PATENT DOCUMENT

Publication Number: US-9049508-B2
Application Number: US-201213689538-A
Country: US
Kind Code: B2

Title: Earphones with cable orientation sensors

Abstract:
An electronic device may be coupled to an accessory such as a pair of earphones. The earphones may have multi-user sensor structures that determine whether or not the earphones are being shared by multiple users. The multi-user sensor structures may include an angle sensor configured to measure an angle at the Y-junction of a cable associated with the pair of headphones. When the first and second speakers are both located in the ears of a single user, the electronic device may perform functions such as playing audio content. When one of the speakers is located in an ear of a first user while the other of the speakers is located in an ear of a second user, the electronic device can automatically take actions such as switching from stereo to mono playback, playing a different type of audio content to each earphone, or other suitable action.

Claims:
What is claimed is: 
     
       1. A method for operating an electronic device that is configured to play audio through a pair of earphones having a cable, comprising:
 with control circuitry in the electronic device, gathering information from sensor structures in the cable of the earphones, wherein the information indicates an orientation of the cable; 
 determining whether the earphones are in the ears of multiple users of the electronic device based on the information; and 
 in response to determining whether the earphones are in the ears of multiple users of the electronic device based on the information from the sensor structures, adjusting audio playback from the control circuitry to the earphones. 
 
     
     
       2. The method defined in  claim 1  wherein adjusting audio playback comprises switching between a single-user mode and a multiple-user mode. 
     
     
       3. The method defined in  claim 1  wherein the information from the sensor structures indicates that the earphones are in the ears of the multiple users of the electronic device and wherein adjusting the audio playback comprises switching from a stereo playback mode to a mono playback mode in response to the information indicating that the earphones are in the ears of the multiple users. 
     
     
       4. The method defined in  claim 1  wherein the information from the sensor structures indicates that the earphones are in the ears of the multiple users of the electronic device and wherein adjusting the audio playback comprises providing a first type of audio content to a first earphone in the pair of earphones and a second type of audio content to a second earphone in the pair of earphones in response to the information indicating that the earphones are in the ears of the multiple users. 
     
     
       5. The method defined in  claim 1  wherein the information from the sensor structures indicates that the earphones are in the ears of a single user of the electronic device and wherein adjusting the audio playback comprises switching from a monophonic playback mode to a stereo playback mode in response to the information indicating that the earphones are in the ears of the single user. 
     
     
       6. The method defined in  claim 1  wherein the information from the sensor structures indicates that the earphones are in the ears of a single user of the electronic device and wherein adjusting the audio playback comprises playing one type of audio content to both of the earphones in response to the information indicating that the earphones are in the ears of the single user. 
     
     
       7. Earphones operable to play audio from an electronic device, comprising:
 an audio connector that is adapted to mate with an audio connector in the electronic device; 
 a cable coupled to the audio connector; 
 left and right earphone speaker housings coupled to the cable; 
 left and right speaker drivers, wherein the left speaker driver is mounted in the left speaker housing and wherein the right speaker driver is mounted in the right speaker housing; and 
 sensor structures configured to measure an angle associated with the cable. 
 
     
     
       8. The earphones defined in  claim 7  wherein the cable has a common cable portion that splits into two cable portions at a junction, wherein the two cable portions are oriented at the angle with respect to each other at the junction, and wherein the sensor structures comprise an angle sensor that is configured to measure the angle at the junction. 
     
     
       9. The earphones defined in  claim 8  wherein the two cable portions are coupled respectively to the left and right earphone speaker housings. 
     
     
       10. The earphones defined in  claim 7  wherein the sensor structures comprise a fiber optic goniometer. 
     
     
       11. The earphones defined in  claim 10  wherein the fiber optic goniometer comprises a light source and a light detector. 
     
     
       12. The earphones defined in  claim 7  wherein the sensor structures comprise a strain gauge. 
     
     
       13. The earphones defined in  claim 12  wherein the cable comprises an insulative sheath surrounding a plurality of wires and wherein the strain gauge comprises conductive lines formed on an inner surface of the insulative sheath. 
     
