Abstract:
Stackable electronic devices are disclosed which can be stacked onto each other in such a manner that electrical contacts with one device mate with electronic contacts on other devices either above or below the device to create an electrical connection between the devices in the stack. Magnets or latches can be used to secure the stacked devices together. The contacts, as well as status indicators, are arranged in common locations on the devices and the devices can be capable of automatically configuring addressing, device capabilities, and wireless communication paths.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to peripheral devices for a mobile hotspot product line. More specifically, the present invention relates to a family of stackable peripheral devices for a mobile hotspot device, including items like external batteries, projectors and speakers. 
       BACKGROUND 
       [0002]    A number of approaches have been considered for managing peripherals to mobile hotspot product lines. The most common approach requires either cables or manual configuration of wireless connectivity. A modular approach is desired, without cabling, with auto-discovery and configuration. 
       SUMMARY 
       [0003]    One embodiment of the invention includes a stackable set of peripherals, held together with magnetics and latches. A 6 pin connector providing power distribution and basic device setup capability can be used. The peripherals can have a common USB connector location and LED location and meaning. A basic configuration can allow for automatic configuration of addressing, discovery of device capability, and configuration of wireless communications paths. Wireless communications paths from the mobile hotspot to the peripheral can be automatically configured and can be used for all subsequent data transport. Embodiments can provide for centralized control by cellular access point, automatic device capability detection and communication establishment, configuration initiated on mating, maintained when unmated, enhanced power management, allowing for central control of charging mechanisms, centralized power management, allowing for dynamic allocation of charging resources. Embodiments may employ a power management process that may provide controlled power up, mobile hotspot control of power distribution, and local battery and external battery support. Embodiments may also provide automatic device detection and configuration, use of SMBus for address allocation, use of power pins to allow controlled power up, use of proprietary device information field to determine capabilities of peripherals, and use of proprietary device configuration fields for configuration of device capabilities (Bluetooth, WiFi, battery primarily). Embodiments may provide a protocol used in the configuration and management of a peripheral from a mobile hotspot where discovery is done through an ARP process. The capability of the peripheral may be provided in an extensible data string. Power charging can be independently enabled for each peripheral by the mobile hotspot or power charging may be automatically enabled in the absence of the mobile hotspot. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIGS. 1A-1D  illustrate an embodiment of the invention employing a pico projector for projecting images on a large surface; 
           [0005]      FIG. 1E  is a table that illustrates various features and accessories available for the different uses of embodiments of the invention; 
           [0006]      FIGS. 2A-2B  illustrate an embodiment of the invention employing a pico projector to allow media sharing by pushing the shared media to a pico projector; 
           [0007]      FIGS. 3A-3C  illustrate an embodiment of the invention employing a pico projector with a mobile app to allow users to use their mobile devices to interact with the app and to project the users&#39; interaction; 
           [0008]      FIGS. 4A-4E  illustrate an embodiment of the invention employing a pico projector to allow users to create and project collaborative projects such as presentations; 
           [0009]      FIGS. 5A-5B  illustrate an embodiment of the invention employing a pico projector to electronically design different styles of makeup and to project the different makeup styles onto a person for previewing how the makeup style would look on the person; 
           [0010]      FIGS. 6A-6D  illustrate an embodiment of the invention employing a pico projector and mobile device to create an interactive whiteboard; 
           [0011]      FIGS. 7A-7H  illustrate various other embodiments of the invention employing pico projectors for various imaginative use cases; 
           [0012]      FIGS. 8A-8D  illustrate a stackable embodiment of the invention having a generally square shape; 
           [0013]      FIGS. 9A-9B  illustrate a stackable embodiment of the invention having a generally hexagonal shape; 
           [0014]      FIG. 9C  illustrates a stackable embodiment of the invention having a generally “donut” shape; 
           [0015]      FIG. 9D  illustrates a stackable embodiment of the invention having a generally square shape stacked in a staggered stack configuration; 
           [0016]      FIGS. 10A-10B  illustrate a stackable embodiment of the invention having a generally round shape; 
