PATENT DOCUMENT

Publication Number: US-9986353-B2
Application Number: US-201715449404-A
Country: US
Kind Code: B2

Title: Earphones with ear presence sensors

Abstract:
An electronic device may be coupled to an accessory such as a pair of earphones. The earphones may have ear presence sensor structures that determine whether or not the ears of a user are present in the vicinity of the earphones. The earphones may contain first and second speakers. When both the first and second speakers are located in the ears of the user, the electronic device may perform functions such as playing audio content. When one of the speakers has been removed from the ears of the user while the other of the speakers remains in the ears of the user, the electronic device can take actions such as pausing the playback of audio content, switching from stereo to monophonic playback, or stopping the playback of content. Suitable actions such as increasing audio drive strength may be taken when both speakers have been removed from the ears.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing configured to be placed in a user&#39;s ear; 
 a speaker mounted in the housing; 
 a touch sensor on the housing; 
 a microphone in the housing; and 
 a light-based sensor attached to the housing, wherein the light-based sensor comprises a light source and a light detector, wherein light emitted by the light source is reflected off of the user&#39;s ear and onto the light detector, and wherein audio playback through the speaker is paused in response to an amount of light that is reflected off of the user&#39;s ear and onto the light detector. 
 
     
     
       2. The electronic device defined in  claim 1 , further comprising:
 storage and processing circuitry that includes at least one integrated circuit in the housing. 
 
     
     
       3. The electronic device defined in  claim 1 , wherein the light-based sensor detects whether the user&#39;s ear is present adjacent to the housing by measuring the amount of the light that is reflected off of the user&#39;s ear and onto the light detector. 
     
     
       4. The electronic device defined in  claim 3 , wherein audio playback through the speaker is resumed in response to the light-based sensor detecting that the user&#39;s ear is present adjacent to the housing. 
     
     
       5. An earphone configured to receive input from a user, the earphone comprising:
 a housing; 
 a speaker in the housing; 
 storage and processing circuitry that includes at least one integrated circuit in the housing; 
 an input component in the housing that receives the input from the user and that adjusts audio playback through the speaker based on the input; 
 a microphone in the housing; 
 a light-based sensor in the housing, the light-based sensor comprising a light source that emits light onto the user and a light detector that receives at least a portion of the light that is reflected off of the user; and 
 a mechanical sensor in the housing, wherein audio playback through the speaker is adjusted based on sensor data from the mechanical sensor and the light that is reflected off of the user and received by the light detector. 
 
     
     
       6. The earphone defined in  claim 5 , wherein the input component is a touch sensor. 
     
     
       7. The earphone defined in  claim 5 , further comprising:
 an additional microphone in the housing, wherein at least one of the microphone and the additional microphone gathers voice input. 
 
     
     
       8. The earphone defined in  claim 5 , wherein the storage and processing circuitry pauses audio playback through the speaker in response to determining that the earphone is not in the ear of the user. 
     
     
       9. The earphone defined in  claim 5 , wherein the storage and processing circuitry initiates audio playback through the speaker in response to determining that the earphone is in the ear of the user. 
     
     
       10. Earphones comprising:
 a speaker; 
 storage and processing circuitry comprising at least one integrated circuit; 
 a touch sensor that receives user input, wherein the touch sensor is a capacitive touch sensor, and wherein the storage and processing circuitry adjusts audio playback through the speaker in response to the user input; 
 a light-based sensor comprising a light source that emits light onto a user&#39;s ear and a light detector that receives at least a portion of the light that is reflected off of the user&#39;s ear; and 
 a mechanical sensor, wherein audio playback through the speaker is adjusted based on sensor data from the mechanical sensor and the light that is reflected off of the user&#39;s ear and received by the light detector. 
 
     
     
       11. The earphones defined in  claim 10 , further comprising: a housing in which the speaker, the storage and processing circuitry, the touch sensor, the light-based sensor, and the mechanical sensor are mounted. 
     
