PATENT DOCUMENT

Publication Number: US-11115746-B1
Application Number: US-202017032602-A
Country: US
Kind Code: B1

Title: Dynamic latching of hinged devices

Abstract:
A charging case for a pair of earbuds that comprises: a body having one or more cavities configured to receive the pair of earbuds; a lid attached to the body and operable between a closed position where the lid is aligned over the one or more cavities covering the pair earbuds and an open position that allows a user to remove the pair of earbuds from the body; one or more sensors that generates sensor data; a controller coupled to receive the sensor data from the sensor and operable to detect when the charging case is in freefall and/or suffers an impact event based, at least in part, on the sensor data and generate a trigger signal in response to detecting the impact event; and an earbud protection mechanism responsive to the trigger signal and operable to retain the pair of earbuds within the charging case.

Claims:
What is claimed is: 
     
       1. A charging case for a portable listening device, the charging case comprising:
 a body defining a recess for storing the portable listening device; 
 a lid operably coupled to the body and operable between a closed position where the lid is aligned over the recess covering the portable listening device and an open position that allows a user to remove the portable listening device from the body; 
 one or more sensors that generate sensor data; 
 a controller coupled to receive the sensor data from the one or more sensors, the controller operable to: (i) detect an event that can lead to the portable listening device being dislodged from the charging case, and (ii) generate a trigger signal in response to detecting the event; and 
 a portable listening device protection mechanism responsive to the trigger signal and operable to retain the portable listening device within the charging case. 
 
     
     
       2. The charging case set forth in  claim 1  wherein the controller is operable to detect when the charging case is in freefall. 
     
     
       3. The charging case set forth in  claim 2  wherein the trigger signal activates the portable listening device protection mechanism and the portable listening device protection mechanism remains activated until the controller detects that a drop event that caused the freefall is over. 
     
     
       4. The charging case set forth in  claim 1  wherein the controller is operable to detect when the charging case is subjected to an impact event. 
     
     
       5. The charging case set forth in  claim 4  wherein the trigger signal momentarily activates the portable listening device protection mechanism for a predetermined time period. 
     
     
       6. The charging case set forth in  claim 1  wherein the portable listening device protection mechanism is operable to lock the lid to the body during the event. 
     
     
       7. The charging case set forth in  claim 1  wherein the portable listening device protection mechanism is operable to impart a force on the portable listening device to secure the portable listening device within the recess during the event. 
     
     
       8. The charging case set forth in  claim 1  wherein the portable listening device comprises a pair of earbuds and the recess includes a first pocket sized and shaped to accept a left earbud in the pair of earbuds and a second pocket sized and shaped to accept a right earbud in the pair of earbuds. 
     
     
       9. The charging case set forth in  claim 1  wherein the portable listening device protection mechanism comprises one or more of an electromagnet, an electropermanent magnet, a mechanical latch or a locking hinge. 
     
     
       10. A charging case for a pair of earbuds, the charging case comprising:
 a body having one or more pockets configured to receive the pair of earbuds; 
 a lid attached to the body and operable between a closed position where the lid is aligned over the one or more pockets covering the pair earbuds and an open position that allows a user to remove the pair of earbuds from the body; 
 a motion sensor that generates motion sensor data; 
 a controller coupled to receive the sensor data from the motion sensor, the controller operable to detect when the charging case is in freefall based, at least in part, on the motion sensor data and generate a trigger signal in response to detecting the charging case is in freefall; and 
 an earbud protection mechanism responsive to the trigger signal and operable to retain the pair of earbuds within the charging case. 
 
     
     
       11. The charging case set forth in  claim 10  wherein the earbud protection mechanism is a dynamic lid retention mechanism configured to lock the lid to the body during the freefall event. 
     
     
       12. The charging case set forth in  claim 11  wherein the dynamic lid retention mechanism comprises a mechanical latch. 
     
     
       13. The charging case set forth in  claim 11  wherein the dynamic lid retention mechanism comprises a locking hinge. 
     
     
       14. The charging case set forth in  claim 10  wherein the earbud protection mechanism is a dynamic earbud retention mechanism configured to impart a force on each of the earbuds in the pair of earbuds to secure the earbuds within the cavity during the freefall event. 
     
     
       15. The charging case set forth in  claim 14  wherein the dynamic earbud retention mechanism comprises a spring-activated mechanical component. 
     
     
       16. A charging case for a pair of earbuds, the charging case comprising:
 a body having one or more cavities configured to receive the pair of earbuds; 
 a lid attached to the body and operable between a closed position where the lid is aligned over the one or more cavities covering the pair earbuds and an open position that allows a user to remove the pair of earbuds from the body; 
 a sensor that generates sensor data; 
 a controller coupled to receive the sensor data from the sensor and operable to detect when the charging case suffers an impact event based, at least in part, on the sensor data and generate a trigger signal in response to detecting the impact event; 
 an earbud protection mechanism responsive to the trigger signal and operable to retain the pair of earbuds within the charging case. 
 
     
     
       17. The charging case set forth in  claim 16  wherein the earbud protection mechanism is a dynamic lid retention mechanism configured to lock the lid in response to the trigger signal. 
     
     
       18. The charging case set forth in  claim 17  wherein the dynamic lid retention mechanism comprises an electromagnet. 
     
     
       19. The charging case set forth in  claim 16  wherein the earbud protection mechanism is a dynamic earbud retention mechanism configured to impart a force on each earbud in the pair of earbuds in response to the trigger signal to secure the earbuds within the cavity during the impact event. 
     