           [0017]      FIGS. 11A-11D  illustrate a disassembled stack of a stackable embodiment of the invention having a generally square shape; 
           [0018]      FIGS. 12A-12D  illustrate an alternative embodiment of the disassembled stack of  FIGS. 11A-11D ; 
           [0019]      FIGS. 13A-13D  illustrate another alternative embodiment of the disassembled stack of  FIGS. 11A-11D ; 
           [0020]      FIGS. 14A-14E  illustrate still another alternative embodiment of the disassembled stack of  FIGS. 11A-11D ; 
           [0021]      FIGS. 15A-15C  illustrate a disassembled stack of a stackable embodiment of the invention having a generally round shape; 
           [0022]      FIGS. 15D-15G  illustrate an alternative embodiment of the disassembled stack of  FIGS. 11A-11D ; 
           [0023]      FIGS. 16A-16D  illustrate another embodiment of the disassembled stack of  FIGS. 11A-11D ; 
           [0024]      FIGS. 17A-17F  illustrate an alternative embodiment of the disassembled stack of  FIGS. 11A-11D ; 
           [0025]      FIG. 18A  shows a top view of a stackable embodiment of the invention having a generally square shape; 
           [0026]      FIG. 18B  shows a bottom view of the stackable embodiment shown in  FIG. 18A ; and 
           [0027]      FIG. 18C  shows a side view of the stackable embodiment shown in  FIG. 18A . 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Embodiments of the invention can include a number of use cases. These use cases can focus on an open development environment, allowing for innovative uses for projectors and speakers, and allowing for an interactive experience using existing handheld devices. The connectivity allowed through the stackable peripheral form factor and control protocol of various embodiments of the invention may enable a series of novel uses of a projector. These use cases address a number of current problems, including a variety of portable entertainment, educational, and medical use cases. For example, as illustrated in the Figures, possible use cases can include the extension of conventional projector scenarios, such as docking a projector to a mobile hotspot to configure connection, removing a projector from the mobile hotspot to locate in desired location, streaming data from a public WiFi network or a mobile hotspot based WiFi network. Embodiments may be useable in hotels, conferences, camping environments, medical environments, educational environments, or social events. Embodiments also provide media sharing applications such as sharing of media content, a smartphone based application may allow for distributed control and user initiated data distribution, embodiment may be useable in a classroom environment, with teacher controlling student access to a centralized projector and/or useable in collaborative design environments. Possible use of motion sensing or laser module technology may provide interactivity. Projection mapping applications may be included such as makeup application instructions and evaluation, providing GPS based directions for hiking, cycling, or other mobile applications, medical applications, allowing for better visualization to both patients and medical staff, gaming applications, allowing for artificial playing field to be projected on a surface, and/or food preparation, allowing for visualization of preparation activities. 
         [0029]    Embodiments of the invention can include media playback that works across mobile device platforms (without cords), wireless screen sharing in a variety of different environments and operating systems, as well as wired connections that work with commonly available cables connecting components to a variety of different devices. Wireless audio can be enabled that provides a truly wireless home theater experience. Embodiments can include automatic configuration so that they “just work” straight out of the box without any complicated setup required by the user, by configuring the devices to automatically pair with other nearby wireless devices. Extended battery life can be achieved through energy conservation and distribution methods included in stackable device as well as through the use of extra batteries configured as stackable elements with other stackable embodiments of the invention. 
         [0030]    One embodiment of the invention includes multiple elements which can perform different functions but which can interface and connect to each other either wirelessly or through stackable elements having similar form factors and common connectors and connector locations so that the stackable elements interconnect through the connectors in any order in which they are stacked. One embodiment of the invention can include a projector and speakers which automatically connect to and interact with a wireless hot spot or mobile device. 
         [0031]    Various different uses of this embodiment are illustrated in the Figures. For example,  FIGS. 1A-1D  illustrate a pico projector and speaker elements interacting with a mobile hotspot of mobile device to project images and/or video from the mobile hotspot or device onto any large surface.  FIG. 1A  illustrates how a family can use the projector and speakers to project a movie onto a large surface, such as a wall, providing the family with a real home theater experience complete with a large movie screen. Because embodiments of the invention can be mobile, the family can bring their projector and speakers with on vacation so that they can enjoy their typical entertainment while away from home, such as in a hotel room as shown in  FIG. 1B . Embodiments of the invention can also be useful in other applications, such as, for displaying a large image of an x-ray in a doctor&#39;s office as illustrated in  FIG. 1C . The pico projector can be configured with automatic keystoning so that images can be displayed undistorted on uneven surfaces as illustrated in  FIG. 1D .  FIG. 1E  illustrates various features and accessories associated with different applications of embodiments of the invention. 