     
       12. The earphones defined in  claim 11 , further comprising:
 first and second microphones mounted in the housing.

Description:
This application is a continuation of U.S. patent application Ser. No. 13/547,371, filed Jul. 12, 2012, which is hereby incorporated by reference herein in its entirety. This application claims the benefit of and claims priority to U.S. patent application Ser. No. 13/547,371, filed Jul. 12, 2012. 
    
    
     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. There can be difficulties associated with using earphones. For example, a user who is listening to audio content using earphones in both ears may occasionally need to remove one or both of the earphones. When doing so, the user may miss content that is being played. For example, if a user needs to momentarily remove earphones to talk to someone, the user may not be able to manually stop content playback before removing the earphones, causing some of the content to be played back without the user&#39;s full attention. 
     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 ear presence sensor structures that determine whether or not the ears of a user are present in the vicinity of the earphones. 
     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 the user, the electronic device may perform functions such as playing audio content. The audio content may be played in stereo using an audio signal strength appropriate for use when the speakers are located in the vicinity of the ears of the user. 
     When one of the speakers has been removed from the ears of the user while the other of the speakers remains in the ears of the user, the electronic device can take actions such as pausing the playback of audio content, switching from stereo to monophonic playback, or stopping the playback of content. 
     Suitable actions such as increasing audio signal strength may be taken when both speakers have been removed from the ears of the user. 
     Ear presence sensor structures may be formed from electrode structures. The electrode structures may be used to measure electrical resistance or capacitance. The electrode structures may be formed from a conductive mesh through which audio may pass. 
     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 in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of an illustrative earphone housing in an accessory in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an illustrative earphone housing that has an ear presence sensor such as a switch in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an earphone housing of the type that may be provided with sensor structures for detecting the presence of an ear or other external object in accordance with an embodiment of the present invention. 
         FIG. 6  is a flow chart of illustrative steps involved in using an accessory and electronic device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic device accessories may be provided with the ability to sense the presence of external objects. For example, an earphone accessory may be provided with sensing structures that can determine whether or not the earphones (i.e., the earphone speakers) are located in the ears of a user. 
       FIG. 1  is a diagram of a system of the type that may be provided with an accessory having sensing structures for detecting the presence of external objects such as the ears of a user. 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  10  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  10  may be implemented using any suitable electronic equipment. 
     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 . Earphone units  28  (which may sometimes be referred to as speakers or earphone housings) may include sensor structures for determining when earphone units  28  have been placed within the ears of a user. 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 earbuds  28 . Electronic device  10  may regulate the volume of sound produced by earbuds  28  by controlling the audio signal strength used in driving the speakers in earbuds  28 . 
     Sensor signals from sensor structures in earbuds  28  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 one or both of earphones  28  is in use in a user&#39;s ears. 
     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 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 the earbuds in which speaker drivers  40  have been mounted are located in the ears of a user, accessory  20  may be provided with ear presence sensor structures  44 . Ear presence sensor structures  44  may be configured to detect whether or not the earbuds (or other earphone units of accessory  20 ) have been placed in the ears of a user. Ear presence sensors may be formed from force sensors, from switches or other mechanical sensors, from capacitive sensors, from resistance-based sensors, from light-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 ear presence sensor structures  44  in determining which actions should be automatically taken by device  10 . 