     
       14. The earphones defined in  claim 7  wherein the sensor structures comprise a resistance-based sensor. 
     
     
       15. The earphones defined in  claim 14  wherein the sensor structures comprise a capacitive sensor. 
     
     
       16. A method for operating a pair of earphones having a cable with a junction at which the cable branches into first and second cable segments each of which has a respective earphone speaker, comprising:
 with angle sensor structures in the cable, measuring an angle that separates the first and second cable segments at the junction to determine whether the pair of earphones is being shared by multiple users; and 
 adjusting audio playback to each earphone speaker in response to determining whether the pair of earphones is being shared by multiple users from measurement of the angle. 
 
     
     
       17. The method defined in  claim 16  wherein adjusting the audio playback comprises switching from single-user mode to multiple-user mode in response to determining that the pair of earphones is being shared by multiple users. 
     
     
       18. The method defined in  claim 17  wherein the single-user mode comprises a stereo playback mode and wherein the multiple-user mode comprises a monophonic playback mode. 
     
     
       19. The method defined in  claim 16  wherein the angle sensor structures comprise a strain gauge located at the junction and wherein determining whether the pair of headphones is being shared by multiple users comprises comparing the measured angle at the junction with a predetermined threshold. 
     
     
       20. The method defined in  claim 16  wherein the angle sensor structures comprise a fiber optic goniometer and wherein determining whether the pair of headphones is being shared by multiple users comprises comparing the measured angle at the junction with a predetermined threshold.

