WO2015021312A1

WO2015021312A1 - Submersion detection for wearable and portable devices

Info

Publication number: WO2015021312A1
Application number: PCT/US2014/050201
Authority: WO
Inventors: Steven SZABADOS; Andrew STIRN
Original assignee: Basis Science, Inc.
Priority date: 2013-08-07
Filing date: 2014-08-07
Publication date: 2015-02-12

Abstract

A system and method for identifying contact with liquid by a device based on sensor measurements and modifying the behavior of the device based on the identified contact.

Description

SUBMERSION DETECTION FOR WEARABLE AND PORTABLE

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 61/863,385 filed August 7, 2013 under 35 USC § 1 19(e), the contents of which is herein incorporated by reference.

BACKGROUND

[0002] Wearable technology enables people to interact with technology in a convenient mariner, since it can be present on the body in the context of all lifestyle activities. Wearable devices can measure the user and his surroundings continuously, and provide immediate information and feedback to the user any time he is wearing the device. When a device is continually worn, however, the device may come into contact with water or be submerged in water. If the device is submerged in water, the behavior of the device may be undesirable. The water may interfere with a display of the device, or the device may process sensed data incorrectly when the device is submerged in water.

BRIEF DESCRIPTION OF DRAWINGS

[0003] The disclosed embodiments have other advantages and features which will be more readily apparent from the detailed description, the appended claims, and the accompanying figures (or drawings). A brief introduction of the figures is below.

[0004] Figure (FIG.) 1 illustrates one embodiment of a. wearable device.

[0005] FIG. 2. illustrates another view of an embodiment of a wearable device.

[0006] FIG. 3 illustrates a rear view of an embodiment of a wearable device.

[0007] FIG. 4 illustrates a flow chart for determining whether a wearable device is in contact with water or submerged according to one embodiment. [0008] FIG. 5 illustrates a system architecture for a system for a wearable device.

DESCRIPTION

[0009] The Figures (FIGS.) and the following description relate to preferred

embodiments by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of what is claimed.

[0010] A wearable device detects when the device is in contact with or submerged in water based on signals measured at multiple sensing locations on the wearable device. For example, if a user wears the device while swimming, showering, while in a hot tub, or walking through a rainstorm, the device detects that it is submerged in water. The detection may be used to identify activities in which the wearer is engaged, or to adjust functionality based on the detected condition.

jOOilj One embodiment of the disclosed device and method includes a system for detecting whether the device is in contact with or submerged in water. In one embodiment, the operation of the device is modified in response to the identification of contact with or submersion in water of the device. Modifying the operation includes disabling those portions of the device which utilize capacitive sensing such as touch screens and sensors.

[0012] FIG. 1 illustrates an example of a wearable device 100 configured to be in close proximity to or in contact with a user. For example, the device 100 may be worn on a. user's appendage or portion thereof, e.g., an arm or a wrist, A fastening system 101 is shown, although the device may alternatively be portable rather than worn. For example, the device 100 may be carried in a pocket of a worn garment or affixed to a bag strap or belt. The fastening system 101 may include removable, exchangeable, or customizable elements.

Furthermore, although embodiments are described herein with respect to a wrist-worn device, other form factors or designed wear locations of the wearable device 100 may alternatively be used. For example, embodiments of the method described herein may be impiemented in arm-worn devices, head-worn devices, clip-on devices, and so forth. In one embodiment, the wearable device 100 is a physiological monitoring device for monitoring activities of its wearer and calculating various physiological and kinematic parameters, such as activity levels, caloric expenditure, step counts, heart-rate, and sleep patterns. However, methods described herein for detecting water submersion may be implemented within any wearable computing or sensing device.

[0013] The wearable device 100 includes a display 102 and several user interaction points 103. The display 102 and user interaction points 103 may be separate components of the device 100, or may be a single component. For example, the display 102 may be a touch- sensitive display configured to receive user touch inputs and display information to the user. The wearable device may also have a display element such as 102 without interaction points, or interaction points 103 without a display element such as 102.

