Haircare appliance

Abstract

A haircare appliance comprising a body 104 around which hair can be wrapped, a sensor arrangement 112 to indicate whether hair is present at a plurality of regions and a control unit configured to det

Description

FIELD OF THE INVENTION The present invention relates to a haircare appliance. 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. SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a haircare appliance comprising: a body having an axis around which hair is wrapped in use, the body having a plurality of regions distributed about the axis; a sensor arrangement configured to output a plurality of signals, each signal being indicative of a presence of hair at a respective one of the plurality of regions; and a control unit configured to determine a direction in which hair is wrapped around the body based on the plurality of signals. This allows the haircare appliance to determine the direction in which hair is wrapped around the body. For example, in order to curl hair, a user may wrap a hair tress around the body of the haircare appliance. The user may wrap the hair tress around the body in either a clockwise direction or an anticlockwise direction (from a given perspective). Determining the direction in which hair is wrapped around the body therefore provides information on the way in which the haircare appliance is currently being used. Moreover, determining the direction in which the hair is wrapped around the body provides information of a greater granularity than, for example, merely determining that there is hair wrapped around the body. The direction in which 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 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. Accordingly, an improved haircare appliance is provided. In some examples, the sensor arrangement is configured to output a first signal indicative of a presence of hair at a first region of the plurality of regions, and a second signal indicative of a presence of hair at a second region of the plurality of regions; the first region and the second region are spaced about the axis by less than 180 degrees; and the control unit is configured to determine the direction in which hair is wrapped around the body based on a timing of one or more changes in each of the first signal and the second signal. This allows for the direction to be determined based on two signals associated with two regions. This 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 control unit. Moreover, this may allow that the sensor arrangement can comprise two sensors, one each for the first region and the second region. This may allow for the direction to be determined whilst minimising cost, weight, size and / or power consumption of the sensor arrangement. The first and second regions being spaced about the axis by less than 180 degrees (that is, spaced by an angle other than 180 degrees) allows for the direction to be determined based on the timing of a change in each of the first and second signals. In some examples, the direction may be determined based on a time of a change in the first signal relative to a time of a change in the second signal. For example, the second region may be positioned 45 degrees clockwise (from a given perspective) about the axis from the first region. If there is a relatively small time gap between the change in the first signal and the change in the second signal, it may be inferred that the hair is wrapped around the body in a clockwise direction (from the given perspective). However, if there is a relatively large time gap between the change in the first signal and the change in the second signal, it may be inferred that the hair is wrapped around the body in an anticlockwise direction (from the given perspective). This may allow for the direction to be determined based one change in each of the first and second signals, which may provide for fast and / or efficient processing by the control unit. In some examples, the control unit is configured to determine the direction in which hair is wrapped around the body based on: a time between a first change in the first signal indicative of hair being present at the first region and a first change in the second signal indicative of hair being present at the second region; and a time between the first change in the second signal indicative of hair being present at the second region and a second change in the first signal indicative of further hair being present at the first region. This may allow for the determination of the direction that is robust to variations in wrapping speed by different users. This may therefore allow for a flexible determination of the direction in which the hair is wrapped around the body. For example, the second region may be positioned 45 degrees clockwise (from a given perspective) from the first region. As a user wraps the hair around the body, the first signal may change (e.g. increase) at a first time, the second signal may change (e.g. increase) at a second time, and the first signal may change (e.g. increase) again at a third time when the hair has made one full wrap around the body. If the difference between the first time and the second time is less than the difference between the second time and the third time, then it may be inferred that the hair is wrapped around the body in a clockwise direction (from the given perspective). However, if the difference between the first time and the second time is more than the difference between the second time and the third time, it may be inferred that the hair is wrapped around the body in an anticlockwise direction (from the given perspective). Reliable and / or flexible determination of the direction may therefore be provided. In some examples, the first region and the second region may be spaced about the axis 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 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. Reliable determination of the direction may therefore be provided. In some examples, the body has at least three of the regions distributed about the axis; the sensor arrangement is configured to output at least three signals, each signal being indicative of a presence of hair at a respective one of the at least three regions; and the control unit is configured to determine the direction in which hair is wrapped around the body based on an order in which the at least three signals change. This may allow for a relatively efficient determination of the direction. For example, a first, second and third region may be distributed about the axis in order, for example such that the second region is clockwise (from a given perspective) about the axis relative to the first region, and the third region is clockwise (from the given perspective) about the axis relative to the second region. If a change (e.g. increase) in a first signal associated with the first region is followed in order by a change (e.g. increase) in a second signal associated with the second region, which in turn is followed in order by a change (e.g. increase) in a third signal associated with the third region, then the control unit may infer that the direction in which the hair is wrapped around the body is clockwise (from the given perspective). However, if the changes in the signals were in the reverse order, the control unit may infer that the direction in which the hair is wrapped around the body is anticlockwise (from the given perspective). Determining the direction based on the order of changes may allow for the control unit 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 is configured to restart the determination of the direction in which hair is wrapped around the body 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. This may allow for a determination of the direction in which hair is currently wrapped around the body. For example, if there is a long gap between two changes, the control unit may infer that the former change is associated with a previous wrapping of hair around the body, and the latter change is associated with a new wrapping of hair around the body. Restarting the determination of the direction from this latter change may therefore help ensure the control unit determined the direction in which the hair is currently wrapped around the body. In other examples, the control unit is configured to restart the determination of the direction 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 a new wrapping of hair around the body. 