Background

[0001] Shoes degrade over time through use. Some degradation is visible, and obvious to a user, such as external damage. However, some degradation is less obvious, and may only be ascertained through the use of measuring equipment.

[0002] For some shoes, particularly those used for intensive exercise, degradation can severely negatively impact the protection that the shoes provide. For example, some shoes are designed to cushion a user’s feet and knees against the repeated impact of running on a hard surface. Once the shoes experience degradation beyond a certain level, the protection is no longer adequate and if they are used for running the user could experience joint damage as a result.

Summary

[0003] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter.

[0004] In various examples there is an apparatus for measuring shoe degradation, comprising at least one Hall effect sensor positioned adjacent a first surface of a sole of a shoe. At least one magnet positioned adjacent a second surface of the sole of the shoe; and a communications assembly in electronic communication with the or each Hall effect sensor via a conductive connector. The communications assembly is operable to transfer data from the Hall effect sensor to an external device. As a result there is an accurate, practical and effective way to measure the thickness of a sole of a shoe. Hall sensors are highly accurate and are able to output measurements in digital form compatible with downstream processes. The Hall effect sensor is able to send digital output along the conductive connector to the communications assembly giving an efficient and robust way to enable measurement data to be output from the shoe.

[0005] Preferably, the communications assembly is a near-field communication, NFC, assembly. By using an NFC assembly a compact, light weight arrangement is achieved.

[0006] Preferably, the external device is an NFC enabled device and as a result a straightforward, secure and efficient way to transfer data from the shoe to an external device is achieved. [0007] Preferably, the external device is a smartphone

[0008] Preferably, in use, the first surface of the sole of the shoe is an upper surface adjacent a foot of a user and the second surface of the sole of the shoe is a lower surface adjacent a ground surface.

[0009] Preferably, the communications assembly is further operable to receive power from the external device. In this way the shoe itself has enhanced safety since it is not necessary to have a power source in the shoe itself.

[0010] Preferably, the electronic communication between the or each Hall effect sensor and the communications assembly uses I2C protocol.

[0011] Preferably the data transferred between the or each Hall effect sensor and the external device comprises a measurement of a distance between at least one Hall effect sensor and at least one magnet.

[0012] Preferably the apparatus comprises only two Hall effect sensors and only two magnets.

[0013] Preferably, the or each Hall effect sensor is positioned vertically above the or each magnet.

[0014] Preferably the apparatus comprises a local power source in electronic communication with the Hall effect sensor.

[0015] Preferably the apparatus comprises a charging port in electronic communication with the Hall effect sensor.

[0016] Preferably the apparatus comprises a wireless technology module in electronic communication with the Hall effect sensor.

[0017] Preferably the wireless technology module is operable to provide communication between the Hall effect sensor and a remote cloud server.

[0018] Preferably the wireless technology module comprises one or more of the following technologies: RFID, Bluetooth, Wi-Fi, LoRa, LiFi, power harvesting from ambient radio waves, and/or ZigBee.

[0019] According to another aspect of the invention there is a method of measuring the degradation of a shoe, comprising the steps of: detecting, via a Hall sensor adjacent a first surface of a sole of a shoe, the magnitude of a magnetic field generated by a magnet adjacent a second surface of the sole of the shoe; determining, using the Hall sensor, a distance between the first surface of the sole of the shoe and the second surface of the sole of the shoe; and transmitting the determined distance from the Hall sensor to a communications assembly via a conductive connector.

[0020] Preferably the method comprises the step of: transmitting the determined distance from the communications assembly to an external device.

[0021] Preferably the transmission of the determined distance from the Hall sensor to the NFC assembly uses I2C protocol.

[0022] Preferably the method comprises transmitting the determined distance from the Hall sensor to a remote cloud server.

[0023] The preferred features may be combined as appropriate, as would be apparent to a skilled person, and may be combined with any of the aspects of the invention.

Brief Description of the Drawings

[0024] Embodiments of the invention will be described, by way of example, with reference to the following drawings, in which:

[0025] Figure 1 represents a shoe equipped with degradation sensing equipment;

[0026] Figure 2 shows a sensor assembly;

[0027] Figure 3 shows a sensor assembly integrated into the sole of a shoe; and

[0028] Figure 4 shows an alternative sensor assembly integrated into the sole of a shoe;

[0029] Figure 5 shows another sensor assembly with two Hall effect sensors;

[0030] Figure 6 shows a sensor assembly integrated into the sole of a shoe for measurement of supination, pronation and sole absorption; [0031] Figure 7 shows another sensor assembly integrated into the sole of a shoe for measurement of sole absorption.

