PATENT DOCUMENT

Publication Number: US-7886573-B2
Application Number: US-42825709-A
Country: US
Kind Code: B2

Title: Mounted shock sensor

Abstract:
This application is directed to a shock sensor mounted in an electronic device. The shock sensor includes both active and passive shock detection methods that allow a technician to determine whether the electronic device was subjected to a shock event that exceeded an impact threshold level. The shock sensor may include shock detection contacts that form an electrical circuit that remains open in the absence of a shock event that exceeds an impact threshold level. In response to a significant shock event, a movable component or substance of the shock sensor may move from a first position to a second position, thereby closing the electrical circuit formed by the shock detection contacts. The change in circuit may be detected and used to provide active indication of whether the electronic device has been subjected to a substantial shock event. In addition, the shock sensor may be observed to passively determine whether the electronic device has been subjected to a substantial shock event.

Claims:
1. A shock sensor, comprising:
 an electrically conductive and magnetically attractive shock detecting chamber; 
 a cantilever spring having a first end fixed to a support structure and a second end disposed within the chamber; and 
 a magnet fixed to the second end of the cantilever spring, the magnet operative to form a portion of an open electrical circuit when it is not magnetically attached to the chamber and further operative to be magnetically attached to the chamber and to close the electrical circuit in response to a shock event. 
 
     
     
       2. The shock sensor of  claim 1 , wherein the chamber is constructed from a magnetic metal. 
     
     
       3. The shock sensor of  claim 1 , further comprising:
 a first shock detection contact electrically coupled to the cantilever spring; and 
 a second shock detection contact electrically coupled to the chamber. 
 
     
     
       4. The shock sensor of  claim 3 , wherein the magnet is operative to short the first and second shock detection contacts in response to the shock event. 
     
     
       5. The shock sensor of  claim 4 , operative to provide active shock detection. 
     
     
       6. The shock sensor of  claim 1 , wherein the magnet remains in contact with the chamber in response to the shock event to provide passive shock detection. 
     
     
       7. The shock sensor of  claim 1 , wherein shock sensor is configured to be reset after the shock event. 
     
     
       8. The shock sensor of  claim 7 , wherein the magnet is detached from the chamber to reset the shock sensor. 
     
     
       9. The shock sensor of  claim 1 , wherein the shock sensor is configured to be soldered to the circuit board of an electronic device. 
     
     
       10. A method for actively and passively indicating the occurrence of a shock event using a single shock sensor, comprising:
 disposing a magnet fixed to a first end of a cantilever beam within a magnetically attractive chamber, wherein the magnet is operative to form a portion of an open electrical circuit when it is not magnetically attached to the chamber and is further operative to close the electrical circuit when the magnet comes into contact with the magnetically attractive chamber; 
 retaining the magnet away from a surface of a magnetically attractive chamber prior to the shock event; 
 deflecting the cantilever beam such that the magnet comes into contact with the surface of the chamber in response to the shock event; 
 providing active indication of whether the shock sensor endured a shock event, wherein providing active indication further comprises providing an electrical signal based on the closed electrical circuit and indicative of the occurrence of the shock event in response to the magnet coming into contact with the surface of the chamber; and 
 providing passive indication of whether the shock sensor endured the shock event, wherein providing passive indication further comprises observing the magnet in contact with the surface of the chamber. 
 
     
     
       11. The method of  claim 10 , further comprising modifying the state of an electronic device in response to providing the electrical signal. 
     
     
       12. A system for actively and passively indicating the occurrence of a shock event, comprising:
 an electronic device; and 
 a shock sensor implemented in the electronic device, wherein the shock sensor further comprises:
 at least one shock detection contact coupled to shock detection circuitry to form an open electrical circuit; and 
 a movable magnet disposed within a magnetically attractive chamber, the magnet configured to move from a first position to a second position, wherein the magnet is not in contact with a surface of the chamber when the magnet is in the first position, and wherein the magnet and surface of the chamber form the open electrical circuitry; 
 wherein in response to a shock event, the magnet moves to the second position, wherein:
 the magnet comes into contact and remains in contact with the surface of the chamber; 
 an electrical signal indicative of shorting the electrical circuit actively indicates the occurrence of the shock event; and 
 the presence of the magnet is observed in the second position to passively indicate the occurrence of the shock event. 
 
 
 
     
     
       13. The system of  claim 12 , wherein the shock detection circuitry is configured to provide an electrical signal in response to the shorting of the electrical circuit. 
     
     
       14. The system of  claim 13 , further comprising a diagnostic device configured to detect the electrical signal. 
     
     
       15. The system of  claim 13 , wherein the electronic device further comprises a processor configured to change the state of the electronic device in response to detecting the electronic signal. 
     
     
       16. The system of  claim 15 , wherein the electronic device further comprises a storage device configured to store the change of state of the electronic signal. 
     
     
       17. The system of  claim 13 , further comprising a RFID tag that is rendered operative to emit a signal when the electrical signal is detected. 
     
     
       18. The system of  claim 12 , wherein the movable component or substance is returned to the first position to reset the shock sensor. 
     
     
       19. The system of  claim 12 , wherein the shock sensor is configured to be soldered to a component of the electronic device. 
     