     
       20. The charging case set forth in  claim 19  wherein the dynamic earbud retention mechanism comprises an electromagnet.

Description:
BACKGROUND 
     The described embodiments relate generally to portable listening devices, such as earbuds and other types of in-ear listening devices, and to cases for storing and charging such devices. 
     Earbuds and other portable listening devices can be used with a wide variety of electronic devices such as portable media players, smart phones, tablet computers, laptop computers and stereo systems among others. Many currently available earbuds and portable listening devices are wireless devices that do not include a cable and instead, wirelessly receive a stream of audio data from a wireless audio source. 
     While wireless portable listening devices have many advantages over wired devices, they also have some potential drawbacks. For example, wireless earbuds typically require a battery, such as a rechargeable battery, that provides power to the wireless communication circuitry and other components of the earbuds. For many currently available wireless earbuds, charge can be restored to the rechargeable battery of the earbuds by placing the earbuds in a charging case that is specifically designed to both store and charge the earbuds. 
     The charging case typically includes a lid that can be opened and closed to reveal an interior cavity that has a preformed shape specifically designed to match the contours of the earbuds. The lid can be held shut by a magnet, a latch or a similar mechanism and a user can place the earbuds in the case and remove the earbuds from the case by opening the lid. For an ideal user-experience, the lid should open easily with a relatively light touch when needed but otherwise stay closed, including when the charging case is mishandled. Typical charging cases include a lid retention mechanism, such as a magnet or spring detent, that preloads a predetermined force selected to balance these two competing criteria. 
     Sharp impact events, however, such as if the case is accidentally dropped onto a hard surface, can overwhelm the preloaded force causing the lid to open. Such events can also result in the earbuds being dislodged from the charging case. 
     BRIEF SUMMARY 
     Various embodiments disclosed herein pertain to a charging case for wireless earbuds or other portable listening devices that can detect drop events and/or impact events that can potentially result in the earbuds or other portable listening device from being dislodged from the charging case. Charging cases according to some embodiments can include sensors that can collect motion data (e.g., detect and measure acceleration and/or rotation of the charging case) and/or other data and use the collected data to detect when the charging case is in freefall state that can be indicative of a drop event. Once a drop event is detected or predicted, the charging case can activate an earbud protection mechanism to keep the case lid closed or the earbuds secured within the charging case until after the drop event is over. In various embodiments the earbud protection mechanism can be one or more of: an electromagnetic magnetic lid retention mechanism, an electromechanical latch or similar mechanical lid retention mechanism, an electronically controlled hinge that increases friction at the hinge to keep the lid closed, and/or a mechanism that physically holds the earbuds within the charging case. 
     In some embodiments, the earbud protection mechanism of the charging case can be a dynamic lid locking mechanism that can be activated during a drop event, or in response to an impact event, to lock (or otherwise increase the retention force on) the lid in the closed position thus preventing the lid from opening and thus preventing the earbuds or other portable listening device from being dislodged from the charging case. The dynamic lid retention mechanism can then release the lock (or release the increased retention force) after the drop event has occurred or is no longer predicted. 
     In some embodiments, the earbud protection mechanism of the charging case can include a dynamic earbud retention mechanism that can be activated during a drop event or in response to an impact event to retain the earbuds within the charging case even if the drop or impact event causes the lid to open. The earbud retention mechanism can then be deactivated after the drop event has occurred or is no longer predicted so that a user can remove the earbuds from the charging case when desired. 
     A charging case for a portable listening device in accordance with some embodiments includes: a body defining a recess for storing the portable listening device; a lid operably coupled to the body and operable between a closed position where the lid is aligned over the recess covering the portable listening device and an open position that allows a user to remove the portable listening device from the body; one or more sensors that generate sensor data; a controller coupled to receive the sensor data from the one or more sensors, the controller operable to: (i) detect an event that can lead to the portable listening device being dislodged from the charging case, and (ii) generate a trigger signal in response to detecting the event; and a portable listening device protection mechanism responsive to the trigger signal and operable to retain the portable listening device within the charging case. 
     In various implementations, the charging case can further include one or more of the following features. The controller can be operable to detect when the charging case is in freefall and the trigger signal can activate the portable listening device protection mechanism and the portable listening device protection mechanism can remain activated until the controller detects that a drop event that caused the freefall is over. The controller can be operable to detect when the charging case is subjected to an impact event and the trigger signal can momentarily activate the portable listening device protection mechanism for a predetermined time period. The portable listening device protection mechanism can be operable to lock the lid to the body during the event. The portable listening device protection mechanism can be operable to impart a force on the portable listening device to secure the portable listening device within the recess during the event. The portable listening device can be a pair of earbuds and the charging case recess can include a first pocket sized and shaped to accept a left earbud in the pair of earbuds and a second pocket sized and shaped to accept a right earbud in the pair of earbuds. The portable listening device protection mechanism can be one or more of an electromagnet, an electropermanent magnet, a mechanical latch or a locking hinge. 
     In some embodiments a charging case for a pair of earbuds is provided. The charging case can include: a body having one or more pockets configured to receive the pair of earbuds; a lid attached to the body and operable between a closed position where the lid is aligned over the one or more pockets covering the pair earbuds and an open position that allows a user to remove the pair of earbuds from the body; a motion sensor that generates motion sensor data; a controller coupled to receive the sensor data from the motion sensor, the controller operable to detect when the charging case is in freefall based, at least in part, on the motion sensor data and generate a trigger signal in response to detecting the charging case is in freefall; and an earbud protection mechanism responsive to the trigger signal and operable to retain the pair of earbuds within the charging case. 
     The earbud protection mechanism can be a dynamic lid retention mechanism configured to lock the lid to the body during the freefall event and, in some instances, the dynamic lid retention mechanism can be a mechanical latch or a locking hinge. The earbud protection mechanism can be a dynamic earbud retention mechanism configured to impart a force on each of the earbuds in the pair of earbuds to secure the earbuds within the cavity during the freefall event and, in some instances, the dynamic earbud retention mechanism can be a spring-activated mechanical component. 
     In still additional embodiments a charging case for a pair of earbuds can include: a body having one or more cavities configured to receive the pair of earbuds; a lid attached to the body and operable between a closed position where the lid is aligned over the one or more cavities covering the pair earbuds and an open position that allows a user to remove the pair of earbuds from the body; and a sensor that generates sensor data; a controller coupled to receive the sensor data from the sensor and operable to detect when the charging case suffers an impact event based, at least in part, on the sensor data and generate a trigger signal in response to detecting the impact event; an earbud protection mechanism responsive to the trigger signal and operable to retain the pair of earbuds within the charging case. 
     The earbud protection mechanism can be a dynamic lid retention mechanism configured to lock the lid in response to the trigger signal and, in some instances, the dynamic lid retention mechanism can be an electromagnet. The earbud protection mechanism can be a dynamic earbud retention mechanism configured to impart a force on each earbud in the pair of earbuds in response to the trigger signal to secure the earbuds within the cavity during the impact event and, in some instances, the dynamic earbud retention mechanism can include an electromagnet. 
     To better understand the nature and advantages of the present invention, reference should be made to the following description and the accompanying figures. It is to be understood, however, that each of the figures is provided for the purpose of illustration only and is not intended as a definition of the limits of the scope of the present invention. Also, as a general rule, and unless it is evident to the contrary from the description, where elements in different figures use identical reference numbers, the elements are generally either identical or at least similar in function or purpose. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified cross-sectional view of an earbud case with its lid closed according to some embodiments of the disclosure; 
         FIG. 2  is a simplified perspective view of the earbud case shown in  FIG. 1  with its lid open; 
         FIG. 3  is simplified block diagram of certain components within a portable wireless listening device system according to some embodiments; 
         FIG. 4A  is a graphs illustrating a typical drop event that can result in one or more earbuds of a charging case being dislodged from the case; 
         FIG. 4B  is a graph showing the velocity of a charging case as it undergoes the drop event depicted in  FIG. 4A ; 
         FIG. 4C  is a graph depicting acceleration forces, as measured by an accelerometer, that a charging case might be subject to during the drop event depicted in  FIG. 4A ; 
         FIG. 5  is a flowchart depicting a method of protecting earbuds during a drop event according to some embodiments of the disclosure; 
         FIG. 6  is a flowchart depicting another method of protecting earbuds during a drop event according to some embodiments of the disclosure; 
         FIG. 7A  illustrates an activation period of an earbud protection mechanism during an example drop event according to some embodiments; 
         FIG. 7B  illustrates multiple momentary activation periods of an earbud protection mechanism during an example drop event according to some embodiments; 
         FIG. 8A  is a simplified cross-sectional view of a charging case with its lid closed that includes an electromagnetic retention mechanism in accordance with some embodiments; 
         FIG. 8B  is a simplified perspective view of a portion of the charging case shown in  FIG. 8A  with its lid open; 