[0032] Common reference numerals are used throughout the figures to indicate similar features.

Detailed Description

[0033] Embodiments of the present invention are described below by way of example only. These examples represent the best ways of putting the invention into practice that are currently known to the Applicant although they are not the only ways in which this could be achieved. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.

[0034] The inventors have recognized that measuring equipment is useful to measure degradation of a sole of a shoe and yet it is difficult to obtain accurate measurements in a robust and practical manner. Any measuring equipment incorporated into a shoe adds weight to the shoe which may be undesired. Measuring equipment incorporated into a shoe may also negatively affect the comfort or safely of a wearer of the shoe. Any measuring equipment in a shoe is likely to be subject to dirt, sweat, temperature changes, pressure changes and other factors which make it challenging to robustly measure characteristics of a shoe and to do so in an accurate manner.

[0035] Another challenge concerns how to transfer measurement data from measurement equipment in a shoe to an external device, since it is not typically practical for a wearer of a shoe to read measurements directly from a shoe.

[0036] Figure 1 represents a shoe 104 equipped with degradation sensing equipment. The degradation sensing equipment comprises a Hall effect sensor 105, a magnet 110, and a communications assembly 115.

[0037] In a first example, the communications assembly 115 provides dual functions of receiving power from an external device 102 and sending a digital signal comprising measurements from the Hall effect sensor 105 to the external device 102. In this case, the external device 102 acts as both a digital signal receiver and a power source (i.e. providing power to the Hall effect sensor 105 and communications assembly 115 in the shoe). In this first example, there is no need for a power source in the shoe itself. The absence of a power source in the shoe itself improves safety, especially where the shoe is likely to become wet or damp. The absence of a power source in the shoe itself also reduces the weight in the shoe and enables weight distribution in the shoe to be evenly distributed as opposed to having a discrete power source such as a fuel cell concentrating weight in a particular part of the shoe.

[0038] In a second example, the degradation sensing equipment further comprises a power source 106 in the shoe, which is used in conjunction with or instead of power received from the external device 102. Having a power source 106 in the shoe itself enables a greater range of types of external device 102 to be used.

[0039] The communications assembly 115 receives digital signals from the Hall effect sensor 105 and communicates those signals to an external device 102 which is a computing device such as a desk top computer, a smart phone, a smart watch, a wearable computer, or any other computing device able to receive digital signals.

[0040] The communications assembly 115 communicates the digital signals from the Hall effect sensor to the external device 102 wirelessly or using a wired connection. In the case of a wired connection, examples include having a physical port such as a USB port, or a magnetic connector in the shoe as part of the communications assembly 115. In these cases, a user takes off the shoe and inserts the corresponding port cable into the shoe in order to connect the communications assembly 115 in the shoe to the external device 102 and obtain measurement data from the Hall effect sensor 105.

[0041] As an alternative to the Hall effect sensor 105, an inductor capacitor circuit may be used, where the inductor capacitor circuit resonates at a resonant frequency related to the distance between the inductor capacitor circuit and the magnet 110. In this case, specialist reading equipment is needed to scan a frequency range to measure a resonant frequency of the inductor capacitor circuit. The determined resonant frequency is an analog measurement that has to be converted into digital form if required to be processed by downstream digital processing mechanisms. To accomplish such scanning, analog measurement and conversion to digital signal output a dedicated reader apparatus may be used. In an example, a wearer of a shoe incorporating an inductor capacitor circuit, takes off the shoe and inserts a reader device into a slot in an underside of the shoe. The reader device scans for the resonant frequency, converts from analog to digital and sends a digital output to a device such as a smart phone. The inventors have recognized this as being a cumbersome arrangement involving apparatus in a shoe, a dedicated reader device and a smart phone i.e. three separate objects to be manipulated by a person. In cases where the dedicated reader device is included in the shoe, there are increased components in the shoe which adds to costs and potentially detriments comfort and performance of the shoe. In cases where a dedicated reader is attached to the shoe it can be difficult for a user to attach the reader correctly and robustness is weakened since moisture and dirt may penetrate the reader.

