Figure 5) around the body 504. 18 09 25 Determining the direction in which hair is wrapped around the body 504 based on these two signals may allow for the number of signals on which the determination is made to be minimised, which may allow for fast and / or efficient determination of the direction by the 5 control unit. Moreover, this may allow that the sensor arrangement 512 can comprise two sensors 514, 516, one each for the first region 508 and the second region 610. This may allow for the direction to be determined whilst minimising cost, weight, size and / or power consumption of the sensor arrangement 512. 10 As mentioned, the first region 508 and the second region 510 may be spaced about the axis A by an angle in the range 45 to 135 degrees, such as 90 degrees. It has been found that this range allows for the time gap between the first change in the first signal and the first change in the second signal, as well as the time gap between the first change in the second signal and the second change in the first signal, to be large enough to be reliably determined over 15 a range of typical wrapping speeds. Moreover, it has been found that this range allows the difference in those time gaps to be large enough to allow reliable determination of the wrapping direction over a range of typical wrapping speeds. In examples, the control unit 120 may restart the determination of the direction in which hair 20 is wrapped around the body 504 in response to each of the plurality of signals indicating that hair is not present at the plurality of regions. For example, this may correspond to a situation in which no hair is present at the body 504, and the control unit 120 may infer that the next change in one of the signals will represent a new wrapping of hair around the body 504. Alternatively, or additionally, in examples, the control unit 120 may be configured to restart 25 the determination of the direction in which hair is wrapped around the body 504 based on a time, between a change in one of the plurality of signals and a change in another of the plurality of signals, being larger than a first threshold. For example, if there is a relatively long gap (e.g. more than a few seconds, such as five seconds) between a change in a first signal of the plurality of signals and another change in any of the plurality of signals, the 30 control unit 120 may infer that the former change is associated with a previous wrapping of hair around the body 504 and the latter change is associated with a new wrapping of hair around the body 504. This may help the control unit 120 to determine the direction in which 18 09 25 the hair is currently wrapped around the body 104, 504, even in the case where not all of the signals indicate that hair is not present at the plurality of regions. In some examples, the control unit 120 is configured to control an operation of the haircare 5 appliance 502 based on the determination of the direction in which hair is wrapped around the body 504. As one example, the control unit 120 may control the feedback device 124 to provide feedback to the user based on the determined direction in which hair is wrapped around the 10 body 104. For example, the control unit 120 may determine whether or not the determined direction in which hair is wrapped around the body 504 matches a predetermined direction and control the feedback device 124 to provide feedback indicative of whether or not the determined direction in which hair is wrapped around the body matches the predetermined direction. If the determined direction matches the predetermined direction, then the control 15 unit 120 may control the feedback device 124 to provide third feedback to the user (such as a particular light) indicating that the direction in which the user is wrapping the hair around the body 504 matches the predetermined direction. If the determined direction does not match the predetermined direction, then the control unit 120 may control the feedback device 124 to provide fourth feedback to the user (such as a different particular light) indicating 20 that the direction in which the user is wrapping the hair around the body 504 does not match the predetermined direction. This may guide the user to operate the haircare appliance 502 as intended. In examples, the control unit 120 may be configured to determine the predetermined 25 direction based on user input received by the input interface 126. For example, the input interface 126 may allow a user to select or otherwise input a particular curl direction that they want to achieve. The control unit 120 may set the predetermined direction to match the input particular curl direction. As another example, the input interface 124 may allow a user to select or otherwise provide input indicative of a style intended to be achieved by use of 30 the haircare appliance 502. The control unit 120 may be configured to determine the predetermined direction based on the received