         [0032]      FIGS. 2A-2B  illustrate another potential use case for a pico projector and speakers for embodiments of the invention. In this use case, a mobile device user is able to push media from his mobile device to the pico projector so that the media can be easily shared with others. Applications (or apps) can also be designed and used with embodiments of the invention to facilitate cooperation and collaboration between multiple users. For  FIGS. 3A-3C  illustrate a use case in which an app is used on a mobile device which allow multiple users to queue up media content in the app which can be pushed to the projector and played for everyone. In the case illustrated in  FIGS. 3A-3C , a video jukebox app is used to allow multiple users to each queue up their favorite music videos which can be replayed by the projector in a party setting.  FIGS. 4A-4E  illustrate a scenario in which a presentation app can be used on a mobile device which allows multiple people to collaborate on a presentation which can be pushed to the projector and displayed on a large surface.  FIGS. 5A-5B  illustrate a use case in which sample makeup schemes can be configured on an app on a mobile device, pushed to the projector, and projected onto a person&#39;s face so that the scheme can be previewed on a person before the makeup is actually applied to the person.  FIGS. 6A-6   d  illustrate a use case in which a digital whiteboard app can be used for multiple users to design and comment on a product design. The design and comments can be pushed to the projector and projected on a large surface allowing all collaborators to easily view the design and comments.  FIGS. 7A-7H  illustrate various other use cases contemplated for various embodiments of the invention. 
         [0033]    A pico projector according to various embodiments of the invention can be configured to automatically adapt to the A2Dp compression/decompression cycle. The projector and audio devices can be configured to support a protocol like APTX Low Latency to reduce latency. When paired with variable latency devices, the projector can be configured to auto-correct to maintain proper A/V sync. There is typically an inherent, obvious delay (up to 150+ ms) in the standard Bluetooth A2DP compression/decompression cycle. This delay is usually only tolerable for audio-only application but it is not ideal for video. A predictable, low latency is better suited for video playback applications. Pico projectors according to the subject application can be configured to automatically handle and down convert a full range of audio encodings. If a user connects a 7.1 DRS source, the projection can be configured to immediately down convert the input to stereo without user intervention. 
         [0034]    Users are typically not satisfied when they experience a case where the projector isn&#39;t able to play audio because it uses a done-convert special encoding. While the device doesn&#39;t need to playback these advanced encodings, it preferably should be able to down convert. A pico projector according to the subject application can be configured to automatically handle and down-convert a full range of video encodings—including 4K and 240 hZ+ sources. Basic video settings like brightness contrast, color temperature, and color modes can be made available. Users can also adjust video rotation and toggle between rear/front projection. Embodiments can also be configured to digitally zoom an image produced by the projector. Preferably, user interaction with video settings should be extremely limited. Embodiments of the invention can be configured so that users do not need to adjust video settings on the projector or source device unless they want to do so. 
         [0035]    Embodiments of the invention can stackable peripherals (each of which can perform a different function) can include a common form factor with common a connector and connector location, common physical dimensions, common peripheral appearances in terms of colors and textures, common location and selection of magnetics, common location and selection of any latching mechanisms, common location and selection of USB connector, and common location and meaning of indicators so that they are easily stable and so that a user can easily learn where to look and what to look for on these stackable devices. The mechanical features of embodiments of the invention can allow for proper orientation and mating of the accessories, the electrical features can allow for proper power distribution and signaling between accessories, and the software features can define the discovery and configuration of accessories. 
         [0036]    The pinout configuration of one embodiment is outlined below: 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Pinouts 
               