     
       20. The system of  claim 19 , wherein the component of the electronic device is a circuit board.

Description:
BACKGROUND OF THE INVENTION 
     This invention is directed to a shock sensor mounted in an electronic device. 
     Some electronic devices are provided with shock sensors to determine the level of shock events to which the electronic device is subjected over the course of its lifetime. In some cases, the shock sensors may be used for warranty purposes (e.g., the warranty is invalid if the electronic device is subjected to a shock event that exceeded the shock event of a 10 foot drop). Shock sensors can be classified in two categories: active shock sensors and passive shock sensors. 
     Active shock sensors can include an accelerometer configured to generate a signal when the accelerometer detects a level of acceleration that corresponds to an impact threshold level. The signal may then be read by detection circuitry without disassembling the electronic device. 
     An inherent limitation of some active shock sensors, such as those that include accelerometers, is that they require power to operate. This means that they consume power while the device operates, and will not function if the device fails (e.g., the device does not power up). In addition, adding an active shock sensor may require circuit board modifications. Furthermore, if the electronic device is severely damaged, the active sensor may be rendered inoperable or diagnostic equipment may not be able to obtain data from the sensor or storage medium containing shock sensing information. Finally, active shock sensors are relatively expensive, at least compared to various passive sensors. 
     Passive shock sensors typically include an ink capsule that is enclosed in a tube. The capsule is constructed such that it breaks when the electronic device is subjected to a shock event that exceeds an impact threshold level. When the capsule ruptures, the ink (or other colored liquid contained in the capsule) is released and fills the tube. A technician may then disassemble the electronic device and observe the shock sensor to determine, based on the location the ink in the shock sensor, whether the electronic device was subjected to a shock event that exceeded the impact threshold level. 
     While passive shock sensors do not exhibit some of the limitations of active shock sensors, they are generally not resettable. This requires the shock sensor to be replaced when the electronic device is repaired or refurbished. In addition, there is typically no method for observing the shock sensor from the outside of the electronic device. Instead, the technician must disassemble the device to access the shock sensor. 
     Accordingly, it would be desirable to provide a shock sensor that exhibits both active and passive attributes. In particular, it would be desirable to provide a shock sensor that can be analyzed without disassembling the device. It would also be desirable to provide a shock sensor that can be analyzed when the device has failed and electronic detection is not possible. 
     SUMMARY OF THE INVENTION 
     A shock sensor by which shock events can be analyzed without disassembling the device is provided. A shock sensor by which shock events can be analyzed when the device has failed is also provided. The shock sensor provides both active and passive attributes for a technician to analyze the shock events endured by an electronic device. 
     In accordance with some embodiments of the invention, a shock sensor that includes shock detection circuitry is provided. The shock detection circuitry may include one or more shock detection contacts (e.g., a wire) that may be electrically coupled to the shock sensor such that in the absence of a significant enough shock event, no signal is provided to indicate the occurrence of a shock event. Signal detection can be performed by a diagnostic device that interfaces (e.g., connects to a docking port) with the assembled electronic device so that a technician can check the shock event status without disassembling the electronic device. 
     Different mechanisms may be used to provide an electrical signal in response to a shock event that exceeds the impact threshold level. Generally, a movable component or substance may be configured to move from a first position in which the shock detection contacts form an open electrical circuit to a second position in which the movable component or substance closes the electrical circuit formed by the shock detection contacts to provide an electrical signal. 
     In one embodiment, shock detection contacts may be inserted in a chamber at a predetermined distance from each other. A reservoir (e.g., similar to an ink capsule) containing a conductive fluid can be enclosed within the chamber. When a shock event exceeds the impact threshold level, the reservoir may rupture and release the conductive fluid in the chamber. The conductive fluid may then short the shock detection contacts extending into the chamber. Detection circuitry may provide an electrical signal in response to the short circuit. 
     In some embodiments, the conductive fluid may also serve as a passive shock sensor. If a diagnostic device is not able to detect an electrical signal, the electronic device may be disassembled to observe the shock sensor. If the conductive fluid is in the chamber and not restrained in the reservoir, the shock sensor passively indicates whether a shock event was experienced that exceeded the impact threshold level. The conductive fluid may be colored to allow easier passive shock detection. 
     In another embodiment, a cantilever spring may be electrically coupled to a first shock detection contact. A second shock detection contact may be electrically coupled to a chamber that encloses the free end of the cantilever spring (e.g., a tube or an open box). In response to a shock event that exceeds the impact threshold level, the cantilever spring bends, and the free end of the cantilever spring comes into contact with the chamber and shorts the first and second shock detection contacts. 
     The free end of the cantilever spring may include a magnet, and the chamber may be constructed from magnetically reactive material such that when a shock event exceeds the impact threshold level, the magnet of the cantilever comes into and remains in contact with the chamber by magnetic attraction, thereby closing the electrical circuit. The position of the cantilever and magnet provides a method for passively determining whether a shock event on the electronic device exceeded the threshold. A technician can disassemble the electronic device and observe the location of the magnet within the chamber. If the magnet is in contact with the chamber, the shock sensor passively indicates a shock event that exceeded the impact threshold level. 