[0014] The user interaction points 103 are sensor interfaces, buttons, or other user interfaces for receiving user inputs into the device 100. In some embodiments, the interaction points 103 are touch sensors that identify when they are touched, for example by a fingertip, nail, stylus, etc. The interaction points 103 can comprise electrodes for measuring the impedance of the environment surrounding the device 100. For example, the user interaction points 103 may be capacitive sensors, measuring changes in capacitance from a. baseline value when a user interacts with the interaction points 103 (e.g., when the user's finger is in contact with an interaction point 103 ). Other types of user interaction points 103 may alternatively be used, such as resistive sensors. Users can interact with the user interaction points 103 to input data into the device .100, navigate functions of the device 100, turn on or turn off the display 102, and so forth. The user interaction points 103 may additionally or alternatively be used for detecting other passive user interactions with the device 100, such as identifying when the device 100 is being worn or is otherwise in proximity to a user.

Interaction points 103 may not be in contact with the skin, as illustrated, or may be in contact with the skin as would be required to assess whether the device is being worn. Alternatively, the interaction points 103 may be hidden sensing elements not configured for user interaction. For example, the interaction points 103 may be touch sensors such as capacitive or resistive sensing elements within the device 100 and covered by an outer surface of the device 100.

[001.5] It should be noted that the device 100 may include additional components not shown in FIG, 1. In one embodiment, the device 100 includes one or more sensors for monitoring various physiological or kinematic parameters of the wearer of the device 100.

[0016] FIG. 2 is a side view of an alternati ve embodiment of the device 100, showing a fastening system 101 , a display 102, and a processor 203. Another alternative embodiment of the wearable device 100 is shown in FIG. 3. FIG. 3 shows a view from beneath the device 100, illustrating a fastening system 101, processor 203, a sensor 301 (such as an

acceierometer or other physiological or kinematic sensor) and one user interaction point 103 visible from beneath,

[0017] The processor 203 is communicatively coupled to the display 102 for controlling the display 102. Under the control of the processor 203, the display 102 displays various pieces of information to a user, enabling the user to view information about functions of the device and, by interacting with the user interaction points 103, navigate the functions of the device,

[0018] The processor 203 is also communicatively coupled to the user interaction points 103 for monitoring the electrical impedance measured at the user interaction points 103. The processor 203 is configured to detect changes in the impedance at each interaction point 103 that signal the proximity of a user's finger to the interaction point 103.

[0019] When a user is interacting with the device 100, the user is likely to be interacting with one user interaction point 103 at a time. For example, the user pushes a single button to invoke the function of the button. Thus, if the processor 203 detects a change in the electrical impedance of a single user interaction point 103, the processor 203 receives the change in electrical impedance as a user input to the device 100,

[0020] In contrast, a change in electrical impedance measured at multiple user interaction points 103 may indicate a change in the environment of the device 100. Specifically , if the capacitance measured at multiple interaction points 103 is significantly different from an established baseline capacitance (or if the measured resistance is significantly different from a baseline resistance), the device 100 may be submerged in water rather than the measured change in the electrical impedance being due to user interaction with device 100. The processor 203 is configured to use electrical impedance measured at two or more of the user interaction points 103 to detect when the device 100 is submerged in water. In some embodiments, the processor 203 is configured to identify the device 100 as submerged if the electrical impedance changes at all of the interaction points 103.

[0021] FIG. 4 is a flowchart illustrating a method 400 for determining whether a wearable device is submerged in water. The steps of the method 400 are performed by the processor 203,

[0022] The processor 203 receives 402 impedances measured at the interaction points 103, Based on impedances measured at multiple interaction points 103, the processor 203 determines 404 that the device 100 is submerged in water. In one embodiment, the processor 203 measures changes in the impedances of the user interaction points 103 to determine 404 when the device 100 is being submerged in water. For example, the processor 203 may detect a sudden change in the capacitance of two or more interaction points 103, and identify the corresponding time as the time the device was submerged. The processor 203 may also monitor a moving average of the impedances of the user interaction points 103 to determine 404 continued submersion of the device 100. If the difference between a baseline impedance and the average impedance measured at two or more interaction points 103 is greater than a threshold delta, the processor 203 determines 404 that the device 100 is submerged. The processor 203 may determine 404 that the device 100 is submerged until the respective impedances of the user interaction points 103 return to the baseline value.