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 determination of the direction in which hair is wrapped around the body. This may allow the haircare appliance to be operated based on the determined direction. In some examples, the haircare appliance comprises a feedback device configured to provide feedback to a user of the haircare appliance in use, and the control unit is configured to control the feedback device to provide feedback to the user based on the determined direction in which hair is wrapped around the body. This may allow the haircare appliance to guide the use of the haircare appliance by the user. 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 determined direction of the wrapping 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 curled in a first direction around the body, away from the face of the person whose hair is being styled. If the control unit determines that the hair is wrapped in the opposite direction to the first direction, the control unit may control 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 re-wrap that hair tress around the body, but this time in the first direction, so as to achieve the selected particular style. Other examples are possible. This feedback allows improved interaction of the user and the haircare appliance and helps the user to use the haircare appliance to achieve a particular style. In some examples, the control unit is configured to: determine whether or not the determined direction in which hair is wrapped around the body matches a predetermined direction; and control the feedback device to provide feedback indicative of whether or not the determined direction in which hair is wrapped around the body matches the predetermined direction. This may allow the haircare appliance to guide the use of the haircare appliance by the user to achieve a particular curl direction. For example, the user may input a desired curl direction, or a desired curl direction may be inferred from a selected particular style, for example. This may be used as the predetermined direction. If the determined direction matches the predetermined direction 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) indicating that the direction in which the user is wrapping the hair around the body matches the predetermined direction. This may give the user confidence to continue wrapping the hair in this direction. If the determined direction does not match the predetermined direction 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 direction in which the user is wrapping the hair around the body does not match the predetermined direction. This may prompt to the user to unwrap the hair from the body and wrap the hair around the body in the opposite direction. 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 a user input, and wherein the control unit is configured to determine the predetermined direction based on the received user input. This allows a user to input a particular curl direction 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 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 input interface is configured to receive user input indicative of a side of a person’s head with which the haircare appliance is to be used, and the control unit is configured to determine the predetermined direction based on the received user input indicative of the side of a person’s head. This may help a user to achieve a desired style. For example, the user input may be indicative of a side of a person’s face at which hair to be curled is located. For example, a user may input that they are about to curl hair on the right side of a person’s face (from the perspective of the person). The control unit may infer from this that, in order to ensure that the hair is curled away from the person’ face, the predetermined direction should be anticlockwise (from the perspective of a handle of the haircare appliance). In this case, if the control unit determines that the direction in which hair is wrapped around the body is clockwise (from the perspective of the handle of the haircare appliance), the control unit may control the feedback device to indicate that hair is being curled in an incorrect direction. In some examples, the input interface is configured to receive user input indicative of a style intended to be achieved by use of the haircare appliance, and wherein the control unit is configured to determine the predetermined direction based on the received user input indicative of the style intended to be achieved. This may help guide a user to use the haircare appliance to achieve a particular style. For example, the input interface 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 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. In some examples, the haircare appliance comprises an airflow generator configured to generate an airflow and an element configured to direct the generated airflow around the body, and the control unit is configured to control the element to direct the airflow around the body in a direction that matches the determined direction in which hair is wrapped around the body. This may provide for a reduction in ‘fly-away’ hairs (that is, hairs that are caused to separate from a main part of the curled hair tress) resulting from the airflow. For example, the haircare appliance may be configured to provide a ‘cold shot’ (that is, a flow of unheated air) to the hair tress that is wrapped around the body, in order to set the curl. The element, for example a valve or a fin, may be configurable to direct the airflow around the body or tangentially away from the body either in a clockwise direction (from a given perspective) or an anticlockwise direction (from the given perspective). If the control unit determines that the hair is wrapped around the body in a clockwise direction (from the given perspective), the control unit may control the element to direct the airflow in the clockwise direction (from the given perspective). If the control unit determines that the hair is wrapped around the body in an anticlockwise direction (from the given perspective), the control unit may control the element to direct the airflow instead in the anticlockwise direction. In this way, the airflow (which, for example, provides the ‘cold shot’) is provided in the same direction as the curl, and hence reduces separation of hairs from the curl. The curl may therefore be more precisely formed. In some examples, the sensor arrangement comprises a plurality of sensors, each sensor being located at a respective one of the plurality of regions and being configured to output one of the plurality of signals. This may provide for a robust way to provide the plurality of signals. For example, each 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, this may allow for the determination to be robust with respect to the failure of one of the sensors. 