     The shock sensor can be reset using a tool to decouple the magnet from the chamber. Once the magnet is returned to an equilibrium position between the walls of the chamber, and the effect of the electrical signal removed (e.g., reset a bit in memory), the shock sensor can be re-used in the electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the present invention, its nature and various advantages will be more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic view of an illustrative shock sensor system that includes both active and passive attributes in accordance with one embodiment of the present invention; 
         FIG. 2  is a schematic view of an illustrative device in which a shock sensor is implemented in accordance with one embodiment of the present invention; 
         FIG. 3A  is a simplified cross-sectional view of an illustrative shock sensor system that includes both active and passive attributes in accordance with one embodiment of the present invention; 
         FIG. 3B  is a simplified cross-sectional view of the illustrative shock sensor system of  FIG. 3A  when the electronic device in which the shock event system is implemented is subjected to a shock event that exceeded the impact threshold level of the sensor in accordance with one embodiment of the present invention; 
         FIG. 4A  is a simplified cross-sectional view of another illustrative shock sensor system that incorporates both active and passive attributes in accordance with one embodiment of the present invention; 
         FIG. 4B  is a simplified cross-sectional view of the shock sensor system of  FIG. 4A  when the sensor has been subjected to a shock event that exceeded the impact threshold level in accordance with one embodiment of the present invention; 
         FIG. 4C  is a simplified cross-sectional view of another configuration for the illustrative shock sensor system of  FIG. 4A  in accordance with one embodiment of the present invention; 
         FIG. 5  is a perspective view of a resetting tool for the shock sensor system of  FIGS. 4A and 4B  in accordance with one embodiment of the present invention; 
         FIG. 6  shows an illustrative flow chart for actively and passively indicating the occurrence of a shock event in accordance with one embodiment of the present invention; and 
         FIG. 7  shows an illustrative flow chart of a process for determining whether an electronic device in which a shock sensor system has been implemented has been subjected to a shock event that exceeded the impact threshold level for the device in accordance with one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In accordance with the present invention, a shock sensor that exhibit attributes of both active shock sensors and passive shock sensors is provided. 
       FIG. 1  is a schematic view of an illustrative shock sensor that includes both active and passive attributes. Shock sensor  100  may include shock detection circuitry  102  configured to provide an electrical signal when the shock sensor is subjected to a shock event that exceeds the impact threshold level of the shock sensor. Shock detection circuitry  102  may be electrically coupled to one or more shock detection contacts  104  by conductive connection  106 . Shock detection contacts  104  may include, for example, a wire, a conductive plate, a conductive region, or any other suitable contact. Conductive connection  106  can include any suitable connection that conducts electricity between shock detection circuitry  102  and shock detection contacts  104  (e.g., a wire). 
     Shock detection contacts  104  and shock detection circuitry  102  may be configured to form an electrical circuit that is open in the absence of a shock event that exceeds the impact threshold level of shock sensor  100 . So long as the electrical circuit remains open, shock detection circuitry may be configured not to provide an electrical signal (or at least a signal that does not indicate that the impact threshold has been exceeded). For example, shock detection contacts  104  may include at least two wires that are maintained at a distance from each other without an electrical coupling. When shock sensor  100  is subjected to a sufficiently large shock event, the state of shock sensor  100  may be changed such that the wires become electrically coupled and the electrical circuit formed by shock detection contacts  104  and shock detection circuitry  102  may be closed. 
     Shock sensor  100  may include movable component or substance  108 . Movable component or substance  108  may be configured to move from a first position to a second position in response to a shock event that exceeds the impact threshold level of shock sensor  100 . In the first position, movable component or substance  108  may be configured to maintain electrical isolation between shock detection contacts  104 . In the second position, movable component or substance  108  may be configured to short shock detection contacts  104  such that the electrical circuit formed by shock detection contacts  104  and shock detection circuitry  102  may be closed. In addition, the first and second positions of movable component or substance  108  may be observably different such that a technician, observing shock sensor  100 , may identify the position of movable component or substance  108  and passively detect shock events. The impact threshold level of shock sensor  100  may be determined by the level of the shock event necessary to cause movable component or substance  108  to move from the first position to the second position. 
     In response to a shock event that causes movable component or substance  108  to short shock detection contacts  104 , shock detection circuitry  102  detects the short circuit. In response to detecting the short circuit, shock detection circuitry  102  may be configured to provide an electrical signal identifying the shock event. In some embodiments, shock detection circuitry  102  may continuously or intermittently provide an electrical signal available for detection. In some embodiments, shock detection circuitry  102  may provide an electrical signal that causes the state of shock sensor  100  to be modified. For example, the electrical signal may cause one or more bits in memory of shock detection circuitry  102 , or in another component of shock sensor  100  (e.g., an RFID tag) to change. In some embodiments, shock detection circuitry  102  may provide an electrical signal that causes the state of the electronic device in which shock sensor  100  is implemented to be modified. For example, the electrical signal may cause one or more bits in the memory of the electronic device to be modified. Shock sensor  100  may use one or more of these approaches (e.g., transmit a signal at different intervals based on the state change of shock sensor  100  or of the electronic device). 