[0023] The processor 203 may perform additional processing steps to identify when the device 100 is submerged. In one embodiment, the processor 203 determines that the device 100 is submerged when the impedances of particular combinations of interaction points 103 change. For example, the processor 203 may determine that the device 100 is submerged in water if impedances of two or more non-adjacent interaction points 103 change, but determine that the device 100 is not submerged if only two adjacent interaction points 103 change. As another exampl e, the processor 203 may monitor only a subset of the interaction points 103, such as the interaction points 103 internal to the device 100, and determine that the device 100 is submerged if impedances of two or more of the monitored interaction points 103 change.

[0024] In another embodiment, the processor 203 records time stamps corresponding to each impedance change. If impedances of multiple interaction points 103 change at the same time (or if the amount of time between impedance changes is less than a threshold length of time, such as 100 milliseconds), the processor 203 determines that the device 100 was submerged at that time. In contrast, if the threshold amount of elapsed time between impedance changes of multiple interaction points 103, the processor 203 determines that the device 100 is not submerged in water. For example, if there is a lag between impedance changes at several interaction points 103, the impedance changes may be caused by a user interaction with the device 100 or by water flowing over the device 100, rather than the device 100 being submerged in water.

[0025] In response to detecting that the device 100 is submerged in water, the processor 203 is configured to modify the behavior of the device 100. In one embodiment, the processor 203 controls the display 102 based on the submersion detection. For example, the processor 203 may deactivate the display 102. Deactivating comprises iurning off or locking at a home screen 406 the display 102 when the processor 203 detects that the device 100 is submerged. By deactivating the display 102, the processor 203 prevents water in contact with the device 100 from scrolling through screens displayed by the display 102 or causing other undesirable behavior. Moreover, by automatically detecting when the device 100 is submerged in water, the processor 203 improves the user experience by not requiring that the user explicitly interact with the device 100 or change the device's mode prior to submerging the device 100.

[0026] In another embodiment, the processor 203 may use the submersion detection as one of several inputs into an algorithm for detecting 407 the context of a wearer. For example, the wearable device 100 could include sensors for measuring internal physiological parameters such as blood flow or respiration. The processor 203 may identify when a wearer is exercising based on higher pulse rate or respiration rate measured by the additional sensors, and use the submersion detection to determine whether the wearer is swimming or exercising on land (e.g., walking or running). As another example, the processor 203 may recei ve acceleration data from an accelerometer of the wearable de vice 100 and calc ulate the number of steps taken by the wearer. Using the submersion detection and the calculated steps, the processor 203 can differentiate between walking through a rainstorm and taking a shower. As yet another example, the processor 203 may use the submersion detection to determine how to process the acceleration data. If the device 100 is not submerged in water, the processor 203 may process the acceleration data to count the number of steps taken by the wearer, whereas if the device 100 is submerged in water a swimming mode is activated and the processor 203 may process the acceleration data to count the number of swimming strokes taken by the wearer.

[0027] By detecting the context of the wearer of the device 100, the processor 203 can improve algorithms for monitoring physiological parameters of the wearer. For example, the processor 203 may monitor users' activity levels. By detecting whether a user is walking, swimming, bathing, and so forth, the processor 203 can more accurately determine the user's activity, exertion levels, and calculations of other physiological and kinematic parameters.

[0028] Turning briefly to FIG. 5, illustrated is a block diagram of an example device 500 able to read instructions from a machine-readable medium and execute them in a processor (or controller), as an example of wearable device 100. Specifically, FIG. 5 shows a diagrammatic representation of a device 500 within which instructions 524 (e.g., software) for causing the device 500 to perform any one or more of the methodologies discussed herein may be executed. The device 500 operates as a standalone device, or may be connected (e.g., networked) to other machines. In a networked deployment, the device 500 may operate in the capacity of a client machine in a server-client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment.