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 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 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 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 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. 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 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 direction, for example by filtering out small and / or slow changes associated with background noise. In some examples, one or more of the signals output by the sensor arrangement are indicative of a presence of hair at a respective one or more regions each having a respective location along the axis; and the control unit is configured to determine a number of wraps of hair around the body based on a plurality of changes in the one or more signals. This allows the number of wraps to be determined. 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 number of wraps of hair around the body. For example, this may be used to control the feedback device to provide feedback to the user and / or to control a temperature to which a heater of the haircare appliance heats the body. Other examples are possible. This may provide for a yet further improved haircare appliance. According to a second aspect of the present invention, there is provided a method of determining a direction in which hair is wrapped around a body of a haircare appliance, the body having an axis around which the hair is wrapped, the body having a plurality of regions distributed about the axis, the method comprising: receiving a plurality of signals, each signal being indicative of a presence of hair at a respective one of the plurality of regions; and determining a direction in which hair is wrapped around the body based on the plurality of signals. This may allow for similar advantages to as described above for the first aspect. In some examples, the method may comprise controlling an operation of the haircare appliance based on the determination of the direction in which hair is wrapped around the body. This may be the same or similar 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 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 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 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: Figure lisa 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 function of time, according to an example; Figure 4a 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 4b 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 another example; Figure 5 is a schematic diagram that illustrates a cross-sectional view of a haircare appliance according to another example; Figure 6 is a schematic diagram that illustrates a cross-sectional view of a haircare appliance according to another example; Figure 7 is a graph that illustrates schematically a plot of signal output by a sensor as a function of time, according to another example; Figure 8a is a schematic diagram that illustrates a side view of a haircare appliance according to another example; Figure 8b is a graph that illustrates schematically a plot of signals output by respective sensors as a function of time, according to an example; 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. DETAILED DESCRIPTION OF THE INVENTION Referring to Figures 1 and 2, there is illustrated a haircare appliance 102 according to an example. The haircare appliance 102 comprises a body 104 having an axis A around which hair is wrapped in use. The body 104 has a plurality of regions 108, 110 distributed about the axis A. The haircare appliance 102 comprises a sensor arrangement 112. The sensor arrangement 112 is configured to output a plurality of signals, each signal being indicative of a presence of hair at a respective region 108,110 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 a direction in which hair is wrapped around the body 104 based on the plurality of signals. The haircare appliance 102 is for curling hair. The haircare appliance 102 comprises a main 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 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 input. For example, the input interface 126 may allow a user to input a particular curl direction or style that they intend to curl the hair in, or a side of a person’s face at which hair to be curled is located. 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 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 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, so as to guide the user’s operation of the haircare appliance. In some examples, the input interface 126 and the feedback device 214 may be provided by the same device, such as a touch screen display. Each region 108, 110 is elongate along the axis A. Each region 108, 110 extends only part way around the axis A. In this example, there are two regions 108, 110, specifically, a first region 108 and a second region 110. More than two regions can be employed. As mentioned, the haircare appliance 102 comprises a sensor arrangement 112 configured to output a plurality of signals, each signal being indicative of a presence of hair at a respective region 108, 110 of the body 104. In this example, the sensor arrangement 112 is configured to output a first signal indicative of a presence of hair at the first region 108, and a second signal indicative of a presence of hair at the second region 110. In this example, the sensor arrangement 112 comprises a plurality of sensors 114, 116 each sensor 114, 116 being located at a respective region 114, 116 of the body 104 and being configured to output one of the plurality of signals. In this example, each sensor 114, 116 is positioned so as to sense radially outwardly from the body 104 (i.e. radially outwardly of the region 108, 110 to which the sensor corresponds). In some examples, one or more of the sensors 114, 116 may be non-contact sensors. For example, a non-contact sensor may be configured to output a signal indicative of hair 230 being present at the sensor 114, 116 without hair 230 necessarily coming into physical contact with the sensor 114, 116. 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, one or more of the sensors 114, 116 may be a contact sensor, i.e. one which is configured to output a signal indicative of hair 230 being present at the sensor 114, 116 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 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, one or more of the sensors 114, 116 may be any sensor whose output is affected by the presence of hair. For example, where the regions 114, 116 are heated, a sensor resistant to high temperature may be chosen (such as the heated element coupled with a temperature sensor described above). In some examples, each 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 of hair 230 to the respective region 108, 110 or otherwise a degree to which hair 230 is present at the respective region 108, 110. In some examples, each 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 respective region 108, 110 at a given time. In other examples, each signal may be binary. For example, each signal may be logically low when hair is not present at the respective region 108, 110 and may be logically high when hair 230 is present at the respective region 108, 110. In some examples, hair being present at a region 108, 110 may correspond to hair 230 being near or proximate to the region 108, 110. In other examples, hair 230 being present at a region may correspond to the hair 230 being in contact with the region 108, 110. The sensor arrangement 112 may be connected to the control unit 120 by wired or wireless means, in order to provide the plurality