[0042] The inventors have recognized that the Hall effect sensor 105 is a discrete component which is sized and shaped to be incorporated in a shoe during manufacture and without causing any significant uneven weight distribution in the shoe. The Hall effect sensor outputs digital signals so there is no need to scan for a resonant frequency or to convert a resonant frequency to a digital signal. Thus, there is no need for a dedicated reader apparatus and a user is able to operate the technology using only the shoe itself and an external device 102 such as a smart phone (i.e. only two objects to be manipulated by a person). Since the Hall effect sensor gives a digital signal as output there is improved accuracy as compared with scanning for a resonant frequency of an inductor capacitor circuit. Scanning for a resonant frequency is subject to interference from nearby conductive objects or electromagnetic fields in the environment whereas such interference is less likely for a Hall effect sensor 105. The process of converting a resonant frequency from analog to a digital signal also introduces noise.

[0043] Using a Hall effect sensor 105 within a shoe is not straightforward since a Hall effect sensor 105 is a component requiring power. As mentioned above, there are problems with incorporating a power source 106 in a shoe itself. The inventors have recognized that it is possible to power the Hall effect sensor 105 in the shoe by using power from the external device 102 wirelessly transmitted to the shoe 104. More detail about how this is achieved technically is given later in this document.

[0044] Figure 2 shows a sensor assembly 100 comprising a Hall effect sensor 105, a magnet 110, a conductive connector 125, a communications assembly 115, and an antenna 120. The Hall effect sensor 105 is aligned with the magnet 110. The Hall effect sensor 105, also referred to as a Hall sensor 105, can detect the existence and extent of a magnetic field generated by the magnet 110. A Hall effect sensor 105 can be used to accurately measure the distance between the Hall effect sensor 105 itself and the magnet 110. The detection of a weaker magnetic field emanating from the magnet 110 would mean that the magnet 110 is further from the Hall effect sensor 105, while the detection of a stronger magnetic field would mean that the magnet 110 is closer to the Hall effect sensor 105. A Hall effect sensor 105 is an active sensor, and as a result can actively transmit a signal carrying measurement data in digital form. [0045] In the example of FIG. 2 the antenna 120 is in the form of a flexible printed circuit on a laminate substrate. The antenna is a loop antenna in this example and is suitable for near field communications (NFC).

[0046] In the arrangement of Figure 2, the Hall effect sensor 105 is in electronic communication with the communication assembly 115, via a conductive connector 125. The conductive connector 125 of one or more examples is a printed metallic strip (not shown). The printed metallic strip is supported by a laminate dielectric substrate which is optionally integral with the substrate of antenna 120. That is, in some case the substrate of antenna 120 and the substrate of the conductive connector 125 are cut as a single piece from a laminate layer so as to reduce manufacturing cost and enable a specified spatial relationship between the antenna and the Hall effect sensor 105 to be achieved. Since the antenna 120 is a printed track on a laminate substrate it may be incorporated into a heel or body of a shoe or may be adhered to an internal surface of a shoe. In the example of FIG. 2 the antenna 120 is incorporated into a heel of a shoe (not shown for clarity).

[0047] In the example of FIG. 2 the Hall effect sensor 105 outputs a digital signal using interintegrated circuit protocol (i2C protocol) which travels along a printed metallic strip to the communication assembly 115. The communication assembly 115 in this case is configured to use i2C protocol. Using i2C protocol is beneficial as it enables communication of complex digital data between the Hall effect sensor 105 and the communication assembly 115 in a fast and accurate manner (i.e. with little introduction of noise or loss of data). This is a significant benefit as compared with transferring an analog signal such as a resonant frequency.

However, it is not essential to use i2C protocol as other digital communications protocols are usable such as serial peripheral interface (SPI), one-wire protocol or controller area network (CAN) protocol.

[0048] The communication assembly 115 comprises an NFC chip and passive circuitry to control communication with the Hall sensor 105 and circuitry for controlling NFC communication through antenna 120 to harvest power from external device 102 and to offer in-package memory for near field communications data exchange format NDEF settings and data buffering.

[0049] In an example, antenna 120 is controlled by communications assembly 115 to enable near field communication (NFC) with the external device 102. In this case, the antenna 120 is used to receive and transmit data with an NFC enabled external device, such as a smartphone (not shown in FIG. 2). The external device (102 of FIG. 1) can issue an instruction, such as a “Read Command”, and receive data from a memory of the communications assembly 115.

