Recursive footwear-based subject presence detection

Abstract

An active footwear may include a system that automatically detects the presence or absence of a foot. In an example, various threshold conditions may be used with sensor data to determine whether a foot is present. In an example, the system may be configured to sample values of a foot presence sensor signal from a foot presence sensor, identify a walking state of the article of footwear using the sampled values of the sensor signal, and conditionally update a sensor signal threshold in response to identifying the walking state. The updated sensor signal threshold and subsequent sensor signal values may be used to determine foot entry, exit, or presence.

Description

Technical Field

[0001] This application is a continuation of and claims the benefit of priority to U.S. Provisional Application Serial No. 63 / 388,910, filed on July 13, 2022, the contents of which are incorporated herein by reference in their entirety. Background Art

[0002] Various shoe-based sensors have been proposed to monitor various conditions. For example, Brown provides several examples of shoe-based sensors in U.S. Pat. No. 5,929,332, entitled "Sensor shoe for monitoring the condition of a foot." Brown mentions that a foot force sensor may include an insole made of a relatively thin, planar, flexible, elastic layer of dielectric material. The foot force sensor may include a conductive interconnect that may have a resistance that changes based on an applied compressive force.

[0003] Brown further discusses shoes worn by diabetic patients or people with various types of foot diseases, where excessive pressure applied to a portion of the foot often causes ulcers. The shoe body may include a force sensing resistor (FSR), and a switching circuit coupled to the resistor may activate an alarm unit to alert the wearer that a threshold pressure level has been reached or exceeded.

[0004] Devices for automatically tightening footwear have been proposed previously. Liu, in U.S. Pat. No. 6,691,433, entitled "Automatic tightening shoe," provides a first fastener mounted on the upper portion of a shoe, and a second fastener connected to a closure member and capable of removably engaging with the first fastener to keep the closure member in a tightened state. Liu teaches a drive unit installed in the heel portion of the sole. The drive unit includes a housing, a spool rotatably mounted in the housing, a pair of pull wires, and a motor unit. Each wire has a first end connected to the spool and a second end corresponding to a wire hole in the second fastener. The motor unit is coupled to the spool. Liu teaches that the motor unit operably drives the rotation of the spool in the housing to wind the pull wire around the spool for pulling the second fastener toward the first fastener. Liu also teaches a conduit unit through which the pull wire can extend. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] To easily identify the discussion of any particular element or act, the most significant digit(s) in a reference number refers to the reference number that first introduces that element.

[0006] Figure 1Examples of various components of an active article of footwear are generally illustrated.

[0007] Figure 2A , Figure 2B and Figure 2C A schematic diagram of a sensor system and motorized lacing engine for footwear.

[0008] Figure 3 An example of the components of a motorized lacing system is generally illustrated.

[0009] Figure 4A and Figure 4B A diagram of a body presence sensor in an insole portion of an active article of footwear is generally illustrated.

[0010] Figure 5A An example of a capacitive sensor system is generally illustrated.

[0011] Figure 5B An example of an electric field generated by a first capacitive sensor system is generally illustrated.

[0012] Figure 5C An example of an electric field generated by a second capacitive sensor system is generally illustrated.

[0013] Figure 6 An example of a first composite electrode assembly is generally illustrated.

[0014] Figure 7 An example of a second composite electrode assembly is schematically illustrated.

[0015] Figure 8 An example of a graph showing capacitance-indicative signals versus time for different electrode combinations in a capacitive sensor system is generally illustrated.

[0016] Fig. 9 An example of a method that may include determining a subject proximity indication using a subject presence sensor is generally illustrated.

[0017] Fig.10 An example of a method that may include using a composite electrode assembly to provide a subject proximity indication is generally illustrated.

[0018] Fig.11 An example of a graph showing a subject position indication signal relative to various thresholds that may be dynamically changed is generally illustrated.

[0019] Fig.12 An example of a method that may include determining footwear usage characteristics based on body position-indicating sensor signals is generally illustrated.

[0020] Fig.13Examples of methods that may include varying one or more thresholds used to determine a footwear condition or footwear usage characteristic are generally illustrated.

[0021] Fig.14 is a block diagram illustrating an example computing device capable of performing aspects of the various techniques discussed herein. DETAILED DESCRIPTION

[0022] The fictional power lace worn by Marty McFly in the 1989 film Back to the Future II Sports shoes popularized the concept of self-tightening shoelaces for the first time. Various styles of powered lacing sneakers that are similar in appearance to the movie prop styles in Back to the Future II have been released, but the internal mechanical systems and surrounding footwear platforms employed are not necessarily suitable for mass production or daily use. Additionally, the designs of previous motorized lacing systems are relatively problematic, such as high manufacturing costs, complexity, difficulty in assembly, lack of maintainability, and weak or fragile mechanical mechanisms. The inventors have developed a modular footwear platform to accommodate motorized lacing engines and non-motorized lacing engines that solves some or all of the problems discussed above, as well as other problems. The components discussed below provide various benefits, including but not limited to maintainable components, interchangeable automatic lacing engines, robust mechanical design, robust control algorithms, reliable operation, streamlined assembly processes, and retail-level customization.

[0023] In an example, a modular automatic lacing footwear platform includes a midsole plate fixed to a midsole in a footwear article, the midsole plate being used to receive a lacing engine. The design of the midsole plate allows the lacing engine to be added to the footwear platform at the latest at the point of purchase. Other aspects of the midsole plate and the modular automatic footwear platform allow for different types of lacing engines to be used interchangeably. For example, the motorized lacing engine discussed below can be changed to a human lacing engine. Alternatively, a fully automatic motorized lacing engine with foot presence sensing or other features can be accommodated within a standard midsole plate.

[0024] The automated footwear platforms discussed herein may include an outsole actuator interface to provide tightening control as well as visual feedback to the end user, for example, using LED lighting projected through a translucent protective outsole material. The actuator may provide tactile and visual feedback to the user to indicate the status of the lacing engine or other automated footwear platform components.

[0025] In an example, the footwear platform includes a foot presence sensor configured to detect when a foot is present in the shoe and to detect an absolute or relative position of the foot inside the shoe or an absolute or relative position of a particular portion of the foot or ankle inside the shoe. When the foot is detected, one or more footwear functions or processes may be initiated (such as automatically and without further user input or command). For example, upon detecting that the foot is properly seated in the footwear against the insole, the control circuit may automatically initiate shoelace tightening, data collection, footwear diagnostics, or other processes.

[0026] Activating or starting the automatic lacing or footwear tightening mechanism too early can potentially inhibit or prevent a user from inserting the foot or putting on the footwear. For example, if the lacing engine is activated before the foot is fully seated against the insole, the user may have difficulty placing the rest of his or her foot into the footwear, or the user may have to manually adjust the lacing tension. The inventors therefore recognize that the problem to be solved includes determining whether the foot is properly or fully seated inside the footwear article, such as whether the toe, midsole (i.e., arch), and heel portions are properly aligned with corresponding portions of the insole or internal footwear cavity. The inventors have further recognized that the problem includes using as few sensors as possible to accurately determine the foot position or foot orientation, such as to reduce sensor costs and assembly costs, and reduce device complexity.

[0027] Solutions to these problems include providing or using a foot presence sensor. In an example, the sensor is configured to generate an electric field or multiple electric fields and sense changes or interruptions in the field. Changes in the electric field or changes in capacitance can be achieved when the foot enters or leaves the footwear, including when some parts of the foot are at a greater distance from the sensor than other parts of the foot. In an example, the sensor is integrated with or contained within the lacing engine housing. In an example, at least a portion of the sensor is disposed external to the lacing engine housing and includes one or more conductive interconnects to a power storage device or processing circuitry within the housing.

[0028] Sensors suitable for foot presence detection can have various configurations. For example, the sensor may include a plate capacitor having at least one plate, the at least one plate being configured to move relative to another plate, such as in response to a pressure or pressure change applied to one or more of the plates. In an example, the sensor may include a plurality of conductive traces, such as being substantially arranged in a plane parallel to or overlapping with a surface of the foot facing footwear (such as the upper surface of an insole, the lower surface of a shoe tongue, or the medial surface of a footwear upper). Such traces may be laterally separated by air gaps (or other insulating materials, such as circuit board substrates), and may be selectively or periodically driven by an electrical drive signal provided by an excitation circuit. In an example, an electrode may include staggered conductive traces, a comb configuration, or a concentric ring or coaxial configuration, or other configurations. The sensor may provide a time-varying signal based on, for example, the movement of the electrodes themselves relative to each other and / or based on interference in an electric field near an electrode caused by the presence, absence, or movement of a foot, footwear, or another object.

[0029] In an example, a foot presence sensor provides an analog electrical output signal that indicates the magnitude of a capacitance detected by the sensor, or indicates a change in capacitance. When a foot is present near the sensor, the output signal may have a first value (e.g., corresponding to a low capacitance), and when a foot is not present, the output signal may have a different second value (e.g., corresponding to a high capacitance).

[0030] In an example, the foot presence sensor signal can provide information in addition to foot presence information or foot position information. For example, there can be detectable changes in the sensor signal associated with a user sit / stand event or other user posture change event, a step event, or other event. In addition, there can be detectable long-term drift in the signal, which can indicate wear and / or remaining life of shoe components such as insoles, orthotics, or other components.

[0031] In an example, the foot presence sensor includes or is coupled to an analog-to-digital (e.g., analog capacitance indication signal to digital) converter circuit that is configured to provide a digital signal indicating the magnitude of the capacitance sensed by the sensor. In an example, the sensor includes or is coupled to a local or remote processor circuit that is configured to provide an interrupt signal or logic signal indicating whether the sensed value meets a specified threshold condition. In an example, the sensor measures a capacitance characteristic relative to a baseline or reference capacitance value, and the baseline or reference can be updated or adjusted to accommodate environmental changes or other changes that can affect the sensed capacitance value.

[0032] In an example, a foot presence sensor is disposed below the foot near the arch or heel area of ​​the insole of the shoe. The sensor may be disposed elsewhere, such as in the ankle area, at the footwear tongue area or other areas of the shoe. The sensor may be substantially planar or flat. In an example, the sensor may be rigid or may be flexible and configured to conform to the contour of the foot or the shoe bed. In some cases, when wearing shoes, an air gap may be provided between a portion of the sensor and the foot, such as having a relatively low dielectric constant or a low relative dielectric constant. A gap filler (e.g., having a dielectric constant relatively high than air or a larger relative dielectric constant) may be disposed above the capacitive sensor to bridge any air gap between the sensor and the foot surface. The gap filler may be compressible or incompressible. In an example, a gap filler is selected to provide a suitable compromise between a dielectric value and the suitability for footwear, so as to provide a sensor with sufficient sensitivity and user comfort under the foot.

[0033] Various components of an automatic footwear platform are discussed below, including a motorized lacing engine, a foot presence sensor, a midsole plate, and various other components of the platform. Although much of the present disclosure focuses on foot presence sensing as a trigger for a motorized lacing engine, many aspects of the designs discussed may be applied to a human lacing engine, or other circuits or features that may interface with a foot presence sensor, such as automating other footwear functions (e.g., data collection, physiological monitoring) or as input or output relative to a virtual environment or metaspace. The term "automatic," such as used in "automatic footwear platform," is not intended to cover only systems that operate without specified user input. Instead, the term "automatic footwear platform" may include various electric and human, automatically activated, and human-activated mechanisms for tightening the lacing or retention system of footwear, or for controlling other aspects of active footwear or components functionally coupled thereto. In an example, the automatic footwear platform is configured to interface with one or more digital worlds, such as by providing a tangible interface to a user's digital avatar.

[0034] Figure 1 An exploded view of components of an active article of footwear is generally illustrated according to an example embodiment. Figure 1 Examples of the invention include a motorized lacing system 100 having a lacing engine 110, a cover 120, an actuator 130, a midsole plate 140, a footwear midsole 155, and an outsole 165. The lacing engine 110 may include a user-replaceable component in the system 100, and may include or may be coupled to one or more foot presence sensors. In an example, the lacing engine 110 includes or is coupled to a capacitive foot presence sensor. Figure 1A capacitive foot presence sensor, not shown in the example, may include a plurality of electrodes. The electrodes may be disposed on or around the article of footwear in various configurations. In one example, one or more of the electrodes may be disposed on a side of the lacing engine 110 that faces the foot. In an example, the electrodes of the capacitive foot presence sensor may be housed within the lacing engine 110, may be integrated with the housing of the lacing engine 110, or may be disposed elsewhere near the lacing engine 110 and coupled to a power source or processing circuitry within the lacing engine 110 using one or more electrical conductors.

[0035] In an example, motorized lacing system 100 may be assembled by securing midsole plate 140 to midsole 155. Next, actuator 130 may be inserted into an opening in the outside of midsole plate 140, such as opposite an interface button that may be embedded in outsole 165. Next, lacing engine 110 may be inserted into midsole plate 140. In an example, lacing engine 110 may be coupled to one or more sensors disposed elsewhere in the footwear. Other assembly methods may be similarly performed to construct motorized lacing system 100. The assembly methods described are provided by way of example and not limitation, and alternative methods are contemplated.

[0036] In an example, lacing system 100 is inserted with a continuous loop of lacing cables, and the lacing cables are aligned with the spools in lacing engine 110. To complete assembly, cover 120 may be inserted into a receiving device in midsole plate 140, secured into a closed position, and locked into a recess in midsole plate 140. Cover 120 may capture lacing engine 110 and, in an example, may help maintain alignment of the lacing cables during operation.