of signals 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 sensors 114, 116 and the signals output by each sensor may be provided directly to the control unit 120 as the plurality of signals. In other examples, the sensor arrangement 112 may comprise the sensors 114, 116 and a multichannel reader (not shown), and the plurality of signals may be provided to the control unit 120 by the multichannel reader (not shown). For example, the multichannel reader may sample each of the signals output by the sensors as a temporal series of values and provide these temporal series of values to the control unit 120 as the plurality of signals. In any case, the sensor arrangement 112 is configured to output a plurality of signals, each signal being indicative of a presence of hair at a respective region 108, 110 of the body 104. Figure 3 illustrates one of the signals output by the sensor arrangement 112 as a function of time, according to an example. The signal is indicative of the presence of hair at the first region 108. Specifically, the signal is the signal output by the sensor 114 corresponding to the first region 108. Before a time, tl, hair is not present at the first region 108. Accordingly, before tl, the signal has a relatively low value, RI, indicating that hair is not present at the first region. At tl, hair becomes present at the first region 108. Accordingly, at tl, the signal changes, specifically it increases by AR to a relatively higher value, R2. This indicates that hair is present at the first region 108. After tl, the hair remains present at the first region. Accordingly, the signal remains at R2. This indicates that hair remains present at the first region 108. The control unit 120 analyses the signal to determine that the change, AR, occurs and hence that hair is present at the first region 104. As mentioned, in the example of Figures 1 and 2, the sensor arrangement 112 is configured to output a first signal indicative of a presence of hair at the first region 104 and a second signal indicative of a presence of hair at the second region 110. Specifically, in this example, a first sensor 114 is located in the first region 108 and is configured to output a first signal indicative of a presence of hair at the first region 108, and a second sensor 116 is located in the second region 110 and is configured to output a second signal indicative of a presence of hair at the second region 110. Further, in this example, the first region 108 / first sensor 114 and the second region 110 / second sensor 116 are spaced about the axis by less than 180 degrees. That is, the first region 108 / first sensor 114 and the second region 110 / second sensor 116 are spaced about the axis from one another by an angle that is other than 180 degrees. Specifically, in this example, the first region 108 / first sensor 114 and the second region 110 / second sensor 116 are spaced about the axis A by an angle in the range 45 to 135 degrees. Specifically, as best seen in Figure 2, in this example, the first region 108 / first sensor 114 and the second region 110 / second sensor 116 are spaced about the axis A by 90 degrees. More specifically, the second region 110 / second sensor 116 is spaced 90 degrees clockwise (in the sense of Figure 2) about the axis A from the first region 108 / first sensor 114. As a result, the distance around the circumference of the body 104 in a clockwise direction, in the sense of Figure 2, between the first region 108 / first sensor 114 and the second region 110 second 116 is less than that between the second region 110 / second region 116 and the first region 108 / first sensor 114. In this example, the control unit 120 is configured to determine the direction in which hair is wrapped around the body 104 based on a timing of one or more changes in each of the first signal and the second signal. Specifically, referring to Figures 4a and 4b, there are illustrated plots of the gradient of the signal output by each of the first sensor 114 and the second sensor 116 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 an increase, in the signal, and hence is indicative of hair being present at the region 108,110 associated with the signal. Figure 4a illustrates the case where hair is being wrapped clockwise (in the sense of Figure 2) around the body 104. Figure 4b illustrates the case where hair is being wrapped anticlockwise (in the sense of Figure 2) around the body 104. In each of Figures 4a and 4b, the solid bars represent a peak in the gradient of the signal associated with the first region 108 / first sensor 114, and the hollow bars represent a positive spike or peak in the gradient of the signal associated with the second region 110 / second sensor 116. Referring first to Figure 4a, at a first time, tl, there is a first change in the first signal indicative of hair being present at the first region 108. This is represented by the first peak associated with the first region 108 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 110. This is represented by the first peak associated with the second region 110 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 108. This is represented by the second peak associated with the first region 108 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 110. This is represented by the second peak associated with the second region 110 at t4. In the example of Figure 4a, 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 less than the 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 104 in a clockwise direction, in the sense of Figure 2, between the first region 108 / first sensor 114 and the second region 110 / second sensor 116, is less than that between the second region 110 / second sensor 116 and the first region 108 / first sensor 114, the control unit 120 infers that hair is being wrapped clockwise (in the sense of Figure 2) around the body 104. In examples, the control unit 120 may be configured to determine that, where Atl <At2, hair is wrapped in a clockwise direction (in the sense of Figure 2) around the body 104. Referring to Figure 4b, at a first time, tl’, there is a first change in the first signal indicative of hair being present at the first region 108. This is represented by the first peak associated with the first region 108 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 110. This is represented by the first peak associated with the second region 110 at time 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 108. This is represented by the second peak associated with the first region 108 at t3’. Following this, at fourth time, t4’, there is a second change in the second signal indicative of further hair being present at the second region 110. This is represented by the second peak associated with the second region 110 at t4’. In the example of Figure 4b, 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 signal at t3 ’. In this case, the control unit 120 infers that hair is being wrapped anti-clockwise (in the sense of Figure 2) around the body 104. In examples, the control unit 120 may be configured to determine that, where Atl >At2, hair is wrapped in an anticlockwise direction (in the sense of Figure 2) around the body 104. In examples, the control unit 120 may restart the determination of the direction in which hair is wrapped around the body 104 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 104, 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 104. Alternatively, or additionally, in examples, the control unit 120 may be configured to restart the determination of the direction in which hair is wrapped around the body 104 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 control unit 120 may infer that the former change is associated with a previous wrapping of hair around the body 104 and the latter change is associated with a new wrapping of hair around the body 104. This may help the control unit 120 to determine the direction in which 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 appliance 102 based on the determination of the direction in which hair is wrapped around the body 104. 