     Detection circuitry  102  may be configured to detect momentary short circuits. Based on the duration of the short circuit, detection circuitry  102  may ignore or process the short circuit. For example, a short circuit that is detected for a very short duration may be processed as a short circuit that occurred because the device was subjected to a substantial shock event and immediately failed. As another example, a short circuit that is detected for a longer duration may be processed as a false positive caused by a temporary displacement of movable component or substance  108  from the first position to the second position. The windows for interpreting the duration of short circuits may be selected in any suitable manner, for example using empirical data. In some embodiments, shock detection circuitry  102  may interface with a processor of the electronic device before interpreting a short circuit (e.g., to determine whether the electronic device has failed). 
     In some embodiments, shock detection circuitry  102  may be incorporated in the electronic device in which shock sensor  100  is implemented. For example, shock detection circuitry  102  may be incorporated in the processor of the electronic device. In such embodiments, the electrical signal provided by shock detection circuitry  102  may be configured to modify the state of the electronic device instead of the state of shock sensor  100 . 
     Shock sensor  100  may be electrically coupled to the electronic device in any suitable manner. In some embodiments, shock sensor  100  may be soldered to a circuit board of the electronic device in which shock sensor  100  is implemented. Soldering shock sensor  100  directly to the circuit board provides an easy, repeatable, and reliable method for coupling shock sensor  100  to the circuit board. Effectively, the shock sensor may simply become another element that is assembled to the electronic devices circuit board. In some embodiments, shock detection circuitry  102 , shock detection contacts  104 , or both may be soldered to a circuit board of the electronic device. 
     To determine whether shock sensor  100  was subject to a shock event even that exceeded the impact threshold level, a technician may use two approaches. A first approach may be to detect the electrical signal provided by shock detection circuitry  102  or to detect the effect of the electrical signal provided by shock detection circuitry  102 . To detect the electronic signal or the electronic signals effect, a technician may use diagnostic device  110 . For example, in embodiments in which shock detection circuitry  102  continually transmits an electrical signal, the technician may couple diagnostic device  110  to shock detection circuitry  102  and detect the impedance, voltage, or current provided by detection circuitry  102 . As another example, if the electronic signal modified the state of shock sensor  100  or of the electronic device, the diagnostic device may be configured to identify the state variable of shock sensor  100  or of the electronic device. Based on the value of the state variable, diagnostic device  110  may determine whether shock sensor  100  was subject to a shock event that exceeded the impact threshold level. 
     In some embodiments, the electronic device, shock sensor  100 , or both may fail and prevent diagnostic device  110  from determining whether an electronic signal was provided by shock detection circuitry  102 . For example, if shock sensor  100  does not have power, diagnostic device  110  cannot determine whether shock detection circuitry  102  would continuously transmit an electronic signal if power were available. As another example, if a shock event caused a complete failure of the electronic device, diagnostic device  110  cannot determine whether shock detection circuitry  102  attempted to modify the state of shock sensor  100  or of the electronic device. 
     When diagnostic device  110  cannot provide a conclusive answer as to whether shock sensor  100  endured a shock event exceeding the impact threshold level, the technician may observe movable component or substance  108 . In some embodiments, the technician may be required to disassemble the electronic device in order to view shock sensor  100  and movable component or substance  108 . If the technician observes that movable component or substance  108  is in the second position, the technician may conclude that shock sensor  100  was subject to a shock event that exceeded the impact threshold level. If instead, the technician observes that movable component or substance  108  is in the first position, the technician may conclude that shock sensor  100  was not subject to a shock event exceeding the impact threshold level. 
     In some embodiments, after determining that shock sensor  100  was subject to a shock event that exceeded the impact threshold level, and thus that movable component or substance  108  moved from the first position to the second position, the technician may reset shock sensor  100 . To reset shock sensor  100 , the technician may return movable component or substance  108  to the first position. In addition, the technician may reset the state of shock sensor  100  and of the electronic device, if necessary (e.g., reset one or more bits in memory). The technician may also reset shock detection circuitry  102  so that it does not provide a continuous electrical signal (indicating the occurrence of a shock event that exceeded the impact threshold level). 
       FIG. 2  shows a simplified block diagram of illustrative portable electronic device  200  in which a shock sensor is implemented. Electronic device  200  may include processor  202 , storage device  204 , user interface  208 , display  210 , CODEC  212 , shock sensor  216 , bus  218 , memory  220 , communications circuitry  222 , and shock detection circuitry  223 . Processor  202  can control the operation of many functions and other circuitry included in electronic device  200 . Processor  202  may drive display  210  and may receive user inputs from user interface  208 . 
     Storage device  204  may store media (e.g., music and video files), software (e.g., for implementing functions on device  200 , preference information (e.g., media playback preferences), lifestyle information (e.g., food preferences), exercise information (e.g., information obtained by exercise monitoring equipment), transaction information (e.g., information such as credit card information), wireless connection information (e.g., information that may enable device to establish a wireless connection such as a telephone connection), subscription information (e.g., information that keeps tracks of podcasts or television shows or other media a user subscribes to), telephone information (e.g., telephone numbers), shock event information (e.g., a history of shock events that exceed an impact threshold level), and any other suitable data. Storage device  204  may include one more storage mediums, including for example, a hard-drive, permanent memory such as ROM, semi-permanent memory such as RAM, or cache. 