[0050] The antenna 120 may alternatively or additionally be used to receive power wirelessly from the external device (102 of FIG. 1). The means of wireless power transfer may include one or more of: NFC power harvesting from the external device, the use of an open interface standard such as Qi or other wireless induction power transmission, and/or general power harvesting from ambient waves. General power harvesting from ambient radio waves is possible using thumbnail sized tags which are also able to communicate using encrypted or plaintext data transfer.

[0051] Power may be received by one or more of the means referenced herein, following which the NFC assembly may transmit data to the external device. Power harvesting and data communication happen at substantially the same time as part of a near field communications process.

[0052] If the assembly 100 were to be installed in the sole of a shoe, the weight of the shoe may be reduced when compared with an alternative arrangement comprising a power source such as a battery cell in the shoe. This reduction in weight minimizes the effect to a user’s performance and user feeling. The cost to produce such a shoe may also be reduced if no local battery is required, as a battery-free assembly is easier to integrate into a shoe production process as fewer components are required.

[0053] Alternatively or additionally, the sensor assembly 100 may use a local power source (i.e. in the shoe) in electronic communication with one or more of the electronic components of the sensor assembly 100. This local power source may include one or more of: a battery cell, a rechargeable battery, and/or a capacitor. In one or more examples, solar or other light power transformation technologies may be used in conjunction with a solar panel to provide the local power source.

[0054] Alternatively or additionally, the sensor assembly 100 may receive power from a hardware connection, such as wires, connectors, and/or probe pins.

[0055] Figure 3 shows a sensor assembly 100 integrated into the sole 205 of a shoe. Users of shoes, for example training shoes, expect to prevent themselves from injuries due to sport activity or daily use. This protection function is provided mainly by the sole of the shoe, with its ability to cushion and absorb shocks. With use, and as time passes, the sole ages and wears. This wear may be affected too by storage conditions of the shoe. Thus, the protection provided changes overtime. [0056] In the example of Figure 3, the sensor assembly 100 is used to measure a thickness of the sole 205. In this example, the Hall effect sensor 105 is positioned adjacent a first surface of the sole 205. The first surface of the sole 205 may be the surface which, when the shoe is in use, is adjacent the foot of a user. The Hall effect sensor 105 may be embedded within or adhered to the first surface of the sole 205.

[0057] In the example of Figure 3, a magnet 110 is positioned adjacent a second surface of the sole 205. The second surface of the sole 205 may be the surface which, when the shoe is in use, is adjacent the ground. The magnet 110 may be embedded within or adhered to the surface of the second surface of the sole 205.

[0058] The distance between the Hall effect sensor 105 and the magnet 110 corresponds to the thickness of the sole 205 because the magnet 110 and Hall effect sensor 105 are aligned such that in use the magnet 110 is substantially vertically below the Hall effect sensor 105. The sensor assembly 100 is calibrated such that, on installation into a new sole 205, the detection of the magnetic field emanating from the magnet 110 corresponds to the thickness of the sole 205 when no degradation has taken place. As the shoe is used, the cumulative effect of the user’s foot inside the shoe will cause the sole 205 to flatten. Therefore, the Hall effect sensor 105 will detect a stronger magnetic field from the magnet 110, and hence determine that the distance between the magnet 110 and the Hall effect sensor 105 has been reduced.

[0059] The distance between the magnet 110 and the Hall effect sensor 105, as determined by the Hall effect sensor 105, is electronically communicated via the conductive connector 125 to the communications assembly 115. Using the antenna 120, this distance, in digital form, may then be received by an external device such as a smartphone. Once the sole 205 has reduced in thickness more than a predetermined value, for example by 50% of its original thickness, the transmission of the distance via the antenna 120 to an external device may be accompanied by an alert that the shoe is no longer safe to use for its intended purpose. In an example 30% compression measured in an idle state of the shoe indicates that the shoe is no longer safe to use as absorbance capability is close to null. Note that the 30% compression value is not intended to be limiting and other percentage compression values or ranges of values are used in some cases. The user may then choose to purchase a replacement, without continuing to train on equipment that is no longer fit for purpose. The user may therefore avoid injuries, such as joint pain when running.