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 body 104. For example, the control unit 120 may determine whether or not the determined direction in which hair is wrapped around the body 104 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 unit 120 may control the feedback device 124 to provide first feedback to the user (such as a particular light) indicating that the direction in which the user is wrapping the hair around the body 104 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 second feedback to the user (such as a different particular light) indicating that the direction in which the user is wrapping the hair around the body 104 does not match the predetermined direction. This may guide the user to operate the haircare appliance 102 as intended. In examples, the control unit 102 may be configured to determine the predetermined 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 126 may allow a user to select or otherwise provide input indicative of a style intended to be achieved by use of the haircare appliance 102. 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 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 haircare appliance 102 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 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’ face, the predetermined direction should be anticlockwise (from the perspective of a main unit 106 of the haircare appliance looking towards the body 104). 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 clockwise (from the perspective of a main unit 106 of the haircare appliance looking towards the body 104). In the examples described above the body 104 has two regions 108, 110 and the direction in which the hair is wrapped around the body 104 is determined based on time in between the signals. However, referring to Figure 5, there is illustrated a haircare appliance 502 according to another example. The haircare appliance 502 of Figure 5 may be the same or similar to the haircare appliance 102 described above with reference to Figures 1 to 4b (that is, it may have at least some or all of the same or similar components or functionality), except that in the haircare appliance 502 of Figure 5, the body 504 has at least three of the regions 508, 510, 512 distributed about the axis A. Specifically, in this example, the body 504 has three regions 508, 510, 512 distributed evenly around the axis A. In this example, the sensor arrangement is configured to output at least three signals, each signal being indicative of a presence of hair at a respective one of the at least three regions 508, 510, 512. Specifically, in this example, the sensor arrangement comprises three sensors, 514, 516, 518, each located at a respective one of the three regions 508, 510, 512. In this example, the control unit 120 may, alternatively or additionally, be configured to determine the direction in which hair is wrapped around the body 504 based on an order in which the at least three signals change. Specifically, in this example, a first region 508, a second region 510 and a third region 512 are distributed about the axis A in order such that the second region 510 is clockwise (in the sense of Figure 5) about the axis A relative to the first region 508, and the third region 512 is clockwise (in the sense of Figure 5) about the axis relative to the second region 510. If a change (e.g. increase) in a first signal associated with the first region 508 is followed in order by a change (e.g. increase) in a second signal associated with the second region 510, which in turn is followed in order by a change (e.g. increase) in a third signal associated with the third region 512, then the control unit infers that the direction in which the hair is wrapped around the body 104 is clockwise (in the sense of Figure 5). 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 104 is anticlockwise (in the sense of Figure 5). In some examples, the control unit 120 may be configured to determine the direction in which hair is wrapped around the body 504 based on a timing between changes in signal output by any two or more of the sensors 514, 516, 518, for example in a similar way to as described above with reference to Figures 1 to 4b, and / or based on an order or sequence in which the changes occur, for example as described above with reference to Figure 5. In the above examples, it is described that the control unit 102 may control the feedback device 124 based on the determined direction in which hair is wrapped around the body 104. However, in other examples the control unit 102 may alternatively or additionally control other operations of the haircare appliance 102 based on the determined direction in which hair is wrapped around the body 104. For example, referring to Figure 6 there is illustrated a haircare appliance 602 according to an example. The haircare appliance 602 may be the same as or similar to the haircare appliance 102, 502 according to any of the examples described above with reference to Figures 1 to 5 (that is, it may have at least some or all of the same or similar components or functionality). However, in this example, the haircare appliance 602 comprises an airflow generator 660 configured to generate an airflow and an element 662 configured to direct the generated airflow around the body 104. The generated airflow may be used to provide a ‘cold shot’ (that is, a flow of unheated air) to the hair tress that is wrapped around the body, in order to set the curl. For example, the airflow generator 660 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 602. The airflow generator 660 may be operable to draw air in from an air inlet 664 of the main part of the haircare appliance 602 and provide the generated airflow to the element 662, which may also be located in the main part of the haircare appliance 602 or may be located in the body 604. The element 662 is operable to direct the airflow either clockwise (see arrow D in Figure 6) or anticlockwise (see arrow E in Figure 6) around the body 604. Specifically, in this example, the body 604 comprises a first set of air outlets 664 arranged to direct airflow tangentially away from the body 604 in a clockwise direction (in the sense of Figure 6) around the body 604 and a second set of air outlets 666 arranged to direct airflow tangentially away from the body in an anti-clockwise direction (in the sense of Figure 6) around the body 604. The element 662 is operable to provide the generated airflow to either the first set of air outlets 664 or the second set of air outlets 666. For example, the element 662 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 6), the control unit 120 may control the element 662 to direct the airflow in the clockwise direction (in the sense of Figure 6), for example by controlling the element 662 to provide or direct the generated airflow to the first set of outlets 664. If the control unit 120 determines that the hair is wrapped around the body in an anticlockwise direction (in the sense of Figure 6), the control unit 120 may control the element 662 to direct the airflow instead in the anticlockwise direction, for example by controlling the element 662 to provide or direct the generated airflow to the second sets of outlets 666. 