     An illustrative earbud with an ear presence sensor is shown in  FIG. 3 . In the example of  FIG. 3 , earbud  28  has a housing such as housing  46  in which one or more speaker drivers such as speakers  40  of  FIG. 2  are mounted. If desired, an auxiliary speaker such as speaker  52  may be mounted on the outside of housing  46  (e.g., to serve as a supplemental speaker for producing loud sounds when earbud  28  is not in the ear of a user). The supplemental speaker can be used to play back the same audio channel that is being played back by speakers  40  or may be used to support a multi-channel audio mode. For example, speakers  40  may be used to play bass and mid-range channel information (e.g., audio in a first frequency range), whereas supplemental speakers  52  may be used to play tweeter information (e.g., audio in a second frequency range that is higher than the first frequency range). As another example, speakers  40  may play right and left stereo information (and center channel information) and supplemental speakers  52  may play surround channel information. 
     Conductive structures such as conductive mesh structures  48  and  50  may be mounted in housing  46 . As shown in  FIG. 3 , for example, mesh structures  48  and  50  may be mounted in the front of housing  46  so that sound from the speakers inside earbud housing  46  may pass through the holes of the mesh. If desired, earbud  28  may contain microphone structures (e.g., when implementing noise cancellation features in earbud  28 ). The use of mesh when forming electrode structures  48  and  50  may allow ambient sound to be picked up by the noise cancellation microphones in housing  46 . 
     Mesh electrodes  48  and  50  (e.g., metal screen structures) or other conductive structures in earbud  28  may be used as first and second terminals in a resistive (resistance-based) sensor. Control circuitry in housing  46  may be used to apply a voltage across the first and second terminals while measuring how much current flows as a result. The control circuitry may use information on the voltage and current signals that are established between electrodes  48  and  50  to determine whether or not earbud  28  has been placed in the ear of a user. In the absence of the user&#39;s ear, the resistance between electrodes  48  and  50  will be relatively high. When, however, earbud  28  has been placed into a user&#39;s ear, contact between electrodes  48  and  50  and the flesh of the ear will give rise to a lower resistance path between electrodes  48  and  50 . To determine whether or not earbud  28  has been placed within the user&#39;s ear, the control circuitry of earbud  28  (and/or control circuitry  32  of  FIG. 2 ) may measure the resistance between electrodes  48  and  50  and may compare the measured resistance to a predetermined threshold. When the measured resistance is below the predetermined threshold, device  10  can conclude that earbud  28  has been placed in the ear of the user. When the measured resistance exceeds the predetermined threshold, device  10  can conclude that earbud  28  is out of the ear. 
     In addition to or instead of using mesh  48  and  50  to measure the resistance of the user&#39;s ear, mesh electrodes  48  and  50  may be used as capacitive sensor electrodes (e.g., to make mutual capacitance measurements or to make self capacitance measurements). Different capacitance values may be detected in the presence and absence of the user&#39;s ear in the vicinity of electrodes  48  and  50 . This allows device  10  to use the capacitance measurements to determine whether or not earbud  28  is in or out of the user&#39;s ear. 
     If desired, earbud  28  may be provided with a switch-based ear presence detector. As shown in  FIG. 4 , for example, switch  54  may be mounted on an exterior surface of earbud housing  46 . Speaker mesh  58  may be mounted on the front of housing  46 . Speaker drivers may be mounted within the interior of housing  46 . During operation of earbud  28 , sound may pass through openings in speaker mesh  58 . Switch  54  may move up and down in directions  56 . When earbud  28  is inserted in an ear of a user, switch  54  may be compressed inward. When earbud  28  is out of the user&#39;s ear, switch  54  may move outwards to regain its original uncompressed state. Device  10  may use information from switch structures such as switch  54  to determine whether or not earbud  28  has been placed in the ear of a user. 
     A cross-sectional side view of an illustrative earbud with a speaker driver and an associated ear presence sensor is shown in  FIG. 5 . As shown in  FIG. 5 , earbud  28  may have a housing such as housing  46 . Speaker  40  may be mounted within housing  46  overlapping an acoustic grill formed from structures such as mesh  48  and  50  or other acoustic mesh. During operation, sound  82  may pass through the acoustic mesh. For example, speaker  40  may produce sound that is received by a user&#39;s ear or other external object  60 . 
     When external object  60  is sufficiently close to earbud  28 , the presence of external object  60  may be detected. For example, control circuitry  45  may measure the resistance between mesh electrodes  48  and  50  using conductive paths  62  or may use capacitance measurements in monitoring for the presence of object  60 . The measured resistance (or capacitance) may then be used to determine whether earbud  28  is in the user&#39;s ear or is out of the user&#39;s ear. Control circuitry  45  may also use sensors such as sensor  44  of  FIG. 5  to monitor for the presence or absence of external objects such as the user&#39;s ear. As shown in  FIG. 5 , sensor  44  may have a transmitter such as transmitter  44 T and may have a receiver such as receiver  44 R. During operation of sensor  44 , sensor  44  may transmit signals such as signal  64  and may gather reflected signals such as signal  66 . The strength of received signal  66  may be used to measure whether or not external object  60  is in the presence of earbud  28 . 