         FIG. 9A  is a simplified cross-sectional view of a charging case with its lid closed that includes a dynamic latch lid retention mechanism in accordance with some embodiments; 
         FIG. 9B  is a simplified perspective view of a portion of the charging case shown in  FIG. 9A  with its lid open; 
         FIG. 9C  is a simplified illustration of a latching mechanism according to some embodiments that can dynamically lock the lid of an earbud charging case; 
         FIG. 10A  is a simplified cross-sectional view of a charging case that includes a locking hinge according to some embodiments along with an exploded view of the locking hinge when the lid of the charging case is in a closed position; 
         FIG. 10B  is a expanded view of the locking hinge of the charging case shown in  FIG. 10A  with the lid between open and closed positions; 
         FIG. 10C  is a expanded view of the locking hinge of the charging case shown in  FIG. 10A  with the lid in the open position; 
         FIG. 10D  is a simplified perspective view of a portion of the charging case shown in  FIG. 10A  with its lid open; 
         FIG. 11  is a simplified cross-sectional view of a charging case according to some embodiments; 
         FIG. 12A  is a simplified cross-sectional view of a charging case that includes a dynamic earbud retention mechanism according to some additional embodiments; and 
         FIG. 12B  is a simplified cross-sectional view of the charging case shown in  FIG. 12A  with the earbud retention mechanism activated. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described in detail with reference to certain embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known details have not been described in detail in order not to unnecessarily obscure the present invention. 
     Embodiments disclosed herein pertain to a charging case for wireless earbuds or other portable listening devices that can detect drop events and/or impact events that can potentially result in the earbuds or other portable listening device from being dislodged from the charging case. In order to simplify the description of various embodiments discussed herein, the discussion below repeatedly refers to a charging case for a “pair of earbuds” or a “pair of wireless earbuds”. It is to be understood, however, that reference to a charging case for a pair of earbuds is simply a shorthand description for a storage or charging case for any relatively small portable wireless listening device including hearing aids or headphones. Additionally, embodiments of the disclosure can also be incorporated into storage cases for other small electronic devices or even mechanical devices that include a lid and, if dropped, might result in the lid opening and the device stored therein being dislodged from the storage case. 
     Charging cases according to some embodiments can include one or more sensors that can collect motion data (e.g., detect and measure acceleration and/or rotation of the charging case) and/or other data concerning the physical environment that the charging case is within and/or properties of the charging case relative to that environment. The collected data can be fed to a controller or other type of processor within the charging case to detect when the charging case is in freefall state that can be indicative of a drop event. Once a drop event is detected or predicted (or upon the detection of a hard impact event), the charging case can activate an earbud protection mechanism to keep the case lid closed or to physically secure the earbuds within the charging case until after the drop event is over. 
     In some embodiments, the earbud protection mechanism of the charging case can be a dynamic lid locking mechanism that can be activated during a drop event to lock (or otherwise increase the retention force on) the lid in the closed position thus preventing the lid from opening and thus preventing the earbuds or other portable listening device from being dislodged from the charging case. The dynamic lid retention mechanism can then release the lock (or release the increased retention force) after the drop event has occurred or is no longer predicted. In other embodiments the earbud protection mechanism of the charging case can be a dynamic lid locking mechanism that can be momentarily activated upon detecting a hard impact event to immediately lock (or otherwise increase the retention force on) the lid in the closed position at the time of impact thus preventing the lid from opening and thus preventing the earbuds or other portable listening device from being dislodged from the charging case. The lid locking mechanism can be activated in such embodiments for a brief moment and then reactivated as necessary if the drop event results in additional hard impact events. 
     In some embodiments, the earbud protection mechanism of the charging case can include a dynamic earbud retention mechanism that can be activated during a drop event or in response to an impact event to retain the earbuds within the charging case even if the drop or impact event results in the lid opening. The earbud retention mechanism can physically hold the earbuds within the charging case, for example physically hold each earbud in a pair of earbuds within a pocket of the charging case specifically designed to store the particular earbud, and then be deactivated after the drop event has occurred or is no longer predicted so that a user can remove the earbuds from the charging case when desired. 
     Example Charging Case 
     In order to better appreciate and understand the present invention, reference is first made to  FIGS. 1 and 2 , which depict an example charging case  100 . It is to be understood that the description of charging case  100  in  FIGS. 1 and 2  is provided for illustrative purposes only and that while charging case  100  represents a specific example of an earbud charging case and a pair of earbuds according to some embodiments, embodiments of the invention are not limited to the specific features of charging case  100  or the particular earbuds stored therein as discussed below. 
       FIG. 1  is a simplified cross-sectional view of an earbud charging case  100  with a lid  110  closed over a case body  120  according to some embodiments, and  FIG. 2  is a simplified see-through perspective view of earbud case  100  with lid  110  in an open position. As shown in  FIGS. 1 and 2 , earbud case  100  includes a case body  120  and a lid  110  that can be pivotally coupled to body  120  by a hinge  115 . Body  120  can include interior space in which a pair of earbuds  140 ,  160  can be stored. 
     The interior space of body  120  can define first and second pockets or cavities  132 ,  134  (shown in  FIG. 1 ) sized and shaped to accept earbuds  140 ,  160 , respectively. In some embodiments, an insert  122  can bonded to and considered a portion of body  120  to form cavities  132 ,  134 . Each of the cavities  132 ,  134  can then be defined by a surface of the insert  122  that conforms to the general shape of the earbuds  140 ,  160 . For example, insert  122  can define a top surface of body  120  that includes two separate upper contoured recesses each of which is sized and shaped to accept a speaker housing portion of one of the left and right earbuds in the pair of earbuds  140 ,  160 . Insert  122  can further define first and second interior tubular sections, one for each of the left and right earbuds, that extend from the two upper contoured recesses and accept the stems  142 ,  162  of the left and right earbuds, respectively. 
     In some embodiments, charging case  100  can further include one or more magnets strategically positioned within the charging case to cooperate with a magnet or magnetic element (e.g., a metal plate) in each earbud such that the earbuds are magnetically held within their respective pockets or cavities. The one or more magnets in the charging case can be selected to impart a sufficient force to secure the earbuds in the case during normal use while still allowing a user to readily remove the earbuds from the case when desired. In balancing these two competing goals, the magnets that secure the earbuds  140 ,  160  in the case may not be sufficiently strong to ensure that the earbuds are not dislodged from the case in a drop event. 
     Lid  110  can be coupled to body  120  by a hinge  115  or similar mechanism that enables the lid to be moved between a closed position in which the lid covers the interior space of case  100  including cavities  132 ,  134  and an open position (illustrated in  FIG. 2 ) in which the cavities are exposed to allow a user to place the earbuds  140 ,  160  within case  100  or remove the earbuds  140 ,  160  from the case. While not shown in  FIG. 1 or 2 , earbud case  100  can also include a battery, charging circuitry to charge the battery and/or charge earbuds  140 ,  160  stored within the case (e.g., with wired contacts and/or wirelessly), a controller, one or more user input devices, and other circuitry and components, some of which are discussed with respect to  FIG. 3  below. 
     In some embodiments, each of the earbud body  120 , lid  110  and insert  122  can be made from a plastic or similar material such as ABS or polycarbonate. Similarly, each earbud  140 ,  160  can include an earbud housing that defines the size and shape of the earbud and can also be made out of a plastic or similar material, including but not limited to ABS or a polycarbonate. In some embodiments, the housing for each earbud  140 ,  160  can include a speaker housing portion and a stem portion (e.g., stems  142 ,  162 ) that coupled to and extends away from the speaker housing portion. Speaker housing portion can include an audio exit and a speaker can be positioned within the housing and operatively coupled to emit sound through the audio exit. The earbud housing can also include a battery, a wireless antenna, circuitry coupled to receive a wireless signal over the antenna, and other components positioned within either the speaker housing portion or the stem portion and protected by the earbud housing. 
     Case  100  can also include a receptacle connector  136  that has an opening at an exterior surface of case  100  (e.g., the bottom surface as shown in  FIG. 1 ). A suitable plug connector can be inserted in the opening to mate with the receptacle connector and transfer power to case  100  (e.g., from a charging cable) to charge a battery (not shown) within case  100  and/or to transfer data between case  100  and another device. Receptacle connector  136  can be, for example, a mini-USB connector, a Lightning connector developed by Apple Inc., the assignee of the present application, a USB-C connector, or any other appropriate connector. In other embodiments, connector  136  is optional and case  100  can instead receive power to charge an internal battery from a wireless power source (not shown) and also wirelessly exchange data with a host or other device. For example, in some embodiments case  100  can include one or more wireless power receiving coils that can wirelessly receive power from one or more wireless power transmit coils within a wireless charging puck, charging mat or similar device. Additionally, in some embodiments case  100  can include a wireless transceiver to wirelessly send and receive data using a Bluetooth or other appropriate interface. 
     Block Diagram 
       FIG. 3  is a block diagram illustrating a portable electronic listening device system  300  according to some embodiments of the present disclosure that includes a charging case  310  and a pair of earbuds  340 ,  360 . Charging case  310  can be representative of charging case  100  and earbuds  340 ,  360  can be representative of earbuds  140 ,  160 . Charging case  310  can include a housing  312  that stores and protects the earbuds  340 ,  360  as well as the various internal components of the charging case. Housing  312  can be, for example, a combination of body  120  and lid  110  discussed above with respect to  FIGS. 1 and 2 . 