Description:
BACKGROUND 
     This relates to electronic devices and, more particularly, to electronic devices with accessories such as earphones. 
     Accessories such as earphones are often used with media players, cellular telephones, and other electronic devices. Users may sometimes want to share earphones to listen to audio playback at the same time. There can be difficulties associated with sharing earphones. For example, audio is typically played in stereo so that left and right earbuds receive corresponding left and right channels of audio. A user who is sharing a set of earphones with another user may therefore miss information that is being sent to the channel associated with the other user&#39;s earbud. 
     It would therefore be desirable to be able to provide improved ways in which to control operation of an electronic device coupled to an accessory. 
     SUMMARY 
     An electronic device may be coupled to an accessory such as a pair of earphones. The earphones may have multi-user sensor structures that determine whether or not the earphones are being used by multiple users. 
     The earphones may contain first and second speakers. For example, the earphones may include a left earbud and a right earbud. When both the first and second speakers are located in the ears of a single user, the electronic device may perform functions in single-user mode such as playing audio content in stereo. 
     When one of the speakers is located in a first user&#39;s ear and the other speaker is located in a second user&#39;s ear, the electronic device may perform functions in multiple-user mode such as providing monophonic playback to each speaker. The monophonic playback provided to each speaker may be the same so that both users hear the same audio content or may be different so that the user&#39;s hear different audio content. 
     The sensor structures may include one or more angle sensors. The angle sensors may be used to determine the angular orientation of each speaker in a pair of earphones to determine whether or not multiple users are wearing the earphones. The angle sensors may be formed from light-based angle sensors such as fiber optic goniometers or may be formed from gauge elements that measure the bending strain along or around a particular axis. 
     The accessory may include a cable having a junction at which the cable branches into first and second cable segments. The cable segments may be oriented at an angle with respect to each other. The sensor structures may be configured to measure the angle at the junction to determine whether or not the accessory is being shared by multiple users. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an illustrative electronic device and associated accessory in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative electronic device and associated accessory in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of a portion of an illustrative accessory having a cable orientation sensor formed from a strain gauge in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of a portion of an illustrative accessory having cable orientation sensors formed from strain gauges in accordance with an embodiment of the present invention. 
         FIG. 5  is a perspective view of a portion of an illustrative accessory having a cable orientation sensor formed from a resistance-based angle sensor in accordance with an embodiment of the present invention. 
         FIG. 6  is a side view of a portion of an illustrative accessory having a cable orientation sensor formed from a capacitive angle sensor in accordance with an embodiment of the present invention. 
         FIG. 7  is a diagram of an illustrative fiber optic goniometer that may be used to measure cable orientation in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional diagram of a portion of an illustrative accessory having a cable orientation sensor formed from a fiber optic goniometer in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional diagram of a portion of an illustrative accessory having a cable orientation sensor formed from a fiber optic goniometer in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional diagram of a portion of an illustrative accessory having a cable orientation sensor formed from a fiber optic goniometer in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional diagram of an illustrative electronic device and associated accessory having a cable orientation sensor formed from a fiber optic goniometer in accordance with an embodiment of the present invention. 
         FIG. 12  is a flow chart of illustrative steps involved in operating an accessory and electronic device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic device accessories such as earphones may be provided with cable orientation sensors configured to measure one or more angles associated with an accessory cable. For example, an accessory provided with angle sensing structures that can determine whether or not the accessory is being shared by multiple users. 
       FIG. 1  is a diagram of a system of the type that may be provided with an accessory having sensing structures for detecting multiple users. As shown in  FIG. 1 , system  8  may include electronic device  10  and accessory  20 . 