             
          
           
               
                   
                 SIGNAL 
                   
               
               
                 PIN# 
                 NAME 
                 Description 
               
               
                   
               
               
                 1 
                 GND 
                 GND-Contact Resistance can be 25 mohms 
               
               
                   
                   
                 max for connector pin; Current rating can be 3A 
               
               
                   
                   
                 (continuous) min. 
               
               
                 2 
                 I2C_SDA 
                 I2C DATA-3.3 V LOGIC. Bidirectional 
               
               
                   
                   
                 signal. Accessory shall not pull this line low when 
               
               
                   
                   
                 powered off. The signal can conform to the standard 
               
               
                   
                   
                 I2C interface as defined by UM10204, and can 
               
               
                   
                   
                 conform to the modifications defined by the 100  
               
               
                   
                   
                 KHz SMBus as defined by SMBus Specification  
               
               
                   
                   
                 V3.0. An appropriate series resistor (~500 ohms)  
               
               
                   
                   
                 can be provided for hot insertion protection. 
               
               
                 3 
                 I2C_SCL 
                 I2C CLOCK-3.3 V LOGIC INPUT to 
               
               
                   
                   
                 accessory. Accessory shall not pull this line low 
               
               
                   
                   
                 when powered off. It should be pulled high with a 
               
               
                   
                   
                 100K resistor 
               
               
                 4 
                 ACC_INT 
                 ACCESSORY INTERRUPT ACTIVE LOW 
               
               
                   
                   
                 OUTPUT, This line should be Tri-stated when there 
               
               
                   
                   
                 is no interrupt and when accessory is powered off. It 
               
               
                   
                   
                 should be pulled hi by a 100K resistor, and protected 
               
               
                   
                   
                 by an appropriate series resistor (~500 ohms) 
               
               
                 5 
                 CHG_EN 
                 CHARGE ENABLE-ACTIVE HIGH 
               
               
                   
                   
                 INPUT-3.3 V LOGIC. This line should be pulled  
               
               
                   
                   
                 high by a 100K resistor. 
               
               
                 6 
                 VBUS 
                 INPUT POWER 4.75 V min −5.5 V max- 
               
               
                   
                   
                 Contact Resistance can be 25 mohms max for 
               
               
                   
                   
                 connector pin; Current rating shall be 3A 
               
               
                   
                   
                 (continuous) min. 
               
               
                   
               
             
          
         
       
     
         [0037]    The signaling configuration for one embodiment of the invention is outlined below: 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Signaling Specification 
               
             
          
           
               
                 Number 
                 Requirement 
                 Comments 
               
               
                   
               
               
                 Sig-1 
                 The device can provide common 
                 There is one on the top and one 
               
               
                   
                 connectors as described below. 
                 on the bottom 
               
               
                 Sig-2 
                 The sample pinout presented 
                   
               
               
                   
                 herein can be supported. 
                   
               
               
                 Sig-3 
                 The 2 wire bus can conform to 
                 100 KHz seems adequate for 
               
               
                   
                 SMBus V2 
                 this case, and specs get a lot 
               
               
                   
                 Supports 100 KHz operation 
                 more complicated at 400 KHz. 
               
               
                   
                 Operates at 3.3 V 
                 ARP processing can require 
               
               
                   
                 Fully supports ARP functionality 
                 additional software and 
               
               
                   
                 Requires a non-persistent slave 
                 hardware, allowing for 
               
               
                   
                 address (Non-PSA) 
                 contention to be seen and acted 
               
               
                   
                 Requires PEC parity generation 
                 upon. 
               
               
                   
                 and processing on all 
                 Non-persistent addresses mean 
               
               
                   
                 transmissions and receptions 
                 that it can clear on “power up”. 
               
               
                   
                 Presence of signal on the I2S-SCL 
                 Since the battery may be 
               
               
                   
                 line shall be considered “power 
                 optional, this uses presence of 
               
               
                   
                 up” in the ARP functionality, 
                 I2C-SCL to indicate “power 
               
               
                   
                 clearing allocated addresses. 
                 up”. 
               
               
                   
                   
                 PEC is recommended in a hot- 
               
               
                   
                   
                 swap environment. 
               