     Charging case  310  can include a battery  314 , which can be any suitable energy storage device, such as a lithium ion battery, capable of storing energy and discharging stored energy to operate the charging case. The discharged energy can be used to power the electrical components of charging case  310  and to charge the pair of earbuds  340 ,  360 . Battery  314  can also be coupled to an earbud interface  318  to provide power to recharge batteries in either or both of earbuds  340 ,  360 . In various embodiments the earbud interface  318  can wirelessly transmit power to the earbuds  340 ,  360  or can transmit power over a wired interface (e.g., through a physical contacts disposed in the charging case and on the earbuds). 
     In some embodiments, battery  314  can also be charged to replenish its stored energy. For instance, battery  314  can be a rechargeable battery coupled to a charging case interface  316  that can include power receiving circuitry. The power receiving circuitry can electrically couple to a power transmitter to receive current from a charging device (not shown). In various embodiments the power receiving circuitry can wirelessly receiver power from the power transmitter, can receive power over a wired interface (e.g., through a physical connector, such as connector  136  shown in  FIGS. 1 and 2 ) and/or can receive power either wirelessly or via a wired interface. 
     Charging case  310  can include a controller  320  coupled to a computer-readable memory  322 . Controller  320  can execute instructions stored in memory  322  for performing functions that can be carried out by the charging case  310 . Controller  320  can be one or more suitable computing devices, such as microprocessors, microcontrollers, computer processing units (CPUs), ASICs, graphics processing units (GPUs), field programmable gate arrays (FPGAs), and the like for operating charging case  310 . Similarly, computer-readable memory  322  can be one or more memory units, such as read only memory (ROM) units, random access memory (RAM) units, programmable read only memory (PROM) units, and the like. In some embodiments computer-readable memory  322  can be part of the same integrated circuit as some or all of the circuitry that makes up controller  320  while in other embodiments the computer-readable memory  322  can be one or more separate integrated circuit chips. 
     Controller  320  can also be operatively coupled to, among other elements, a wireless communication system  324 , a user interface  326 , various sensors  328 , and an earbud protection mechanism  330 . Wireless communication system  324  can include an antenna and a wireless transceiver for wirelessly receiving and transmitting data to a host electronic device or any other appropriate electronic device. Wireless communication system can implement any appropriate wireless communication protocol(s) and in some embodiments can implement one or more of a WiFi protocol or a Bluetooth protocol to exchange data/commands with an appropriate communication system of a host or other electronic device. User interface  326  can include input and/or output devices. For example, user interface  326  can include one or more LEDs for providing indications of certain operations performed by the charging case (e.g., whether battery  314  is being charged, or whether wireless communication system  324  is wirelessly exchanging data with another device), an input button or touch interface that enables a user to activate one or more features of the charging case (e.g., to initiate wireless pairing of the earbuds with a host device), an active driver (e.g., a speaker) for outputting audible sounds to a user for notification purposes, a microphone for receiving sound from the environment, and any other suitable input and/or output device. 
     Sensors  328  can include motion sensors (e.g., an accelerometer, a gyroscopic sensor and the like), distance or position sensors (e.g., radar, lidar, ultrasonic, and the like), location sensors (e.g., global position system, compass), image sensors (e.g., one or photodetectors, a CCD image sensor or a CMOS image sensor), shock sensors, magnetic sensors (e.g., a hall effect sensor and/or magnetometer), sound or audio sensors (e.g., speakers, microphones) which can be used as a sonar combination, and any other type of sensor that can measure a parameter of an external entity and/or environment that the charging case  310  is positioned within. The sensors  328  can be in communication with the controller  320  and can provide input to the controller (e.g., one or more signals indicative of measurements from the sensors). In some embodiments the input provided by sensors  328  to controller  320  enable the controller to predict or determine whether the charging case  310  is in a freefall position, how fast the charging case device  100  is falling, and/or how far away (or how much time) until a predicted impact event. In some embodiments the input provided by sensors  320  can also enable (or can instead enable) the controller to determine when charging case  310  experienced an impact event that could potentially result in one or more of the earbuds  340 ,  360  being dislodged from the charging case. The sensors  328  can be positioned substantially anywhere on or within the charging case  310  and can include a single sensor  328  or multiple sensors  328 . 
     Charging case  310  can also include an earbud protection mechanism  330  that can be activated by controller  320  when the controller predicts or detects a freefall event or when the controller detects an impact event. In some embodiments the earbud protection mechanism  330  can be a dynamic lid locking device that can be activated by controller  320  to lock the lid during a freefall event or immediately upon the detection of an impact event in order to prevent the earbuds from being dislodged from the charging case. In other embodiments the earbud protective mechanism can be an earbud retention mechanism that dynamically secures the earbuds within the charging case thus preventing the buds from being dislodged during a drop event. In still other embodiments, the earbud protection mechanism can be both a dynamic lid locking device and an earbud retention mechanism. The earbud protection mechanism can be any of the devices described below with respect to  FIGS. 8A to 12B , such as the dynamic lid locking devices described with respect to  FIGS. 8A to 10D  or the earbud retention devices described with respect to  FIGS. 11A to 12B . 
     According to some embodiments of the present disclosure, each earbud (or other type of wireless listening device)  340 ,  360  can include a housing  342  that houses the internal components of the earbud. In some embodiments, housing  342  can be formed of a monolithic outer structure that includes a speaker housing portion and a stem that extends away from the speaker housing portion. Embodiments of the disclosure are not limited to any particular form factor, however, of the earbuds  340 ,  360 . Within housing  342 , each earbud can include a controller  344 , a computer-readable memory  346 , wireless communication circuitry  348 , one or more sensors and/or user interface components  350 , audio components  352  and a battery  354 . The battery  354  can provide power to the circuitry and electrical components within the earbud, and an earbud interface  356  can couple each earbud to the charging case  310  to enable the earbuds to receive an electrical charge from the charging case to recharge the battery  354 . 
     Controller  344  can execute instructions stored in memory  346  for performing functions that can be carried out by the earbud including converting streams of audio data received digitally via the wireless communication circuitry  348  to signals that drive the audio components  352  to output the desired audio content. Controller  344  can be one or more suitable computing devices, such as microprocessors, microcontrollers, central processing units (CPUs), ASICs, graphics processing units (GPUs), field programmable gate arrays (FPGAs), and the like for operating the earbud. Similarly, computer-readable memory  346  can be one or more memory units, such as read only memory (ROM) units, random access memory (RAM) units, programmable read only memory (PROM) units, and the like. In some embodiments computer-readable memory  322  can be part of the same integrated circuit as some or all of the circuitry that makes up controller  344  while in other embodiments the computer-readable memory can be one or more separate integrated circuit chips. 
     The audio components  352  can include at least one audio driver, such as an active speaker, and one or more microphones. The microphones can be used to pick up voice commands or voice streams from a user of the earbuds that can then be transmitted to a host device via the wireless communication circuitry and, in some embodiments, can be used for active noise cancellation. In some embodiments that include multiple microphones, the microphones can be positioned at different locations on housing  342  strategically chosen to maximize sound capture and/or to improve noise cancellation capabilities of the earbuds  340 ,  360 . 
     The wireless communication circuitry  348  can include a wireless radio that can be both an input and an output device. The wireless radio can enable the earbuds to receive an audio signal from a host device (e.g., a smart phone, a tablet computer, a laptop computer, a television or the like) that can then be played back over the audio driver under the coordination of controller  344 . In some embodiments one or more of earbuds  340 ,  360  can include a radio that can also transmit an audio signal such as a microphone signal from one or more of the earbuds. In yet further embodiments, one or more of earbuds  340 ,  360  can include a radio that can transmit communication signals that can command the receiving device (e.g., a host device such as a smartphone) to perform one or more functions such as, but not limited to, connect a phone call, disconnect a phone call, pause audio playback, fast forward or rewind audio playback or mute a microphone signal. The wireless radio can employ any short range, low power communication protocol such as Bluetooth®, low power Bluetooth®, or Zigbee among protocols. 
     The sensor and user interface components  350  can include one or more buttons or a touch sensor that registers a user&#39;s touch and can be activated, for example, by a user to answer a cell phone call, change the volume of earbud speaker, and/or to advance or replay tracks in a playlist. In some embodiments the buttons or touch sensor can also be used to command earbuds  340 ,  360  to enter a pairing mode that can be indicated, for example, by an LED or similar light that is part of user interface components  350  on either or both earbuds. The sensor and user interface components  350  can also include one or more motion sensors (such as an accelerometer, gyroscope or the like) or other sensors that can detect whether the earbud is in a freefall condition. 