     Electronic device  10  may include a display such as display  14 . Display  14  may be a touch screen that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components or may be a display that is not touch-sensitive. Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. Configurations in which display  14  includes display layers that form liquid crystal display (LCD) pixels may sometimes be described herein as an example. This is, however, merely illustrative. Display  14  may include display pixels formed using any suitable type of display technology. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass or clear plastic. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button such as button  16  and an opening such as opening  18  may be used to form a speaker port. 
     Device  10  may have a housing such as housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. 
     Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). The periphery of housing  12  may, if desired, include walls. One or more openings may be formed in housing  12  to accommodate connector ports, buttons, and other components. For example, an opening may be formed in the wall of housing  12  to accommodate audio connector  24  and other connectors (e.g., digital data port connectors, etc.). Audio connector  24  may be a female audio connector (sometimes referred to as an audio jack) that has two pins (contacts), three pins, four pins, or more than four pins (as examples). Audio connector  24  may mate with male audio connector  22  (sometimes referred to as an audio plug) in accessory  20 . 
     Accessory  20  may be a pair of earphones (e.g., earbuds or earphones with other types of speakers), other audio equipment (e.g., an audio device with a single earbud unit), or other electronic equipment that communicates with electronic device  10 . The use of a pair of headphones in system  8  is sometimes described herein as an example. This is, however, merely illustrative. Accessory  20  may be implemented using any suitable electronic equipment. 
     It should be understood that the term “earphones” may refer to any suitable type of audio headset (e.g., headphones, over-the-ear headphones, earbuds, earbud-type headphones with ear hooks, etc.). 
     As shown in  FIG. 1 , accessory  20  may include a communications path such as cable  26  that is coupled to audio plug  22 . Cable  26  may contain conductive lines (e.g., wires) that are coupled to respective contacts (pins) in audio connector  22 . The conductive lines of cable  26  may be used to route audio signals from device  10  to speakers in earphone units  28  (which may sometimes be referred to as speakers or earphone housings). Cable  26  may include sensor structures for determining when accessory  20  is being shared by multiple users. 
     Microphone signals may be gathered using a microphone mounted in controller unit  30 . Controller unit  30  may also have buttons that receive user input from a user of system  8 . A user may, for example, manually control the playback of media by pressing button  30 A to play media or increase audio volume, by pressing button  30 B to pause or stop media playback, and by pressing button  30 C to reverse media playback or decrease audio volume (as examples). 
     The circuitry of controller  30  may communicate with the circuitry of device  10  using the wires or other conductive paths in cable  26  (e.g., using digital and/or analog communications signals). The paths in cable  26  may also be coupled to speaker drivers in earphones  28 , so that audio signals from device  10  may be played through the speakers in earphone units  28 . Electronic device  10  may regulate the volume of sound produced by earphone units  28  by controlling the audio signal strength used in driving the speakers in earbuds  28 . 
     Sensor signals from sensor structures in cable  26  may be conveyed to device  10  using the conductive paths of cable  26 . Electronic device  10  may process the sensor signals and take suitable action based on a determination of whether or not earphone units  28  are in the ears of multiple users. 
     A schematic diagram showing illustrative components that may be used in device  10  and accessory  20  of system  8  is shown in  FIG. 2 . As shown in  FIG. 2 , electronic device  10  may include control circuitry  32  and input-output circuitry  34 . Control circuitry  32  may include storage and processing circuitry that is configured to execute software that controls the operation of device  10 . Control circuitry  32  may be implemented using one or more integrated circuits such as microprocessors, application specific integrated circuits, memory, and other storage and processing circuitry. 
     Input-output circuitry  34  may include components for receiving input from external equipment and for supplying output. For example, input-output circuitry  34  may include user interface components for providing a user of device  10  with output and for gathering input from a user. As shown in  FIG. 2 , input-output circuitry  34  may include communications circuitry  36 . Communications circuitry  36  may include wireless circuitry such as radio-frequency transceiver circuitry with a radio-frequency receiver and/or a radio-frequency transmitter. Radio-frequency transceiver circuitry in the wireless circuitry may be used to handle wireless signals in communications bands such as the 2.4 GHz and 5 GHz WiFi® bands, cellular telephone bands, and other wireless communications frequencies of interest. Communications circuitry  36  may also include wired communications circuitry such as circuitry for communicating with external equipment over serial and/or parallel digital data paths. 