[0029] The device 500 may he any machine capable of executing instructions 524 (sequential or otherwise) corresponding to program code (or software) that specify actions to be taken by that device. The example device 500 includes one or more processors, such as the processor 203 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), one or more application specific integrated circuits (ASICs), one or more radio-frequency integrated circ uits (RFICs), or any combination of these), and a memory 504, which are configured to communicate with each other via a bus 508. The device 500 may further include one or more displays, such as display 102 (e.g., a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, or a plasma display). The device 500 also includes sensor or user interfaces, such as the interaction points 103, and, optionally, a network interface device 520, configured to communicate via the bus 508.

[0030] The memory 504 stores instructions 524 (e.g., software) embodying any one or more of the methodologies or func tions described herein, such as the method 400 for determining whether the wearable device 100 is submerged in water. The instructions 524 (e.g., software) may also reside, completely or at least partially, within the processor 203 (e.g., within a processor's cache memory) during execution thereof by the device 500. The memory- 504 and the processor 203 constitute machine-readable media. The term "machine- readable medium" shall be taken to include any medium that is capable of storing instructions (e.g., instructions 524) for execution by the machine and that cause the machine to perform any one or more of the methodologies disclosed herein. The term "machine-readable medium" includes, but not be limited to, data repositories in the form of solid-state memories, optical media, and magnetic media. The instructions 524 (e.g., software) may be transmitted or received over a network 526 via the network interface device 520.

[0031] In one embodiment, the processor 203 receives 402 impedances from each of the interaction points 103 every 2 milliseconds (i.e., a sampling frequency of 500 Hz). The received data for each button is filtered via a low pass filter. The filter's cutoff can be, for example, 5Hz. The raw value is subtracted from the filtered value and if the absolute value of the result exceeds a threshold, the processor 203 identifies the possibility of the de vice being submerged. The threshold is specific to the type of interaction point such as the type of sensing material used in it. If the signal from each of the interaction points 103 indicates possible submersion, the processor 203 identifies the device as being submerged and deactivates the touch functionality of the display 102.

[0032] Some portions of above description describe the embodiments in terms of algorithms and symbolic representations of operations on information. These algorithmic descriptions and representations are commonly used by those skilled in the data processing arts to convey the substance of their work effectively to others skilled in the art. These operations, while described functionally, computationally, or logically, are understood to be implemented by computer programs or equivalent electrical circuits, microcode, or the like. The described operations may be embodied in software, firmware, hardware, or any combinations thereof.

[0033] As used herein any reference to "One embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment,

[0034] Some embodiments may be described using the expression "coupled" and "connected" along with their derivatives. It should be understood that these terms are not intended as synonyms for each other. For example, some embodiments may be described using the term "connected" to indicate that two or more elements are in direct physical or electrical contact with each other. In another example, some embodiments may be described using the term "coupled" to indicate thai two or more elements are in direct physical or electrical contact. The term "coupled," however, may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments are not limited in this context.

[0035] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is tme (or present), and both A and B are true (or present).

[0036] In addition, use of the "a" or "an" are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0037] Upon reading this disclosure, those of skill in the art will appreciate still additional alternative structural and functional designs for a system and a process for modifying operation of a device in response to an identified context through the disclosed principles herein. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes and variations, which will be apparent to those skilled in the art, may be made in the arrangement, operation and details of the method and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.

Claims

1. A method for identifying a device as in contact with a liquid, the method comprising: receiving from each of a plurality of touch sensors a signal indicating the touch sensor is being touched, each signal including a time stamp;

identifying an amount of elapsed time between each signal;

responsive to the received signals and the amount of elapsed time, determining that the device is in contact with a liquid; and

modifying operation of the device in response to the determined contact with liquid.

2. The method of claim 1 wherein the touch sensors are capacitive sensors.

3. The method of claim 2 wherein the signals comprise a measurement of impedance and determining that the device is in contact with a liquid comprises determining the device is in contact with a liquid if each of the received impedances exceed a predetermined threshold.