               
                 Sig-4 
                 The accessory can draw power 
                 Power draw from the VBUS 
               
               
                   
                 from VBUS in the following scenario:  
                 line can be directly under control of 
               
               
                   
                 CHG_EN is high 
                 the mobile hotspot. It can be pulled 
               
               
                   
                 VBUS is above 4.75 V 
                 high on each accessory so they will 
               
               
                   
                 The device has NOT been sent a 
                 charge when no mobile hotspot is 
               
               
                   
                 command to disable charging 
                 present, and pulled low on the mobile 
               
               
                   
                   
                 hotspot so that a dead mobile hotspot 
               
               
                   
                   
                 can receive all VBUS power. 
               
               
                 Sig-5 
                 The accessory can be capable of 
                 This signal is not really needed, 
               
               
                   
                 asserting the ACC_INT signal, when a 
                 but is being provided to cover 
               
               
                   
                 pre-defined and agreed upon event 
                 future contingencies. 
               
               
                   
                 requires notification of the mobile  
                 The mobile hotspot should be 
               
               
                   
                 hotspot bus master. 
                 polling for ARQ at least at 10 
               
               
                   
                 At this time, it will be asserted on 
                 sec intervals. 
               
               
                   
                 connection of the device to the 
                 This will allow responses to be 
               
               
                   
                 mobile hotspot, as determined by 
                 much faster, hopefully within 1 
               
               
                   
                 presence of signal on the I2S-SCL 
                 sec of the SMBus being 
               
               
                   
                 line. 
                 available. 
               
               
                   
                 Additional functionality may be 
                   
               
               
                   
                 defined in the future. 
                   
               
               
                 Sig-6 
                 The device can be capable of 
                   
               
               
                   
                 communicating on the SMBus within  
                   
               
               
                   
                 500 ms of detection of signal on the  
                   
               
               
                   
                 I2S-SCL line. 
                   
               
               
                 Sig-7 
                 The device can be configured to 
                   
               
               
                   
                 draw no more than 500 mA of current 
                   
               
               
                   
                 from the VBUS line. 
                   
               
               
                 Sig-8 
                 The device can have a micro USB 
                 The local USB should be in the 
               
               
                   
                 plug, located as specified herein 
                 same locations for all devices, and is 
               
               
                   
                 This can support charging the 
                 used for local power and local 
               
               
                   
                 device battery and communication 
                 communications only. 
               
               
                   
                 with the device. 
                   
               
               
                   
                 The device battery, and the USB 
                   
               
               
                   
                 plug will not support charging of 
                   
               
               
                   
                 the VBUS power line. 
                   
               
               
                 Sig-9 
                 INFORMATIONAL: 
                 This should allow us to register 
               
               
                   
                 The mobile hotspot may perform 
                 devices within 1 sec of 
               
               
                   
                 the following functions in terms of  
                 connection 
               
               
                   
                 ARQ functionality: 
                 The addresses can be be 
               
               
                   
                 An ARQ will be sent every 10 sec 
                 assigned to the devices in order 
               
               
                   
                 to see if new devices are present. 
                 of connection. 
               
               
                   
                 If ACC_INT is asserted, the 
                 If multiple devices are 
               
               
                   
                 mobile hotspot will immediately 
                 connected at once, they are 
               
               
                   
                 perform an ARQ. 
                 assigned addresses in order of 
               
               
                   
                 Through the ARQ protocol, the 
                 UDID. 
               
               
                   
                 mobile hotspot will assign 
                 If more than 8 devices request 
               
               
                   
                 addresses, starting at the lowest 
                 an address, they will be given 
               
               
                   
                 UDID and continuing to the 
                 addresses, but denied access to 
               
               
                   
                 highest UDID. 
                 VBUS and not enabled for use 
               
               
                   
                 If there are more than 8 devices, 
                 by the mobile hotspot. 
               
               
                   
                 addresses will continue to be 
                   
               
               
                   
                 powered up, but will be told to 
                   
               
               
                   
                 disconnect from VBUS, and will 
                   
               
               
                   
                 not be enabled for use by the 
                   
               
               
                   
                 mobile hotspot 
               
               
                   
               
             
          
         
       
     
         [0038]    The software specification for one embodiment of the invention is provided below: This section specifies a software interface which may be used to configure and to maintain the stackable peripheral accessories. The basic philosophy is:
       All transfers can be performed by block transfers with PEC. These can be automatically made longer as more data is available, so to some degree, functionality can be added incrementally.   At this time, only 2 command codes are defined although 128 are available, so more can be used in the future.   There can be a READ block presented at a known command code (0x01) that presents the device type identity (UTF8) and a bitmask of device capabilities.   There can be a second READ block presented at a known command code (0x02) that presents device configuration and status.   There can be a WRITE block presented at a known command code (0x02) that accepts configuration information.       
 