[0037] Midsole plate 140 includes lacing engine cavity 141, medial and lateral lacing guides 142, front flange 143, rear flange 144, upper (top) and lower (bottom) surfaces, and actuator cutout 145. Lacing engine cavity 141 is configured to receive lacing engine 110. In this example, lacing engine cavity 141 retains lacing engine 110 in the lateral and front / rear directions, but does not include features to lock lacing engine 110 into cavity 141. Optionally, lacing engine cavity 141 includes detents, tabs, or other mechanical features along one or more sidewalls to securely retain lacing engine 110 within lacing engine cavity 141.

[0038] Lace guide 142 may help guide the lacing cable into position with lacing engine 110. Lace guide 142 may include chamfered edges and downwardly sloping ramps to help guide the laces or lacing cables into a desired position relative to lacing engine 110. In this example, lace guide 142 includes an opening in the side of midsole plate 140 that is many times wider than a typical lacing cable diameter, although other sizes may be used.

[0039] exist Figure 1 In the example of the embodiment of the present invention, the midsole plate 140 includes a sculptured or contoured front flange 143 that further extends on the medial side of the midsole plate 140. The example front flange 143 is designed to provide additional support under the arch of the footwear platform. However, in other examples, the front flange 143 may be less obvious on the medial side. In this example, the rear flange 144 includes a profile with extensions on both the medial side and the lateral side. The illustrated rear flange 144 can provide enhanced lateral stability for the lacing engine 110.

[0040] In an example, one or more electrodes may be embedded or disposed on the midsole plate 140 and may form part of a foot presence sensor, such as part of a capacitive foot presence sensor. In an example, the lacing engine 110 includes a sensor circuit electrically coupled to one or more electrodes on the midsole plate 140. The sensor circuit may be configured to use the electric field or capacitance information sensed from the electrodes to determine whether the foot is present or not in a region adjacent to the midsole plate 140. That is, the sensor may be configured to sense information about whether the foot is present in a foot receiving cavity or void inside the footwear article. In an example, the electrode extends from the frontmost edge of the front flange 143 to the rearmost edge of the rear flange 144, and in other examples, the electrode extends over a portion of one or both of the flanges.

[0041] In an example, footwear or motorized lacing system 100 includes or is docked with one or more sensors, which can monitor or determine the presence of a foot in the footwear, the absence of a foot in the footwear, or the foot position characteristics in the footwear. Based on information from one or more such foot presence sensors, the footwear including motorized lacing system 100 can be configured to perform various functions. For example, a foot presence sensor can be configured to provide binary information about whether a foot is present or not present in the footwear. In an example, a processor circuit coupled to the foot presence sensor receives and interprets digital or analog signal information, and provides binary information about whether a foot is present or not present in the footwear. If the binary signal from the foot presence sensor indicates that a foot is present, the lacing engine 110 in the motorized lacing system 100 can be activated to automatically increase or decrease the tension on the lacing cable or other footwear contraction device to tighten or loosen the footwear around the foot. In an example, lacing engine 110 or other portion of an article of footwear includes processor circuitry that can receive or interpret signals from a foot presence sensor and initiate various responsive actions.

[0042] In an example, the foot presence sensor can be configured to provide information about the position of the foot when the foot enters the footwear. Typically, only when the foot is properly positioned or seated in the footwear, such as against all or a portion of the insole, can the motorized lacing system 100 be activated to tighten the lacing cables. The foot presence sensor, which senses information about the foot's travel or position, can provide information about whether the foot is fully or partially seated, such as relative to the insole or relative to some other feature of the footwear article. The automatic lacing procedure can be interrupted or delayed until the information from the sensor indicates that the foot is in the proper position.

[0043] In an example, the foot presence sensor can be configured to provide information about the absolute or relative position of the foot inside the footwear. For example, the foot presence sensor can be configured to sense whether the footwear is a good "fit" for a given foot, such as by determining the relative position of one or more of the arch, heel, toe, or other parts of the foot, such as relative to a corresponding portion of the footwear configured to receive such foot parts. In an example, the foot presence sensor can be configured to sense whether the position of the foot or foot part changes over time relative to a specified or previously recorded reference position, such as due to lacing cables loosening over time, or due to the natural expansion and contraction of the foot itself.

[0044] In an example, a foot presence sensor may include an electrical, magnetic, thermal, capacitive, pressure, optical, or other sensor device that may be configured to sense or receive information about the presence or proximity of a subject. For example, an electrical sensor may include an impedance sensor configured to measure an impedance characteristic between at least two electrodes. When a subject such as a foot is positioned close to or adjacent to the electrodes, the electrical sensor may provide a sensor signal having a first value, and when the subject is positioned away from the electrodes, the electrical sensor may provide a sensor signal having a different second value. For example, a first impedance value may be associated with an empty footwear condition, and a smaller second impedance value may be associated with an occupied footwear condition.

[0045] In an example, the foot presence sensor may include an AC signal generator circuit and an antenna configured to transmit or receive high frequency signal information, such as radio frequency information. Based on the proximity of the subject relative to the antenna, one or more electrical signal characteristics (such as impedance, frequency, or signal amplitude) may be received and analyzed to determine whether the subject is present. In an example, a received signal strength indicator (RSSI) provides information about the power level in a received radio signal. Changes in the RSSI (such as changes relative to some baseline or reference value) may be used to identify the presence or absence of a subject. In an example, WiFi frequencies may be used in one or more of the 2.4 GHz, 3.6 GHz, 4.9 GHz, 5 GHz, and 5.9 GHz bands, for example. In an example, frequencies in the kilohertz range may be used, such as approximately 400 kHz. In an example, power signal changes may be detected in the milliwatt or microwatt range.

[0046] Any of a variety of different types of foot presence sensors (e.g., sensors configured to measure capacitance, impedance, magnetic fields, temperature, light, pressure, etc.) may be used independently, or information from two or more different sensors or sensor types may be used together to provide more information about the foot's presence, absence, orientation, fit with the footwear, or other information about the foot and / or its relationship to the footwear.

[0047] FIG. 2A to FIG. 2C A sensor system and a motorized tether engine are generally illustrated, according to some example embodiments. Figure 2AVarious features of an example of a lacing engine 110 are described, including a housing structure 150, a housing screw 108, a lace channel 112 (also referred to as a lace guide slot 112), a lace channel transition 114, a spool recess 115, a button opening 122, a button 121, a button membrane seal 124, a programming seat 128, a spool 131, and a lace groove 132 in the spool 131. Other designs may be similarly used. For example, other types of switches may be used, such as a sealed dome switch, or the membrane seal 124 may be omitted, etc. In an example, the lacing engine 110 may include one or more interconnects or electrical contacts for docking a circuit inside the lacing engine 110 with a circuit outside the lacing engine 110 (such as an external foot presence sensor or component thereof, an external actuator such as a switch or button, or other device or component).

[0048] The lacing engine 110 may be held together by one or more screws, such as case screws 108. Case screws 108 may be positioned near the main drive mechanism to enhance the structural integrity of the lacing engine 110. Case screws 108 also serve to aid in the assembly process, such as holding the housing structure 150 together for ultrasonic welding of exterior seams.

[0049] exist Figure 2A In an example of, lacing engine 110 includes a lacing channel 112 to receive laces or lacing cables when the engine is assembled into an automated footwear platform. Lacing channel 112 may include channel walls having chamfered edges to provide a smooth guide surface against which or within which the lacing cable may travel during operation. A portion of the smooth guide surface of lacing channel 112 may include a channel transition 114, which may be a widened portion of lacing channel 112 leading to a spool recess 115. Spool recess 115 transitions from channel transition 114 to a generally circular section that closely conforms to the contour of spool 131. Spool recess 115 may help retain a wound lacing cable as well as maintain the position of spool 131. Other aspects of the design may provide other means for retaining spool 131. In Figure 2A In the example of FIG. 1 , the spool 131 is shaped like half of a yo-yo with a lacing groove 132 extending through the flat top surface and a spool shaft ( FIG. 132 ) extending downwardly from the opposite side. Figure 2A not shown).

[0050] The outside of the lacing engine 110 includes a button opening 122 that accommodates a button 121, which can be configured to activate or adjust one or more features of the automatic footwear platform. The button 121 can provide an external interface for activating various switches included in the lacing engine 110. In some instances, the housing structure 150 includes a button membrane seal 124 to provide protection from dust and water. In this instance, the button membrane seal 124 is a transparent plastic (or similar material) up to several mils (thousandths of an inch) thick, which can be adhered from the upper surface of the housing structure 150, such as above the corners and below the outside. In another example, the button membrane seal 124 is a vinyl adhesive backing film of approximately 2 mils thick covering the button 121 and the button opening 122. Other types of buttons and sealants can be used similarly.

[0051] Figure 2B 1 is an illustration of a housing structure 150 including a top section 102 and a bottom section 104. In this example, the top section 102 includes features such as a recess for receiving a housing screw 108, a lace channel 112, a lace channel transition 114, a spool recess 115, a button opening 122, and a button seal recess 126. In the example, the button seal recess 126 is a portion of the top section 102 that is cut away to provide an insert for the button membrane seal 124.

[0052] exist Figure 2B In the example of FIG. 1 , the bottom section 104 includes features such as a wireless charger inlet 105, a connector 106, and a grease barrier 109. Also illustrated but not specifically identified is a case screw base for receiving a case screw 108, and various features within the grease barrier 109 for retaining portions of the drive mechanism. The grease barrier 109 is designed to keep grease or similar compounds surrounding the drive mechanism away from the various electrical components of the lacing engine 110.

[0053] The housing structure 150 may include one or more electrodes 170 in one or both of the top section 102 and the bottom section 104 embedded in or applied to a surface of the structure. Figure 2BThe electrodes 170 in the example are shown as being coupled to the bottom segment 104. In the example, the electrodes 170 comprise a portion of a capacitance-based foot presence sensor circuit (e.g., see the body presence sensor 302 discussed herein). Although illustrated as complementary and interleaved conductors, the electrodes 170 may have various shapes, sizes, or orientations, as further detailed herein. Additionally or alternatively, one or more of the electrodes 170 may be coupled to the top segment 102. The electrodes 170 coupled to the top segment 102 and / or the bottom segment 104 may be used for wireless power transfer and / or as part of a capacitance-based foot presence sensor circuit. In the example, the electrodes 170 include one or more portions disposed on an outer surface of the shell structure 150, and in another example, the electrodes 170 include one or more portions disposed on an inner surface of the shell structure 150.

[0054] Figure 2C 1 is an illustration of various internal components of the lacing engine 110 according to an example embodiment. In this example, the lacing engine 110 includes a spool magnet 136, an O-ring seal 138, a worm drive 140, a sleeve 141, a worm drive key, a gear box 148, a gear motor 145, a motor encoder 146, a motor circuit board 147, a worm gear 151, a circuit board 160, a motor mount 161, a battery connection 162, and a wired charging mount 163. The spool magnet 136 is detected by, for example, a magnetometer ( Figure 2C The circuit board 160 may include one or more interfaces or interconnects for a foot presence sensor or one or more other sensors. In an example, the circuit board 160 includes one or more traces or conductive planes that provide a portion of a foot presence sensor.

[0055] In the illustrated example, the main drive components of the lacing engine 110 include a worm drive 140, a worm gear 151, a gear motor 145, and a gear box 148. The worm gear 151 is designed to inhibit the back drive of the worm drive 140 and the gear motor 145, which means that the main input force entering from the lacing cable via the spool 131 can be decomposed on the relatively large worm gear and worm drive teeth. This arrangement is to avoid the gear box 148 from needing to include gears of sufficient strength to withstand both the dynamic loads from the active use of the footwear platform or the tightening loads from the tightening lacing system. The worm drive 140 includes additional features that help protect various vulnerable parts of the drive system, such as a worm drive key. In this example, the worm drive key is a radial slot in the motor end of the worm drive 140, which is docked with a pin by a drive shaft coming out of the gear box 148. This arrangement prevents the worm drive 140 from exerting undue axial forces on the gearbox 148 or gear motor 145 by allowing the worm drive 140 to move freely in the axial direction (away from the gearbox 148 ), transferring these axial loads to the sleeve 141 and housing structure 150 .

[0056] Figure 3 A block diagram of components of a motorized lacing system 300 according to an example embodiment is generally illustrated. System 300 includes some, but not necessarily all, components of a motorized lacing system, such as housing structure 150 including an interface button 301, a body presence sensor 302, and a printed circuit board assembly (PCBA) encapsulating a processor circuit 320, a battery 321, a charging coil 322, an encoder 325, a motion sensor 324, and a drive mechanism 340. Drive mechanism 340 may include, among other things, a motor 341, a transmission 342, and a lace spool 343. Motion sensor 324 may include, among other things, a single-axis or multi-axis accelerometer, a magnetometer, a gyrometer, or other sensor or device configured to sense motion of housing structure 150, or one or more components within or coupled to housing structure 150.

[0057] exist Figure 3 In the example of , the processor circuit 320 (sometimes referred to herein as a control circuit or controller) communicates data or power signals with one or more of the interface button 301, the subject presence sensor 302, the battery 321, the charging coil 322, and the drive mechanism 340. The transmission 342 couples the motor 341 to the spool 343 to form the drive mechanism 340. Figure 3 As illustrated in the example of , the button 301 , the subject presence sensor 302 , and the environmental sensor 350 may be disposed outside the housing structure 150 or partially disposed outside the housing structure 150 .