user input indicative of the style intended to be achieved. For example, the input interface 126 may allow the user to select one of a plurality of styles. For example, a first style may involve curling hair in a first direction. The 18 09 25 control unit may infer, from the selection of the first style, that hair is to be curled in the first direction and may set the predetermined direction to the first direction accordingly to match the first direction. As another example, the input interface 126 may allow a user to select or otherwise provide input indicative of a side of a person’s head or face with which the 5 haircare appliance 502 is to be used. In this case, the control unit 120 may determine the predetermined direction based on the received user input indicative of the side of a person’s head or face. For example, it may be that, according to a particular style or otherwise, hair is to be curled in a direction away from the face of the person whose hair is being curled. A user may input that they are about to curl hair on the right side of a person’s face (from the 10 perspective of the person). The control unit 120 may infer from this that, in order to ensure that the hair is curled away from the person’s face, the predetermined direction should be anticlockwise (from the perspective of a main unit 506 of the haircare appliance looking towards the body 504). Conversely, a user may input that they are about to curl hair on the left side of a person’s face and the control unit 120 may determine that the predetermined is 15 clockwise (from the perspective of a main unit 506 of the haircare appliance looking towards the body 504). This may help guide a user’s use of the haircare appliance 502 to achieve a desired style. In the examples described above with reference to Figures 5 to 6b, there are two regions 20 508, 510 distributed about the axis A and the direction in which the hair is wrapped around the body 504 is determined based on time between changes in the signals. However, referring to Figure 7, there is illustrated a haircare appliance 702 according to another example. The haircare appliance 702 of Figure 7 may be the same as or similar to the haircare appliance 102, 402, 502 according to any one of the examples described above with 25 reference to Figures 1 to 6b (that is, it may have at least some or all of the same or similar components or functionality), except that in the haircare appliance 702 of Figure 7, the body 704 has at least three regions 708, 710, 712 distributed about the axis A. Specifically, in this example, the body 704 has three regions 708, 710, 712 distributed evenly around the axis A. In this example, the sensor arrangement is configured to output at least three signals, each 30 signal being indicative of a presence of hair at a respective one of the at least three regions 708, 710, 712. Specifically, in this example, the sensor arrangement comprises three sensors, 714, 716, 718, each located at a respective one of the three regions 708, 710, 712. In this example, the control unit 120 may, alternatively, or additionally, be configured to determine 18 09 25 the direction in which hair is wrapped around the body 704 based on an order in which the at least three signals change. Specifically, in this example, a first region 708, a second region 710 and a third region 712 5 are distributed about the axis A in order such that the second region 710 is clockwise (in the sense of Figure 7) about the axis A relative to the first region 708, and the third region 712 is clockwise (in the sense of Figure 7) about the axis relative to the second region 710. If a change (e.g. increase) in a first signal associated with the first region 708 is followed in order by a change (e.g. increase) in a second signal associated with the second region 710, which 10 in turn is followed in order by a change (e.g. increase) in a third signal associated with the third region 712, then the control unit infers that the direction in which the hair is wrapped around the body 704 is clockwise (in the sense of Figure 7). However, if the changes in the signals are in the reverse order, the control unit infers that the direction in which the hair is wrapped around the body 704 is anticlockwise (in the sense of Figure 7). Determining the 15 direction based on the order of changes may allow for the control unit 120 to determine the direction relatively efficiently (for example, without necessarily having to determine and compare time gaps between changes). In some examples, the control unit 120 may be configured to determine the direction in 20 which hair is wrapped around the body 704 based on a timing between changes in signal output by any two or more of the sensors 714, 716, 718, for example in a similar way to as described above with reference to Figures 5 to 6b, and / or based on an order or sequence in which the changes occur, for example as described above with reference to Figure 7. 