     The Earbuds  340 ,  360  can communicate digitally with the charging case  310  by way of the earbud interfaces  356  in the earbuds and the earbud interface  318  in the charging case. In some embodiments, when either or both of earbuds  340 ,  360  are positioned within the earbud case  310 , the sensor components  350  can provide sensor data to the controller  320  in earbud case  310  through these earbud interfaces. In such embodiments, data from sensor components  350  can be relied upon by controller  320  in addition to, or instead of, data from sensors  328  in predicting or determining that the earbud case  310  is in a free fall state or incurred an impact event. Keeping the earbuds  340 ,  360  ON when the earbuds are stored in the charging case requires energy from either the earbud batteries  354  or the charging case battery  314 . To save battery power, in some embodiments where signals from one or more of the sensors  350  can be used by controller  320  to predict or detect a drop event or detect an impact event, the earbuds  340 ,  360  can be placed in a low power or sleep state where only components that are necessary to operate the particular sensors that send data to controller  320  are in an active states. In other embodiments, the earbuds can be placed in a deep sleep state where the sensors  350  are inactive and the earbuds require only nominal power when the earbuds are stored in charging case  310  and the case is at rest (e.g., as determined by the sensors  328  in the charging case). If one or more of the sensors  328  detect that the charging case is being handled by a user (e.g., moved in any direction), the charging case can send a signal to the earbuds  340 ,  360  to wake one (or both) of the earbuds up and set the earbud in a low power state in which the sensor is active so that data from the sensor  350  can be received by controller  320  to help the controller detect a drop or impact event. 
     Example Drop Event 
     The sensors  328  in charging case  310  (and/or the sensors  350  in one or both of earbuds  340 ,  360 ) can generate sensor data from their environment that can be used by controller  320  to predict or detect a drop or similar freefall event and/or to detect a hard impact event—any of which can result in one or both of the earbuds being dislodged from the charging case. To illustrate events that can occur, and example sensor readings that can be generated during, a typical drop event, reference is made to  FIGS. 4A-4C . Specifically,  FIG. 4A  is a graph that plots the height of a charging case over time (t) as it is dropped from a height of H onto a hard surface (height=0), such as a wood or tile floor;  FIG. 4B  depicts the velocity at which the charging case moves during the drop event illustrated in  FIG. 4A ; and  FIG. 4C  depicts the acceleration force (e.g., as measured by an accelerometer) that the charging case is subject to during the drop event during the drop event depicted in  FIG. 4A . The data in each of the graphs  4 A- 4 C is plotted along the same time line such that the events shown in  FIG. 4A  are synchronized (along the X-axis, which represents elapsed time during the drop event, in each of  FIGS. 4A-4C ) with the events shown in  FIGS. 4B and 4C . 
     As shown in  FIGS. 4A-4C , prior to a drop event (time period A, shown in  FIG. 4C ), the charging case can be subject to arbitrary motion and or acceleration as it is carried by a user. When the charging case is at rest, the velocity of the case is essentially zero ( FIG. 4B ) and the nominal force on the case can be approximately equal to the force of gravity (1G or 9.8 m/see) upwards as shown in  FIG. 4C . During the initial freefall phase of a drop event (time period B), as the charging case is dropped from a height, H, (at time to) towards the floor, the velocity of the charging case increases ( FIG. 4B ) and the gravity force is reduced to essentially zero as gravity acts on the charging case to pull it downwards ( FIG. 4C ). Once the case hits the floor (time t 1 ), an initial high amplitude pulse can be generated by the (the initial impact event at time C) and the direction of its velocity instantly changes as the charging case bounces off the floor and changes direction from its downward fall to an upward trajectory. The charging case can then bounce one or more times (time period D shown in  FIG. 4C , times t 2  to t 4 ) resulting in several secondary impact events that are represented by readings from the accelerometer ( FIG. 4C ) having smaller and smaller amplitudes before finally coming to rest at the end of the drop event (time period E, time t 5 ) when it returns to 1 g acceleration. 
     Embodiments of the disclosure can use measurements, such as those shown in  FIGS. 4A-4C , from motion sensors and/or measurements from other sensors present in the charging case and/or present in the portable listening device stored in the charging case, to predict when the charging case is in a state of freefall and/or to detect when an impact event occurs, such as the impact events that occur at times t 1 , t 2 , t 3  and t 4  shown above. Based on the predictions made, embodiments can dynamically lock the lid of the charging case or activate a mechanism to increase a retention force on each of the left and right earbuds within the charging case to prevent the earbuds device from being dislodged during the impact events. 
     Two different approaches to protect the portable listening device stored within a charging case are described below with respect to  FIGS. 5 and 6 . In each approach a controller in the charging case, such as controller  320  discussed above, is operatively coupled to one or more sensors that measure parameters of the environment that the charging case is positioned within. Based on the sensor signals, the controller determines whether or not to generate a trigger signal that can dynamically lock the lid of the charging case or activate an earbud retention mechanism to increase a retention force on the pair of earbuds stored within the charging case. In a first approach, described with respect to  FIG. 5 , the controller generates a trigger signal when it predicts or detects that the charging case is in a freefall state. The locking or retention mechanism can then be maintained in an active state until the controller determines that the drop event that initiated the freefall state is over and the charging case is at rest. The controller can then deactivates the locking or retention mechanism. In the second approach, described with respect to  FIG. 6 , the controller monitors the sensor data and detects when the charging case is subject to a hard impact event, such as when the case is dropped and lands on a tile or wooden floor. When a hard impact event is detected, the controller instantaneously generates a trigger signal that can active a lid lock or earbud retention mechanism. Different embodiments can implement either the first or the second approach depending on, among other factors, the response time required to activate the particular lid locking mechanism or the earbud retention mechanism employed in the charging case and the amount of power required to activate and maintain the different mechanisms in a triggered or engaged state. 
     Example Method—Freefall Prediction 
       FIG. 5  is a flowchart depicting steps of a method  500  for preventing an earbud or other portable listening device from being dislodged from a charging case in accordance some embodiments. Method  500  can be carried out by a processor or other type of controller within a charging case, such as controller  320  discussed above. In some embodiments method  500  can be implemented by the controller on an ongoing basis when the charging case is in an ON state. That is, measurements and other readings from sensors of the charging case can be regularly monitored by the controller  320  to predict or detect a potential drop event and action can be taken whenever such measurements meet one or more predetermined criteria that are indicative of freefall or a drop event. Thus, as shown in  FIG. 5 , method  500  can start with a charging case in a normal operation mode (block  510 ) in which measurements and other signals from sensors  328  on the charging case (and/or sensors  356  on the earbuds) are monitored by controller  320  of the charging case. In some embodiments, block  510  includes generating sensor data from a motion sensor (e.g., an accelerometer and/or a gyroscope) within the sensors  328  on the charging case and transmitting the sensor data to the charging case controller. 
     The controller  320  can then evaluate the received sensor data to predict or determine if the received is indicative of a freefall or otherwise indicative of a drop event (block  512 ). If the controller predicts or determines that the charging case is in freefall, the controller can further evaluate the received sensor data in block  512  to determine if (and when) action should be taken in an attempt to better retain the earbuds within the case by, for example, activating an earbud protection mechanism (block  514 ). The controller can, in block  514 , also determine an optimal or precise time to activate the earbud protection mechanism as set forth below. 
     In some embodiments, controller  320  can employ an artificial intelligence engine to predict or determine if a charging case is in free fall. The artificial intelligence (AI) engine can be trained over hundreds or thousands or more drop events to recognize the signal characteristics (i.e., measured sensor values) in a drop event. The AI engine can also be trained to distinguish the signal characteristics that are indicative of a minor drop event (e.g., one from a relatively short height) that is unlikely to result in the lid of the charging case opening versus a more serious drop event (e.g., one from a relatively high height) that is likely to result in the lid opening and one or more of the earbuds being dislodged from the charging case. The AI engine can take into account, among other variables, the height at which the charging case is dropped (i.e., the height that freefall is initially detected), the velocity of the charging case as it falls, the amplitude of the accelerometer readings, rotation of the charging case during the fall as measured by a gyroscope, the surface upon which the charging case will fall onto (e.g., a tile or wooden floor versus carpet or grass) and/or other data measured by various sensors during the drop event and/or upon an initial impact of the charging case with a surface and subsequent impacts. 
     In other embodiments, controller  320  can predict or detect a drop event based on comparing received sensor data to previously measured sensor data that is indicative of a drop event. For example, data from hundreds, thousands or more drop events can be analyzed in a testing environment to select different predetermined criteria of sensor signals received at the controller that have been proven or otherwise demonstrated to be indicative of a drop event and/or impact events that are likely to lead to the one or more earbuds being dislodged from the charging case. Such predetermined measurements can be stored in memory  322  and, in block  512 , controller  320  can compare the sensor data it regularly receives with the predetermined threshold(s) of one or more signals that have been previously determined to indicate a drop event. In some embodiments the algorithm can be relatively simple, for example, block  514  can activate the earbud protection mechanism detects that the charging case reaches a velocity greater than X. In other embodiments, the algorithm can be more complex and rely on multiple variables including one or more of: acceleration, rotation, velocity, the surface over which the charging case is dropped (e.g., as determined by a image sensor) and others. 
     It is worth noting that not all freefall instances are an indication of a drop event. For example, a user may have a habit of repeatedly tossing his or her charging case in the air like a ball or as a juggling exercise. In such instances, and assuming the charging case is caught, the case does not undergo an actual drop event. In some embodiments, with enough training of an appropriate AI routine or enough test data, the controller  320  can distinguish between a number of actions that can cause or simulate freefall that are not an actual drop event and thus do not result in a hard impact. Depending on how accurately the AI routine is trained or how conservatively the drop detection algorithm is programmed, repeatedly tossing a charging case in the air and catching the case will not result in the controller generating a trigger signal. 
     As stated above, if controller  320  predicts or detects a freefall event (block  512 ), the controller can generate a trigger signal that activates an earbud protection mechanism within the charging case (block  514 ). Specific examples of different earbud protection mechanisms are described below with respect to  FIGS. 8A-12B . 