     Memory  220  may include one or more different types of memory which may be used for performing device functions. For example, memory  220  may include cache, Flash, ROM, and/or RAM. Memory may be specifically dedicated to storing firmware. For example, memory may be provided for store firmware for device applications (e.g., operating system, user interface functions, and processor functions). 
     Shock sensor  216  may be provided for detecting shock events to which device  200  is subject in accordance with an embodiment of the present invention. Shock sensor  216  may communicate with other circuitry in device  200  directly (not shown in this FIG.) or indirectly via bus  218 . 
     Shock detection circuitry  223  may be provided to monitor shock sensor  216 . Shock detection circuitry  223  may be configured, in response to determining that shock sensor  216  was subject to a substantial shock event, to provide an electrical signal to processor  202 , directing the processor to change the state of shock system  216  or device  200  (e.g., change one or more bits in storage  204  or memory  220 ). In some embodiments, shock detection circuitry may be configured to provide an electrical signal continuously or at least various intervals. 
     Bus  218  may provide a data transfer path for transferring data to, from, or between storage device  204 , shock sensor  216 , shock detection circuitry  213 , communications circuitry  222 , memory  220 , and processor  202 . Coder/decoder (CODEC)  212  may be included to convert digital audio signals into an analog signal, which may be provided to an output port (not shown). 
     Communications circuitry  222  may be included in a carrier circuitry portion (delimited by dashed lines  225 ) of device  200 . Carrier circuitry portion  225  may be dedicated primarily to processing telephone functions and other wireless communications (e.g., Wi-Fi or Bluetooth). It is understood that the carrier circuitry portion operate independent of other device components operating in device  200 . That is, carrier circuitry may be an independently operating subsystem within device  200  that may communicate with other components within device  200 . 
     User interface  208  may allow a user to interact with the device  200 . For example, the user input device  208  can take a variety of forms, such as a button, keypad, dial, a click wheel, or a touch screen. Communications circuitry  222  may include circuitry for wireless communication (e.g., short-range and/or long range communication). For example, the wireless communication circuitry may be Wi-Fi enabling circuitry that permits wireless communication according to one of the 802.11 standards or a private network. Other wireless network protocols standards could also be used, either in alternative to the identified protocols or in addition to the identified protocol. Another network standard may be Bluetooth. 
     Communications circuitry  222  may also include circuitry that enables device  200  to be electrically coupled to another device (e.g., a computer or an accessory device) and communicate with that other device. As indicated above, communications circuitry  222  may also include baseband circuitry for performing relatively long-range communications (e.g., telephone communications). If desired, communications circuitry  222  may include circuitry for supporting both relatively long-range and short-range communications. For example, communications circuitry  222  may support telephone, Wi-Fi, and Bluetooth communications. 
     In one embodiment, device  200  may be a portable computing device dedicated to processing media, such as audio and video. For example, device  200  may be a media player (e.g., MP3 player), a game player, a remote controller, a portable communication device, a remote ordering interface, an audio tour player, or other suitable personal device. In another embodiment, device  200  may be a portable device dedicated to providing media processing and telephone functionality in a single integrated unit. Device  200  may be battery-operated and highly portable so as to allow a user to listen to music, play games or video, record video or take pictures, place and take telephone calls, communicate with others, control other devices, and any combination thereof. In addition, device  200  may be sized such that it fits relatively easily into a pocket or hand of the user. By being handheld, device  200  is relatively small and easily handled and utilized by its user and thus may be taken practically anywhere the user travels. 
       FIGS. 3A ,  3 B,  4 A and  4 B describe illustrative shock sensors that include shock detection contacts and a movable component or substance that can be moved from a first position to a second position. These illustrative shock sensors will be described in more detail in the following discussion. 
       FIG. 3A  is a simplified cross-sectional view of an illustrative shock sensor system that includes both active and passive attributes. Sensor  300  includes chamber  302  that may be mounted in an electronic device (not shown). Contacts  304  and  306  extend inside chamber  302  and may be soldered to a circuit board of the electronic device (e.g., a flex board or a rigid board). Contacts  304  and  306  are separated such that, in the absence of a conductor between contacts  304  and  306 , the electrical circuit formed by contacts  304  and  306  is OPEN. 
     Chamber  302  may be constructed from any suitable material including, for example, glass, plastic and composite materials. Chamber  302  can be transparent or translucent to permit an operator to view the location and color of fluid in the chamber (e.g., to passively determine whether chamber  302  was subjected to a shock event that exceeded the impact threshold level). To prevent liquid from leaving chamber  302  through the chamber wall at the location where contacts  304  and  306  extend into the chamber, chamber  302  may be constructed such that contacts  304  and  306  are inserted into the chamber wall when portions of the chamber are selectively melted. For example, chamber  302  may be heated to a viscous state and contacts  304  and  306  (e.g., the tips of exposed wires) may be inserted through the viscous chamber wall. When chamber  302  is cooled and becomes solid, contacts  304  and  306  extend securely through the chamber wall. 
     Contacts  304  and  306  may be any suitable conductive material. For example, contacts  304  and  306  may be constructed from copper, silver, gold, aluminum, nickel, lead, graphite, or any other suitable conductor. Contacts  304  and  306  can be soldered to the circuit board using flux to prevent the formation of metal oxides and to enhance wetting. Fluid  312  of shock sensor  300  (discussed in more detail below) can be selected such that it does not boil at soldering temperatures (e.g., so that it does not boil and cause reservoir  310  or membrane  314  to rupture when contacts  304  and  306  are electrically coupled to a circuit board). 