     Input-output devices  38  may include buttons such as sliding switches, push buttons, menu buttons, buttons based on dome switches, keys on a keypad or keyboard, or other switch-based structures. Input-output devices  38  may also include status indicator lights, vibrators, display touch sensors, speakers, microphones, camera sensors, ambient light sensors, proximity sensors, and other input-output structures. 
     Electronic device  10  may be coupled to components in accessory  20  using cables such as cable  26  of accessory  20 . Accessory  20  may include speakers such as a pair of speaker drivers  40  (e.g., a left speaker and a right speaker). If desired, accessory  20  may include more than one driver per earbud. For example, each earbud in accessory  20  may have a tweeter, a midrange driver, and a bass driver (as an example). Speaker drivers  40  may be mounted in earbuds or other types of earphone housings. The use of left and right earbuds to house respective left and right speaker drivers  40  is sometimes described herein as an example. 
     If desired, accessory  20  may include user input devices  42  such as buttons (see, e.g., the buttons associated with button controller  30  of  FIG. 1 ), touch-based input devices (e.g., touch screens, touch pads, touch buttons), a microphone to gather voice input, and other user input devices. 
     To determine whether or not accessory  20  is being shared by multiple users, accessory  20  may be provided with multi-user sensor structures  44 . Multi-user sensor structures  44  may be configured to detect whether or not the earbuds (or other earphone units of accessory  20 ) are being used by multiple users. Multi-user sensor structures may be formed from strain gauge elements, from light-based sensors such as optical fiber goniometers, from force sensors, from switches or other mechanical sensors, from capacitive sensors, from resistance-based sensors, and from acoustic-based sensors such as ultrasonic acoustic-based sensors (as examples). 
     Control circuitry  45  in accessory  20  (e.g., storage and processing circuits formed from one or more integrated circuits or other circuitry) and/or control circuitry  32  of electronic device  10  may use information from multi-user sensor structures  44  in determining which actions should be automatically taken by device  10 . 
     A portion of an illustrative accessory with a multi-user presence sensor is shown in  FIG. 3 . As shown in  FIG. 3 , accessory  20  has a tubular insulative sheath such as sheath  46  that surrounds one, two, or more than two wires. In the  FIG. 3  example, sheath  46  surrounds conductive wire bundles  48 L and  48 R. Wire bundle  48 L may be electrically coupled between connector  22  and a left earbud  28  ( FIG. 1 ), whereas wire bundle  48 R may be electrically coupled between connector  22  and a right earbud  28 . 
     As shown in  FIG. 3 , cable  26  may have a junction such as junction  52  (sometimes referred to as a Y-junction) at which common cable portion  26 C branches into two cable segments  26 L and  26 R. Cable segments  26 L and  26 R may be oriented at an angle with respect to each other. The angle that separates left branch  26 L from right branch  26 R may be indicative of whether or not accessory  20  is being shared between multiple users. For example, a relatively large angle between left branch  26 L and right branch  26 R may indicate that one earbud  28  is in a first user&#39;s ear while the other earbud  28  is in a second user&#39;s ear. 
     A gauge element such as strain gauge element  50  may be formed at Y-junction  52  of cable  26 . As shown in  FIG. 3 , strain gauge element  50  may include conductive lines such as conductive lines  54  (e.g., a pattern of metallic foil or other suitable conductive material). Conductive lines  54  may be formed directly on the inner surface of sheath  46  or may, if desired, be formed on a flexible support structure that has been attached to the inner surface of sheath  46  (e.g., with adhesive). 
     As conductive lines  54  are strained or deformed (e.g., by being flexed or strained about axis  56 ), the electrical resistance of strain gauge  50  may change. For example, as θ 1  between left branch  26 L and right branch  26 R increases, conductive lines  54  on strain gauge  50  will be stretched, thereby increasing the electrical resistance of strain gauge  50 . As θ 1  between left branch  26 L and right branch  26 R decreases, conductive lines  54  on strain gauge  50  will be compressed, thereby decreasing the electrical resistance of strain gauge  50 . 
     The strain of cable  26  at Y-junction  52  measured by strain gauge  50  may be proportional to the angle θ 1  between left branch  26 L and right branch  26 R of cable  26 . Thus, strain gauge  50  may serve as an angle sensor (sometimes referred to as a goniometer) for measuring the angle θ 1  between left branch  26 L and right branch  26 R of cable  26 . 
     To determine whether or not accessory  20  is being shared by multiple users, the control circuitry of accessory  20  (and/or control circuitry  32  of  FIG. 2 ) may measure the angle θ 1  between left branch  26 L and right branch  26 R of cable  26  using strain gauge  50 . The control circuitry may compare the measured angle with a predetermined threshold. When the measured angle is above the predetermined threshold, device  10  can conclude that accessory  20  is being shared by multiple users. When the measured angle is below the predetermined threshold, device  10  can conclude that accessory  20  is not being shared by multiple users. 