     In some embodiments, the trigger signal generated by method  500  can activate the earbud protection mechanism for essentially the entire duration of the drop event, from a moment in time when freefall is initially detected prior to the initial impact event to a moment in time when the drop event is over and the charging case has come to rest (block  516 ). For example,  FIG. 7A  is a graph that depicts the measurements of the motion sensor shown in  FIG. 4C  and overlays a time period  700  (represented by the light gray block) that starts at a time, t start , and ends at a time, t end , during which the earbud protection mechanism is in operation. In some embodiments t start  can be the instant that method  500  detects freefall. 
     In some embodiments, controller  320  can predict when the charging case is going to hit the ground and activate the trigger signal shortly before the predicted impact event. For example, the sensors  356  can include a position sensor that determines the distance to the impact surface and/or the time that it will take the charging case to reach the impact surface at its current rate of fall. The sensors  356  can utilize images, sonar, radar, and so on in order to determine the distance to the ground. If the impact surface is not detected (e.g., if the impact surface is too far away to be determined by the sensor  356 ), sensor readings can be continuously monitored for a predetermined amount of time allowing the charging case to drop further until the potential impact surface is in range and detected. Thus, block  514  can include a delay time between when freefall is initially detected and when the trigger signal is generated (time t start ). 
     In some embodiments, controller  320  can determine the delay time by estimating the time to impact based on the freefall velocity and the distance to the impact surface. The estimated time to impact can then be used by controller  320  to time the generation of the trigger signal. For example, knowing the activation or response time for the particular earbud protection mechanism(s) employed within the charging case, controller  320  can generate the trigger signal at a predetermined time prior to the predicted impact event that is early enough to allow the earbud protection mechanism to be fully activated and engaged at the time of impact. In some instances controller  320  can delay generation of the trigger signal until a point in time when the controller determines that the charging case is within a predetermined distance from the impact surface, for example, within one foot. 
     In determining the distance to the impact surface it can be helpful to determine the orientation angle of the charging case during freefall. In some embodiments controller  320  can calculate the orientation angle based on input from various ones of the sensors  356 . As the charging case may rotate during freefall, the orientation can rapidly change and controller  320  can determine a rotational axis of the charging case as part of the orientation calculation rather than simply a current orientation of the device. Additionally, the orientation determination can include not only the position of the charging case relative to a “normal” position, but also its height in space. For example, the orientation angle may be a three-dimensional vector, e.g., along x, y, and z axis. 
     In still other embodiments, once freefall is detected a distance to impact (or time to impact) can be automatically determined based on a predetermined value or algorithm. For example, a typical user will carry an earbud charging case at a height between 3-5 feet above the ground. In some embodiments, controller  320  can generate the trigger signal based on a predetermined height at the lower end of this typical range (e.g., at two feet) knowing the drops below the predetermined height are unlikely to result in the lid  110  opening and, if the charging case is dropped from a higher height, activating the earbud protection mechanism early will still protect the earbuds from being dislodged. 
     After the earbud protection mechanism  330  has been activated, controller  320  can continuously monitor the sensors to determine when the drop event has ended (block  516 ). For example, when the sensor readings indicate that the earbud charging case has come to rest. Alternatively, in some instances it possible for controller  320  to incorrectly detect or predict a freefall event (block  512 ), which in turn, can results in the earbud protection mechanism being activated (block  514 ) unnecessarily. During block  516 , sensor data is still continuously being fed into and thus monitored by controller  320 . In a false trigger situation such as that just described, the controller  320  can eventually recognize that a freefall event did not occur and that “predicted” drop event is over. Once the controller detects the drop event is over (or that a drop event was incorrectly predicted), the earbud protection mechanism can be deactivated (block  518 ) and the operation of the charging case returns to normal (block  520 ), i.e., sensor data is continuously monitored (block  510 ) to potentially detect the next drop event. 
     Example Method—Hard Impact Detection 
       FIG. 6  is a flowchart depicting steps of a method  600  for preventing a portable listening device from being dislodged from a charging case in accordance additional embodiments. As is the case with method  500 , method  6500  can be carried out by a processor or other type of controller within a charging case, such as controller  320  discussed above. Method  600  can be implemented by the controller on an ongoing basis when the charging case is in an ON state such that measurements and other readings from sensors in the charging case can be constantly monitored by the controller  320  to detect a hard impact event so that action can be immediately taken to lessen the potential consequences of such an impact event. 
     As shown in  FIG. 6 , method  600  can start with a charging case in a normal operation mode (block  610 ) in which measurements and other signals from sensors  328  on the charging case (and/or sensors  356  on the earbuds) are monitored by controller  320  of the charging case. In some embodiments, block  610  includes generating sensor data from a motion sensor (e.g., an accelerometer and/or a gyroscope) within the sensors  328  on the charging case and transmitting the sensor data to the charging case controller. 
     When controller  320  detects a hard impact event (block  612 ), the earbud protection mechanism(s) of the charging case can be immediately activated (block  614 ) to prevent the lid from opening and/or to protect the earbuds from being dislodged from the charging case. In some embodiments the activation of the earbud protection mechanism in block  614  is a momentary event that can, for example, be measured in a fractions of a second. For example, if the earbud protection mechanism includes an electromagnet that locks the lid closed or the retains the earbuds in the charging case, block  614  can include pulsing a strong current to the electromagnet for a brief period of time that is sufficient to ensure that the impact event does not open the lid or dislodge the earbuds. The amount of current required to pulse the electromagnet drains a certain amount of energy from the battery  314  of the charging case. Thus, once the impact event is over and the lid is not in immediate danger of opening (and the earbuds are not in immediate danger of being dislodged), the current pulse can be discontinued to save battery power. 
     The impact detection algorithm in block  612  can include evaluating, by the controller  320 , received sensor data to determine if the sensor data is indicative of a hard impact event. Similar to the freefall detection algorithm in method  500 , the evaluation can be done using artificial intelligence techniques or can be done based on predetermined thresholds (e.g., an amplitude pulse greater than or equal to X as measured by an accelerometer). As an example, an artificial intelligence routine can be trained over hundreds, thousands, or more drop events to recognize the signal characteristics of a hard impact event that result in the lid of the charging case opening and one or more of the earbuds being dislodged from the case. The algorithm can take into account the height of the fall, the velocity of the charging case as it falls and the amplitude of the accelerometer or other sensors on both an initial impact and subsequent impacts to determine if action should be taken in an attempt to better retain the earbuds within the case. Similarly, data from hundreds, thousands, or more impact events can be analyzed to select different predetermined criteria in the sensor signals received at the controller that have been proven or otherwise demonstrated to be indicative of impact events that are likely to lead to the one or more earbuds being dislodged from the charging case. 
     Not all impact events are going to result in the lid of the charging case opening and one or more of the earbuds within the case being dislodged. For example, if a charging case is dropped from a relatively short height onto a soft surface, such as carpet or grass, the force and impact to the case will be less than if the case is dropped from a higher height and onto a hard surface, such as a tile or concrete floor. Additionally, how the charging case lands on the surface can also effect the force of the impact event. For example, if the charging case is dropped such that it lands with its flat front or back surface hitting the floor, the lid may be less likely to open than if the case is dropped such that a corner of the charging case hits the floor. In some embodiments the AI or other evaluation algorithm(s) employed by controller  320  can distinguish different types of drop events such as these and only activate the earbud protection mechanisms when impact events occur that are recognized as likely causing the lid to open and one or more of the earbuds to be dislodged. 
     In still other embodiments, the controller  320  can generate a trigger signal in block  612  only if it detects that the lid of the charging case is actually opening. For example, in some embodiments, the lid can be held in a closed position by a pair of magnets (one in the lid and one in the body). A hall effect sensor can detect and measure the magnetic field generated between the two magnets. Thus, in some embodiments controller  320  can generate a trigger signal if the controller predicts or detects that the charging case is in freefall and then detects that the magnetic field between the lid and body magnets is lessening, which can be indicative of the lid begging to open due to an impact event. Upon detecting that the lid is opening, the controller can activate the earbud protection mechanism to secure the earbuds in the charging case. 
     In some drop events, the charging case can bounce across the floor creating multiple impact events and thus multiple opportunities for the lid to open. Such a scenario was depicted, for example, in  FIGS. 4A-4C  discussed above. In some embodiments, method  600  will momentarily active the earbud protection mechanism at each impact instance during a drop event. Thus, as shown in  FIG. 7B , method  600  can momentarily activate the earbud protection mechanism event on five separate occasions in response to each of the high amplitude pulses generated by the accelerometer. 
     Earbud Protective Mechanisms 