     Chamber  302  includes reservoir  310  enclosed within chamber  302  (e.g., attached to the inner surface of chamber  302  at one end of the chamber). Reservoir  310  may at least partially be filled with conductive fluid  312 . Fluid  312  may be maintained within reservoir  310  by membrane  314 , which may be coupled to tip  311  of chamber  310 . Membrane  314  may be constructed to rupture in response to a shock event that exceeded the impact threshold level of shock sensor  300 . 
     In some embodiments, reservoir  310  may be incorporated in chamber  302  such that membrane  314  separates chamber  302  into two sections. Membrane  314  may be coupled to reservoir  310  or to chamber  302  in any suitable manner. For example, an adhesive may be used to attach membrane  314  to reservoir  310 . The adhesive may be selected such that it releases membrane  314  when the shock event on the electronic device exceeds the impact threshold level. As another example, membrane  314  may be manufactured as part of reservoir  310  (e.g., molded in the reservoir). 
     In some embodiments, reservoir  310  can be configured to rupture when the electronic device receives a shock event that exceeds the impact threshold level. In such embodiments, entire reservoir  310  can be constructed as membrane  314 . Reservoir  310  and membrane  314  may be formed from any suitable material such that reservoir  310  and membrane  314  are weaker, and therefore will break or separate before chamber  302  breaks. Such materials may include, for example, glass, plastic, composite materials, or any other such materials. 
       FIG. 3B  is a simplified cross-sectional view of the illustrative shock sensor system of  FIG. 3A  when the electronic device in which the shock event system is implemented is subjected to a shock event that exceeded the impact threshold level of the sensor. When the electronic device is subjected to such a shock event, conductive fluid  312  escapes from reservoir  310  and fills chamber  302 . Because conductive fluid  312  is conductive, it closes the electrical circuit between contacts  304  and  306 , resulting in transmission of a different electrical signal to detection circuitry. 
     Membrane  314 , reservoir  310 , or both may break or separate to allow conductive fluid  312  to fill chamber  310 . In the example shown in  FIG. 3B , membrane  314  ruptured, and is no longer shown in  FIG. 3B . Conductive fluid  312  may be colored such that it may be clearly visible within reservoir  310  or chamber  302 . 
     To set the impact threshold level at which shock sensor  300  allows conductive fluid  312  to short contacts  304  and  306 , a number of parameters may be adjusted. These parameters include, for example, the density and volume of conductive fluid  312  in reservoir  310 , the diameter of reservoir  310 , the strength of membrane  314 , the manner in which membrane  314  may be coupled to reservoir  310 , the wall thickness of reservoir  310 , or any other suitable parameter. 
     With shock sensor  300 , there are two methods for determining whether the electronic device in which the shock sensor was implemented was subjected to a shock event that exceeded the impact threshold level. First, when conductive fluid  312  fills chamber  302 , the electrical circuit between contacts  304  and  306  may be closed and an electrical signal may be provided. The electrical signal may be received or identified by a suitable diagnostic device. 
     If the electronic device is so damaged that it is not able to transmit an electronic signal indicative of shock event status, shock sensor  300  provides passive shock detection for determining whether the electronic device was subjected to a shock event or impact that exceeded the impact threshold level. In some embodiments, the electronic device may need to be opened to observe chamber  302  to determine whether conductive fluid  312  is visible within entire chamber  302  (indicating that shock sensor  300  was subjected to a shock event that exceeded the impact threshold level). 
     It should be understood that detection of a passive attribute of the shock sensor need not always require that the electronic device be opened or disassembled. In some embodiments, the electronic device may include a transparent part that permits a technician to see chamber  302 . In some embodiments, a passive RFID tag may be electrically coupled to contacts  304  and  306 . The RFID tag may provide a signal when contacts  304  and  306  are shorted together by, for example, conductive fluid  312 . When contacts  304  and  306  are shorted, this short circuit may close a circuit connecting in the RFID tag, thereby enabling the RFID tag to emit a signal (which may indicate that the electronic device has been subject to a shock event that exceeds the impact threshold level) in response to receiving a signal from a RFID detection device. If the RFID detection device does not receive a signal from the RFID tag, this may indicate that the electronic device has not been subject to an excessive shock event. An advantage of using a passive RFID tag may be that it does not require a power source to operate, as it receives power in the signal provided by the RFID detection device. If desired, active RFID tags may be used in lieu of passive RFID tags. It is understood that RFID tags may be used for any shock sensor embodiment described herein. 
       FIG. 4A  is a simplified cross-sectional view of another illustrative shock sensor system that incorporates both active and passive attributes. Shock sensor  400  includes chamber  402  and spring  404 . Chamber  402  encloses spring  404  in at least two directions (e.g., up and down, as shown in  FIG. 4A ). Chamber  402  can be a tubular structure, a rectangular structure (e.g., similar to box  102  of  FIG. 1 ), or any other suitable structure for disposing spring  404  within the structure. In some embodiments, as shown in  FIG. 4C , chamber  402  may be coupled to the fixed end of spring  404  at contact point  405  (e.g., the open end of chamber  402  is by the free end of spring  404 , and not by the fixed end). 
     Chamber  402  may be constructed from any suitable material. In particular, chamber  402  may be constructed from an electrically conducting material to transmit electrical signals when shock sensor  400  is subjected to a shock event that exceeded the impact threshold level. Chamber  402  may also be constructed from a material that has magnetic properties. For chamber  402  to exhibit both of these properties, chamber  402  may be constructed from, for example, steel, iron, iron based alloys, or any other material that may be both electrically conductive and magnetic. Other suitable materials may include permanent magnets and electro-magnets. 