[0060] Alternatively or additionally, the distance between the magnet 110 and the Hall effect sensor 105, as determined by the Hall effect sensor 105, is electronically communicated via the conductive connector 125 to the communications assembly 115 (see FIG. 1) which uses wireless technology to send a wireless communications signal to the external device. The wireless technology may comprise one or more of the following technologies: radio frequency identification (RFID), Bluetooth (trade mark), power harvesting from ambient radio waves, WiFi, the physical proprietary radio communication “LoRa” (trade mark), Li-Fi, and/or other communications protocols such as “ZigBee” (trade mark).

[0061] Once the data regarding the distance between the magnet 110 and the Hall effect sensor 105 has been received by the communications assembly 115, the wireless technology may transmit the data to an external device which is a remote server, optionally a cloudbased server. For example, a Wi-Fi module integrated into the sole 205 may receive data regarding the thickness of the sole 205. If the thickness of the sole 205 is below a predetermined value, then the sole 205 may no longer provide adequate support for a user. The Wi-Fi module is operable to transmit this information wirelessly, via a remote server, to a user’s smartphone. The user is then alerted to this potential risk, and may take remedial action such as replacing the shoe.

[0062] Figure 4 shows an alternative sensor assembly integrated into the sole of a shoe. In this arrangement, a plurality of magnets 110, 110’, 110” are used alongside a plurality of corresponding Hall effect sensors 105, 105’. In this example, three Hall effect sensors 105, 105’, 105”, and three magnets 110, 110’, 110” are used. However it is appreciated that any number of Hall effect sensors and magnets may be used, where each Hall effect sensor has a magnet substantially in alignment with an axis of the Hall effect sensor.

[0063] In the example as shown in Figure 4, the Hall effect sensor 105 detects the magnetic field strength of magnet 110 which is the nearest magnet. The Hall effect sensor 105’ detects the magnetic field strength of magnet 110’. The Hall effect sensor 105” detects the magnetic field strength of magnet 110”. In such a way, each Hall effect sensor 105, 105’, 105”, is arranged to detect only the magnetic field strength of the magnet 110, 110’, 110” closest to it. The magnets and Hall effect sensors are positioned relative to one another so there is no significant interference between them.

[0064] The three Hall effect sensors 105, 105’, 105”, 105’” is paired with a magnet as described above and illustrated in Figure 4. A first Hall sensor magnet pair 105, 110 is located in a heel of the shoe so as to measure thickness of the sole in a region where compression may occur through contact with a heel of a wearer of the shoe. The first Hall sensor is on a flexible substrate which is elongate and extends from a mid point of the heel to a back of the shoe where antenna 120 is located. The flexible substrate extends along an outer edge of the sole until reaching an area which is under the ball of a foot of a wearer when the shoe is worn. The flexible substrate turns and runs under the ball of the foot extending to a second edge of the sole. In this way the flexible substrate generally forms a L shape. A second and a third Hall sensor 105”, 105’ are located on the flexible substrate so as to fall generally under a ball of the foot of a wearer. The second and third Hall sensors are located with one on a right hand side of the shoe and another on a left hand side of the shoe. The substrate supports a conductive track enabling digital signals to be communicated between the Hall effect sensor and magnet pairs and the communications assembly 115 in a back of the shoe. Each of the Hall effect sensors 105, 105’, 105”, is, in use, positioned generally vertically above a corresponding magnet 110, 110’, 110”,

[0065] By detecting the magnetic field strength of the magnets 110, 110’, 110”, closest to each of the Hall effect sensors 105, 105’, 105”, each of the Hall effect sensors 105, 105’, 105” is able to determine a distance representing the thickness of the sole 205 at a particular location in the sole. In this example, three different thicknesses of the sole 205 are measured.

[0066] Using three Hall effect sensor and magnet pairs in the arrangement of Figure 4 is found to give useful and accurate measurements of the sole thickness without affecting comfort of the wearer. Using three Hall effect sensor and magnet pairs is especially useful for wearers who have uneven gait or posture which differentially affects pressure over the sole during use.