     Methods  500  and  600  discussed above activate an earbud protection mechanism to prevent the earbuds from being dislodged from their charging case in a drop event or other type of situation that causes a hard impact to the charging case. The earbud protection mechanism can be dynamically activated by a controller (e.g., via a trigger signal) to ensure that the earbuds are secured within the charging case during a drop or impact event. As discussed above, the controller can receive one or more input signals from one or more sensors in the case or in one or both of the earbuds stored within the case and use the received input signals to predict or detect a drop event or an actual impact event. In some embodiments the earbud protection mechanism can lock the lid to prevent the lid from opening during a drop event and in some embodiments the earbud protection mechanism can lock the earbuds within charging case so that even if the case lid does open due to the event, the earbuds will remain in the case. Various examples of earbud protection mechanisms according to embodiments of the invention are discussed below in conjunction with  FIGS. 8A-12B . 
     1) Electromagnet Lid Retention 
     Reference is now made to  FIGS. 8A and 8B  where  FIG. 8A  is a simplified cross-sectional view of a charging case  900  according to some embodiments of the disclosure and  FIG. 8B  is a simplified perspective view of a portion of charging case  900 . Charging case  900  can be an implementation of charging case  100  and, for ease of discussion,  FIGS. 8A and 8B  can include the same references numbers as used in  FIGS. 1 and 2  when referring to elements described above with respect to charging case  100 . As shown in  FIGS. 8A and 8B , charging case  900  can include a lid  110  that is pivotably coupled to a body  120  by hinge  115 . Charging case  900  can be designed such that lid  110  can be opened easily by a user with a light touch when desired but otherwise stay closed. 
     In some embodiments, hinge  115  can be a bi-stable hinge that has two stable states: an open state and a closed state. The bi-stable hinge can have a neutral position where it does not pull to open or close the lid, but once the lid moves in one direction past the neutral position, the bi-stable hinge can either pull the lid open or pull the lid closed. Such a bi-stable design can provide a pleasant user experience and serve to ensure that lid  110  can be easily closed to better protect the earbuds stored within charging case  100 . 
     To keep lid  110  in a closed position, charging case  900  can include a lid retention mechanism that includes a first magnetic element  812  disposed within lid  110  and a second magnetic element  814  disposed within body  120 . At least one of the magnetic elements  812 ,  814  can be a magnet and the other can be either a metal or similar element made of a magnetic material or a second magnet. The magnetic elements  812  and  814  can be positioned along a front portion of the charging case, opposite hinge  115 , and aligned with each other such that when lid  110  is closed a magnetic field is generated between the two elements  812 ,  814  that attracts the two elements to each other and secures the lid  110  in a closed position. 
     When hinge  115  is a bi-stable hinge, charging case  900  can also include a second set of magnetic elements positioned adjacent to hinge  115  including a magnetic element  822  disposed within lid  110  and a magnetic element  824  disposed within body  120 . Magnetic elements  822  and  824  can each be magnets and can be oriented such that they repel one another. Magnetic elements  812 ,  814 ,  822  and  824  can be oriented and selected to create an over center configuration for lid  110  where the lid is in a first stable position when in the closed position (illustrated in  FIG. 8A ) and is in a second stable position when in the open position (illustrated in  FIG. 8B ), but is in an unstable position in-between the closed position and the open position. In some embodiments this can be achieved by the attractive forces between the pair of magnetic elements  812 ,  814  over powering the repulsive forces of the pair of magnetic elements  822 ,  824  when lid  110  is transitioned from the open position to the closed position. 
     According to embodiments of the disclosure, the lid retention mechanism that keeps lid  110  shut when the lid is in the closed position can be a dynamic lid retention mechanism that includes at least one electromagnet. For example, at least one of magnetic elements  812  or  814  can be an electromagnet that can be activated to increase the magnetic force between the elements  812  and  814  in response to the trigger signal generated by controller  312  as discussed above. As one specific example, magnetic element  814  can include an electromagnet. Thus, during a drop event, a controller, such as controller  320  (not shown in  FIG. 8A or 8B ), within the charging case can detect the drop event (or detect when the charging case impacts an object, for example, a floor, during a drop event) using any of the techniques described above. Upon detecting such an event, the controller can generate a trigger signal that sends a relatively strong current through a magnetic winding around magnetic element  814  creating a magnetic field between the two magnetic elements  812 ,  814  that is sufficiently strong to keep the lid  110  closed over the body during the drop event and/or its associated impact events. In some embodiments, current can be momentarily pulsed to the electromagnet (e.g., applied for 5, 10 or 20 milliseconds) only when an impact event is detected as described above with respect to method  600  and shown graphically in  FIG. 7B . 
     In some embodiments, the lid retention component  814  can include a permanent magnet in addition to an electromagnet. The permanent magnet can create a first magnetic field that acts upon lid retention component  812  and is sufficiently strong to secure the lid to the body during normal use (e.g., when the lid is closed by a user). The first magnetic field might not be strong enough to secure lid  110  to body  120  during certain hard impact events, however, such as a drop from five or six feet onto a hard surface. To prevent the lid from opening during such an event, the electromagnet portion of magnetic component  814  (which can be a coil wound around the permanent magnet) can be dynamically activated by the controller during a drop event to momentarily increase the lid attraction force imparted on retention component  302  by adding a second magnetic field to the first field for a predetermined amount of time. The second magnetic field can be generated by drawing a relatively high current from a battery within the charging case (e.g., battery  314 ) and supplying the current through a magnetic winding around the lid retention magnet under the control of controller. Such an embodiment provides a relatively simple, solid-state and low cost approach to locking the lid during a drop event. In some embodiments, the electromagnet can be activated during the entire time drop event (e.g., period  700  as shown in  FIG. 7A ). In some other embodiments, however, in order to conserve energy within battery  314 , the electromagnet can be instantaneously pulsed for a brief moment (e.g., for 5, 10 or 20 milliseconds) when a hard impact is detected as shown by time periods  710  in  FIG. 7B . 
     2) Mechanical Latch 
       FIG. 9A  is a simplified cross-sectional view of a charging case  900  according to some embodiments and  FIG. 9B  is a simplified partial perspective view of the charging case  900 . Charging case  900  can be an implementation of charging case  100  discussed above and, to avoid repetition, various elements of charging case  900  that are similar to those discussed above with respect to other charging cases described herein are labeled with the same reference numbers. 
     As shown in  FIGS. 9A and 9B , charging case  900  can include a lid retention mechanism that includes a first component  912  in the lid  110  and a second component  914  in the body  120 . One of the components  912 ,  914  can be a mechanical latch and the other can be a feature (e.g., a hook or an indentation) that the mechanical latch can latch onto to secure the two components  912 ,  914  together. For example, component  914  can be a mechanical latch that can be responsive to the trigger signal generated by controller  320  to latch onto component  912 , which can be an indentation or hook, and lock lid  110  to body  120 . In this manner the latch  914  can physically block or otherwise prevent the lid  110  from opening while the latch  914  is engaged with component  912 . Activating latch  914  can be a one-time event that, in some embodiments, requires less current (and thus less battery power) than activating one or more electromagnets as discussed above. The response time of a mechanical latch can be slightly slower than that of an electromagnet, however, so in some embodiments latch  914  can be triggered as soon as freefall is detected and can remain in the latched (locked) state as shown by time period  700  in  FIG. 7A  until the controller detects that drop event is completed or determines that the freefall event was a false trigger. 
       FIG. 9C  is a simplified cross-sectional illustration of a small portion of a charging case, such as case  900 , that includes a mechanical latch  914  that can, in response to a trigger signal, release out of sidewall  920  portion of body  120  and latch onto a notch (first component)  912  formed in a sidewall  910  of lid  110 .  FIG. 9C  shows latch  914  in the activated position such that the latch is engaged with the first component  912  to secure lid  110  in the locked position. The embodiment depicted in  FIG. 9C  is just one illustrative example of a mechanical latching mechanism that can be incorporated into a charging case according to embodiments of the disclosure. Embodiments of the disclosure are not limited to this one specific example and a person of ordinary skill in the art will recognize many other implementations of mechanical latches that could can lock lid  110  during a drop or impact event based on the disclosure herein. 
     3) Locking Hinge 
     Some embodiments of charging cases according to the present disclosure can include a hinge that can be locked in response to a trigger signal to ensure that the lid remains closed during a drop or similar event. One, non-limiting example of a locking hinge design in accordance with some embodiments is shown in  FIG. 10A , which is a simplified cross-sectional view of a charging case  1000  according to some embodiments. Charging case  1000  includes a lid  110  that is pivotably coupled to a body  120  by a hinge  1015 . The hinge  1015  can be a spring activated hinge that can provide bi-stable operation of the lid similar to that discussed above. For example, hinge  1015  can have an closed position (illustrated in  FIG. 10A ) where lid  110  covers the earbud receiving area of body  120  and an open position (illustrated in  FIG. 10C ) where lid  110  is pivotably displaced from body  120  into a position that allows the earbuds to be removed from charging case  1000 . A spring actuated over center mechanism  1030  is shown in more detail in the expanded view portion of  FIG. 10A . As shown, lid  110  includes an extension  1032  attached to the lid and disposed on an opposite side of a pivotable joint  1034  from the lid. Thus, when lid  110  rotates about pivotable joint  1034 , extension  1032  also rotates about the pivotable joint. Extension  1032  can have a rounded distal end that is in contact with a spring loaded arm  1036  such that the lid resists rotating from the open position to the closed position until the lid is moved past an over center position (illustrated in  FIG. 10B ) when the lid is then impelled to the open position (illustrated in  FIG. 10C ). Spring loaded arm  1036  can be attached at a first end to a second pivotable joint  1038  and have a rounded distal tip at its opposite end. A torsion spring (not shown) can impart a rotational force to spring loaded arm  1036  that resists the lid transitioning from the closed position towards the open position. 