     Spring  404  may be a cantilever spring that may be fixed to shock sensor  400  (or to the electronic device in which shock sensor  400  is implemented) at contact point  405 . Contact point  405  may be a point of plate  406  that may be fixed with respect to chamber  402 . In some embodiments, contact point  405  may be on chamber  402  (e.g., if chamber  402  extends where plate  406  is shown in  FIG. 4A ). At its resting position, spring  404  may be configured to be equidistant from each section of chamber  402 . In some embodiments, spring  404  and plate  406  may be constructed from electrically conductive material. 
     Magnet  410  may be coupled to the free tip of spring  404 . Magnet  410  may be any suitable magnet, for example a permanent magnet. Magnet  410  may be constructed in any suitable shape. In the example of  FIG. 4A , magnet  410  may be spherical. Other suitable shapes may include, for example, cylindrical, polyhedral, trapezoidal, or rectangular. 
     The polarity of magnet  410  and chamber  402  may be configured such that magnet  410  may be attracted to chamber  402 . For example, top portion  411  of magnet  410  may be a north pole, and upper wall  412  may be a south pole such that top portion  411  may be magnetically attracted to upper wall  412 . Similarly, bottom portion  413  of magnet  411  may be a south pole, and lower wall  414  may be a north pole such that bottom portion  413  may be magnetically attracted to lower wall  414 . The strength of the magnetic attraction between walls  412  and  414  and the portions of magnet  410  may be configured such that magnet  410  remains in an equilibrium position at equal distances from each of upper and lower walls  412  and  414 , respectively. 
     Shock sensor  400  includes shock detection circuitry  420  for transmitting a signal when shock sensor  400  is subjected to a shock event that exceeded the impact threshold level. Circuitry  420  may be electrically coupled to chamber  402  and to plate  406  by paths  422  and  424 , respectively. When the circuit between paths  422  and  424  is closed, an electrical signal or a change in a state may be detected by shock detection circuitry  420 . Detection circuitry  420  may register or store the occurrence of an excessive shock event so that such information can be provided, for example, to a diagnostic device. In the embodiment of  FIG. 4C , circuitry  420  may be electrically coupled by paths  422  and  424  to different portions of chamber  402  that are electrically insulated from each other. 
     In some embodiments, detection circuitry  420  may transmit an electrical signal continuously or at various intervals in response to determining that the circuit between paths  422  and  424  has been closed. In some embodiments, detection circuitry  420  may change the state of shock sensor  400 , for example by changing one or more bits in the memory of detection circuitry  420 . In some embodiments, detection circuitry  420  may change the state of the electronic device, for example by changing one or more bits in the memory of the electronic device. 
     When shock sensor  400  is subjected to a shock event that exceeds the impact threshold level, spring  404  bends and magnet  410  comes into contact with chamber  402 .  FIG. 4B  is a simplified cross-sectional view of the shock sensor system of  FIG. 4A  when the sensor has been subjected to a shock event that exceeds the impact threshold level. 
     When bottom magnet  410  comes into contact with chamber  402 , the electrical circuit formed by paths  422  and  424  may be closed, and an electrical signal may be transmitted to detection circuitry  420 . The electrical signal can be transmitted because all of plate  406 , spring  404 , magnet  410  and chamber  402  are constructed from electrically conductive materials. 
     In addition, because bottom portion  413  and lower wall  414  are subject to a magnetic attraction forces magnet  410  remains in contact with chamber  402  after the shock event has dissipated. An external force may be required to release magnet  410  from chamber  402 . 
     The impact threshold level for shock sensor  400  depends on a number of parameters. These parameters include the distance between chamber  402  and magnet  410 , the magnetic permeability and magnetic strength of magnet  410  and chamber  402 , the spring constant of spring  404 , the length of spring  404 , the mass of magnet  410 , and any other suitable parameter. These parameters may be chosen to define a particular impact threshold level. 
     With shock sensor  400 , there are two methods for determining whether the electronic device in which the shock sensor was implemented was subjected to a shock event that exceeded the impact threshold level. First, when magnet  410  comes into contact with chamber  402 , the electrical circuit formed by paths  422  and  424  may be closed, providing an electrical signal that can be received by detection circuitry  420 . The electrical signal can then be identified or measured, thus providing the functionality of an active shock sensor. 
     In addition, shock sensor  400  also exhibits the functionality of a passive shock sensor. If the electronic device is so damaged that a shock event signal is not capable of being read by diagnostic equipment, shock sensor  400  may be observed to determine the location of magnet  410  within chamber  402 . In particular, if magnet  410  is in contact with chamber  402 , it indicates that shock sensor  400 , and therefore the electronic device in which it is implemented, was subjected to a shock event that exceeded the impact threshold level and caused magnet  410  to bend spring  404  so far that magnet  410  came into contact with chamber  402 . In some embodiments, a technician may be required to at least in part disassemble the electronic device to view shock sensor  400 . 
     Unlike many purely passive shock sensors, shock sensor  400  may be not a single use sensor. Instead, shock sensor  400  may be reset within the electronic device by returning magnet  410  to its equilibrium position away from chamber  402  and by resetting the state of the electronic device (e.g., resetting the bit in memory that was modified to indicate a shock event that exceeded the impact threshold level). 
     To reset magnet  410 , the technician may use an appropriate tool.  FIG. 5  is a perspective view of a resetting tool for the shock sensor system of  FIGS. 4A and 4B . Tool  500  may be a U-shaped device that may be configured to fit between chamber  402  and spring  404  ( FIG. 4B ). Tool  500  includes points  502  and  504  that may be configured to slide between magnet  410  and chamber  402  such that point  502  or  504  separates magnet  410  from chamber  402 . Tool  500  may have any suitable thickness  506 . In some embodiments, thickness  506  may be selected such that magnet  410  may be released from the magnetic attraction of chamber  402  when magnet  410  is at a distance  506  from the wall. 
     Tool  500  may be constructed from non-magnetic material to avoid undesired interactions with chamber  402  or magnet  410 . A technician may insert tool  500  into shock sensor  400  in any suitable manner. For example, chamber  402  may include a aperture configured to receive points  502  and  504 . As another example, tool  500  may be inserted in the space between chamber  402  and plate  406 . 