25 In some examples the control unit 120 may control alternative or additional operations of the haircare appliance 502, 702 based on the determined direction in which hair is wrapped around the body 504, 704. For example, referring to Figure 8 there is illustrated a haircare appliance 802 according to an example. The haircare appliance 802 may be the same as or similar to the haircare appliance 102, 502 according to any of the examples described above 30 with reference to Figures 1 to 7 (that is, it may have at least some or all of the same or similar components or functionality), except that in this example the haircare appliance 802 comprises an airflow generator 860 configured to generate an airflow and an element 862 configured to direct the generated airflow around the body 804. The generated airflow may 18 09 25 be used to provide a ‘cold shot’ (that is, a flow of unheated air) to the hair tress that is wrapped around the body 804, in order to set the curl. For example, the airflow generator 860 may comprise a motor configured to drive an impeller (not shown), and may be located in the main part or handle (not shown in Figure 6) of the haircare appliance 802. The airflow 5 generator 860 may be operable to draw air in from an air inlet 864 of the main part of the haircare appliance 802 and provide the generated airflow to the element 862, which may also be located in the main part of the haircare appliance 802 or may be located in the body 804. The element 862 is operable to direct the airflow either clockwise (see arrow D in Figure 8) or anticlockwise (see arrow E in Figure 8) around the body 804. Specifically, in 10 this example, the body 804 comprises a first set of air outlets 864 arranged to direct airflow tangentially away from the body 804 in a clockwise direction (in the sense of Figure 8) around the body 804 and a second set of air outlets 866 arranged to direct airflow tangentially away from the body in an anti-clockwise direction (in the sense of Figure 8) around the body 804. The element 862 is operable to provide the generated airflow to either the first set of 15 air outlets 864 or the second set of air outlets 866. For example, the element 862 may be provided by one or more values operable to allow or restrict airflow to the sets of outlets, or for example a fin operable to direct the airflow to either one or the other sets of outlets. If the control unit 120 determines that the hair is wrapped around the body in a clockwise direction (in the sense of Figure 8), the control unit 120 may control the element 862 to 20 direct the airflow in the clockwise direction (in the sense of Figure 8), for example by controlling the element 862 to provide or direct the generated airflow to the first set of outlets 864. If the control unit 120 determines that the hair is wrapped around the body in an anticlockwise direction (in the sense of Figure 8), the control unit 120 may control the element 862 to direct the airflow instead in the anticlockwise direction, for example by 25 controlling the element 862 to provide or direct the generated airflow to the second sets of outlets 866. In this way, the airflow (which, for example, provides the ‘cold shot’) may be provided in the same direction as the curl, and hence reduce separation of hairs from the curl. 30 In the examples described above with reference to Figures 5 to 8, the body 504, 704 of the haircare appliance 502, 702 was in the form of a cylinder and the regions were distributed around the circumference of the cylinder. However, it will be appreciated that this need not necessarily be the case, and that in other examples, other forms of the body and other 18 09 25 distributions of the regions of the body may be used. For example, a body having a triangular or square or pentagonal or any polygonal cross section may be used, and the regions may be distributed about the permitter. 5 In the examples described above with reference to Figures 1 to 8, the body 104, 404, 504, 704, 804 is attachable to the main part 106, 406 of the haircare appliance 102, 402, 502, 702, 802, but it will be appreciated that this need not necessarily be the case and that in some examples the body 104, 404, 504, 704, 804 may be integral to the haircare appliance 102, 402, 502, 702, 802. 