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. In the examples described above with reference to Figures 1 to 6, the body 104, 504, 604 of the haircare appliance 102, 502, 602 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 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. In the examples described above with reference to Figures 1 to 6, the control unit 120 is configured to determine a direction in which hair is wrapped around the body 104, 504, 604. In some examples, the control unit 120 may also be configured to determine a number of wraps of hair around the body 104, 504, 604 based on a plurality of changes in one or more of the signals. For example, one complete turn or revolution of a hair tress around the body 104, 504, 604 may equate to one wrap of hair around the body 104, 504. 604. Multiple complete turns or revolutions of the hair around the body 104, 504, 604 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 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. Referring to Figure 7, there is illustrated a plot of a signal 770 indicative of a presence of hair at the first region 108, 508 as a function of time. Specifically, Figure 7 is a plot of the signal 770 output by the first sensor 114, 514 as a function of time, according to an example. Before a first time, Tl, there is no hair present in the first region 108, 508, and accordingly the signal 770 has a relatively low value, RI’, indicating that hair is not present at the first region 108, 508. At Tl, a user begins to wrap a hair tress around the body 104, 504 and hair becomes present at the first region 108, 508. Accordingly, the signal 770 undergoes a first change, ARI, specifically an increase, from RI’ to a higher value, R2’. This indicates that hair is present at the first region 108, 508. The user continues to wrap the hair tress around the body 104, 504 and at a second time, T2, the hair tress has completed one complete turn around the body 104, 504. Accordingly, the signal 770 undergoes a further change, AR2, specifically a further increase, from R2’ to the yet higher value, R3’. This indicates that further hair is present at the first region 108, 508, and hence that the hair tress has completed one complete turn around the body 104, 504. Based on the two changes in the signal 770, ARI and AR2, the control unit 120 determines that the number of wraps of hair around the body 104 is one. More generally, in examples, the control unit 120 may be configured to determine the number of wraps of hair around the body 104, 504 based on a first change in a first signal indicative of hair being present at the first region 108, 508 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 108, 508. For example, the first change may indicate an initial engagement a hair tress 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. More 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 these examples, each 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 one or more signals to be reliably mapped to a number of wraps of the hair around the body 104. In the example described above with reference to Figure 7, the number of wraps is determined based on a plurality of changes in the signal indicative of a presence of hair at the first region 108, 508 which extends along the axis A of the elongate body 104, 504. However, in other examples, the body may have a second plurality of regions distributed along the axis A of the body. For example, referring to Figure 8a, there is illustrated a haircare appliance 802 according to another example. The haircare appliance 702 may be the same as or similar to the haircare appliance of any of the examples described above 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 the body 804 of the haircare appliance 802 has a second plurality of regions 808, 810, 812 distributed along the axis A of the body 804. In this example, the sensor arrangement 812 is also configured to output a second plurality of signals, each signal being indicative of a presence of hair at respective one of the second plurality of regions 808, 810, 812. Specifically, in this example, the sensor arrangement 812 comprises three sensors 814, 816, 818 arranged in a row along the axis A of the body 804. A first sensor 814 is located in the first region 808, a second sensor 816 is located in the second region 810, and a third sensor 818 is located in the third region 812. In this example, the control unit 102 is configured to determine the number of wraps of hair around the body based on a change in each of the second plurality of signals. 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 A of the body 804 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 120 may be improved. In examples, in order to curl hair, a user may wrap a hair tress 830 around and along the body (that is, around and along the axis A of the body 804) so that the hair tress becomes helical in shape (as in Figure 8). In this case, each complete revolution or turn of hair may occur at a respective different location along the axis of the body 804. Having the plurality of regions distributed along the axis A of the body 804 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 804 based on a change in one of the plurality of signals indicative of hair being present at one of the plurality of regions 808 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 810, 812. 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 started at an end of the body towards the handle 806. Referring to Figure 8b there is illustrated a plot of the signals associated with each of the second plurality of regions 808, 810, 812 of the body 804 of Figure 8a. Specifically, a first signal 880 is indicative of a presence of hair at the first region 808, a second signal 882 is indicative of a presence of hair at the second region 810, and a third signal 884 is indicative of a presence of hair at the third region 812. A first change (specifically the increase), ARI’, in the first signal 880 at a first time, Tl’, indicates an initial engagement of the hair with the body 804. There is also a small increase in the second signal 882 at Tl’ as the hair tress partially overlaps the second region 810. A subsequent change (specifically the subsequent increase), AR2’, in the second signal 883 at a second time, T2’, indicates a first full revolution or turn of the hair 830 around the body 804. The further subsequent change (specifically the subsequent increase), AR3’, in the third signal 884 at third time, T3’, indicates a second full revolution or turn of the hair 830 around the body 804. Based on the three successive increases in the signals, the control unit 120 infers that there are two wraps of hair around the body 804. It will be appreciated that any number of regions and signals may be used. A specific example is six regions and respective signals. In some examples, the control unit 120 may alternatively or additionally determine the number of wraps of hair around the body 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 starting from the end of the body closest to the handle 806 and moving towards the end of the body 804 furthest from the handle. In the examples of Figures 8a and 8b therefore, the first signal 880 should not, in normal use, change after the second signal 882 changes, and the second signal 882 should not change after the third signal 884 changes. Accordingly, in some examples, the determination of the number of wraps of hair around the body 804 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. 