         [0044]    With respect to discover, the stackable peripherals may use ARP protocol of SMBus which are described in more detail herein. With respect to device ID: 
         [0000]    
       
         
               
               
               
             
           
               
                   
               
               
                 Number 
                 Requirement 
                 Comments 
               
               
                   
               
             
             
               
                 Sw-1 
                 The device can provide device ID 
                 The (0) indicates a read. 
               
               
                   
                 information at Command Code  
                 Block format automatically 
               
               
                   
                 0000 001 (0) b consisting of 
                 adjusts length to accommodate 
               
               
                   
                 UTF8 representation of device name, 
                 all data. 
               
               
                   
                 between 0 and 50 characters, ending 
                 PEC provides error detection, 
               
               
                   
                 in &lt;EoTxt&gt; (0x03) 
                 and mobile hotspot may have 
               
               
                   
                 Bitmask of capabilities 
                 to request a retransmission. 
               
               
                   
                 b0-WiFi 
                 Device name should be 
               
               
                   
                 b1-Bluetooth 
                 uniquely defined by us 
               
               
                   
                 b2-Projector 
                   
               
               
                   
                 b3-Speaker 
                   
               
               
                   
                 b4-Battery Charger 
                   
               
               
                   
                 Filled with “0” to complete 
                   
               
               
                   
                 byte 
                   
               
               
                 Sw-2 
                 The device may provide device 
                 The (0) indicates a read. 
               
               
                   
                 configuration and status for each capability 
                 This approach allows for each 
               
               
                   
                 independently. The Command Code at 
                 capability to be independently 
               
               
                   
                 which the capability is located can be 0000 
                 read and configured without an 
               
               
                   
                 010 (0) b for the first capability, 0000 011 
                 arbitrarily long number of 
               
               
                   
                 (0)b for the second capability, . . . , where  
                 command codes. 
               
               
                   
                 the format of capabilities is described below. 
                   
               
               
                 Sw-3 
                 The device may provide the ability to 
                 The (1) indicates a read. 
               
               
                   
                 configure each capability independently,  
                   
               
               
                   
                 by receiving a block write at the Command 
                 This approach allows for each 
               
               
                   
                 Code corresponding to the capability bit 
                 capability to be independently 
               
               
                   
                 mask. The Command Code at which the  
                 read and configured without an 
               
               
                   
                 first capability is configured is located at  
                 arbitrarily long number of 
               
               
                   
                 000 010 (1) b, 0000 0011 (1) b for the  
                 command codes. 
               
               
                   
                 second capability, . . . , where the format  
                   
               
               
                   
                 of capabilities is described below. 
                   
               
               
                 Sw-4 
                 The accessory may draw power from 
                 Power draw from the VBUS 
               
               
                   
                 VBUS only in the following scenario: 
                 line is directly under control of the 
               
               
                   
                 CHG_EN is high 
                 mobile hotspot. It&#39;s pulled high on 
               
               
                   
                 VBUS is above 4.75 V 
                 each accessory so they will charge 
               
               
                   
                 The device has NOT been sent a 
                 when no mobile hotspot is present, 
               
               
                   
                 command to disable charging 
                 and pulled low on the mobile hotspot 
               
               
                   
                   
                 so that a dead mobile hotspot will 
               
               
                   
                   
                 receive all VBUS power. 
               