10 Some of the examples described above referred to a specific number of regions, however it will be appreciated that in other examples other numbers of regions may be used. In the examples described above with reference to Figures 1 to 8, the control unit 120 was 15 included in a haircare appliance 102, 402, 502, 702, 802 and specifically a main part 106, 406 of the haircare appliance 102, 402, 502, 702, 802, and the haircare appliance 102, 402, 502, 702, 802 also included the sensor arrangement 112, 412, 512, 712 located in an attachment 104, 404, 504, 704 to the main part 106, 406 but it will be appreciated that this need not necessarily be the case. For example, in some examples the body 104, the sensor 20 arrangement 112 and the control unit 120 may be provided in an integrated haircare appliance 102. As another example, the body 104, the sensor arrangement 112 and the control unit 120 may all be provided in an attachment 104 to a main part 106 of the haircare appliance 102. As another example, one of the sensor arrangement 112 and the control unit 120 may be provided in an attachment 104 to a main part 106 and the other of the sensor 25 arrangement 112 and the control unit 120 may be provided in the main part 106. It will be appreciated that other configurations may be used. Further, it will be appreciated that in some examples the control unit 120 may in principle be located anywhere and may be provided separately from other components of the haircare appliance 102. For example, the plurality of signals may, for example, be transmitted to and received by the control unit 120 30 over a wireless connection to the sensor arrangement 112 and / or the result of the determination by the control unit 120 may be transmitted to and received by the haircare appliance 102 for example over a wireless connection, which may in turn, for example, control an operation of the haircare appliance 102 on the basis of the determination. 18 09 25 Referring to Figure 9 there is illustrated a control unit 922 according to an example. The control unit 922 may have the same or similar features as the control unit described above with reference to Figures 1 to 8. In this example, the control unit 922 comprises an input 5 interface 923, an output interface 925, a processor 927 and a memory 929. The input interface 923 may, for example, receive one or more signals, each signal being indicative of a presence of hair at a respective one or more regions of a body of a haircare appliance, for example according to any of the examples described above. These one or more signals may be received from a sensor arrangement 928 configured to output the one or more signals. 10 These one or more signals may be received by wired or wireless means. The processor 927 may be configured to, in combination with the memory 929, determine the number of wraps of hair around the body of the haircare appliance based on a plurality of changes in the one or more signals, for example according to any of the examples described above. For example, the memory 929 may store a computer program which, when executed by the 15 processor 929, causes the processor to receive the one or more signals and determine the number of wraps of hair around the body of the haircare appliance, for example according to any of the examples above. The output interface 925 may be configured to output the determination as required, for example to a separate controller (not shown) configured to control operation of the haircare appliance. In other examples, the control unit 922 may be 20 configured to control operation of the appliance in response to the determination of the number of wraps around the body. In these examples, the output interface 925 may be configured to output control signals or instructions to components of the haircare appliance, such as a feedback interface 924 and a heater 926 for heating at least a portion of the body, in order to control an operation of the appliance (for example according to any of the 25 examples described above). These control signals may be transmitted by wired or wireless means. Referring to Figure 10, there is illustrated a method of determining a number of wraps of hair around a body of a haircare appliance, the body having an axis around which the hair is 30 wrapped, the body having one or more regions each having a respective location along the axis. The method comprises, in step 1080, receiving one or more signals, each signal being indicative of a presence of hair at a respective one of the one or more regions. For example, one or more signals 330, 440, 442, 444 may be according to any one of the examples described above with reference to Figures 1 to 9. The method comprises, in step 1082, determining a number of wraps of hair around the body based on a plurality of changes in the one or more signals. For example, the determination may be according to any of the examples described above with reference to Figures 1 to 9. For example, the method may 5 be performed by the control unit 120 according to any one of the examples described above with reference to Figures 1 to 9. In some examples, the method may comprise steps corresponding to any of the functionality described above with reference to Figures 1 to 9, for example any of the functionality of the example control unit 120 described above with reference to Figures 1 to 9. 10 Whilst particular examples have been described, it should be understood that these are illustrative examples only and that various modifications may be made without departing from the scope of the invention as defined by the claims. LO 15 CM co 18 09 25