[0058] In an alternative embodiment, one or more of the button 301, the subject presence sensor 302, and the environmental sensor 350 may be enclosed in the housing structure 150. In an example, the subject presence sensor 302 is disposed inside the housing structure 150 to protect the sensor from sweat and dust or debris. Minimizing or eliminating connections through the walls of the housing structure 150 can help increase the durability and reliability of the assembly.

[0059] In an example, the processor circuit 320 controls one or more aspects of the drive mechanism 340. For example, the processor circuit 320 can be configured to receive information from the button 301 and / or from the subject presence sensor 302 and / or from the motion sensor 324, and in response, control the drive mechanism 340 to tighten or loosen the footwear around the foot. In an example, the processor circuit 320 is additionally or alternatively configured to issue commands to obtain or record sensor information from the subject presence sensor 302 or other sensors, as well as other functions. In an example, the processor circuit 320 adjusts the operation of the drive mechanism 340 by detecting the presence of the foot using the subject presence sensor 302, detecting the orientation or position of the foot using the subject presence sensor 302, or detecting a specified posture using the motion sensor 324.

[0060] In an example, system 300 includes environmental sensor 350. Information from environmental sensor 350 can be used to update or adjust a baseline or reference value of subject presence sensor 302. For example, subject presence sensor 302 can include a capacitive sensor, and the capacitance value measured by a capacitive foot presence sensor can change over time, such as in response to environmental conditions near the sensor. Thus, using information from environmental sensor 350, processor circuit 320 and / or subject presence sensor 302 can be configured to update or adjust the measured or sensed capacitance value.

[0061] In an example, the body presence sensor 302 can be disabled, or the signal from the body presence sensor 302 can be ignored by the processor circuit 320 under various conditions. For example, if the drive mechanism 340 is activated and actively winding or unwinding, the processor circuit 320 can be configured to ignore interruptions or other signals from the body presence sensor 302. In an example, if the footwear is charged, such as using the charging coil 322 or the wired charging dock 163, the processor circuit 320 can be configured to ignore interruptions or other signals from the body presence sensor 302.

[0062] Figure 4A and Figure 4BA diagram of a subject presence sensor, such as a capacitive-based foot presence sensor for use in an insole of an article of footwear, is generally illustrated according to an example embodiment. The subject presence sensor may be provided below the surface of an object or subject 402, such as a foot, when the article incorporating the sensor is worn.

[0063] exist Figure 4A In the example, the subject presence sensor may include a first electrode assembly 406 coupled to a control circuit 404. In the example, the control circuit 404 includes a processor circuit 320. Figure 4A In an example, the first electrode assembly 406 and / or the control circuit 404 may be included in or mounted to an interior portion of the housing 410 (such as may include the housing structure 150), or may be coupled to a PCBA inside the housing 410. In an example, the first electrode assembly 406 may be disposed at or adjacent to a foot-facing surface of the housing 410. In an example, the first electrode assembly 406 includes a plurality of conductors or traces distributed across an interior upper surface area of ​​the housing 410.

[0064] exist Figure 4B , the subject presence sensor can include a second electrode assembly 414 coupled to the control circuit 404. The second electrode assembly 414 can be mounted to the exterior of the housing 410 or adjacent thereto and can be electrically coupled to a PCBA inside the housing 410, such as using a flexible connector 416. In an example, the second electrode assembly 414 can be disposed at or adjacent to a foot-facing surface of the housing 410. In an example, the second electrode assembly 414 includes a flexible circuit that is secured to an interior or exterior surface of the housing 410 and is coupled to the control circuit 404 using one or more conductors.

[0065] In an example, the control circuit 404 includes a general purpose processor or a dedicated processor. The control circuit 404 can be configured to provide an AC drive signal to a selected pair of multiple electrodes including the first electrode assembly 406 or the second electrode assembly 414. In response to the AC drive signal, the control circuit 404 can sense information about changes in the electric field at the electrode assembly or changes in the electric field adjacent to the electrode assembly, such as based on corresponding changes in the proximity of the object or subject 402 to the electrode, as explained in more detail below.

[0066] Various materials may be provided between the body 402 and the electrode assembly, such as the first electrode assembly 406 or the second electrode assembly 414. For example, inter-electrode insulation, material of the housing 410, insole material, dielectric insert 412, socks or other foot coverings, body tape, kinesio tape, or other materials may be interposed between the body 402 and one or more electrodes and may change the dielectric properties of the footwear and thereby affect the detection sensitivity of the body sensor. The control circuit 404 may be configured to update or adjust the excitation signal or sensing parameter based on the amount or type of intervening material in order to enhance the sensitivity or signal-to-noise ratio of the sensor.

[0067] exist Figure 4A or Figure 4B In an example, the first electrode assembly 406 or the second electrode assembly 414 can be excited by a signal generator in the control circuit 404, and therefore, the electric field can be at least partially projected from the foot-facing side of the electrode assembly. In an example, a drive shield located below the sensing electrode can be used at least in part to block the electric field below the electrode assembly. The drive shield and the electrode assembly can be electrically insulated from each other. For example, if the first electrode assembly 406 is on one surface of the PCBA, the drive shield can be on the bottom layer of the PCBA, or on any of the multiple inner layers on a multi-layer PCBA. In an example, the drive shield can have a surface area equal to or greater than that of the electrode including the first electrode assembly 406 or the second electrode assembly 414, and in some examples, the drive shield can be centered directly below the electrode assembly.

[0068] In an example, a driven shield may receive a drive signal (e.g., from a control circuit 404) and, in response, generate an electric field. The field generated by the driven shield may have substantially the same polarity, phase, and / or amplitude as the field generated by the first electrode assembly 406 or the second electrode assembly 414. The field from the driven shield may repel the electric field of other electrode assemblies, and thereby isolate the sensor field from various parasitic effects, such as undesirable coupling with the ground plane of the PCBA. The field generated by the driven shield may help direct detection and focused detection of a specific area, may help reduce environmental impacts, and may help reduce parasitic capacitance effects. In an example, a driven shield is included and may help reduce the effects of temperature changes on the sensor assembly. Temperature may affect parasitic offset characteristics, and, for example, temperature changes may cause parasitic ground plane capacitance changes. Using a shield such as one inserted between the sensor electrode and ground may help mitigate the effects of parasitic ground plane capacitance measured from the sensor.

[0069] In an example, a preferred location in which housing 410 is positioned is in the arch region of the footwear because it is an area that is less likely to be felt by the wearer or cause discomfort to the wearer. One advantage of using capacitive sensing to detect the presence of the foot in footwear includes that the capacitive sensor can function well even when the sensor is disposed in the arch region and the user has a relatively or abnormally high arch of the foot. For example, the sensor drive signal amplitude or morphological characteristics can be changed or selected based on the desired signal-to-noise ratio of the signal received from the capacitive sensor. In an example, the sensor drive signal can be updated or adjusted each time the footwear is used to accommodate changes in one or more materials (e.g., socks, insoles, etc.) disposed between the body 402 and the body sensor electrode assembly.

[0070] In an example, an electrode assembly of a capacitive sensor (such as first electrode assembly 406 or second electrode assembly 414) can include a plurality of different electrodes that can be selectively coupled or decoupled to form various electrode pairs that can be driven individually or used as sensors individually. For example, different pairs can be configured to sense respective signals, and the difference between the signals can be used to determine various characteristics of a foot or footwear. In an example, electrodes comprising different electrode pairs can be oriented along different axes, or can be substantially concentric or adjacent electrodes.

[0071] Figure 5A A capacitive sensor system 500 for subject or foot presence detection according to an example embodiment is generally illustrated. An example of the capacitive sensor system 500 includes a subject 402 (e.g., representing a foot in or near an active footwear article) and a first electrode 514 and a second electrode 516. In an example, the first electrode 514 and / or the second electrode 516 may include different components of the first electrode assembly 406 or the second electrode assembly 414 or the subject presence sensor 302. Each of the electrodes may include a plate, a trace, or other conductor including a conductive material such as copper, carbon, silver, or conductive foil, among other conductive materials. In an example, any conductive material may be used for the electrode including conductive films, inks, deposited metals, or other materials.

[0072] exist Figure 5A In the example, the first electrode 514 and the second electrode 516 are illustrated as being vertically spaced relative to each other (and relative to the body 402), however, the electrodes may be similarly spaced horizontally or otherwise offset or spaced apart. In an example, the electrodes may be disposed in a plane that is substantially or approximately parallel to a lower surface of the body 402 to be detected. That is, at least a portion of the electrode may include a surface that is parallel to a corresponding lower portion or lower surface of the body 402. In some examples, the electrode may be contoured or shaped to correspond to, for example, a curvature or arch area of ​​the foot. In Figure 5AIn the example of , the first electrode 514 is configured as a driving electrode or a transmitting electrode and is coupled to a signal generator that provides an excitation signal 518. In the example, the signal generator comprises a part of the control circuit 404.

[0073] As a result of exciting the electrodes using the excitation signal 518, an electric field 526 may be generated primarily between the first electrode 514 and the second electrode 516. That is, various components of the generated electric field 526 may extend between the electrodes, and other edge components of the generated electric field 526 may extend in other directions. For example, an edge component may extend from the transmitter electrode or the first electrode 514 away from the housing 410 (at Figure 5A ), and may terminate back at a receiver electrode or second electrode 516 or elsewhere.

[0074] Information about electric field 526 may be sensed or received, for example, using second electrode 516, including information about changes or interruptions in the field due to the proximity of subject 402. The sensed signal from second electrode 516 may be processed using various circuits (e.g., using control circuit 404) and may be used to provide an analog or digital signal indicating the presence or absence of subject 402.

[0075] For example, a sigma-delta analog-to-digital converter circuit 520 (ADC) can be used to measure the field strength of the electric field 526 detected by the second electrode 516. The ADC can be configured to convert an analog capacitance indication signal into a digital signal. In an example, when an object such as a body 402 intrudes into the electric field 526 including its edge component, the electrical environment near the electrode changes. When the body 402 enters the field, a portion of the electric field 526 is shunted (e.g., grounded or absorbed) instead of being received and terminated at the second electrode 516, or passes through the body 402 (e.g., instead of passing through the air) before being received at the second electrode 516. This field interruption can cause a capacitance change that can be detected by a sensor using the first electrode 514 and the second electrode 516.

[0076] In an example, the second electrode 516 can receive electric field information substantially continuously, and the information can be continuously or periodically sampled by the analog-to-digital converter circuit 520. A filter circuit 522 can be used to process the information from the analog-to-digital converter circuit 520 to introduce an offset or calibration factor. The system can then provide a digital output signal 524. In an example, the filter circuit 522 can introduce a capacitive offset, which can be specified or programmed (e.g., internal to the control circuit 404) or can be based on another capacitor used to track changes in the environment over time, temperature, and other variable characteristics of the environment.

[0077] In an example, digital output signal 524 can include binary information about the presence, absence, or location of determined subject 402, such as by comparing the measured value to a specified threshold. In an example, digital output signal 524 includes qualitative information about the measured capacitance, such as can be used (e.g., by control circuit 404) to provide an indication of the likelihood that subject 402 is present or absent.

[0078] Periodically, or if subject presence sensor 302 is not activated (e.g., as determined using information from motion sensor 324), a capacitance indication value may be measured and stored as a reference value, a baseline value, or an ambient value. When a foot or subject (e.g., subject 402) approaches subject presence sensor 302 and its electrodes, the measured capacitance may decrease or increase, such as relative to a stored reference value. In an example, one or more threshold capacitance levels may be stored, for example, in an on-chip register with control circuit 404. When the measured capacitance value exceeds a specified threshold, it may be determined that subject 402 is present (or not present) in the footwear containing subject presence sensor 302.

[0079] The subject presence sensor 302 and the various electrodes comprising the subject presence sensor 302 can take a variety of different forms, such as illustrated in several non-limiting examples below. In an example, the electrodes of the subject presence sensor 302 can be arranged in a grid pattern. In an example where the subject presence sensor 302 is a capacitive sensor, the sensor electrode grid can include a variable capacitor at each intersection of each row and each column of the grid. Optionally, the electrode grid includes electrodes arranged in one or more rows or columns. A voltage signal can be applied to the rows or columns, and the subject or foot near the sensor surface can affect the local electric field, and the mutual capacitance effect can be reduced. In an example, the capacitance change at multiple points on the grid can be measured to determine the subject position relative to the grid or relative to the footwear article, such as by measuring the voltage on each axis. In an example, the mutual capacitance measurement technology can provide information from multiple locations around the grid at the same time.

[0080] In an example, mutual capacitance measurements use an orthogonal grid of transmit and receive electrodes. In such a grid-based sensor system, measurements may be detected for each of a plurality of discrete XY coordinate pairs. In an example, capacitance information from a plurality of capacitors may be used to determine foot presence or foot orientation in footwear. In another example, capacitance information from one or more capacitors may be acquired over time and analyzed to determine foot presence or foot orientation. In an example, rate of change information about the X and / or Y detection coordinates may be used to determine when or if the foot is properly or fully positioned relative to the insole in the footwear.

[0081] In an example, a body presence sensor 302 including a self-capacitance based foot presence sensor can have the same XY grid as a body presence sensor 302 including a mutual capacitance sensor, but the columns and rows can operate independently. In a self-capacitance sensor, the capacitive load of the body at each column or row can be detected independently.