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 808, 810, 812, 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 808. In some examples, the control unit 120 may be configured to control an operation of the haircare appliance 102, 502, 802 based on the determined number of wraps of hair around the body. This may be in addition to or instead of control of the operation of the haircare appliance 102, 502, 802 based on the determined direction in which hair is wrapped around the body, as described above. For 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 body 104, 504, 804. For example, the control unit 120 may compare the determined number of wraps of hair around the body 104, 504, 804 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, 504, 804 is fewer or more than the predetermined number of wraps, or is not within a 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. 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 120 may control the feedback device 124 to provide first feedback 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, 504, 804. If the number of wraps is over or under the predetermined number of wraps then the control unit 120 may control the feedback device 124 to provide second feedback to the user indicating that the number of wraps does not match the predetermined number. In examples, the predetermined number of wraps may be input by the user into the user 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 should be wrapped a particular number of times around the body 104, 504, 804. The control unit 120 may accordingly set the predetermined number of wraps as the particular number of wraps according to the selected style. In some examples, the body 102, 504, 804 may be removeable from the main unit 106, 806, and the feedback may be indicative of an instruction to replace the body 104, 504, 804 with a body of a different diameter. For example, the haircare appliance may comprise the main part 106, 806 and a plurality of attachments that are attachable to the main part and each including a body 104, 504, 804 around which the hair is wrapped in use. The control unit 120 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. In this case, the control unit 120 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 104, 504, 704 has a larger diameter. Conversely, the control unit 120 may determine that the number of wraps of hair around the body 104, 504, 704 is smaller, for example much smaller and / or consistently smaller, than the desired number of curls. In this case, the control unit 120 may control the feedback device to provide feedback to the user that they could or should use a body 104, 504, 804 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 guide the user to interact with the appliance to achieve a desired curl or style. 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, 504, 804 and a circumference of the body 104, 504, 804. In examples, the circumference of the body 104, 504, 804, or a proxy for circumference such as the diameter of the body may, for example, be stored by the control unit 120, determined by the control unit 120 based on an identity of the body 104, 504, 804, communicated to the control unit 120 by the body 104, 504, 804, and / or input by the user using the input interface 126. The length of the hair may be calculated by multiplying the circumference by the determined number of wraps. In examples, the control unit may be configured to determine a style to recommend to the 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 number of wraps may be set accordingly. Other examples are possible. As mentioned, in examples the haircare appliance 102, 502, 804 comprises a heater 121 configured to heat at least a portion of the body 104, 504, 804. In some examples, the control unit 120 may be configured to control the heater 121 to heat the at least a portion of the body 104, 504, 804 to a particular temperature based on the particular determined 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 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, 804, the control unit 120 may infer (or calculate based on the circumference of the body 104, 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 that is located towards the handle 106, 806 of the haircare appliance 102, 802 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, 804 towards the handle 106, 806 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 120 may be configured to determine that a current number of wraps around the body 104, 504, 804 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 currently being wrapped is shorter and hence newer hair, and hence may control the heater 121 to heat the body 104, 504, 804 to a relatively lower temperature in order to avoid damaging the newer hair. In the examples described above with reference to Figures 1 to 8b, the body 104, 504, 804 is attachable to the main part 106, 806 of the haircare appliance 102, 802, but it will be appreciated that this need not necessarily be the case and that in some examples the body 104, 504, 804 may be integral to the haircare appliance 102, 502, 802. 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 8b, the control unit 120 was included in a haircare appliance 102 and specifically a main part 106 of the haircare appliance 102, and the haircare appliance 102 also included the sensor arrangement 112 located in an attachment 104 to the main part 106, but it will be appreciated that this need not necessarily be the case. For example, in some examples the body 104, the sensor 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 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 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. 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 interface 923, an output interface 925, a processor 927 and a memory 929. The input interface 923 may, for example, receive a plurality of signals, each signal being indicative of a presence of hair at a respective region of a body of a haircare appliance, for example according to any of the examples described above. These signals may be received from a sensor arrangement 928 configured to output the plurality of signals. These signals may be received by wired or wireless means. The processor 927 may be configured to, in combination with the memory 929, determine the direction in which hair is wrapped around the body based on the plurality of 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 processor 929, causes the processor to receive the plurality of signals and determine the direction in which hair is wrapped around the body, 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 configured to control operation of the appliance in response to the determination of the direction. 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 an element 926 for directing a generated airflow, in order to control an operation of the appliance (for example according to any of the 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 direction in which hair is wrapped around a body of a haircare appliance the body having an axis around which the hair is wrapped, the body having a plurality of regions distributed about the axis. The method comprises, in step 1080, receiving a plurality of signals, each signal being indicative of a presence of hair at a respective one of the plurality of regions. For example, the plurality of signals 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 direction in which hair is wrapped around the body based on the plurality of 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 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 5 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. 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 10 from the scope of the invention as defined by the claims.