Claims

1. A haircare appliance comprising:a body having an axis around which hair is wrapped in use, the body having one or 5 more regions each having a respective location along the axis;a sensor arrangement configured to output one or more signals, each signal being indicative of a presence of hair at a respective one of the one or more regions; anda control unit configured to determine a number of wraps of hair around the body based on a plurality of changes in the one or more signals;10 wherein the body has a plurality of regions distributed along the axis of the body,wherein the sensor arrangement is configured to output a plurality of signals, each signal being indicative of a presence of hair at respective one of the plurality of regions; and wherein the control unit is configured to determine the number of wraps of hair around the body based on a change in each of the plurality of signals.

152. The haircare appliance according to claim 1, wherein each region extends only part way around the axis.

3. The haircare appliance according to claim 1 or claim 2, wherein a first signal of the 20 one or more signals is indicative of a presence of hair at a first region extending along the axis of the body, and wherein the control unit is configured to determine the number of wraps of hair around the body based on a plurality of changes in the first signal.

4. The haircare appliance according to claim 3, wherein the control unit is configured 25 to determine the number of wraps of hair around the body based on a first change in the first signal indicative of hair being present at the first region and a number of one or more further changes in the first signal, each further change being indicative of further hair being present at the first region.30 5. The haircare appliance according to any one of the preceding claims, wherein thecontrol unit is configured to determine the number of wraps of hair around the body based on a change in one of the plurality of signals indicative of hair being present at one of the plurality of regions and a number of one or more changes in a respective one or more others18 09 25of the plurality of signals, each of the one or more changes being indicative of hair being present at a respective one of the regions.

6. The haircare appliance according to any one of the preceding claim, wherein the 5 plurality of regions are arranged in a row extending along the axis of the body.

7. The haircare appliance according to any one of the preceding claims, wherein the control unit is configured to determine the number of wraps of hair around the body based on an order in which the plurality of signals change.

108. The haircare appliance according to any one of claim 1 to claim 7, wherein the control unit is configured to control an operation of the haircare appliance based on the determined number of wraps of hair around the body.15 9. The haircare appliance according to claim 8, wherein the haircare appliancecomprises a feedback device configured to provide feedback to a user of the haircare appliance in use, and wherein the control unit is configured to control the feedback device to provide feedback to the user based on the determined number of wraps of hair around the body.2010. The haircare appliance according to claim 9, wherein the control unit is configured to:compare the determined number of wraps of hair around the body to a predetermined number of wraps; and25 control the feedback device to provide feedback to the user based on the comparison.

11. The haircare appliance according to claim 10, wherein the haircare appliance comprises an input interface configured to receive a user input, and wherein the control unit is configured to determine the predetermined number of wraps based on the received user 30 input.18 09 2512. The haircare appliance according to any one of claim 9 to claim 11, wherein the body is removeable, and wherein the feedback is indicative of an instruction to replace the body with a body of a different diameter.5 13. The haircare appliance according to any one of claim 9 to claim 12, wherein thecontrol unit is configured to determine a length of a user’s hair based on the determined number of wraps of the hair around the body and a circumference of the body; determine a style to recommend to the user based on the determined length of the user’s hair; and control the feedback device to provide feedback indicative of the determined style.1014. The haircare appliance according to any one of claim 8 to claim 13, wherein the haircare appliance comprises a heater configured to heat at least a portion of the body, and wherein the control unit is configured to control the heather to heat the at least a portion of the body to a particular temperature based on the particular determined number of wraps of 15 hair around the body.

15. The haircare appliance according to any one of claim 1 to claim 14, wherein the sensor arrangement comprises one or more sensors, each sensor being configured to output a respective one of the one or more signals.2016. The haircare appliance according to claim 15, wherein one or more of the sensors are non-contact sensors.

17. The haircare appliance according to any one of claim 1 to claim 16, wherein each 25 signal comprises a temporal series of values or the control unit samples each signal as a temporal series of values, and each of the values is indicative of the degree to which hair is present at the respective region at a given time.

18. The haircare appliance according to any one of claim 1 to claim 17, wherein the body 30 has a plurality of regions distributed about the axis; wherein a plurality of signals output by the sensor arrangement are each indicative of a presence of hair at a respective one of the plurality of regions distributed about the axis; and wherein the control unit is configured to determine a direction in which hair is wrapped around the body based on the plurality ofsignals each indicative of a presence of hair at a respective one of the plurality of regions distributed about the axis.

19. A method of determining a number of wraps of hair around a body of a haircare 5 appliance, the body having an axis around which the hair is wrapped, the body having one or more regions each having a respective location along the axis, the method comprising:receiving one or more signals, each signal being indicative of a presence of hair at a respective one of the one or more regions; anddetermining a number of wraps of hair around the body based on a plurality of 10 changes in the one or more signals;wherein the body has a plurality of regions distributed along the axis of the body, wherein the sensor arrangement is configured to output a plurality of signals, each signal being indicative of a presence of hair at respective one of the plurality of regions; andwherein determining the number of wraps of hair around the body is based on a LO 15 change in each of the plurality of signals.CMCO

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