     Sensor  44  may be a light-based sensor. For example, transmitter  44 T may be a light-emitting diode or laser that emits light  64  (e.g., infrared light, visible light, etc.) and receiver  44 R may be a light detector (e.g., a photodiode or phototransistor) that measures the amount of light  64  that is reflected as reflected light  66  from external object  60 . When the amount of light that is reflected from external object  60  is high, device  10  can conclude that earbud  28  is in the user&#39;s ear. When the amount of light that is reflected from external object  60  is low, device  10  can conclude that earbud  28  is out of the user&#39;s ear. 
     If desired, sensor  44  may be a sensor that emits and receives acoustic signals. For example, transmitter  44 T may be an ultrasonic signal transducer that transmits ultrasonic signals  64 . Receiver  44 R may be an ultrasonic signal receiver that measures the amount of corresponding ultrasonic signal  66  that is reflected from external object  60 . When the amount of ultrasonic signal that is reflected from external object  60  is low, device  10  can conclude that earbud  28  is not in the user&#39;s ear. When the amount of ultrasonic signal that is reflected from external object  60  is high, device  10  can conclude that earbud  28  is currently in the user&#39;s ear. 
     In force-based sensor schemes, the resistance of a compressible foam may be measured or a strain gauge output can be monitored. When force is present, electronic device  10  can conclude that earbud  28  has been inserted into a user&#39;s ear, whereas when force is not present, electronic device  10  can conclude that earbud  28  has remained outside of the user&#39;s ear. Force indicative of a user&#39;s ear pressing against earbud  28  may also be monitored using piezo-electric force sensors or other force sensors. 
       FIG. 6  is a flow chart of illustrative steps involved in using system  8 . During the operations of step  70 , earbuds  28  may be located in the ears of a user and device  10  may be operated normally while using sensor circuitry  44  to monitor for the presence or absence of each earbud  28  of accessory  20  within the ears of a user. 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  70  include audio-based operations such as playing media content using an audio signal strength that results in a playback volume that is appropriate for listening through earbuds  28 , 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 stereo 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  70 , device  10  can use ear presence detectors  44  to determine whether or not earbuds  28  remain within the user&#39;s ears. If it is determined that one of the earbuds has been removed so that only a single earbud remains in the ear of a user, device  10  can take appropriate action at step  72 . For example, in response to determining that only one earbud remains in the user&#39;s ear, control circuitry  45  and/or  32  may automatically switch the type audio playback scheme that is being used from multichannel or stereo sound to mono sound. Because only one earbud is being actively used, the use of a stereo playback scheme no longer is appropriate and could cause the user to miss information that is being sent to the channel associated with the absent earbud. As another example, if device  10  was playing music files, was playing video that includes audio, or was playing other audio content to the user, detection of removal of one earbud from the user&#39;s ear may indicate that the user has removed the earbud to allow the user to be able to better hear sounds in the user&#39;s environment (e.g., to converse with someone). Accordingly, in response to detection of removal of one of the earbuds from the user&#39;s ear, device  10  may automatically pause audio playback. Playback may also be completely stopped by device (e.g., by control circuitry  32 ) in response to detection of earbud removal (i.e., device  10  may perform the same type of stopping operation that would be performed in response to user selection of an on-screen stop option or user actuation of a stop button). Other actions may be taken in response to detection of removal of one earbud from the user&#39;s ear, if desired. These examples are merely illustrative. 
     Following the operations of step  72 , control circuitry  30  may, at step  74  operate device  10  in a one-earbud-in mode while using ear presence detectors to monitor the state of each earbud. In particular, device  10  may operate in a mono audio mode or may operate in a mode in which audio playback has been paused or stopped (as examples). While operating device  10  in a one-earbud-in mode, control circuitry  32  and/or  45  may use ear presence sensor structures  44  to monitor for changes in the status of earbuds  28 . If, during the operations of step  74 , device  10  senses that the removed earbud has been returned to the user&#39;s ear so that both earbuds are inserted in the user&#39;s ears, appropriate action may be taken at step  76 . For example, device  10  may switch the audio mode from mono to stereo (or other multi-channel audio mode), device  10  may resume the playback of paused or stopped audio content, etc. Operations may then proceed to step  70 , where device  10  may operate in a two-earbud-in mode while monitoring ear presence sensor structures  44  to determine whether one or both earbuds have been removed from the user&#39;s ears. 