     If desired, strain gauges  50  may be formed in other locations of cable  26 . For example, as shown in  FIG. 4 , strain gauge elements  50  may be formed in outer portions  58  of cable  26 . Similar to the example of  FIG. 3 , strain gauge elements  50  of  FIG. 4  may be formed on an inner surface of cable sheath  46 . With this type of configuration, a first strain gauge  50  may be configured to measure the angle θ 2  between left branch  26 L of cable  26  and common cable portion  26 C (e.g., the portion of cable  26  that surrounds both wires  48 L and  48 R), while a second strain gauge  50  may be configured to measure the angle θ 3  between right branch  26 R of cable  26  and common cable portion  26 C. 
     Control circuitry  45  in accessory  20  or circuitry  32  in device  10  may compare θ 2  and/or θ 3  with a predetermined threshold. When one or both measured angles is above the predetermined threshold, device  10  can conclude that accessory  20  is not being shared by multiple users. When one or both measured angles is below the predetermined threshold, device  10  can conclude that accessory  20  is being shared by multiple users. 
     If desired, accessory  20  may be provided with forced-based sensors or resistance-based sensors for determining whether or not accessory  20  is being shared by multiple users. For example, as shown in  FIG. 5 , multi-user sensor structure  60  may be formed in the crevice of Y-junction  52 . Sensor structure  60  may, for example, be a compressible foam with a measureable resistance. As the angle between left branch  26 L and right branch  26 R of cable  26  increases, the resistance of foam  60  may also increase. As the angle between left branch  26 L and right branch  26 R of cable  26  decreases, the resistance of foam  60  may decrease. When control circuitry of accessory  20  or device  10  determines that the resistance is above a predetermined threshold, device  10  can conclude that accessory  20  is being shared by multiple users. 
     If desired, forced-based sensor schemes such as piezo-electric force sensors or other force sensors may be used to determine whether or not accessory  20  is being shared by multiple users. 
     Capacitive sensors may also be used to determine whether or not accessory  20  is being shared my multiple users. For example, as shown in  FIG. 6 , sensor  62  may include first and second electrical conductors formed at Y-junction  52  of cable  26 . A first conductive plate (e.g., a metal foil or other conductive structure) may be formed on left branch  26 L of cable  26  and a second may be formed on right branch  26 R of cable  26 . As the angle between left branch  26 L and right branch  26 R decreases, the overlapping area between the conductive plates may increase, thereby increasing the capacitance of sensor structure  62 . As the angle between left branch  26 L and right branch  26 R increases, the overlapping area between the conductive plates may decrease, thereby decreasing the capacitance of sensor structure  62 . When control circuitry of accessory  20  or device  10  determines that the capacitance is below a predetermined threshold, device  10  can conclude that accessory  20  is being shared by multiple users. 
     If desired, other capacitive sensors may be used to determine whether or not accessory  20  is being shared by multiple users. The example of  FIG. 6  is merely illustrative. 
     Light-based sensors such as fiber optic goniometers may also be used to determine whether or not accessory  20  is being shared by multiple users. For example, a fiber optic goniometer may be used to measure the angle between left and right branches of cable  26 , or the angle between a left or right branch of cable  26  and the common portion of cable  26 . A diagram illustrating how fiber optic goniometers may be used to measure angles is shown in  FIG. 7 . 
     As shown in  FIG. 7 , fiber optic goniometer  72  may include a fiber optic cable such as fiber optic cable  68  interconnected between a light source such as light source  64  and a light detector such as light detector  66 . Light source  64  may include, for example, one or more laser diodes, one or more light-emitting diodes, or other sources of light. Light detector  66  may include one or more photodetectors such as p-i-n diodes, p-n junction diodes, photodiode arrays, etc. 
     Fiber optic cable  68  may be looped around a series of three wave-plate structures such as wave-plate structures  70 . Wave-plate structures  70  may, for example, include a half-wave-plate sandwiched between two quarter-wave-plates. Goniometer  72  may also include one or more polarizers such as linear polarizers for creating linearly polarized light. 
     As light passes through fiber optic cable  68 , a change in polarization occurs when the plane of wave-plate  70 C rotates with respect to the plane of wave-plates  70 A and  70 B. For example, when the plane of wave-plate  70 C rotates in direction  75  relative to the plane of wave-plates  70 A and  70 B, a change in polarization of the light within fiber  68  occurs. The rotation angle may be determined from the intensity of light received by photodetector  66 . 