4. The method of claim 1 wherein the touch sensors are resistive sensors.

5. The method any previous claim wherein the plurality of touch sensors comprise at least three touch sensors.

6. The method of any previous claim wherein determining that the device is in contact with a liquid comprises determining that the elapsed time is below a threshold.

7. The method of any previous claim wherein modifying the operation of the device comprises deactivating the touch screen.

8. The method of claim 7 wherein deactivating the touch screen comprises locking the touch screen at a home screen.

9. The method of claim 7 wherein deactivating the touch screen comprises turning off the touch screen.

10. The method of any one of claims 1-6 wherein modifying the operation of the device comprises activating a swimming mode on the device.

11. The method of any previous claim wherein contact with liquid comprises

submerged in liquid.

12. The method of any previous claim wherein the liquid comprises water,

13. A system for identifying a device as in contact with a liquid, the system comprising a non-transitory computer-readable storage medium storing executable computer program instructions for performing steps comprising:

receiving from each of a plurality of touch sensors a signal indicating the touch sensor is being touched, each signal including a time stamp; identifying an amount of elapsed time between each signal;

14. The system of claim 13 wherein the plurality of sensors comprise capacitive sensors.

15. The system of claim 14 wherein the signals comprise a measurement of impedance and determining that the device is in contact with a liquid comprises determining the device is in contact with a liquid if each of the received impedances exceed a predetermined threshold.

16. The system of claim 13 wherein the touch sensors are resistive sensors.

17. The system of any one of claims 13-16 wherein the plurality of sensors comprise at least three sensors.

18. ^'The system of any one of claims 13-18 wherein determining that the device is in contact with a liquid comprises determining that the elapsed time is below a threshold.

19. The system of any one of claims 13-18 wherein modifying the operation of the device comprises deactivating the touch screen.

20. The system of claim 19 wherein deactivating the touch screen comprises locking the touch screen at a home screen.

21. The system of claim 19 wherein deactivating the touch screen comprises turning off the touch screen.

22. The system of any one of claims 13-18 wherein modifying the operation of the device comprises activating a swimming mode on the device,

23. The system of any one of claims 13-22 wherein contact with liquid comprises submerged in liquid,

24. The system of any one of claims 13-24 wherein the liquid is water.

25. A non-transitory computer-readable storage medium storing executable computer program instructions for performing steps comprising:

receiving from each of a plurality of touch sensors a signal indicating the touch sensor is being touched, each signal including a. time stamp;

identifying an amount of elapsed time between each signal ;

26. The non-transitory compuier-readable storage medium of claim 25 wherein the plurality of sensors comprise capacitive sensors.

27. The non-transiiory compuier-readable storage medium of claim 26 wherein the signals comprise a measurement of impedance and determining that the device is in contact with a liquid comprises determining the device is in contact with a liquid if each of the received impedances exceed a predetermined threshold.

28. The non-transitory computer-readable storage medium of claim 25 wherein the touch sensors are resistive sensors.

29. The non-transitory computer-readable storage medium of any one of claims 25-28 wherein the plurality of sensors comprise at least three sensors,

30. The non-transitory computer-readable storage medium of any one of claims 25-29 wherein determining that the device is in contact with a liquid comprises determining that the elapsed time is below a threshold.

31. The non-transitory computer-readable storage medium of any one of claims 25-30 wherein modifying the operation of the device comprises deactivating the touch screen.

32. The non-transitory computer- readable storage medium of claim 31 wherein deactivating the touch screen comprises locking the touch screen at a home screen.

33. The non-transitory computer-readable storage medium of claim 31 wherein deactivating the touch screen comprises turning off the touch screen.

34. The non-transitory computer-readable storage medium of any one of claims 25-30 wherein modifying the operation of the device comprises activating a swimming mode on the device.

35. The non-transitory computer- readable storage medium of any one of claims 25-34 wherein contact with liquid comprises submerged in liquid.

36. The non-transitory computer-readable storage medium of any one of claims 25-35 wherein the liquid is water.