[0082] Figure 5B and Figure 5C Examples of different configurations of electrodes that may include a subject presence sensor 302 are generally illustrated. The accompanying drawings illustrate descriptions of electrostatic fields or electric fields generated from different electrode configurations. For each pair of electrodes or capacitor plates, the effective dielectric between the electrodes includes an air gap (or other material) disposed between the electrodes. For each electrode pair, any portion of the subject or foot that is close to it may become part of the effective dielectric of a given pair, or may affect the effective dielectric of a given pair. That is, a variable dielectric may be provided between each electrode pair based on the proximity of the subject to the corresponding electrode. For example, the closer the subject or foot is to a given electrode pair, the greater the value of the effective dielectric may be. When the dielectric constant value increases, the capacitance value increases. This capacitance value change may be received by the processor circuit 320 and used to indicate whether the subject is present at or near the subject presence sensor 302.

[0083] Figure 5B The diagram is similar to Figure 5A The configuration shown in the example is a vertically stacked electrode configuration. Figure 5B Examples include a top electrode 502 and a bottom electrode 504. When the top electrode 502 and the bottom electrode 504 are coupled to receive corresponding portions of an AC drive signal (e.g., including an excitation signal 518), a first projected electric field 506 can be provided. The first projected electric field 506 can include field lines or field components extending in three dimensions, including components extending linearly or laterally between the top electrode 502 and the bottom electrode 504 as illustrated. Some field components can extend away from or around the edges of the electrodes, as illustrated by lines extending to the left or right of the top electrode 502 and the bottom electrode 504. It should be understood that some components extend into or away from the page to provide a three-dimensional field. The shape of the first projected electric field 506 can be generally spherical or can be non-spherical, and can have a profile according to, for example, the size or position or orientation of various electrodes that contribute to or are configured to selectively (e.g., passively or actively) block the field.

[0084] Figure 5C A horizontally spaced electrode configuration is illustrated. Figure 5CExamples include a left electrode 508 and a right electrode 510. When the left electrode 508 and the right electrode 510 are coupled to receive corresponding portions of an AC drive signal (e.g., including the excitation signal 518), a second projected electric field 512 can be provided. The second projected electric field 512 can include field lines or field components extending in three dimensions, including components extending linearly or laterally between the left electrode 508 and the right electrode 510 as illustrated. It should be understood that some components extend into or away from the page to provide a three-dimensional field, as similarly described above.

[0085] In an example, a dielectric member such as dielectric insert 412 may be provided between body 402 and one or more of the electrodes of body presence sensor 302. The dielectric member may have a dielectric permittivity that is the same as or greater than the permittivity of air (e.g., k=1.0). The dielectric member may increase the sensitivity of body presence sensor 302 to changes in the position or location of body 402 by providing a conduit that helps to selectively direct the generated electric field to a specific area. For example, the dielectric member may help focus the generated electric field to a central foot receiving portion of an article of footwear.

[0086] In an example, the dielectric member may increase the sensitivity of subject presence sensor 302 by extending the electric field outward or laterally away from or pushing the electric field away from the electrodes of subject presence sensor 302. This change in sensitivity may be desirable in some cases, or it may be undesirable if it increases the sensitivity of subject presence sensor 302 or other adjacent materials, such as conductive surfaces or liquids on or near which the article of footwear may be used. In other words, the increased sensitivity may be undesirable if the presence of a subject is falsely detected due to environmental changes or due to factors other than, for example, the presence of a foot being present inside the article of footwear.

[0087] The inventors have recognized that a solution to the sensitivity or electric field location problem may include or use a subject presence sensor 302 that includes three or more electrodes. The electrodes may be paired in various combinations and driven together, such as in a time division multiplexed manner, to more accurately detect subject presence. The inventors have further recognized that this solution may help improve the sensor's resistance to drift due to sweat or other environmental influences. For example, using information about multiple electric fields together may help reduce the sensitivity of subject presence sensor 302 to objects at the sides of the sensor, and may help reduce sensitivity to objects opposite the sensor's focal area (e.g., the interior of an article of footwear).

[0088] The inventors have recognized that another problem to be solved includes obtaining appropriate sensitivity of or response from a capacitive foot presence sensor, for example, when all or a portion of the foot presence sensor is separated from a foot or body to be detected (such as by an air gap or other intervening material). The inventors have recognized that a solution may include using multiple electrodes having specific shapes, sizes, and orientations to enhance the orientation and relative strength of the electric field generated when the electrodes are energized. That is, the inventors have identified an optimal electrode configuration for capacitive foot presence sensing. The inventors also recognized that the solution may include using information from multiple electrode sensing pairs together.

[0089] Figure 6 An example of a first composite electrode assembly 602 that may include a plurality of conductors is generally illustrated. In an example, the first composite electrode assembly 602 includes a portion of the subject presence sensor 302. The example of the first composite electrode assembly 602 includes a main electrode or center electrode 604 and a ring electrode 606. The ring electrode 606 and the center electrode 604 may be separated by an insulator 612 or non-conductive region. In an example, the ring electrode 606 completely surrounds or encloses the center electrode 604, and in other examples, the ring electrode 606 extends partially but not completely around the perimeter of the center electrode 604.

[0090] In an example, the center electrode 604 and the ring electrode 606 can be coplanar conductive plates or traces and are disposed on a common or shared substrate, such as FR4, polyimide, PET, or other materials. Each of the center electrode 604 and the ring electrode 606 can be coupled to a drive circuit to receive an excitation signal, such as the excitation signal 518 from the control circuit 404. One of the center electrode 604 or the ring electrode 606 can be configured by the control circuit 404 to function as an anode or a cathode. For example, the center electrode 604 can be coupled to the control circuit 404 using a first wire 608, and the ring electrode 606 can be coupled to the control circuit 404 using a different second wire 610, and each wire can receive a different drive signal or a different portion of a drive signal from the control circuit 404.

[0091] In an example, the ring electrode 606 and the center electrode 604 may be driven using respective portions of the AC excitation signal. That is, one of the ring electrode 606 and the center electrode 604 may be used as a drive electrode, and the other of the ring electrode 606 and the center electrode 604 may be used as a reference or ground electrode. In response to the AC excitation signal, the electric field generated generally corresponds (in part) to Figure 5C The electric field extending between the left electrode 508 and the adjacent right electrode 510 is illustrated in the example of FIG.

[0092] In an example, the insulator 612 can provide a generally uniform or non-uniform spacing between the outer edge of the center electrode 604 and the inner edge of the ring electrode 606. In some examples, the insulator 612 can provide a gap of about 1 to 2 mm between the electrodes. Increasing the gap distance may help generate a larger electric field at the expense of higher power consumption. In general, the spacing can be selected as a compromise between power consumption constraints and the desired characteristics of the electric field to be generated.

[0093] The inventors have also recognized that noise tolerance, ground fault avoidance, and resistance to external influences of the generated electric field may be other variables to consider in the design of subject presence sensor 302 and the electrodes used therein. For example, when ring electrode 606 is used as a detection electrode and center electrode 604 is used as a reference electrode, then the sensitivity of the sensor to noise and external influences may be minimized relative to other configurations that use center electrode 604 as a detection electrode and ring electrode 606 as a reference.

[0094] Additionally, the system may have greater resistance to ground faults when the generated electric field is more concentrated in the confined interior space and lateral fields are minimized. Ground faults may include erroneous readings due to subject presence sensor 302 being positioned at or near physical ground (i.e., the earth), such as may have different dielectric constant or conductivity characteristics (e.g., to asphalt, concrete, dust, metal, etc.). In some cases, such a grounded substrate may change the sensitivity of subject presence sensor 302 to a subject in the focused detection zone, or may cause subject presence sensor 302 to falsely indicate the presence of a subject.

[0095] Figure 7 An example of a second composite electrode assembly 702 is generally illustrated. The second composite electrode assembly 702 may include Figure 6 The first composite electrode assembly 602 and at least one other electrode of the example. For example, the second composite electrode assembly 702 may include a planar electrode 704, which may be disposed adjacent to the first composite electrode assembly 602 but spaced apart from the first composite electrode assembly 602. The planar electrode 704 may be coupled to an excitation circuit, such as including the control circuit 404, using a third wire 710.

[0096] exist Figure 7In the example of , the second composite electrode assembly 702 includes the first composite electrode assembly 602 separated from the planar electrode 704 by an electrode gap 708. The electrode gap 708 can be an air gap, or one or more intermediate components can be provided between the electrodes. For example, a circuit housing 706 (e.g., including housing 410) can be provided between the first composite electrode assembly 602 and the planar electrode 704. In the example, the circuit housing 706 provides a fixed gap between at least a portion of the planar electrode 704 and at least a portion of the first composite electrode assembly 602. In Figure 7 In the example of the circuit housing 706, the circuit housing 706 has an outer perimeter that is generally smaller than each of the adjacent electrode assemblies, however, other configurations or sizes of the housing can be similarly used. In other examples, the circuit housing 706 is located elsewhere, and different insulating dielectric materials can be interposed between the electrode assemblies.

[0097] In an example, the control circuit 404 can be configured to provide a corresponding component of the AC drive signal to any pair of electrodes in the second composite electrode assembly 702. Each corresponding pair of drive electrodes can include a different sensor (sometimes referred to herein as a capacitive sensor or a subject presence sensor). For example, the control circuit 404 can provide a corresponding component of the first AC drive signal to the ring electrode 606 and the center electrode 604, or can provide a corresponding component of the second AC drive signal to the ring electrode 606 and the planar electrode 704, or can provide a corresponding component of the third AC drive signal to the center electrode 604 and the planar electrode 704. The various AC signals can have different amplitude, frequency, duty cycle, or waveform morphology (shape) characteristics, such as can be selected according to the expected or desired characteristics of the electric field to be generated.

[0098] In an example, the control circuit 404 can be configured to electrically couple any two or more of the electrodes and use the coupled electrodes as a composite electrode. As used herein, a "composite electrode" refers to two or more discrete conductors or electrode features that are electrically coupled and driven together. For example, the ring electrode 606 and the center electrode 604 can be electrically coupled as a first composite electrode. The first composite electrode can receive a first portion of an AC signal from the control circuit 404, and the planar electrode 704 can receive a complementary second portion of the AC signal from the control circuit 404. Similarly, any one of the ring electrode 606 or the center electrode 604 can be electrically coupled to the planar electrode 704 and driven together with the planar electrode 704, and the other of the ring electrode 606 and the center electrode 604 can be driven separately. Therefore, depending on the specific electrode configuration used, a plurality of different electric fields can be generated in and around the second composite electrode assembly 702.

[0099] exist Figure 7In the example of FIG. 4 , the control circuit 404 can be configured to provide the first field 712 by driving the center electrode 604 and the ring electrode 606 of the first composite electrode assembly 602 using respective components of the first AC signal. The first field 712 and various characteristics of the first field 712, such as its direction and reach, can be affected by which of the ring electrode 606 and the center electrode 604 is selected as the anode and which is selected as the cathode.

[0100] The control circuit 404 can also be configured to provide the second field 714 by providing respective components of the second AC signal to the planar electrode 704 and to the electrically coupled combination of the ring electrode 606 and the center electrode 604. In an example, the first AC signal and the second AC signal can be provided at different times or in a time division multiplexed manner, such as with or without blanking periods between excitation intervals.

[0101] The inventors have recognized that different combinations of electrodes used for excitation may have or exhibit different sensitivities to noise, to the effects of moisture or liquids, and to the presence or proximity of the subject 402. For example, if the ring electrode 606 and the center electrode 604 are driven separately relative to the planar electrode 704, they may exhibit different sensitivities to the proximity of the subject 402 and different resistances or sensitivities to noise and liquids.

[0102] In some instances, capacitance-based foot sensing technologies can generally be relatively invariant to sweat or moisture on the insole or in the sock surrounding the foot. The effect of this moisture can be to reduce the dynamic range of detection, as the presence of moisture can increase the measured capacitance. However, in some instances, the dynamic range is sufficient to accommodate this effect within the expected moisture levels in the footwear.

[0103] The inventors have recognized that a subject presence sensor 302, such as one that includes or uses multiple different electrode combinations to generate correspondingly different electric fields, can be used to detect the presence of liquid or sweat, including but not limited to, in an article of footwear. For example, when any two of at least three different electrode combinations are used, a signal drift (e.g., relative to a baseline or reference value) due to liquid saturation can be represented by a difference between the two signals, and the difference can be proportional to the amount of liquid present. In other words, information about the difference between multiple electric field indication signals can be used, for example, to separate and remove the effects of liquid saturation from subject presence detection. Thus, noise or signal corruption attributable to the presence of liquid can be identified and removed to improve the accuracy of foot presence determination.

[0104] Reference again Figure 7In the example of the second composite electrode assembly 702 in FIG. 1 , the ring electrode 606 and the center electrode 604 can have different sensitivities or different responses to the presence and volume of liquid at the sensor when driven individually relative to the planar electrode 704. Similarly, when the planar electrode 704 is driven relative to the combination of the ring electrode 606 and the center electrode 604, the sensor can have another different sensitivity to the presence and volume of liquid.