               
                 Sw-5 
                 Bluetooth Configuration shall be: 
                   
               
               
                   
                 Bluetooth Friendly Name &lt;EOTxt&gt; 
                   
               
               
                   
                 Discoverable (1 bit) 
                   
               
               
                   
                 Connectible (1 bit) 
                   
               
               
                   
                 Send URCs (1 bit) 
                   
               
               
                   
                 Start Bluetooth (1 bit) 
                   
               
               
                   
                 Start BT in Test Mode 
                   
               
               
                   
                 Start BT in pass-through mode 
                   
               
               
                   
                 Start BT in HCI mode 
                   
               
               
                   
                 Start BTLE 
                   
               
               
                   
                 Clear persistent Bluetooth data 
                   
               
               
                   
                 Delete BT Local Keys 
                   
               
               
                   
                 Delete bonded device database 
                   
               
               
                   
                 Delete GATT database 
               
               
                   
               
             
          
         
       
     
         [0045]    It is contemplated that the peripheral devices will be stackable. A number of different stackable configurations have been contemplated. Several embodiments of stackable configurations are illustrated in the figures. For example,  FIGS. 8A-8D  illustrate a generally square-shaped set of peripherals which can be stacked in various different ways.  FIGS. 9A-9B  illustrate stackable peripherals having a hexagonal shape,  FIG. 9C  illustrates donut-shaped stackable peripherals, and  FIG. 9D  illustrates the square-shaped peripherals of  FIGS. 8A-8D  stacked in an alternative arrangement. 
         [0046]      FIGS. 10A-10B  illustrate generally circular-shaped stackable peripherals  100 . As shown in  FIG. 10A , LEDs  102  can be used to indicate the status, etc. of each individual peripheral. The peripherals can be configured so that the LEDs  102  all line up when the peripherals are in a stacked position. In this manner, it is easy for the user to find and identify the status of each individual peripheral.  FIGS. 11A-11D  illustrate some of the connector details and design of various embodiments of peripherals  110  designed in according with various aspects of the invention. In this embodiment, the top of each peripheral includes a recess  112  configured to mate with a protrusion  114  on the bottom of another peripheral  110 . Electrical contacts  116  can be hidden deep in the recess  112  in a location which mates with contacts  118  in the protrusion  114  of another peripheral  110 . In this manner, the peripherals  110  mate with each other in a stackable manner and are electrically connected to each other through the electrical contacts  116  and  118 . 
         [0047]      FIGS. 12A-12B  illustrate a generally square peripheral  120  having a beveled edge  122  in its protrusion  124  in which the electrical contacts  126  are located so that the contacts  126  do not touch the surface of a table or other structure onto which the peripheral  120  may be placed. The corresponding edges of the recess  128  in the top of the peripheral  120  can also be beveled to mate with the beveled edge  122  of the protrusion  124 . In  FIGS. 12C-12D , the top of a peripheral  130  can include a trap door  132  which can protect the contacts when the peripheral  130  is not mated with another peripheral  130 . The bottom of each peripheral  130  can include a contact block  134  which is configured to push down the trap door  132  so that the contacts hid by the trap door  132  are exposed and can mate with contacts in the contact block  134 . 
         [0048]      FIGS. 13A-13B  illustrate alternative embodiments of the peripherals  140  of  FIGS. 11A-11D . In  FIGS. 13A-13B , the recess  142  and protrusions  144  are reversed so that the top of each peripheral includes the protrusion  144  and the bottom of each peripheral  142  includes the corresponding recess. Similarly,  FIGS. 13C-13D  illustrate an alternative peripheral  150  embodiment of  FIGS. 12A-12D  with the protrusions  152  and recesses  154  similarly reversed.  FIGS. 14A-14C  illustrate an embodiment of peripheral  160  in which the contact block  162  can be configured to rotate. In the unmated position, the contact block  162  is rotated to protect the contacts (see  FIG. 14A ) while in the mated position, the contact block  162  is rotated to expose the contacts so that they can mate with contacts in another peripheral  160  (see  FIG. 14C ).  FIGS. 14D-14E  illustrate a similar alternative embodiment as that shown in  FIGS. 14A-14C , however, in the peripherals  170  illustrated in  FIGS. 14D-14E , the contact block  172  is fixed (i.e. it does not rotate). This is a simpler and generally less expensive design than that illustrated in  FIGS. 14A-14C , however, the contact in this embodiment remain exposed at all times which may lead to damage. Similar alternative embodiments are illustrated in  FIGS. 15A-15G, 16A-16D , and  17 A- 17 F.  FIGS. 18A-18C  illustrate top, bottom, and cross-sectional side views of one embodiment of peripheral designed in accordance with the present invention.