       FIG. 8  is an illustrative example showing how a fiber optic goniometer of the type shown in  FIG. 7  may be used to determine whether or not accessory  20  is being shared by multiple users. In the example of  FIG. 8 , light source  64  is located in common portion  26 C of cable  26  and emits light into fiber optic cable  68  in direction  74 . A light detector such as light detector  66  may be located in each earbud  28 . Light source  64  may emit light into a single optical fiber that splits into two fiber segments (e.g., with a first fiber segment associated with left branch  26 L and a second fiber segment associated with right branch  26 R) or, if desired, light source  64  may be optically coupled to two optical fibers  68  that are separate from each other. In either case, a set of wave-plates such as wave-plates  70  may be located at each bending location where the angle is to be measured. 
     In the example of  FIG. 8 , goniometer  72  is configured to measure the angle θ 4  between left branch  26 L and common portion  26 C of cable  26  and to measure the angle θ 5  between right branch  26 R and common portion  26 C of cable  26 . 
     Control circuitry  45  in accessory  20  or circuitry  32  in device  10  may compare θ 4  and/or θ 5  with a predetermined threshold. When one or both measured angles is above the predetermined threshold, device  10  can conclude that accessory  20  is not being shared by multiple users. When one or both measured angles is below the predetermined threshold, device  10  can conclude that accessory  20  is being shared by multiple users. 
     The configuration of  FIG. 8  in which light source  64  is located in common portion  26 C of cable  26  and in which light detectors  66  are located in both earbuds  28  is merely illustrative. If desired, goniometer  72  may have a configuration of the type shown in  FIG. 9 . In the example of  FIG. 9 , light source  64  is located in one of earbuds  28  and light detector  66  is located in the other of earbuds  28 . Fiber optic cable  68  may be coupled between light source  64  and light detector  66  such that cable  68  forms a V-shape with a bend at Y-junction  52  of cable  26 . 
     With this type of configuration, goniometer  72  may be configured to measure the angle θ 6  between left branch  26 L and right branch  26 R of cable  26 . When this angle is determined to be above a predetermined threshold, device  10  may conclude that accessory  20  is being shared by multiple users. 
     The example of  FIG. 9  in which light source  64  is located in left earbud  28 L and light detector  66  is located in right earbud  28 R is merely illustrative. If desired, light source  64  may be located in right earbud  28 R and light detector  66  may be located left earbud  28 L. 
     Another illustrative configuration in which a fiber optic goniometer is used to determine whether or not accessory  20  is being shared by multiple users is shown in  FIG. 10 . In the example of  FIG. 10 , light source  64  is located in controller unit  30  of accessory  20  (e.g., associated with left branch  26 L of cable  26 ) and light detector  66  is located in earbud  28  (e.g., in right earbud  28 R). Fiber optic cable  68  may be coupled between light source  64  and light detector  66  such that cable  68  forms a partial V-shape with a bend at Y-junction  52  of cable  26 . 
     Goniometer  72  of  FIG. 10  may be similar to that of  FIG. 9  in that it is configured to measure the angle θ 7  between left branch  26 L and right branch  26 R of cable  26 . When this angle is determined to be above a predetermined threshold, device  10  may conclude that accessory  20  is being shared by multiple users. 
     If desired, light source  64  may be located in electronic device  10 . An illustrative example in which light source  64  is located in device  10  is shown in  FIG. 11 . As shown in  FIG. 11 , a light source such as light source  64  may be located in connector  24  of device  10  and a light detector such as light detector  66  may be located in each earbud of accessory  20 . With this type of arrangement, connector  24  may be configured to support both optical as well as electrical connections with accessory  20 . Accessory  20  may include an optical coupling member such as optical coupling member  76  for coupling optical fiber  68  of goniometer  72  with light source  64  in connector  24  of device  10 . Light source  64  may emit light into a single optical fiber that splits into two fiber segments (e.g., with a first fiber segment associated with left branch  26 L and a second fiber segment associated with right branch  26 R) or, if desired, light source  64  may be optically coupled to two optical fibers  68  that are separate from each other. 
     Similar to the configuration of goniometer  72  of  FIG. 8 , goniometer  72  of  FIG. 11  may be configured to measure the angle θ 8  between left branch  26 L and common portion  26 C of cable  26  and to measure the angle θ 9  between right branch  26 R and common portion  26 C of cable  26 . 
     Control circuitry  45  in accessory  20  or circuitry  32  in device  10  may compare θ 8  and/or θ 9  with a predetermined threshold. When one or both measured angles is above the predetermined threshold, device  10  can conclude that accessory  20  is not being shared by multiple users. When one or both measured angles is below the predetermined threshold, device  10  can conclude that accessory  20  is being shared by multiple users. 