[0105] Figure 8 A first graph 800 is generally illustrated showing capacitance indicative signals (in "counts" as a proxy for capacitance) over time for different electrode combinations in a subject presence sensor including or using the second composite electrode assembly 702. The first graph 800 represents a period during which liquid is incrementally introduced into an article of footwear (e.g., saline solution is introduced at a rate of about 10 mL per minute), and the footwear includes the second composite electrode assembly 702. The responses of the various different electrode combinations are measured at different time-multiplexed intervals to monitor the effects of the liquid.

[0106] In the example of the first graph 800, the first trace 802 represents a shift in the response of the capacitance-indicative signal from the center electrode 604 when the center electrode 604 is driven relative to the planar electrode 704. The second trace 804 represents a shift in the response of the capacitance-indicative signal from the ring electrode 606 when the ring electrode 606 is driven relative to the planar electrode 704. The combined trace 806 represents a shift in the response of the capacitance-indicative signal from the electrically coupled pair of the ring electrode 606 and the center electrode 604 when the electrically coupled pair of the ring electrode 606 and the center electrode 604 is driven relative to the planar electrode 704. The difference signal 808 represents the difference between the second trace 804 and the combined trace 806.

[0107] exist Figure 8 In the example of , as more liquid is added and the saturation increases, the amplitude of the difference signal 808 increases and is proportional to the amount of liquid present. In other words, information about the saturation level of liquid in or around the body presence sensor 302 can be measured using the amplitude information measured from multiple different electrode pairs. The liquid saturation level information can then be used, for example, to correct or calibrate the response information from any one or more electrode pairs, such as by indicating the need to introduce an offset or correction factor to mitigate the effects of any liquid present.

[0108] Fig. 9 An example of a first method 900 is generally illustrated, which may include determining a subject proximity indication using information from a subject presence sensor 302, and the subject presence sensor 302 may include or use at least three different electrodes. For example, the subject presence sensor 302 may include or use a second composite electrode assembly 702.

[0109] At block 902, the first method 900 may include providing time-division multiplexed first and second excitation signals to respective first and second electrode pairs, thereby generating respective first and second electric fields. For example, block 902 may include using an excitation circuit to generate a first AC signal, and components of the first AC signal may be provided to respective electrodes in the body presence sensor 302. In an example, at least one electrode in the body presence sensor 302 is or includes a combination of two or more electrodes, such as the ring electrode 606 and the center electrode 604 of the first composite electrode assembly 602. Block 902 may also include using an excitation circuit to generate a second AC signal, and components of the second AC signal may be provided to respective other electrodes in the body presence sensor 302. In response to the first and second AC signals, corresponding first and second electric fields may be generated, for example, in or near a foot receiving cavity in an article of footwear.

[0110] In an example, block 902 may include providing the first excitation signal and the second excitation signal to correspondingly different electrode pairs at different times. The different times may include non-overlapping excitation intervals. In an example, a blanking period or interval without an excitation signal may be between the excitation signals. The first excitation signal and the second excitation signal may be transmitted in a repetitive order, for example, over a long period of time. In other words, the first excitation signal and the second excitation signal may be provided intermittently at different times, respectively. The duration of each excitation interval may be, for example, several milliseconds or longer.

[0111] At block 904, the first method 900 may include receiving a first response signal and a second response signal from a first electrode pair and a second electrode pair of the subject presence sensor 302. For example, the control circuit 404 may be configured to receive information about any interruptions detected in the electric field from each of the electrode pairs. The interruptions may, for example, indicate the presence, absence, or change of position of the subject at or near the subject presence sensor 302. In an example, block 904 may include receiving a capacitance indication signal representing a change in capacitance measured by the electrode pair.

[0112] At block 906, the first method 900 may include determining a liquid saturation level in an article including the bulk presence sensor 302. Block 906 may include determining the bulk saturation level using the response signal received at block 904. For example, block 906 may include or use the control circuit 404 to measure the first response signal and the second response signal and determine a difference between the two response signals. The magnitude of the difference may be proportional to the liquid saturation level in the article.

[0113] At block 908, the first method 900 may include determining an indication of subject proximity relative to the subject presence sensor 302. For example, block 908 may include using the response signal received at block 904, and optionally using information about the liquid saturation level from block 906, to determine whether the subject is near the subject presence sensor 302 or is likely to be near the subject presence sensor 302.

[0114] In an example, block 908 may include determining a subject proximity indication using a comparison of one or more of the response signals (e.g., from block 904) or a portion thereof with a specified threshold. In an example, block 908 may include or use information about a morphological feature of one of the response signals to determine the subject proximity indication. In an example, the subject proximity indication may include binary information about the presence or absence of a subject (e.g., a foot inside a footwear), or may include relative information about whether a subject is fully present or partially present. For example, the subject proximity indication may include information about whether a footwear donning or footwear doffing event is occurring (i.e., if a foot is present but not seated in or near a footbed of a footwear article). In an example, block 908 may include or use information about a liquid saturation level from block 906 to adjust a value or feature, such as a threshold or morphological feature, used to determine the subject proximity indication.

[0115] Fig.10 An example of a second method 1000 is generally illustrated, which may include using a Figure 7 The second composite electrode assembly 702 is used to provide a subject proximity indication. Fig.10 In the example of , second composite electrode assembly 702 may comprise a portion of body presence sensor 302 in an article of footwear and may be used to determine the presence or absence of a foot in the footwear.

[0116] At block 1002, the second method 1000 may include electrically coupling first and second conductors or electrodes to form a first composite electrode. For example, block 1002 may include electrically coupling the ring electrode 606 and the center electrode 604 of the first composite electrode assembly 602 so that the ring electrode and the center electrode may be electrically driven together. At block 1004, the second method 1000 may include providing a first AC signal to the first composite electrode. For example, block 1004 may include providing respective components of the first AC signal to the planar electrode 704 and to the first composite electrode.

[0117] At block 1006, the second method 1000 may include receiving a first response signal in response to the first AC signal. The first response signal may include information about the first electric field or about a change in the first electric field. The first electric field may be a field generated using the first composite electrode when the first composite electrode is excited by the first AC signal.

[0118] At block 1008, the second method 1000 may include electrically isolating the first conductor and the second conductor of the composite electrode. For example, block 1008 may include electrically decoupling the ring electrode 606 from the center electrode 604. When the electrodes are decoupled, they may be driven separately and independently.

[0119] At block 1010, the second method 1000 may include electrically coupling the first conductor and the reference electrode to form a second composite electrode. In an example, block 1010 may include electrically coupling the center electrode 604 to the planar electrode 704 so that the center electrode and the planar electrode may be electrically driven together. At block 1012, the second method 1000 may include providing a second AC signal to the second composite electrode. For example, block 1012 may include providing respective components of the second AC signal to the ring electrode 606 and to the second composite electrode. In an example, the first AC signal and the second AC signal are identical, and in other examples, the first AC signal and the second AC signal may have different signal characteristics.

[0120] At block 1014, the second method 1000 may include receiving a second response signal in response to the second AC signal. The second response signal may include information about the second electric field or about changes in the second electric field. The second electric field may be a field generated using the second composite electrode when the second composite electrode is excited by the second AC signal.

[0121] At block 1016, the second method 1000 may include determining a subject proximity indication using the first response signal received at block 1006 and using the second response signal received at block 1014. In an example, block 1016 may include combining (e.g., by summing or differencing) the first response signal and the second response signal to determine a signal of interest, and the signal of interest may be used to determine the subject proximity indication, for example, by comparing to a specified reference threshold or reference condition.

[0122] The inventors have also recognized that a problem to be solved includes determining when or whether to update threshold conditions that may be used to detect the presence or absence of a subject at or near subject presence sensor 302. The inventors have recognized that the solution may include or use an algorithm that dynamically or continuously updates the threshold conditions to track the changing real-world conditions of subject presence sensor 302 in use. In an example, the solution may include or use a recursive filter, such as a Kalman filter, to help ensure smooth and predictable operation and immunity to noisy input signals.

[0123] For example, events such as "put on" events and "take off" events or state information such as "put on shoes" and "take off shoes" classifications can be identified using algorithms to estimate, filter, and track subject position indication signals such as can be received from subject presence sensor 302. The algorithm can compare the filtered estimate to various thresholds to determine whether an event has occurred and whether a particular state or state change is indicated. In an example, the subject position indication signal represents relative changes, and the sensor itself may be susceptible to external influences or noise. Therefore, the thresholds can be dynamically updated to ensure proper operation when usage conditions change.

[0124] In an example, the algorithm includes sampling a subject position indication signal from subject presence sensor 302. After each sample is collected, a future sample value may be estimated, for example, using a recursive estimation filter such as a Kalman filter. Then, subsequent actual samples may be measured, and the difference between the estimated future sample value and the actual sample value may be determined. The difference may be considered an error signal. The error signal may be used to update future prediction values, etc.

[0125] Since noise is inherent to sensor systems, it is generally not assumed that the measured values ​​of the subject position indication signal are precise or absolutely correct. Instead, the updated prediction or future predicted values ​​can be a weighted combination of previous predictions and measured values, which weighted combination helps reduce errors over time and provides a reasonable approximation of the subject presence information sensed by the sensor.

[0126] Fig.11 An example of a second graph 1100 including information about dynamic threshold updates, subject position indication signals, and prediction signals is generally illustrated. For example, the second graph 1100 includes a raw signal 1102 corresponding to an output from a subject presence sensor 302 and indicating a position or proximity of a subject (e.g., a foot) relative to the sensor. The second graph 1100 includes a prediction signal 1104 corresponding to an output of a recursive filter that receives the raw signal 1102 as input. In an example, the prediction signal 1104 represents an output or calculated signal based on a low-pass filtered version of the raw signal 1102. The prediction signal 1104 can represent an estimate of a joint probability distribution of values ​​measured by the subject presence sensor 302 over a particular time frame. In other words, the prediction signal 1104 can represent the result of processing multiple measurements (e.g., from a sequential time series of measurements) from the subject presence sensor 302, including noise, to produce an estimated or predicted output.

[0127] In an example, the prediction signal 1104 may include the output of a Kalman filter, or include or use the output of a function of a Kalman filter or similar recursive filter or algorithm. The filter may receive the original signal 1102 and provide an estimated future value. After measuring the actual future value, the variable providing the further estimated future value is then updated based on the error between the original estimated future value and the actual future value. In an example, a weighted average that is conducive to more accurate results may be used to calculate the estimated future value. In an example, the filter may operate in real time using information about the current sensor output value and the previously calculated estimated value. Various techniques may be used to optimize or enhance the accuracy of the filter, or to customize the filter to work best in a specific environment, such as a body sensor for the interior of footwear.

[0128] The second chart 1100 also includes various thresholds that can be used with the prediction signal 1104 to determine various status information about the subject or the subject relative to the subject presence sensor 302 or relative to the article including the subject presence sensor 302. For example, when the subject presence sensor 302 is implemented inside the footwear and is configured to detect the foot, the thresholds can be used with the prediction signal 1104 to determine whether the footwear is on or off the foot, and if the footwear is on the foot, the thresholds can be used to determine whether the user is in a specific posture, such as sitting or standing. Any one or more of the thresholds can be updated or changed dynamically or on the fly to accommodate different users, such as those who may have different anatomical structures, different gaits, or may be in different environments.

[0129] The example of the second chart 1100 includes a wearing threshold 1112 and a disengagement threshold 1114. The value of the prediction signal 1104 can be compared with the wearing threshold 1112 to determine whether the foot is or may be inside the footwear. The value of the prediction signal 1104 can be compared with the disengagement threshold 1114 to determine whether the foot is or may be moving out of the footwear or outside the footwear. For example, if the value of the prediction signal 1104 exceeds the wearing threshold 1112, the footwear can be considered to be occupied by the foot (i.e., state 1110=wearing). If after determining that the footwear is occupied, the value of the prediction signal 1104 is lower than the disengagement threshold 1114, the footwear can be considered not to be occupied by the foot (i.e., state 1110=disengagement). In an example, information from one or more other sensors (e.g., motion sensor 324, such as an accelerometer) can be used together with the threshold comparison of the prediction signal 1104 to verify or increase the confidence of the state determination. For example, when the prediction signal 1104 exceeds the wear threshold 1112 and when the accelerometer indicates that the footwear is moving, the footwear may be considered to be occupied by the foot.

[0130] The example of the second graph 1100 includes a load threshold 1106 and an unload threshold 1108. The value of the prediction signal 1104 can be compared to the load threshold 1106 to determine whether the user is standing or "loading" the sensor. The value of the prediction signal 1104 can be compared to the unload threshold 1108 to determine whether the user is sitting or the user is "unloading" the sensor.

[0131] Fig.12 An example of a third method 1200 is generally illustrated, which may include or use information about a subject position indicating sensor signal from a subject presence sensor 302 to determine a footwear usage characteristic of an active footwear article. At block 1202, the third method 1200 may include measuring a foot presence indicating sensor signal value. For example, block 1202 may include measuring a signal value from the subject presence sensor 302, and the measured value may indicate an interruption or change in an electric field generated by the subject presence sensor 302.