Claims

1. A haircare appliance comprising:a body having an axis around which hair is wrapped in use, the body having a plurality of regions distributed about the axis;a sensor arrangement configured to output a plurality of signals, each signal being indicative of a presence of hair at a respective one of the plurality of regions; anda control unit configured to determine a direction in which hair is wrapped around the body based on the plurality of signals.

2. The haircare appliance according to claim 1, wherein the sensor arrangement is configured to output a first signal indicative of a presence of hair at a first region of the plurality of regions, and a second signal indicative of a presence of hair at a second region of the plurality of regions; wherein the first region and the second region are spaced about the axis by less than 180 degrees; and wherein the control unit is configured to determine the direction in which hair is wrapped around the body based on a timing of one or more changes in each of the first signal and the second signal.

3. The haircare appliance according to claim 2, wherein the control unit is configured to determine the direction in which hair is wrapped around the body based on:a time between a first change in the first signal indicative of hair being present at the first region and a first change in the second signal indicative of hair being present at the second region; anda time between the first change in the second signal indicative of hair being present at the second region and a second change in the first signal indicative of further hair being present at the first region.

4. The haircare appliance according to claim 2 or claim 3, wherein the first region and the second region are spaced about the axis by an angle in the range 45 to 135 degrees.

5. The haircare appliance according to any one of claim 1 to claim 4, wherein the body has at least three of the regions distributed about the axis, wherein the sensor arrangement is configured to output at least three signals, each signal being indicative of a presence ofhair at a respective one of the at least three regions, and wherein the control unit is configured to determine the direction in which hair is wrapped around the body based on an order in which the at least three signals change.

6. The haircare appliance according to any one of claim 1 to claim 5, wherein the control unit is configured to restart the determination of the direction in which hair is wrapped around the body 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.

7. The haircare appliance according to any one of claim 1 to claim 6, wherein the control unit is configured to control an operation of the haircare appliance based on the determination of the direction in which hair is wrapped around the body.

8. The haircare appliance according to claim 7, wherein the haircare appliance comprises 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 direction in which hair is wrapped around the body.

9. The haircare appliance according to claim 8, wherein the control unit is configured to:determine whether or not the determined direction in which hair is wrapped around the body matches a predetermined direction; andcontrol the feedback device to provide feedback indicative of whether or not the determined direction in which hair is wrapped around the body matches the predetermined direction.

10. The haircare appliance according to claim 9, 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 direction based on the received user input.

11. The haircare appliance according to claim 10, wherein the input interface is configured to receive user input indicative of a side of a person’s head with which thehaircare appliance is to be used, and wherein the control unit is configured to determine the predetermined direction based on the received user input indicative of the side of a person’s head.

12. The haircare appliance according to claim 10 or claim 11, wherein the input interface is configured to receive and user input indicative of a style intended to be achieved by use of the haircare appliance, and wherein the control unit is configured to determine the predetermined direction based on the received user input indicative of the style intended to be achieved.

13. The haircare appliance according to any one of claim 7 to claim 12, wherein the haircare appliance comprises an airflow generator configured to generate an airflow and an element configured to direct the generated airflow around the body, and wherein the control unit is configured to control the element to direct the airflow around the body in a direction that matches the determined direction in which hair is wrapped around the body.

14. The haircare appliance according to any one of claim 1 to claim 13, wherein the sensor arrangement comprises a plurality of sensors, each sensor being located at a respective one of the plurality of regions and being configured to output one of the plurality of signals.

15. The haircare appliance according to claim 14, wherein one or more of the sensors are non-contact sensors.

16. The haircare appliance according to any one of claim 1 to claim 15, wherein 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.

17. The haircare appliance according to any one of claim 1 to claim 16, wherein one or more of the signals output by the sensor arrangement are indicative of a presence of hair at a respective one or more regions each having a respective location along the axis; andwherein the control unit is configured to determine a number of wraps of hair around the body based on a plurality of changes in the one or more signals.

18. The haircare appliance according to claim 17 wherein the control unit is configured 5 to control an operation of the haircare appliance based on the determined number of wraps of hair around the body.

19. A method of determining a direction in which hair is wrapped around a body of a haircare appliance, the body having an axis around which the hair is wrapped, the body 10 having a plurality of regions distributed about the axis, the method comprising:receiving a plurality of signals, each signal being indicative of a presence of hair at a respective one of the plurality of regions; anddetermining a direction in which hair is wrapped around the body based on the plurality of signals.1520. The method according to claim 19, wherein the method further comprises: controlling an operation of the haircare appliance based on the determination of the direction in which hair is wrapped around the body.20

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