     If, during the operations of step  70 , it is determined that both the left and right earbuds have been removed from the user&#39;s ears, device  10  may take suitable action at step  80 . For example, in response to detecting that both earbuds are out of the user&#39;s ears, device  10  may conclude that the user is interested in using earbuds  28  as desk-top speakers. Because ear presence sensor structures  44  have confirmed that neither earbud is in the user&#39;s ear, device  10  can safely increase playback volume (i.e., audio signal drive strength) through the speakers to a loud level (e.g., a level that is in excess of a comfortable listening level for use when earbuds  28  are in the user&#39;s ears and that is sufficient to allow earbuds  28  to be used as regular non-earbud out-of-ear speakers). Both earbuds are in the same out-of-ear state, so audio may be played in stereo or other multi-channel formats may be used. As another example, device  10  can conclude that the user has removed earbuds  28  from the user&#39;s ear because the user temporarily is interested to listening to sounds in the user&#39;s surroundings and not the media that is being played through the earbuds. Device  10  can therefore pause or stop media playback. 
     After taking suitable actions at step  80 , device  10  can be operated in a two-earbuds-out mode (step  78 ). For example, device  10  may use earbuds  28  as desktop speakers by playing music through earbuds  28  at a volume (audio signal drive strength) sufficient to be listened to comfortably by the user and potentially other listeners in the vicinity of earbuds  28  (i.e., at a normal music playback volume). If desired, an auxiliary speaker such as speaker  52  of  FIG. 3  may be used as a supplemental speaker during audio playback in the two-earbuds-out mode. Supplemental speakers  52  may be used in playing multi-channel audio or may be used in playing high frequency audio or audio in another frequency range. As another example, device  10  may operate with paused or stopped audio playback during step  78 . 
     During the operations of step  78 , ear presence sensor structures  44  may be used to monitor for the presence of earbuds  28  in the ears of the user. If it is determined that one of the earbuds has been placed in the ear of the user, appropriate actions may be taken at step  72 . For example, if device  10  was using earbuds  28  as desktop speakers by playing stereo audio loudly through earbuds  28  using a relatively high audio signal drive strength, device  10  may reduce the audio signal drive strength to a low level so that playback volume is reduced to a volume level that is acceptable for use of an earbud in the user&#39;s ear. Device  10  may also switch to a mono playback mode. If, during the operations of step  78 , ear presence sensor structures  44  determine that both earbuds have been placed in the user&#39;s ears, appropriate action may be taken at step  76 . For example, if device  10  was using earbuds  28  as desktop speakers, device  10  may reduce audio signal strength and therefore playback volume sufficiently to allow earbuds  28  to be safely used in the user&#39;s ears. 
     During the operations of step  74 , sensor structures  44  may detect that both earbuds have been removed from the user&#39;s ears. In this situation, device  10  may take appropriate action at step  80 . For example, device  10  may conclude that earbuds  28  are both not in the user&#39;s ears so that earbuds  28  may be safely used as desktop speakers. Playback volume may therefore be increased. 
     If desired, different audio amplifiers may be used for playback during earbud-in modes and earbud-out modes. For example, a low power audio amplifier that uses a low audio signal strength may be used to play audio through earbuds  28  when earbuds  28  are in the ears of the user and a high power audio amplifier that uses a high audio signal strength may be used by device  10  to play audio through earbuds  28  when earbuds  28  are both out of the user&#39;s ears. 
     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: 20170303
Publication Date: 20180529
Grant Date: 20180529
Priority Date: 20120712
Inventors: PUSKARICH, PAUL G.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R29/001", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R5/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2430/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2430/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/04", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R5/033", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R29/001", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R3/007", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R3/007", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 49914014