[0132] At box 1204, the third method 1200 may include identifying the walking state of the footwear. For example, box 1204 may include receiving information about the movement of the footwear from a motion sensor 324 (such as an accelerometer), or receiving information from a subject presence sensor 302. In an example, box 1204 may include receiving motion information and processing the information to identify whether the signal includes or indicates a periodic signal that may correspond to walking or running. In an example, box 1204 may include processing motion information to identify a footwear movement signal indicating that the footwear is or may be experiencing a putting on or taking off event. That is, the processing may compare the measured motion information with a motion profile or template to determine whether the footwear motion corresponds to a motion consistent with the user putting on or taking off the footwear. For example, a portion of the spectral content (e.g., frequency and energy information) from a sensor signal may be compared with, for example, a template or other spectral content from the same signal to distinguish the walking state. In an example, a machine learning algorithm may be applied to analyze motion information (e.g., from one or more of the motion sensor 324 or the subject presence sensor 302 or other sensors such as those that can communicate with the active footwear) to provide ambulatory state information, such as distinguishing between walking, running, or other use rhythms or patterns or no use. In an example, if no movement or walking of the footwear is identified at block 1204, the third method 1200 may indicate a stationary state of the footwear, and the method may return to block 1202 without proceeding to block 1206.

[0133] At block 1206, the third method 1200 may include determining a predicted subsequent value of the foot presence indication sensor signal value. Block 1206 may include using a processor (such as the processor circuit 320) to receive a sensor signal from the subject presence sensor 302, and based on the current value of the sensor signal, using an algorithm to predict a next or subsequent value of the sensor signal. In an example, block 1206 may include or use an estimation filter, such as a recursive estimation filter or other filter, that finds coefficients that minimize a cost function associated with the input signal and may be used to provide an output representing a prediction of a subsequent value of the input signal.

[0134] At block 1208, the third method 1200 may include updating the sensor signal threshold based on the predicted subsequent value of the sensor signal. For example, block 1208 may include updating one or more of the wearing threshold 1112, the disengaging threshold 1114, the load threshold 1106, or the unloaded threshold 1108, such as may be used to determine status information about the footwear or about a user of the footwear.

[0135] In an example, the third method 1200 may proceed from block 1208 to block 1210 and / or block 1212. At block 1210, the third method 1200 may include determining that a foot enters the footwear (i.e., a donning event) or that a foot leaves the footwear (i.e., a doffing event) based on a comparison of the current value of the sensor signal with an updated donning threshold or disengagement threshold from block 1208. At block 1212, the third method 1200 may include determining a load characteristic of the footwear based on a comparison of the current value of the sensor signal with an uploaded load threshold from block 1208. For example, block 1212 may include determining whether the user is or may be standing or sitting while donning the footwear.

[0136] Fig.13 An example of a fourth method 1300 is generally illustrated, which may include or use information about a subject position indicating sensor signal from a subject presence sensor 302 to change a threshold or determine a footwear state or footwear use characteristic. An initial threshold may be set or determined, for example, based on historical data or based on data from a user population of the subject presence sensor 302. During use, sensor signal delta information from the subject presence sensor 302 may be received and processed using a recursive filter to make predictions about future values ​​of the sensor signal. One or more thresholds, such as may be used to indicate a state or change of state, may be updated or changed to accommodate each user or user environment.

[0137] The fourth method 1300 can begin at block 1302, initializing variables. For example, block 1302 can include initializing a predicted value of a sensor signal from the subject presence sensor 302 to an initial value (e.g., zero). Block 1302 can include initializing a threshold value (such as a wearing threshold 1112, a disengagement threshold 1114, a load threshold 1106, or an unloaded threshold 1108) to a corresponding baseline value, such as can be based on previous data from the same user or the same footwear, or can be based on population data or other historical data. In an example, block 1302 can include initializing one or more scaling factors, as further explained below, which can be used throughout the fourth method 1300. In an example, the predicted initial value of the sensor signal and the threshold conditions can be optimized to minimize false triggers or false indications of the presence or absence of a foot in the footwear.

[0138] At block 1304, the fourth method 1300 includes measuring a signal value from the subject presence sensor 302. For example, block 1304 may include measuring a raw or unfiltered value from the subject presence sensor 302. The measured value may indicate a capacitance or change in an electric field generated by the subject presence sensor 302 inside the footwear in a zone that may be affected by the presence or absence of a subject or foot.

[0139] At block 1306, a residual value may be calculated based on the measured signal value and the predicted value of the sensor signal from block 1304. In an example, the residual value may be based on the difference between the predicted value and the measured actual value of the sensor signal from subject presence sensor 302. The predicted value may initially be an initial value (e.g., zero), but may be updated or changed using an estimation filter as described elsewhere herein.

[0140] At block 1308, the residual value from block 1306 may be scaled according to a scaling factor. The scaling factor may be a specific scalar value selected based on, for example, historical data, population data, or other data to optimize the fourth method 1300 and improve the accuracy of the algorithm. In an example, the scaling factor may be initialized at block 1302 and may be updated periodically, or may be a static value.

[0141] At block 1310, the fourth method 1300 may include updating the predicted value of the sensor signal to provide an updated predicted value. In an example, the updated predicted value may be a function of the residual value or the scaled residual value and the earlier or previous predicted value. For example, the updated predicted value may be the sum of the previous predicted value and the scaled residual from block 1308.

[0142] At block 1312, the fourth method 1300 may further process the sensor signal using the updated prediction value to provide a state signal. For example, the value of the state signal may correspond to the difference between the current measured value of the sensor signal (e.g., from block 1304) and the updated prediction value from block 1310. At block 1314, the fourth method 1300 may include determining a variance of the state signal. That is, block 1314 may include quantifying the deviation of the state signal from its mean or other expected value.

[0143] At decision block 1316, the fourth method 1300 may include comparing the determined variance from block 1314 to a variance threshold. The variance threshold may optionally be one of the variables initialized at block 1302, and may be a static threshold or a dynamic threshold. At decision block 1316, if the determined variance is relatively low or less than the variance threshold, the fourth method 1300 may proceed to decision block 1326. If the determined variance is relatively high or greater than the variance threshold, the fourth method 1300 may proceed to block 1318.

[0144] At block 1318, the fourth method 1300 may include updating various thresholds based on the magnitude of the previous threshold and the determined variance from block 1314. For example, at block 1318, the shoe-on threshold 1112 or the shoe-off threshold 1114 may be updated based on the previous corresponding threshold and the sum of the scaled residuals from block 1308 (e.g., the updated wear threshold 1112 may be the sum of the previous wear threshold 1112 and the scaled residuals, or the updated detachment threshold 1114 may be the sum of the previous detachment threshold 1114 and the scaled residuals). Similarly, the shoe load threshold 1106 or the shoe unload threshold 1108 may be updated based on the previous corresponding threshold and the sum of the scaled residuals from block 1308 (e.g., the updated load threshold 1106 may be the sum of the previous load threshold 1106 and the scaled residuals, or the updated unload threshold 1108 may be the sum of the previous unload threshold 1108 and the scaled residuals).

[0145] After the threshold update at block 1318, the fourth method 1300 may include a decision block 1320 to determine the state of the footwear including the subject presence sensor 302. For example, at decision block 1320, if the updated predicted value of the sensor signal (e.g., as determined at block 1310) is greater than the updated wear threshold 1112, the footwear may be considered occupied or worn on the foot. Conversely, if the updated predicted value of the sensor signal (e.g., as determined at block 1310) is less than the updated wear threshold 1112, the footwear may be considered unoccupied or detached from the foot. After the state determination, the fourth method 1300 may proceed to decision block 1326.

[0146] At decision block 1326, the fourth method 1300 may include determining whether a walking or stepping event is detected. Stepping events may be detected in a variety of ways, including using information from the motion sensor 324 or using information from the subject presence sensor 302 or from a different sensor about the periodicity or other characteristics of the sensor signal. In an example, the periodicity may generally correspond to a foot drop or foot lift (or footwear drop or footwear lift) event that is evident in a change in the amplitude or frequency of the sensor signal. If a walking or stepping event is not detected at decision block 1326, the fourth method 1300 may return to block 1304 without further updating the threshold or scaling factor. If a walking or stepping event is detected at decision block 1326, the fourth method 1300 may proceed to block 1328.

[0147] At block 1328, one or more thresholds or scaling factors may be updated for further analysis of the footwear condition. For example, at block 1328, the wear threshold 1112 or the disengagement threshold 1114 may be updated based on the previous value of the corresponding threshold and the specified scaling factor. For example, the wear threshold 1112 may be updated based on a minimum value (e.g., a local minimum value) of the sensor signal (or the predicted signal) scaled according to a first scaling factor. The disengagement threshold 1114 may be updated based on the same minimum value of the sensor signal scaled by the same first scaling factor or a different scaling factor. In an example, the unloaded threshold 1108 may be similarly updated based on a maximum value (e.g., a local maximum value) of the sensor signal (or the predicted signal) scaled according to a second scaling factor. The load threshold 1106 may be similarly updated based on the same maximum value of the sensor signal (or the predicted signal) scaled according to a third scaling factor. In an example, the value of the second scaling factor may be less than the value of the third scaling factor. Any one or more of the scaling factors may be specific to a user, a specific article of footwear, a specific use condition or environment, or may be a global scaling factor. After block 1328, fourth method 1300 may proceed to block 1304 and the updated threshold may be used for subsequent footwear state determinations. Fourth method 1300 may be used as a loop to continuously and dynamically update the threshold for footwear state (state / status) determinations.

[0148] Fig.14is a graphical representation of a machine 1400 within which instructions 1408 (e.g., software, programs, applications, applet programs, apps, or other executable code) may be executed for causing the machine 1400 to perform any one or more of the methods discussed herein. For example, the instructions 1408 may cause the machine 1400 to perform any one or more of the methods described herein, such as controlling a footwear system using or in response to information from a subject presence indication sensor. The instructions 1408 convert a general, non-programmed machine 1400 into a specific machine 1400 that is programmed to perform the functions described and illustrated in the manner described. The machine 1400 may operate as a standalone device, or may be coupled (e.g., networked) to other machines to coordinate the actions or actuations of multiple different shoes or footwear systems. In a networked deployment, the machine 1400 may operate as a server machine or a client machine in a server-client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine 1400 may include, but is not limited to, a server computer, a client computer, a personal computer (PC), a tablet computer, a laptop computer, a netbook, a set-top box (STB), a PDA, an entertainment media system, a cellular phone, a smart phone, a mobile device, a wearable device (e.g., a smart watch), a smart home device (e.g., a smart appliance), other smart devices, web appliances, a network router, a network switch, a network bridge, or any machine capable of sequentially or otherwise executing the actions to be taken by the specified machine 1400 of the instructions 1408. In addition, while only a single machine 1400 is illustrated, the term "machine" should also be understood to include a collection of machines that individually or jointly execute the instructions 1408 to perform any one or more of the methodologies discussed herein.

[0149] The machine 1400 may include a processor 1402, a memory 1404, and an I / O component 1442, which may be configured to communicate with each other via a bus 1444. In an example embodiment, the processor 1402 (e.g., a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP), an ASIC, a radio frequency integrated circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, a processor 1406 that executes instructions 1408 and a processor 1410. The term "processor" is intended to include a multi-core processor, which may include two or more independent processors (sometimes referred to as "cores") that may execute instructions simultaneously. Although Fig.14 A multiprocessor 1402 is shown, but the machine 1400 may include a single processor with a single core, a single processor with multiple cores (eg, a multi-core processor), multiple processors with a single core, multiple processors with multiple cores, or any combination thereof.

[0150] The memory 1404 includes a main memory 1412, a static memory 1414, and a storage unit 1416, all of which are accessible to the processor 1402 via a bus 1444. The main memory 1404, the static memory 1414, and the storage unit 1416 store instructions 1408 that implement any one or more of the methods or functions described herein. During execution of the instructions 1408 by the machine 1400, the instructions 1408 may also reside, completely or partially, within the main memory 1412, within the static memory 1414, within a machine-readable medium 1418 within the storage unit 1416, within at least one of the processors 1402 (e.g., within a cache memory of the processor), or any suitable combination thereof.

[0151] I / O components 1442 may include a variety of components to receive input, provide output, generate output, transmit information, exchange information, capture measurements, etc. The specific I / O components 1442 included in a particular machine will depend on the type of machine. For example, a portable machine such as a mobile phone may include a touch input device or other such input mechanism, while a headless server machine may not include such a touch input device. It is understood that I / O components 1442 may include Fig.14 1420. In various example embodiments, the I / O components 1442 may include an output component 1428 and an input component 1430. The output component 1428 may include a visual component (e.g., a display such as a plasma display panel (PDP), a light emitting diode (LED) display, a liquid crystal display (LCD), a projector, or a cathode ray tube (CRT)), an acoustic component (e.g., a speaker), a tactile component (e.g., a vibrating motor, a resistive mechanism), other signal generators such as the control circuit 404 or the processor circuit 320, etc. The input component 1430 may include an alphanumeric input component (e.g., a keyboard, a touch screen configured to receive alphanumeric input, an optical keyboard, or other alphanumeric input component), a point-based input component (e.g., a mouse, a touch pad, a trackball, a joystick, a motion sensor, or another pointing device), a tactile input component (e.g., a physical button, a touch screen or other tactile input component that provides a touch location and / or a touch force or a touch gesture), an audio input component (e.g., a microphone), etc.