[0067] As in relation to other examples described herein, the data gathered by the Hall effect sensors 105, 105’, 105”, in relation to the thickness of the sole 205 at three different points may be used to determine the efficacy and hence safety of the shoe as a whole. In one example, all three distances may be averaged to determine a mean thickness of the sole 205. If the mean thickness of the sole 205 is below a predetermined value, then the shoe requires replacement. In another example, different thicknesses of the sole 205 as measured by a plurality of Hall effect sensors may be given different weightings. For example, a more compressed part of the sole 205 adjacent the heel of a user may be sufficient to require replacement of the shoe, but a similarly compressed part of the sole 205 adjacent the toes of a user may not require replacement of the shoe. In another example, one of the Hall effect sensors which gives a maximum measurement is selected and its measurement value is compared to a threshold for triggering an alert.

[0068] The measurement data from the Hall effect sensors is sent to the communications assembly 115. In some cases each Hall effect sensor includes an identifier with the digital measurement data it outputs and the communications assembly 115 uses the identifiers to tell which measurement data is from which Hall effect sensor.

[0069] In some cases the communications assembly sends the measurement data to the external device without any aggregation. In the example of Figure 5 there are two Hall effect sensor and magnet pairs 105, 110 and 105’ 110’. A first Hall effect sensor and magnet pair 105, 110 is located in a heel of the sole as for Figure 4. A second Hall effect sensor and magnet pair 105’, 110’ is located in the sole so as to be under a ball of the foot of a wearer in use. A flexible substrate in the form of an elongate track runs between the Hall effect sensor and magnet pairs along a side of the sole of the shoe. The substrate supports a conductive track enabling digital signals to be communicated between the Hall effect sensor and magnet pairs and the communications assembly 115 in a back of the shoe. Measurements are sent from the Hall effect sensors together with identifiers. The communications assembly 115 receives the measurements and is able to send the measurements to an external device via antenna 120.

[0070] The arrangement of Figure 5 with only two Hall effect sensor and magnet pairs is found to be particularly useful since the arrangement is compact and light weight as well as robust. If one Hall effect sensor malfunctions the other Hall effect sensor is likely still workable and the arrangement continues to operate to provide measurement data to an external device.

[0071] Figure 3 shows a sensor assembly integrated into the sole of a shoe for sole absorption measurement. Sole absorption is a measure of the ability of a sole of a shoe to absorb force from surfaces external to the shoe, such as when a wearer of the shoe is running or walking. Figure 3 illustrates how the sensor assembly is used to measure sole absorption. Sole absorption is measured as a ratio between the thickness of the sole at the current time and the thickness of the sole of the shoe immediately after manufacture . As explained with reference to figure 3, the distance between the Hall effect sensor 105 and the magnet 110 corresponds to the thickness of the sole 205 because the magnet 110 and Hall effect sensor 105 are aligned such that in use the magnet 110 is substantially vertically below the Hall effect sensor 105. The sensor assembly 100 is calibrated such that, on installation into a new sole 205, the detection of the magnetic field emanating from the magnet 110 corresponds to the thickness of the sole 205 when no degradation has taken place. As the shoe is used, the cumulative effect of the user’s foot inside the shoe will cause the sole 205 to flatten. Therefore, the Hall effect sensor 105 will detect a stronger magnetic field from the magnet 110, and hence determine that the distance between the magnet 110 and the Hall effect sensor 105 has been reduced. Sole absorption reduces as the thickness of the sole reduces after manufacture and/or due to aging of the sole. In the arrangement of figure 3 the sensor assembly is able to monitor the cushioning ability of the sole (one sensor is sufficient for this).

[0072] Figure 5 shows a sensor assembly integrated into the sole of a shoe for drop measurement. Drop measurement is a measurement of the angle between the upper surface of the sole and the floor, which when the shoe is being worn encourages the wearer to go forward. Figure 5 is included to show how drop measurements are possible using two sensors, one in a heel of a sole of a shoe and one in a toe position of a sole of a shoe. A thickness of the sole of the shoe is measured by both sensors. A difference between the measurements is related to the angle between the upper surface of the sole and a ground surface.

[0073] Figure 6 shows a sensor assembly integrated into the sole of a shoe for measurement of supination, pronation and sole absorption. In the example of figure 6 there are two sensors. The arrangement is the same as that of figure 4 except that the sensor in the heel of the sole is omitted and the substrate ends in a curved portion 800 joining to the antenna 120. In figure 6, a plurality of magnets 110’, 110” are used alongside a plurality of corresponding Hall effect sensors 105’, 105”. In this example, two Hall effect sensors 105’, 105”, and two magnets 110’, 110” are used. Each Hall effect sensor has a magnet substantially in alignment with an axis of the Hall effect sensor.