       FIG. 6  shows an illustrative flow chart for actively and passively indicating the occurrence of a shock event. Process  600  begins at step  602 . At step  604 , the movable component or substance of a shock sensor moves from a first position to a second position. For example, the movable component or substance may move to a second position in response to a shock event that exceeds an impact threshold level of the shock sensor. The movable component or substance may include, for example, conductive fluid retained within a chamber, or a cantilever spring with a magnet enclosed by a chamber. 
     At step  606 , detection circuitry of the shock sensor provides an electrical signal. For example, the detection circuitry may monitor the movable component or substance, and provide an electrical signal in response to the movable component or substance moving to the second position. In some embodiments, the detection circuitry may monitor shock detection contacts that are configured to be short circuited by the movable component or substance when it is in the second position. The electrical signal may be continuously or intermittently provided for detection by a diagnosis device. Alternatively or in addition, the electrical signal may cause the shock sensor or an electronic device in which the shock sensor is implemented to change its state (e.g., change one or more bits in memory). The diagnosis device may then be configured to detect the change in state. The electrical signal or of its effect may be used to actively detect the occurrence of shock events. 
     At step  608 , a technician observes the movable component or substance. For example, the technician may observe whether the movable component or substance is in the second position, passively indicating the occurrence of a shock event. The movable component or substance may be configured to remain in the second position after a substantial shock event to provide passive detection of shock events. In some embodiments, the technician may be required to disassemble the electronic device in which the shock sensor is implemented to observe the movable component or substance. Process  600  then ends at step  610 . 
       FIG. 7  shows an illustrative flow chart of a process for determining whether an electronic device in which a shock sensor system has been implemented has been subjected to a shock event that exceeded the impact threshold level for the device. Process  700  begins at step  702 . At step  704 , a technician connects a diagnostic device to an electronic device including an active/passive shock sensor according to an embodiment of the invention. The diagnostic device may check paths  302  and  304  ( FIG. 3A ) or paths  420  and  422  ( FIG. 4A ). At step  706 , the diagnostic device determines whether an electrical signal indicating that a shock event exceeding the impact threshold level is present. For example, the diagnostic device may detect an electrical signal or the detection circuitry may identify a change of state of the electronic device (e.g., a bit changed in memory). The electrical signal may be transmitted because a movable component or substance of the shock sensor closed the electrical circuit between the shock sensor cables. This is an examination of the active feature of the shock sensor. If the detection circuitry detects an electrical signal, process  700  moves to step  708 . 
     At step  708 , the technician determines, based on the presence of the electrical signal, that the electronic device was subjected to a shock event that exceeded the impact threshold level. Process  700  then ends at step  710 . 
     If, at step  706 , the detection circuitry instead does not detect an electrical signal, process  700  moves to step  712 . At step  712 , the technician determines whether the electronic device is too badly damaged to provide active shock detection. For example, the technician may determine whether the device powers up. As another example, the technician may determine whether individual components of the electronic device are operating when provided with power. If the technician determines that the electronic device is not too badly damaged to provide active shock detection, process  700  moves to step  714 . 
     At step  714 , the technician determines, based on the absence of the electrical signal and on the powering up of the electronic device, that the electronic device was not subjected to a shock event that exceeded the impact threshold level. Process  700  then ends at step  716 . 
     If, at step  712 , the technician instead determines that the electronic device is too badly damaged to provide active shock detection, process  700  moves to step  718 . At step  718 , the technician opens the electronic device to examine the shock sensor. This is an examination of the passive aspect of the shock sensor. At step  720 , the technician determines whether the shock sensor passively indicates that the electronic device was subjected to a shock event that exceeded the impact threshold level. To do so, the technician may determine whether a movable component or substance of the shock sensor moved from a first position to a second position. For example, the technician may determine whether fluid  312  is present in chamber  302  ( FIG. 3B ). As another example, the technician may determine whether magnet  410  is in contact with chamber  402  ( FIG. 4B ). If the technician determines that the shock sensor does not passively indicate that the electronic device was subjected to an exceedingly high shock event, process  700  moves to step  714 . 
     If, at step  720 , the technician instead determines that the shock sensor passively indicates that the electronic device was subjected to an exceeding shock event, process  700  moves to step  708 . In some embodiments, after step  708 , process  700  may include a step for resetting the shock sensor. For example, the technician may return magnet  410  to its equilibrium position away from chamber  402  ( FIGS. 4A ,  5 ). Process  700  then ends. 
     The above described embodiments of the present invention are presented for purposes of illustration and not of limitation, and the present invention is limited only by the claims which follow.

Metadata:
Filing Date: 20090422
Publication Date: 20110215
Grant Date: 20110215
Priority Date: 20070315
Inventors: ZADESKY STEPHEN P.
ROTHKOPF FLETCHER R.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H29/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H35/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H29/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H35/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01P15/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01P15/06", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 39762116