       FIG. 12  is a flow chart of illustrative steps involved in using system  8 . During the operations of step  80 , earbuds  28  may be located in the ears of a single user and device  10  may be operated normally (e.g., in single-user mode) while using sensor circuitry  44  to monitor for earbuds  28  being shared among multiple users. Circuitry  32  (and/or circuitry  45 , if desired) may be used in evaluating sensor data and taking appropriate action. Configurations in which control circuitry  32  is used in taking action based on sensor data are sometimes described herein as an example. 
     Examples of operations that may be performed by device  10  during step  80  include audio-based operations such as playing media content, providing a user with audio associated with a telephone call, providing audio associated with a video chat session to the user, or otherwise presenting audio content through earbuds  28 . Audio may be played in a stereophonic (stereo) sound scheme so that left and right earbuds receive corresponding left and right channels of audio, may be played using a multi-channel surround sound scheme, or may be played using a monophonic (mono) sound scheme in which both the left and right channels of audio are identical. 
     During the monitoring operation of step  80 , device  10  can use multi-user sensor structures  44  to determine whether or not accessory  20  is being shared among multiple users. For example, sensors  44  may determine whether or not one earbud  28  is in a first user&#39;s ear while the other earbud  28  is in a second user&#39;s ear. 
     If it is determined that multiple users are sharing accessory  20  (e.g., that one earbud is in a first user&#39;s ear and the other earbud is in a second user&#39;s ear), device  10  can take appropriate action at step  82 . For example, in response to determining that multiple user&#39;s are sharing accessory  20 , control circuitry  45  and/or  32  may automatically switch from single-user mode to multiple user mode. This may include switching the type of audio playback scheme that is being used from multichannel or stereo sound to mono sound. Because each user is only wearing one of the earbuds in his or her ear, the use of stereo playback scheme is no longer appropriate and could cause the user to miss information that is being sent to the channel associated with the absent earbud (e.g., the earbud being worn by the other user). 
     As another example, detection of multiple users sharing accessory  20  may indicate that different content is desired simultaneously. For example, two users may prefer to listen to different audio content at the same time using the same pair of headphones. Accordingly, in response to detection of multiple users using accessory  20 , device  10  may automatically provide two different types of audio content (e.g., a first type of audio content to left earbud  28 L and a second type of audio content to right earbud  28 R). Whether or not this type of action is taken in response to detection of multiple users may be based on user preferences (e.g., based on settings previously chosen by a user). If desired, the two different types of content provided to each earbud  28  may also be based on user preferences. Other actions may be taken in response to detection of multiple users using accessory  20 . These examples are merely illustrative. 
     Following the operations of step  82 , control circuitry  32  may, at step  84 , operate device  10  in a multiple-user mode. In particular, device  10  may operate in a mono audio mode and/or may operate in a mode in which different types of audio playback are provided to each speaker in earbuds  28  (as examples). While operating device  10  and accessory  20  in multiple-user mode, control circuitry  32  and/or  45  may use multi-user sensor structures  44  to monitor for changes in the status of accessory  20  (e.g., to monitor for changes in the angle between left and right branches of cable  26  or for changes in the angle between a left or right branch and the common portion of cable  26 ). 
     If, during the operations of step  84 , device  10  senses that both earbuds are located in the ears of a single user, appropriate action may be taken at step  86 . For example, device  10  may switch from multiple-user mode to single-user mode. This may include, for example, switching the audio mode from mono to stereo (or other multi-channel audio mode) and/or resuming the playback of one type of audio content. Operations may then proceed to step  80 , where device  10  may operate in a single-user mode while monitoring multi-user sensor structures  44  to determine whether or not multiple users are sharing accessory  20 . 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20121129
Publication Date: 20150602
Grant Date: 20150602
Priority Date: 20121129
Inventors: PUSKARICH PAUL G.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R5/033", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04S1/005", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2420/03", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2420/03", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04S1/005", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 50773332