[0074] In the example as shown in Figure 6, the Hall effect sensor 105’ detects the magnetic field strength of magnet 110’. The Hall effect sensor 105” detects the magnetic field strength of magnet 110”. In such a way, each Hall effect sensor 105’, 105”, is arranged to detect only the magnetic field strength of the magnet 110’, 110” closest to it. The magnets and Hall effect sensors are positioned relative to one another so there is no significant interference between them.

[0075] The two Hall sensors are on a flexible substrate which is elongate and extends from a back of the shoe where antenna 120 is located. The flexible substrate extends along an outer edge of the sole until reaching an area which is under the ball of a foot of a wearer when the shoe is worn. The flexible substrate turns and runs under the ball of the foot extending to a second edge of the sole. In this way the flexible substrate generally forms a L shape. The Hall sensors 105”, 105’ are located on the flexible substrate so as to fall generally under a ball of the foot of a wearer. The Hall sensors are located with one on a right hand side of the shoe and another on a left hand side of the shoe. The substrate supports a conductive track enabling digital signals to be communicated between the Hall effect sensor and magnet pairs and the communications assembly 115 in a back of the shoe. Each of the Hall effect sensors 105’, 105”, is, in use, positioned generally vertically above a corresponding magnet 110’, 110”.

[0076] By detecting the magnetic field strength of the magnets 110’, 110”, closest to each of the Hall effect sensors 105’, 105”, each of the Hall effect sensors 105, 105’, 105” is able to determine a distance representing the thickness of the sole 205 at a particular location in the sole. In this example, two different thicknesses of the sole 205 are measured. The difference between the thicknesses measured by the two different Hall effect sensors is a measurement of supination or pronation. An aggregate of the thicknesses measured by the two different Hall effect sensors is a measurement of absorption ability of the sole.

[0077] Figure 7 shows another sensor assembly integrated into the sole of a shoe for measurement of sole absorption. It shows that the antenna 120 may be placed anywhere in the shoe and not only at the rear part. In the example of figure 9 a magnet 110 is located in a heel of a sole of a shoe and is positioned vertically below a Hall effect sensor 105. The Hall effect sensor is on a flexible substrate which is elongate and extends from the Hall effect sensor towards a side of the sole of the shoe so that when a wearer of the shoe is standing the flexible substrate abuts a side of the sole that will be in contact with another shoe heel when the wearer stands with their heels together. The flexible substrate follows a path which comprises one or more folds or undulations 900, where a fold or undulation creates a loop in the flexible substrate where the loop protrudes towards a base of the sole of the shoe. The fold or undulation aids fixation of the assembly in the sole and allows flexibility due to movement of the sole when a person wears the shoe. It is not essential to include the folds or undulations 900. The flexible substrate connects to an antenna 120 and communications assembly 115. In an example the antenna 120 and communications assembly are added to the shoe after the finished production of the shoe, in an accessory fashion, for example.

[0078] Figure 4 shows a sensor assembly integrated into the sole of a shoe for measurement of supination, pronation, drop and sole absorption. Figure 4 illustrates how the sensor assembly, with three sensors, is able to measure supination, pronation and sole absorption. The two sensors in a ball of the foot region of the sole measure thickness of the sole. The difference between the thickness measurements from these two sensors gives a measure of an amount of supination or pronation. A difference in thickness measurements between the sensor in the heel region of the sole and either of the thicknesses from the other two sensors gives a measurement of the drop. A difference in thickness measurement between the sensor in the heel region of the sole and an aggregate of the thickness measurement from the other two sensors also gives a measurement of the drop. A thickness measurement from any one or more of the three sensors gives a measurement of sole absorption.

[0079] In an example, a user takes off his or her shoe, where the shoe incorporates a Hall effect sensor and places a smart phone close to the sole of the shoe such as within 5 centimeters of the back of the shoe (position of the hall effect sensor and the antenna could be adjusted according the technical requirements). The shoe harvests power from the smart phone (or any smart devices) and the Hall effect sensor uses the harvested power to measure a thickness of a sole of the shoe when the shoe is not being worn. A communications assembly in the shoe uses the harvested power to send a digital signal it receives from the Hall effect sensor to the smart phone (or any smart devices). By repeating this process over time there is a simple, low cost, accurate way of measuring degradation of a sole of a shoe.