     In accordance with some embodiments of the disclosure, hinge  1015  can include one or more locking mechanisms  1040  that can be activated by controller  320  in response to detecting that the charging case  1000  is in freefall or incurred a hard impact event. For example, on some embodiments locking mechanism  1040  can be an electromagnetic brake that imparts a force on one or both of extension  1032  or spring arm  1036  to prevent either or both of those components from pivoting around pivotable joints  1034 ,  1038 , which in turn, can prevent the lid from opening during an drop event. In other embodiments, the locking mechanism  1040  can include any one or more of the following to prevent lid  110  from opening: one or both of pivotable joints  1034 ,  1038  can temporarily change shape (e.g., an electrically activated shape memory alloy) in response to a trigger signal which can intentionally bind hinge  1015 ; hinge  1015  can include a ferrofluid that changes viscosity in response to a trigger signal to impart additional friction on the hinge. 
     4) Electromagnetic Earbud Lock 
     Reference is now made to  FIG. 11 , which is a simplified cross-sectional view of a charging case  1100  according to some embodiments of the disclosure. Charging case  1100  can be an implementation of charging case  100  and, for ease of discussion,  FIG. 11  includes the same references numbers as used in  FIGS. 1 and 2  when referring to elements described above with respect to charging case  100 . As shown in  FIG. 11 , charging case  1100  can include a lid  110  that is pivotably coupled to a body  120  by hinge  115 . Charging case  1100 , and all the charging cases disclosed herein, can be designed such that lid  110  can be opened easily by a user with a light touch when desired but otherwise stay closed. 
     While not shown in  FIG. 1 or 2  charging cases according to various embodiments of the disclosure can include one or more magnets within the body  120  of the charging case that cooperate with magnetic elements in each of the earbuds  140 ,  160  to magnetically secure the earbuds within their respective pockets or cavities formed within body  120 . Such magnets can keep the earbuds  140 ,  160  in the charging case if, for example, the case is turned upside down when the lid  110  is open. The magnets might not be strong enough, however, to ensure that the earbuds remain in the charging case during a drop event. 
     Charging case  1100  can include a dynamic earbud retention mechanism that secures the earbuds within the charging case so that the earbuds are not inadvertently dislodged during the event. The dynamic earbud protection mechanism employed in charging case  1100  can be one or more electromagnets that can be activated by controller  320  via the trigger signal to increase the magnetic force that retains the earbuds  140 ,  160  in case  1100 . For example, charging case  1100  can include a first electromagnet  1102  and a second electromagnet  1104  that are aligned with and/or arranged around a portion of earbuds  140 ,  160 , respectively. Electromagnets  1102 ,  1104  can be strategically placed within charging case  1100  such that, when activated, the magnets generate a magnetic field that attracts magnetic elements (e.g., a magnet, a plate of magnetic material and/or feature of the earbuds made from a magnetic metal, such as electrical contacts) within each earbud, such as magnetic element  1112  in earbud  140  and magnetic element  1114  in earbud  160 . The generated magnetic field can add to or otherwise increase the initial magnetic field that retains the earbuds within their pockets to a level that effectively locks the earbuds within the pockets so that they are not dislodged during a drop event even if lid  110  is opened during the event. 
     Thus, during a drop event, a controller, such as controller  320  (not shown in  FIG. 11 ), within charging case  1100  can detect (or detect a hard impact event) using any of the techniques described above. Upon detecting such an event, the controller can generate a trigger signal that sends a relatively strong current through a magnetic winding around electromagnets  1102  and  1104  creating a first magnetic field between electromagnet  1102  and magnetic element  1112  and a second magnetic field between electromagnet  1104  and magnetic element  1114 . In some embodiments, current can be momentarily pulsed to the electromagnets  1102  and  1104  only when an impact event it detected as described above with respect to method  600  and shown graphically in  FIG. 7B . 
     While  FIG. 11  depicts electromagnets  1102  and  1104  as encircling a bottom portion of the stems  142  and  162  of earbuds  140 ,  160 , respectively, embodiments of the disclosure are not limited to any particular location or arrangement of the electromagnets. For example, in some embodiments a single electromagnet can be positioned between the two earbuds  140 ,  160  that, when activated, creates a strong enough magnetic field to interact with magnetic elements within the earbuds and secure both earbuds within the charging case during a drop event. In other embodiments, electromagnets  1102  and  1104  can be positioned near the speaker portion of the earbuds  140 ,  160  and can, for example, generate a magnetic field that attracts the speaker magnet of each earbud to secure the earbuds within the charging case. Numerous other positions of the electromagnet(s) and/or arrangements are possible. 
     5) Mechanical Earbud Lock 
     In still additional embodiments, a dynamic earbud retention mechanism that secures the earbuds within the charging case can be a mechanical mechanism that grabs or otherwise imparts a force on the earbuds to ensure that the earbuds are not dislodged from the charging case during a drop event.  FIGS. 12A and 12B  are simplified cross-sectional views of a charging case  1200  according to some embodiments of the disclosure. Charging case  1200  can be an implementation of charging case  100  and, for ease of discussion,  FIGS. 12A and 12B  include the same references numbers as used in  FIGS. 1 and 2  when referring to elements described above with respect to charging case  100 . 
     As shown in  FIGS. 12A and 12B , charging case  1100  can include a lid  110  that is pivotably coupled to a body  120  by hinge  115 . Charging case  1200  can also include a dynamic earbud retention mechanism  1202 .  FIG. 12A  depicts charging case  1200  with the dynamic earbud retention  1202  mechanism in a released or inactive state, while  FIG. 12B  depicts charging case  1200  with the dynamic earbud retention mechanism  1202  in an engaged or active state. 
     Dynamic earbud retention mechanism  1202  can include an element that can be activated in response to the trigger signal generated by controller  320  to engage with the housing of each of the earbuds  140 ,  160 . For example, in some embodiments the dynamic earbud retention mechanism can be a spring activated arm or finger that folds into the charging case during normal operation so that the arm or finger does not obstruct the pockets that earbuds  140 ,  160  fit into and may not even be readily visible within the charging case. If controller  320  detects a drop event or impact event, however, the controller can generate a trigger signal that activates the earbud retention mechanism  1202  such that it extends out of the location in which it normally resides into the pockets or cavities that secure the earbuds  140 ,  160  within the charging case. When activated, the earbud retention mechanism  1202  can be pressed against a housing of each earbud as shown in  FIG. 12B . In some embodiments, earbud retention mechanism  1202  can narrow the opening of the pocket or cavity though which a portion of the earbud is disposed thus physically preventing the earbud from being removed from the charging case until the earbud retention mechanism is deactivated. In some embodiments, earbud retention mechanism  1202  can impart forces  1204 ,  1206  upon the respective earbuds  140 ,  160  that presses the earbuds against the inner walls of the pockets or cavities that each earbud is retained in creating sufficient friction between the earbud and the housing of the charging case to secure the earbuds within the charging case during a drop event. 
     The embodiment depicted in  FIGS. 12A and 12B  is just one illustrative example of a mechanical earbud retention mechanism that can be incorporated into a charging case according to embodiments of the disclosure. Embodiments of the disclosure are not limited to this one specific example and a person of ordinary skill in the art will recognize many other implementations of mechanical earbud retention mechanisms that can secure earbuds within their storage and charging case during a drop or impact event based on the disclosure herein. 
     Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like may be used to describe an element and/or feature&#39;s relationship to another element(s) and/or feature(s) as, for example, illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and/or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” and/or “beneath” other elements or features would then be oriented “above” the other elements or features. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. For example, while several specific examples of embodiments of the invention described above use measurements from an accelerometer to determine when a charging case is in a freefall state or when it undergoes a sharp impact event, the invention is not limited to analyzing data from an accelerometer to determine such. In other embodiments, other types of sensors can be employed and thus other values of data and other types of data can be relied upon by a controller for such determinations. In some specific embodiments, both acceleration and rotation data can be used to predict or detect freefall or a hard impact event. 
     As another example, while several embodiments described above included electromagnets as an element that can be activated by a controller to secure the lid of the charging case and/or the earbuds within the charging case, other embodiments can employ electropermanent magnets instead of electromagnets. An electropermanent magnet can be activated by a trigger signal and, once activated, can provide a permanent magnetic force until it is deactivated. Thus, while some embodiments pulse a current to momentarily charge electromagnets during an impact event as shown in  FIG. 7B , in other embodiments electropermanent magnets can be used in similar arrangements as the electromagnets but can be activated upon predicting or detecting freefall and then deactivated after the controller determines a drop event is over or was a false event as shown in  FIG. 7A . Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not target to be exhaustive or to limit the embodiments to the precise forms disclosed. Also, while different embodiments of the invention were disclosed above, the specific details of particular embodiments may be combined in any suitable manner without departing from the spirit and scope of embodiments of the invention. Further, it will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. 
     Finally, it is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users.

Metadata:
Filing Date: 20200925
Publication Date: 20210907
Grant Date: 20210907
Priority Date: 20200925
Inventors: MORRISON, SCOTT D.
KALINICHEV, Kirill
ERGUN, ALI N.
Assignee: APPLE INC
CPC Classifications: [{"code": "A45C11/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "A45C15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0044", "inventive": true, "first": false, "tree": "[]"}, {"code": "A45C11/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R3/007", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1025", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1025", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1025", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 77559080