[0152] In further example embodiments, the I / O component 1442 may include various sensors, such as may include one or more of a biometric component 1432, a motion component 1434, an environmental component 1436, or a position component 1438, as well as a variety of other components. For example, the biometric component 1432 includes components for detecting expressions (e.g., hand expressions, facial expressions, voice expressions, subject gestures, or eye tracking), measuring biosignals (e.g., blood pressure, heart rate, body temperature, sweat, muscle oxygenation, or brain waves), identifying people (e.g., voice recognition, retinal recognition, facial recognition, fingerprint recognition, or EEG-based recognition), etc. The motion component 1434 may include a motion sensor 324, such as may include an acceleration sensor component (e.g., an accelerometer), a gravity sensor component, a rotation sensor component (e.g., a gyroscope), etc. Environmental component 1436 includes, for example, an illumination sensor component (e.g., a photometer), a temperature sensor component (e.g., one or more thermometers that detect ambient temperature), a humidity sensor component, a pressure sensor component (e.g., a barometer), an acoustic sensor component (e.g., one or more microphones that detect background noise), a proximity sensor component (e.g., an infrared sensor that detects nearby objects), a gas sensor (e.g., a gas detection sensor that detects dangerous gas concentrations or measures pollutants in the atmosphere for safety), or other components that can provide indications, measurements, or signals corresponding to the surrounding physical environment. Position component 1438 includes a position sensor component (e.g., a GPS receiver component), an altitude sensor component (e.g., an altimeter or barometer that detects air pressure, from which altitude can be derived), an orientation sensor component (e.g., a magnetometer), etc.

[0153] Communications can be implemented using a wide range of technologies. I / O components 1442 also include communications components 1440 that are operable to couple machine 1400 to network 1420 or device 1422 via coupling 1424 and coupling 1426, respectively. For example, communications components 1440 may include a network interface component or another suitable device that interfaces with network 1420. In other examples, communications components 1440 may include wired communications components, wireless communications components, cellular communications components, near field communications (NFC) components, Components (e.g. Low energy consumption), Components, as well as other communication components that provide communication via other modalities. Device 1422 can be another machine or any of a variety of peripheral devices (e.g., a peripheral device coupled via USB).

[0154] In addition, the communication component 1440 can detect an identifier or include a component operable to detect an identifier. For example, the communication component 1440 can include a radio frequency identification (RFID) tag reader component, an NFC smart tag detection component, an optical reader component (e.g., an optical sensor for detecting one-dimensional bar codes such as universal product code (UPC) bar codes, multi-dimensional bar codes, and other optical codes), or an acoustic detection component (e.g., a microphone for identifying tagged audio signals). In addition, various information can be derived via the communication component 1440, such as a location via Internet Protocol (IP) geolocation, a location via Internet Protocol (IP), ... The location of signal triangulation, the location of an NFC beacon signal via detection that can indicate a specific location, etc.

[0155] Various memories (e.g., memory 1404, main memory 1412, static memory 1414, and / or memory of processor 1402) and / or storage unit 1416 may store one or more sets of instructions and data structures (e.g., software) that embody or are used by any one or more of the methods or functions described herein. These instructions (e.g., instructions 1408) result in various operations when executed by processor 1402 to implement the disclosed embodiments.

[0156] The instructions 1408 may be transmitted or received using a transmission medium via a network interface device (e.g., a network interface component included in the communication component 1440) and using any of a number of well-known transmission protocols (e.g., Hypertext Transfer Protocol (HTTP)) over the network 1420. Similarly, the instructions 1408 may be transmitted or received using a transmission medium via a coupling 1426 (e.g., a peer-to-peer coupling) to the device 1422.

[0157] Various examples of the present disclosure can help provide solutions to the subject presence sensing related problems identified herein. Example 1 can include a footwear sensor system, the footwear sensor system including: a first capacitive sensor, the first capacitive sensor including a first electrode pair in a footwear article, the first capacitive sensor configured to use a first excitation signal to provide a first electric field at least partially inside the footwear article; a second capacitive sensor, the second capacitive sensor including a second electrode pair in the footwear article, the second capacitive sensor configured to use a second excitation signal to provide a second electric field at least partially inside the footwear article; a signal generator, the signal generator configured to provide the first excitation signal and the second excitation signal; and a processor circuit configured to provide a foot presence indication based on information received from the first capacitive sensor and the second capacitive sensor about interruptions in the first electric field and the second electric field.

[0158] In Example 2, the subject matter of Example 1 can include a first electrode pair including a ring electrode and a reference electrode.

[0159] In Example 3, the subject matter of Example 2 can include an annular electrode occupying a first plane, a reference electrode occupying a second plane, and the first plane and the second plane are separated by at least a fixed distance.

[0160] In Example 4, the subject matter of any one or more of Examples 2-3 can include a reference electrode having a conductor having a planar surface area that exceeds a surface area of ​​the ring electrode.

[0161] In Example 5, the subject matter of any one or more of Examples 2 to 4 may include a second electrode pair including a planar electrode and a reference electrode.

[0162] In Example 6, the subject matter of Example 5 may include a planar electrode disposed coaxially with the annular electrode, and the planar electrode and the annular electrode may be spaced apart.

[0163] In Example 7, the subject matter of any one or more of Examples 5 to 6 may include a planar electrode and an annular electrode sharing a substrate (ie, including a common substrate) in a first plane.

[0164] In Example 8, the subject matter of Example 7 can include a reference electrode occupying a second plane that can be spaced apart from the first plane.

[0165] In Example 9, the subject matter of any one or more of Examples 1 to 8 can include that the first electrode pair includes a first electrode and a reference electrode, the second electrode pair can include a second electrode and a reference electrode, and the signal generator can be configured to provide a third excitation signal between the first electrode and the second electrode. In response, the third electric field can extend between the first electrode and the second electrode and into the foot-receiving cavity of the footwear article.

[0166] In Example 10, the subject matter of Example 9 includes an article of footwear, and the electrodes of the first capacitive sensor and the second capacitive sensor include respective planar electrode portions disposed parallel to a footbed of the article of footwear.

[0167] In Example 11, the subject matter of Example 10 includes a sensor housing configured to be disposed in an arch region or a central region of a footbed of an article of footwear.

[0168] In Example 12, the subject matter of any one or more of Examples 1 to 11 may include a first excitation signal and a second excitation signal having respective different frequency characteristics.

[0169] In Example 13, the subject matter of any one or more of Examples 1 to 12 may include a first excitation signal and a second excitation signal having respective different amplitude characteristics.

[0170] In Example 14, the subject matter of any one or more of Examples 1 to 13 may include a signal generator configured to provide the first excitation signal and the second excitation signal in a time division multiplexed manner.

[0171] In Example 15, the subject matter of any one or more of Examples 1 to 14 may include a signal generator configured to provide the first excitation signal and the second excitation signal simultaneously.

[0172] In Example 16, the subject matter of any one or more of Examples 1 to 15 may include a processor circuit configured to receive a first response signal from a first capacitive sensor in response to a first excitation signal and to receive a second response signal from a second capacitive sensor in response to a second excitation signal, and the processor circuit may be configured to provide a foot presence indication based on a sum of the first response signal and the second response signal.

[0173] In Example 17, the subject matter of any one or more of Examples 1 to 16 may include a processor circuit configured to receive a first response signal from a first capacitive sensor in response to a first excitation signal and to receive a second response signal from a second capacitive sensor in response to a second excitation signal, and the processor circuit may be configured to provide a foot presence indication based on a difference between the first response signal and the second response signal.

[0174] In Example 18, the subject matter of Example 17 may include a first electrode pair of a first capacitive sensor, the first electrode pair including a reference electrode and a composite electrode, and the composite electrode includes a coplanar and coaxial main electrode and a ring electrode, and a second electrode pair of a second capacitive sensor may include the reference electrode and the ring electrode. In Example 18, the signal generator may be configured to provide a first excitation signal to the composite electrode during a first excitation interval and to provide a second excitation signal to the ring electrode during a second excitation interval, and the main electrode may be electrically decoupled from the ring electrode during the second excitation interval.

[0175] In Example 19, the subject matter of any one or more of Examples 1 to 18 may include a processor circuit configured to determine a liquid saturation level of one or more portions of the footwear article based on information received from the first capacitive sensor and the second capacitive sensor, and the processor circuit may be configured to provide a foot presence indication using the determined liquid saturation level.

[0176] Example 20 is a footwear system comprising a first electrode, a second electrode, a third electrode, a signal generator, and a processor circuit, the signal generator being configured to provide excitation signals to corresponding electrode groups of the first electrode, the second electrode, and / or the third electrode at corresponding different times, the processor circuit being configured to receive electric field information from the corresponding electrode groups and, in response, determine whether a foot is present or not present in a foot receiving cavity of the footwear article.

[0177] In Example 21, the subject matter of Example 20 may include a first electrode group including a first electrode and a second electrode electrically coupled as an anode and a third electrode as a cathode; a second electrode group including the first electrode as an anode and the third electrode as a cathode, and the second electrode may be electrically isolated from the first electrode and the third electrode, and the signal generator may be configured to provide a first AC excitation signal to the first electrode group at a first time and to provide a second AC excitation signal to the second electrode group at a different second time.

[0178] In Example 22, the subject matter of Example 21 can include a processor circuit configured to receive a first response signal from a first electrode group at a first time and a second response signal from a second electrode group at a second time, and the processor circuit can be configured to use information about a difference between the first response signal and the second response signal to determine a liquid saturation of a portion of the footwear article.

[0179] In Example 23, the subject matter of Example 22 can include a processor circuit configured to use the determined liquid saturation to determine whether a foot is present or absent in a foot-receiving cavity of the article of footwear.

[0180] In Example 24, the subject matter of any one or more of Examples 20 to 23 may include a signal generator configured to provide a first AC excitation signal between a first electrode and a second electrode at a first time, and the signal generator may be configured to provide a second AC excitation signal between a third electrode and a composite electrode including the first electrode and the second electrode at a second time.

[0181] Example 25 is a method that includes providing time-division multiplexed first and second excitation signals from a signal generator circuit to respective first and second electrode pairs in an article of footwear, thereby generating respective first and second electric fields in the article of footwear. Example 25 may also include receiving respective first and second response signals from the first and second electrode pairs at a processor circuit, and determining an indication of foot proximity of a foot within the article of footwear using the received first and second response signals (e.g., by processing the first and second response signals together, such as by summing, differentiating, or otherwise operating on the signals or information from the signals).

[0182] In Example 26, the subject matter of Example 25 may include: providing a first excitation signal to a first electrode pair includes providing a first AC signal between a reference electrode and an electrically coupled ring electrode and a main electrode, and providing a second excitation signal to a second electrode pair may include providing a second AC signal between the reference electrode and the ring electrode.

[0183] In Example 27, the subject matter of Example 26 can include determining the foot proximity indication using information about a difference between the first response signal and the second response signal.

[0184] In Example 28, the subject matter of any one or more of Examples 25 to 27 includes determining a liquid saturation level of a portion of the article of footwear using the first response signal and the second response signal, and determining the foot proximity indication includes using the determined liquid saturation level.

[0185] In Example 29, the subject matter of any one or more of Examples 25 to 28 can include providing a first excitation signal including electrically coupling a first conductor portion and a second conductor portion of the composite electrode, and providing a second excitation signal including electrically isolating the first conductor portion and the second conductor portion of the composite electrode.

[0186] In Example 30, the subject matter of Example 29 can include providing a second excitation signal including electrically coupling the second conductor portion to the reference electrode.

[0187] Example 31 is a sensor signal processing method, comprising: sampling the value of a sensor signal from a foot presence sensor in a footwear article; using the sampled value of the sensor signal to identify the walking state of the footwear article; updating the sensor signal threshold in response to identifying the walking state; and determining whether the foot enters the footwear article or the foot leaves the footwear article based on the updated sensor signal threshold and subsequent values ​​of the sensor signal.

[0188] In Example 32, the subject matter of Example 31 can include identifying an ambulatory state, comprising comparing one or more values ​​of the sensor signal to a reference threshold.

[0189] In Example 33, the subject matter of any one or more of Examples 31 to 32 may include identifying a walking state, including filtering a sensor signal using a low pass filter to provide a filtered signal, and analyzing a series of values ​​of the filtered signal to distinguish between a walking state of the footwear article and a stationary state of the footwear article.

[0190] In Example 34, the subject matter of any one or more of Examples 31 to 33 may include updating the sensor signal threshold, including determining a predicted value of the sensor signal based on a previous value of the sensor signal. In Example 34, when the predicted value of the sensor signal meets or exceeds a reference threshold, the example may include updating the sensor signal threshold to have a threshold based in part on the predicted value of the sensor signal or based on a current value of the sensor signal.

[0191] In Example 35, the subject matter of Example 34 can include the reference threshold being based on a magnitude of a difference between a predicted value and a current value of the sensor signal.

[0192] In Example 36, the subject matter of any one or more of Examples 31 to 35 may include identifying a walking state, including identifying a periodicity of a sensor signal over time that corresponds to shoe-down and shoe-lift events (e.g., corresponding to one or more step events), and updating a sensor signal threshold may include using an amplitude characteristic of the sensor signal over time.

[0193] In Example 37, the subject matter of Example 36 may include updating a sensor signal threshold, including using a minimum characteristic of the sensor signal to determine a foot presence / absence threshold, and determining a foot entering or exiting a footwear article may include using the foot presence / absence threshold.

[0194] In Example 38, the subject matter of any one or more of Examples 36 to 37 includes updating a footwear load threshold using a maximum value characteristic of the sensor signal, and determining a footwear load state of the article of footwear based on the footwear load threshold and subsequent values ​​of the sensor signal.

[0195] In Example 39, the subject matter of any one or more of Examples 31 to 38 includes processing a sensor signal from a foot presence sensor using a recursive estimation filter to provide a predicted sensor value, and wherein determining whether a foot enters an article of footwear or a foot leaves an article of footwear includes using an updated sensor signal threshold and using information about a difference between the predicted sensor value and a subsequent value of the sensor signal.

[0196] In Example 40, the subject matter of any one or more of Examples 31 to 39 may include sampling a value of a sensor signal, including sampling a capacitance-indicative value of a sensor signal from a capacitance-based foot presence sensor.

[0197] Example 41 is a sensor signal processing method, comprising: sampling the value of a sensor signal from a foot presence sensor in a footwear article; using the sampled value of the sensor signal to identify the walking state of the footwear article; updating the sensor signal threshold in response to identifying the walking state; and determining the load characteristics of the footwear article based on the updated sensor signal threshold and subsequent values ​​of the sensor signal.

[0198] In Example 42, the subject matter of Example 41 may include using a recursive estimation filter to process a sensor signal from a foot presence sensor to provide a predicted sensor value; identifying a variance between the predicted sensor value and a subsequent value of the sensor signal from the foot presence sensor; and identifying an ambulance state of the footwear article in response to the variance exceeding a specified variance threshold.

[0199] In Example 43, the subject matter of Example 42 can include updating a sensor signal threshold, including determining a maximum value characteristic of the sensor signal; and calculating an updated sensor signal threshold based on the maximum value characteristic and a specified scaling factor.

[0200] In Example 44, the subject matter of Example 43 includes determining a minimum characteristic of the sensor signal, and calculating a foot presence threshold based on the minimum characteristic and a second specified scaling factor.

[0201] In Example 45, the subject matter of any one or more of Examples 41 to 44 includes: processing a sensor signal from a foot presence sensor using a recursive estimation filter to provide a predicted sensor value; identifying a variance between the predicted sensor value and a subsequent value of the sensor signal from the foot presence sensor; and updating a sensor signal threshold based on a previous threshold and the identified variance.

[0202] In Example 46, the subject matter of any one or more of Examples 41 to 45 may include determining a load characteristic of the article of footwear, including determining that a foot is present within the article of footwear, and including determining whether subsequent values ​​of the sensor signal represent a standing or sitting posture of a wearer of the article of footwear.

[0203] In Example 47, the subject matter of any one or more of Examples 41 to 46 may include determining a load characteristic of an article of footwear, including determining a relative amount of force applied by a foot to a footbed of the article of footwear.

[0204] In Example 48, the subject matter of any one or more of Examples 41 to 47 can include sampling a value of a sensor signal, including sampling a capacitance-indicative value of a sensor signal from a capacitance-based foot presence sensor.

[0205] Example 49 is a footwear article comprising: a foot presence sensor, the foot presence sensor comprising a plurality of electrodes configured to generate and detect changes in an electric field inside the footwear article, wherein the changes indicate the presence or position of a foot inside the footwear article; and a processor circuit configured to receive a foot position indication signal from the foot presence sensor, process the signal using a recursive estimation algorithm to provide a predicted sensor value, compare the predicted sensor value with a subsequent value of the foot position indication signal from the foot presence sensor to provide a comparison result, and determine at least one of foot presence, foot absence, or footwear load characteristics of the footwear article based on the comparison result.

[0206] In Example 50, the subject matter of Example 49 can include a foot presence sensor including a plurality of electrodes disposed in or on a footbed of an article of footwear.

[0207] In Example 51, the subject matter of Example 50 includes a dielectric member between the foot presence sensor and the foot-receiving cavity of the article of footwear, the dielectric member having a dielectric constant greater than the dielectric constant of air.

[0208] In Example 52, the subject matter of any one or more of Examples 49 to 51 may include a processor circuit configured to change the foot presence / absence threshold or the footwear load threshold based on a minimum or maximum amplitude characteristic of the foot position indication signal.

[0209] In Example 53, the subject matter of any one or more of Examples 49 to 52 may include a foot presence sensor comprising a capacitance-based foot presence sensor configured to provide information to a foot position indication signal corresponding to a changing capacitance measured by the foot presence sensor.

[0210] Example 54 is at least one machine-readable medium comprising instructions that, when executed by a processing circuit, cause the processing circuit to perform operations to implement any of Examples 1-53.

[0211] Example 55 is an apparatus comprising a device for implementing any one of Examples 1-53.

[0212] Example 56 is a system implementing any one of Examples 1 to 53.

[0213] Example 57 is a method of implementing any one of Examples 1 to 53.

[0214] Each of these non-limiting embodiments may stand alone or may be combined in various permutations or combinations with one or more of the other aspects, examples, or features discussed elsewhere herein.

[0215] The above description includes reference to the accompanying drawings that form a part of the detailed description. The accompanying drawings illustrate specific embodiments in which the present invention may be implemented in a graphical manner. These embodiments are also referred to as "examples" in this article. Such examples may include elements other than those elements shown or described. However, the inventors also contemplate examples that only provide those elements shown or described therein. In addition, the inventors also contemplate examples using any combination or arrangement of those elements (or one or more aspects thereof) shown or described relative to a specific example (or one or more aspects thereof) or relative to other examples (or one or more aspects thereof) shown or described herein.

[0216] In this document, the terms "a" or "an" are used to include one or more than one, independent of any other instances or usages of "at least one" or "one or more", as is common in patent documents. In this document, unless otherwise indicated, the term "or" is used to refer to non-exclusivity, or so that "A or B" includes "A but not B", "B but not A", and "A and B". In this document, the terms "including" and "in which" are used as the plain English equivalents of the corresponding terms "comprising" and "wherein". In addition, in the following claims, the term "including / comprising" is open-ended, that is, systems, devices, articles, compositions, formulations, or processes that include elements other than those listed after such term in the claim are still considered to fall within the scope of the claim. In addition, in the appended claims, the terms "first", "second", and "third", etc. are used only as labels and are not intended to impose numerical requirements on their objects.

[0217] Unless the context indicates otherwise, geometric terms such as "parallel," "perpendicular," "circular," or "square" are not intended to require absolute mathematical precision. Rather, such geometric terms allow for variations due to manufacturing or equivalent functions. For example, if an element is described as "circular" or "substantially circular," components that are not exactly circular (e.g., components that are slightly elliptical or multi-faceted polygons) are still encompassed in this specification.

[0218] The method examples described herein may be at least partially machine or computer implemented. Some examples may include a computer-readable medium or machine-readable medium encoded with instructions, which are operable to configure an electronic device to perform the method described in the above example. The implementation of such methods may include code, such as microcode, assembly language code, high-level language code, etc. This code may include computer-readable instructions for performing various methods. The code may form part of a computer program product. In addition, in an example, such as during execution or at other times, the code may be tangibly stored on one or more volatile, non-temporary or non-volatile tangible computer-readable media. Examples of these tangible computer-readable media may include, but are not limited to, hard disks, removable disks, removable optical disks (e.g., optical disks and digital video disks), cassettes, memory cards or sticks, random access memory (RAM), read-only memory (ROM), etc.

[0219] The above description is intended to be illustrative and not restrictive. For example, the examples described above (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used by a person of ordinary skill in the art, such as after reviewing the above description. An abstract is provided to allow the reader to quickly determine the nature of the technical disclosure. The abstract is submitted, and it should not be understood as being used to interpret or limit the scope or meaning of the claims. In addition, in the above detailed description, various features may be combined together to simplify the present disclosure. This should not be interpreted as intended to be required for any claim to disclose features that are not required for protection. On the contrary, the subject matter of the present invention may be less than all the features of a specific disclosed embodiment. Therefore, the attached claims are thus incorporated into the specific embodiments as examples or embodiments, wherein each claim is independently a separate embodiment, and it is envisioned that such embodiments may be combined with each other in various combinations or arrangements. The scope of the present invention should be determined with reference to the attached claims and the full range of equivalents to which such claims are entitled.

Claims

1. A sensor signal processing method, comprising: sampling a value of a sensor signal from a foot presence sensor in the article of footwear; Using the sampled value of the sensor signal to identify the walking state of the footwear; updating a sensor signal threshold in response to identifying the ambulatory state; as well as Entry of a foot into the article of footwear or exit of a foot from the article of footwear is determined based on the updated sensor signal threshold and subsequent values ​​of the sensor signal. 2 . The method of claim 1 , wherein identifying the ambulatory state comprises comparing one or more values ​​of the sensor signal to a reference threshold.

3. The method according to claim 1, wherein identifying the walking state comprises: filtering the sensor signal using a low pass filter to provide a filtered signal; as well as A series of values ​​of the filtered signal are analyzed to distinguish the walking state of the article of footwear from a stationary state of the article of footwear.

4. The method of claim 1 , wherein updating the sensor signal threshold comprises: determining a predicted value of the sensor signal based on previous values ​​of the sensor signal; as well as When the predicted value of the sensor signal meets or exceeds a reference threshold, the sensor signal threshold is updated to have a threshold based in part on the predicted value of the sensor signal or based on a current value of the sensor signal. The method of claim 4 , wherein the reference threshold is based on a magnitude of a difference between the predicted value and the current value of the sensor signal.

6. The method of claim 1 , wherein identifying the ambulatory state comprises identifying a periodicity in the sensor signal over time, the periodicity corresponding to shoe drop and shoe lift events; and Wherein updating the sensor signal threshold comprises using an amplitude characteristic of the sensor signal over time.

7. The method of claim 6, wherein updating the sensor signal threshold comprises using a minimum value characteristic of the sensor signal to determine a foot presence / absence threshold; and Wherein determining that the foot has entered the article of footwear or that the foot has exited the article of footwear comprises using the foot presence / absence threshold.

8. The method according to claim 6, further comprising: updating a footwear load threshold using a maximum value characteristic of the sensor signal; A footwear load state of the article of footwear is determined based on the footwear load threshold and the subsequent value of the sensor signal.

9. The method of claim 1 , further comprising processing the sensor signal from the foot presence sensor using a recursive estimation filter to provide a predicted sensor value; Wherein determining that the foot enters the article of footwear or the foot leaves the article of footwear comprises using the updated sensor signal threshold and using information about a difference between the predicted sensor value and the subsequent value of the sensor signal.

10. The method of claim 1, wherein sampling the value of the sensor signal comprises sampling a capacitance-indicative value of a sensor signal from a capacitance-based foot presence sensor.

11. A sensor signal processing method, comprising: sampling a value of a sensor signal from a foot presence sensor in the article of footwear; Using the sampled value of the sensor signal to identify the walking state of the footwear; updating a sensor signal threshold in response to identifying the ambulatory state; as well as A load characteristic of the article of footwear is determined based on the updated sensor signal threshold and subsequent values ​​of the sensor signal.

12. The method according to claim 11, further comprising: processing the sensor signal from the foot presence sensor using a recursive estimation filter to provide a predicted sensor value; identifying a variance between the predicted sensor value and a subsequent value of the sensor signal from the foot presence sensor; as well as The ambulatory state of the article of footwear is identified in response to the variance exceeding a specified variance threshold.

13. The method of claim 12, wherein updating the sensor signal threshold comprises: determining a maximum characteristic of the sensor signal; as well as An updated sensor signal threshold is calculated based on the maximum value characteristic and a specified scaling factor.

14. The method according to claim 13, further comprising: determining a minimum characteristic of the sensor signal; as well as A foot presence threshold is calculated based on the minimum characteristic and a second specified scaling factor.

15. The method according to claim 11, further comprising: processing the sensor signal from the foot presence sensor using a recursive estimation filter to provide a predicted sensor value; identifying a variance between the predicted sensor value and a subsequent value of the sensor signal from the foot presence sensor; as well as The sensor signal threshold is updated based on the previous threshold and the identified variance.

16. The method of claim 11, wherein determining the load characteristic of the article of footwear comprises determining the presence of a foot inside the article of footwear and comprises determining whether the subsequent value of the sensor signal represents a standing or sitting position of a wearer of the article of footwear.

17. The method of claim 11, wherein determining the load characteristic of the article of footwear comprises determining a relative amount of force applied by a foot to a footbed of the article of footwear.

18. The method of claim 11, wherein sampling the value of the sensor signal comprises sampling a capacitance-indicative value of a sensor signal from a capacitance-based foot presence sensor.

19. A footwear article comprising: a foot presence sensor comprising a plurality of electrodes configured to generate and detect changes in an electric field within the article of footwear, wherein the changes indicate the presence or location of a foot within the article of footwear; A processor circuit configured to: receiving a foot position indication signal from the foot presence sensor; processing the signal using a recursive estimation algorithm to provide a predicted sensor value; comparing the predicted sensor value to a subsequent value of the foot position indicative signal from the foot presence sensor to provide a comparison result; as well as At least one of a foot presence, a foot absence, or a footwear load characteristic of the article of footwear is determined based on the comparison.

20. The article of footwear of claim 19, wherein the foot presence sensor including the plurality of electrodes is disposed in or on a footbed of the article of footwear.

21. The article of footwear of claim 20, further comprising a dielectric member interposed between the foot presence sensor and a foot receiving cavity of the article of footwear, the dielectric member having a dielectric constant greater than a dielectric constant of air.

22. The article of footwear of claim 19, wherein the processor circuit is further configured to vary a foot presence / absence threshold or a footwear load threshold based on a minimum or maximum amplitude characteristic of the foot position-indicative signal.

23. The article of footwear according to claim 19, wherein the foot presence sensor comprises a capacitance-based foot presence sensor configured to provide information to the foot position indication signal corresponding to a changing capacitance measured by the foot presence sensor.

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