[0080] In an example, the apparatus described herein is arranged to measure shoe degradation of a shoe that is free from contact with surfaces external to the shoe. In an example, a person wearing the shoe sits on a chair and raises one foot with the shoe on it. Because the shoe is elevated and is in the air without contact with surfaces external to the shoe, the Hall effect sensor is able to measure the state of the sole of the shoe in a rest state, that is, similar to the state when the shoe is unworn (i.e. is not being worn). This is because the force of the foot on the inside of the shoe is reduced since the foot is elevated without contact with surfaces external to the shoe. The person sits on the chair with their foot raised and brings a smart phone or other external device into proximity with the shoe in order to power the Hall effect sensor and enable measurement of the sole of the shoe. It is not essential for the person to sit on a chair as in some cases the person is able to stand on one leg, or lean against a wall.

[0081] In examples the shoe is elevated such that the external surface of the sole of the shoe is not in contact with the ground, as it would be during normal use. During elevation of the shoe, the user may or may not be wearing the shoe. The user may be elevating the shoe for the measurement of shoe degradation while it is being worn on their foot, or lifting the shoe away from external surface contact using an alternative means.

[0082] In an example there is a method of measuring the degradation of a shoe that is free from contact with surfaces external to the shoe, comprising the steps of: using an NFC communications assembly, harvesting power at the shoe from an external device which is NFC enabled, without contact between the external device and the shoe, the shoe incorporating a Hall effect sensor adjacent a first surface of a sole of the shoe; detecting, via the Hall effect sensor using the harvested power, the magnitude of a magnetic field generated by a magnet adjacent a second surface of the sole of the shoe; determining, using the Hall effect sensor, a distance between the first surface of the sole of the shoe and the second surface of the sole of the shoe; transmitting the determined distance from the Hall effect sensor to the NFC communications assembly via a conductive connector; and transmitting the determined distance from the NFC communications assembly to the external device.

[0083] Since the shoe is free from contact with surfaces external to the shoe measurements are independent of ferees acting on the shoe from other surfaces external to the shoe. If the shoe is in contact with the floor then external forces due to gravity and friction influence the measurements from the Hall effect sensor. For example, the method is for measuring the degradation of a shoe that is not being worn.

[0084] In examples the method comprises transitioning the NFC communications assembly from a resting mode into a command mode in dependence on receipt of a trigger from the external device; and during the command mode, setting up a configuration of the Hall effect sensor and reading from the Hall effect sensor. During the resting mode the NFC communications assembly is at rest and does not harvest power or take readings from the Hall sensor. During the command mode the NFC communications assembly harvests power from the external device and takes readings from the Hall sensor. The trigger from the external device is a message sent using NFC from the external device to the NFC communications assembly.

[0085] In examples the NFC communications assembly is configured to carry out one or more of the following actions in dependence on a command from the external device without the need of an intermediary microcontroller: Hall effect sensor configuration set up, Hall effect sensor measurement control, interpret readings from the Hall effect sensor, interpret commands from the external device. A different command is used for each of the actions. That is, the external device sends a command using NFC to the shoe for triggering Hall effect sensor configuration set up. It sends a different command to trigger interpretation of readings from the Hall effect sensor by the NFC communications assembly in the shoe. The NFC communications assembly in the shoe knows the different commands it might receive from the external device and what to do in response to each of those. Thus there is no need for an intermediary microcontroller.

[0086] In examples the Hall effect sensor and the magnet are vertically paired by being generally aligned with a same axis perpendicular to the sole of the shoe.

[0087] An apparatus for measuring shoe degradation of a shoe that is free from contact with surfaces external to the shoe, comprising: at least one Hall effect sensor positioned adjacent a first surface of a sole of the shoe; at least one magnet positioned adjacent a second surface of the sole of the shoe; and a near field communications NFC communications assembly in electronic communication with the or each Hall effect sensor via a conductive connector; wherein the NFC communications assembly is operable to transfer data from the Hall effect sensor to an external device, and receive power from the external device, where the external device is NFC enabled and is not in physical connection with the shoe.

[0088] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages.

[0089] Any reference to 'an' item refers to one or more of those items. The term 'comprising' is used herein to mean including the method blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

[0090] The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.

[0091] It will be understood that the above description of a preferred embodiment is given by way of example only and that various modifications may be made by those skilled in the art . Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention.