Abstract:
A data exchange system that exchanges data with a host device comprising controller and a host housing comprises at least one button assembly and a button reader system. The at least one button assembly comprises an encoder for storing data, a button coil, and a switch. Closing the switch forms an antenna circuit. The button reader system comprises a decoder and at least one reader coil defining at least one button position on the host housing. When the at least one button assembly is arranged at the at least one button position, the controller of the host device causes the decoder to obtain data from the encoder through the button coil and the reader coil when the switch is closed.

Description:
RELATED APPLICATIONS 
   This application claims priority of U.S. Provisional Patent Application Ser. Nos. 60/788,633 filed Jun. 20, 2006, and 60/788,870 filed Jun. 20, 2006. The contents of all related application listed above are incorporated herein by reference. 

   TECHNICAL FIELD 
   The present invention relates to radio frequency identification (RFID) systems and, in particular, to RFID systems that store data in a manner that allows the downloading of data to be controlled. 
   BACKGROUND OF THE INVENTION 
   RFID systems are becoming ubiquitous in everyday life. An RFID system contains two basic elements: a tag unit and an interrogator unit. The tag unit typically comprises an IC and an antenna. The IC comprises memory and processing circuitry. The interrogator unit contains an RF transceiver, processing circuitry, and an antenna. Power to the tag IC may be provided by the interrogator unit, so the tag unit need not contain a power storage system such as a battery. A tag unit that does not contain a power storage system is referred to as a passive tag unit. The interrogator portion may generate a signal that activates any tag unit within reach of the signal. When activated, any tag unit within signal reach transmits any data stored on the memory to the interrogator unit. 
   In many contexts, the data stored by a tag unit is not confidential. However, in other contexts, the stored data is confidential, and it is desirable to limit access to the data stored on a tag unit. The present invention relates to RFID systems and methods designed to limit access to data stored on a tag unit. 
   The present invention is of particular significance in the context of a button assembly that stores personal information such as telephone numbers, addresses, and the like. The present invention will thus be described herein in the context of RFID systems and methods that allow personal data to be transmitted from a button assembly to an electronic device such as a telephone or computer for storage and/or further processing. However, the principles of the present invention may have broader application, and the principles of the present invention should be determined by the claims appended hereto and not the following detailed description of the invention. 
   SUMMARY OF THE INVENTION 
   The present invention may be embodied as a data exchange system that exchanges data with a host device comprising controller and a host housing comprises at least one button assembly and a button reader system. The at least one button assembly comprises an encoder for storing data, a button coil, and a switch. Closing the switch forms an antenna circuit. The button reader system comprises a decoder and at least one reader coil defining at least one button position on the host housing. When the at least one button assembly is arranged at the at least one button position, the controller of the host device causes the decoder to obtain data from the encoder through the button coil and the reader coil when the switch is closed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a cell phone configured to include an example data exchange system constructed in accordance with, and embodying the principles of the present invention; 
       FIG. 2  is a block diagram of the cell phone and example data exchange system of  FIG. 1 ; 
       FIG. 3  is a perspective view of a computing device adapted to include a data exchange system similar to that employed by the cell phone of  FIG. 1 ; and 
       FIG. 4  is a block diagram of the computing device and example data exchange system of  FIG. 3 ; and 
       FIG. 5  is a perspective view of a pet wearing a collar to which is attached a button assembly for use by a data exchange system such as those described with respect to  FIGS. 1-3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The principles of the present invention may be embodied in many different forms, and two example data exchange systems using the principles of the present invention will be described below. 
   I. First Example Data Exchange System 
   Referring initially to  FIG. 1  of the drawing, depicted at  20  therein is a first example data exchange system constructed in accordance with, and embodying, the principles of the present invention. The first example data exchange system  20  is used to transfer data between a cell phone device  22  and a plurality of button assemblies  24   a ,  24   b , and  24   c.    
   The example cell phone device  22  comprises a controller  30 , an RF system  32 , a power supply  34 , and a plurality of peripherals connected to the controller  30 . As is conventional, the cell phone system  22  may contain additional features such as GPS systems, camera subsystems, and the like. 
   The controller  30  comprises memory and software for implementing conventional phone digital processing and logic as will be described in further detail below. The RF system  32  converts a baseband signal into an RF signal for transmission in accordance with any one of a number of conventional cellular telephone standards. The power supply  34  is conventional in that it generates, based on battery and/or line power, power signals appropriate for the electronic components of the phone device  22 . The controller  30 , RF system  32 , and power supply  34  are or may be conventional. 
   The example cell phone device  22  comprises peripherals in the form a display  36   a , a roller  36   b , a button  36   c , a keypad  36   d , audio input  36   e , and audio output  36   f . Again, the device  22  may contain additional peripheral systems including touch screen readers, stylus based pointing devices, trackballs, voice recognition systems, vibrator systems, and the like. 
   The peripherals  36   a ,  36   b ,  36   c ,  36   d ,  36   e , and  36   f  also are or may be conventional. Software running on the controller  30  generates a user interface that is displayed on the display  36   a . The roller  36   b , button  36   c , keypad  36   d  allow a user to navigate the user interface and input data into cell phone device  22 . The audio input system  36   e  allows the user to enter voice signals into the device  22 , while the audio output system  36   f  allows the device  22  to generate sounds such as voice signals and alarms. 
   The example cell phone device  22  further comprises a cell phone housing  38 . The controller  30 , RF system  32 , and power supply  34  are supported within the cell phone housing  38 . The example peripherals  36   a ,  36   b ,  36   c ,  36   d ,  36   e , and  36   f  are all supported by the housing  38  such that the user of the cell phone device  22  may perceive or access these peripherals. Cell phone housings come in many different configurations, and the example cell phone housing  38  depicted in  FIG. 1  is presented by way of illustration only. 
   The example cell phone device  22  further comprises a button reader system  40 . The button reader system  40  comprises an RFID decoder  42 , a multiplexer  44 , and one or more reader coils  46   a ,  46   b , and  46   c . Each of the reader coils  46   a ,  46   b , and  46   c  is associated with a button position  48   a ,  48   b , and  48   c  on the cell phone housing  38  as shown in  FIG. 1 . 
   While the example cell phone device  22  comprises three reader coils and associated button positions, a cell phone device of the present invention can employ as few as one reader coil and associated button position or any number of coils and button positions as can be accommodated by the housing  38 . If only one reader coil and associated button position is provided, the multiplexer  44  may not be required. 
   The example button assemblies  24  are the same, but the physical construction and electronic circuits of one or more these button assemblies  24  may be different from the others. Each of the example button assemblies  24  comprises an RFID encoder  50 , a switch  52 , and a button coil  54 . The encoder  50 , switch  52 , and coil  54  are contained within a button housing  56 . 
   Each button housing  56  is sized and dimensioned to be supported by the cell phone housing  38  at any one of the button positions  48   a ,  48   b , and  48   c .  FIG. 1  identifies one button assembly  24   a  at the button position  48   a , one button assembly  24   b  at the button position  48   b , and one button assembly  24   c  at the button position  48   c . The button housing  56  may form a friction fit with the cell phone housing  38  or may include a positive mechanical latch to support the button housing  56  at a desired one of the button positions  48 . 
   When the switch  52  is in a closed state, an antenna circuit  58  is formed that includes the RFID encoder  50  and the button coil  54 . When the switch  52  is closed, the antenna circuit  58  allows the RFID encoder  50  to be energized. When energized, the RFID encoder  50  generates an RF data signal that is transmitted from the button coil  54 . The RF data signal contains data stored by the RFID encoder  50 . 
   The controller  30  runs software configured to operate the multiplexer  44  to connect a selected one of the reader coils  46  to the RFID decoder  42 . The controller  30  further operates the RFID decoder  42  to energize the selected reader coil  46 . Typically, the controller  30  will operate the multiplexer  44  to cycle among the plurality of reader coils  46  if more than one reader coil  46  is used. 
   When the selected reader coil  46  is energized by the RFID decoder  42  as described above, the selected reader coil  46  transmits an RF power signal. If the button coil  54  of any one of the button assemblies  24  is within range of the RF power signal generated by the selected reader coil  46 , any button coil  54  adjacent to the selected reader coil  46  converts the RF power signal into a current capable of energizing the RFID encoder  50  connected to the adjacent button coil  54 . 
   If the switch  52  connected to the button coil  54  that receives the RF power signal is open, the antenna circuit  58  is not formed, and the RFID encoder  50  is not energized. If, however, the switch  52  connected to the button coil  54  that receives the RF power signal is closed, the antenna circuit  58  is formed, and the adjacent button coil  54  generates a current that energizes the RFID encoder  50 . As described above, the RFID encoder  50  generates the RF data signal when energized. The adjacent button coil  54  thus transmits the RF data signal to the selected reader coil  46  adjacent thereto. 
   The selected reader coil  46  receives the RF data signal and converts the RF data signal into a current that is received by the RFID decoder  42  through the multiplexer  44 . The RFID decoder  42  extracts from the RF data signal the data stored by the RFID encoder  50  connected to the adjacent button coil  54 . 
   The RFID encoder  50  then passes the extracted data to the controller  30 . In the example data exchange system  20 , the extracted data corresponds to a telephone number or a portion of a telephone number. The controller  30  generates DTMF signals corresponding to the telephone number or portion of a telephone number. The controller  30  may generate appropriate dialing signals using existing dialing capabilities of the cell phone device  22 . 
   The RFID decoder  42  and RFID encoder  50  are or may be conventional. The RFID system formed by the decoder  42  and encoder  50  can be used both to transmit data from the button assemblies  24  to the button reader system  40  and, under appropriate conditions, form a conventional RFID programming system to allow programming of the RFID encoder  50  of the button assemblies  24 . Alternatively, data may be stored directly onto the RFID encoder  50  using electrical contacts (not shown). 
   The power to the button assemblies  24  is provided by the power supply  34  through the RFID decoder  42 . Typically, the power supply  34  will comprise a power management system to minimize power consumption when the cell phone device  22  is operating under battery power. As part of this power management system, the controller  30  may be programmed to controller the RFID decoder  42  and multiplexer  44  to minimize power consumption by the button reader system  40 . 
   II. Second Example Data Exchange System 
   Referring now to  FIG. 3  of the drawing, depicted at  120  therein is a second example data exchange system constructed in accordance with, and embodying, the principles of the present invention. The first example data exchange system  120  is used to transfer data between a computing device  122  and a plurality of button assemblies  24 . 
   The example computing device  122  is a conventional portable or laptop computer comprising a controller  130  and a power supply  132 . As is conventional, the controller  130  runs an operating system. Typically, the operating system defines a user interface and/or hosts application programs that define a user interface. The power supply  132  provides power to the controller  130  and any peripheral devices forming part of the computing device  122 . The example controller  130  and power supply  132  are or may be conventional and will not be described herein beyond the extent necessary for a complete understanding of the present invention. 
   The example computing device  122  comprises peripherals in the form a display  134   a , a touch pad  134   b , dedicated function buttons  134   c , a keypad  134   d . The peripherals  134   a ,  134   b ,  134   c , and  134   d  are connected to the controller  130  in a conventional manner. Again, the device  122  may contain additional peripheral systems including stylus based pointing devices, audio input and output systems, trackballs, voice recognition systems, network connection systems, and the like. 
   The peripherals  134   a ,  134   b ,  134   c , and  134   d  also are or may be conventional. Software running on the controller  130  generates a user interface that is displayed on the display  134   a . The touch pad  134   b , dedicated function buttons  134   c , and keypad  134   d  allow a user to navigate the user interface and input data into computing device  122 . 
   The example computing device  122  further comprises a housing  136 . The example peripherals  134   a ,  134   b ,  134   c , and  134   d  are all supported by the housing  136  such that the user of the computing device  122  may perceive or access these peripherals. Housings for computing devices come in many different configurations, and the example housing  136  depicted in  FIG. 1  is presented by way of illustration only. 
   The example computing device  122  further comprises a button reader system  140 . The button reader system  140  comprises an RFID decoder  142 , a multiplexer  144 , and one or more reader coils  146   a ,  146   b , and  146   c . Each of the reader coils  146   a ,  146   b , and  146   c  is associated with a button position  148   a ,  148   b , and  148   c  on the housing  136  as shown in  FIG. 3 .  FIG. 4  illustrates that the button assembly  24   a  is associated with the button position  148   a , the button assembly  24   b  is associated with the button position  148   b , and the button assembly  24   c  is associated with the button position  148   c.    
   While the example computing device  122  comprises three reader coils and associated button positions, a computing device of the present invention can employ as few as one reader coil and associated button position or any number of coils and button positions as can be accommodated by the housing  136 . Again, if only one reader coil and associated button position are provided, the multiplexer  144  may be omitted. 
   The example button assemblies  24  are the same, but the physical construction and electronic circuits of one or more these button assemblies  24  may be different from the others. 
   Each of the example button assemblies  24  comprises an RFID encoder  150 , a switch  152 , and a button coil  154 . The encoder  150 , switch  152 , and coil  154  are contained within a button housing  156 . 
   The button housing  156  is sized and dimensioned to be supported by the housing  136  at any one of the button positions  148   a ,  148   b , and  148   c . The button housing  156  may form a friction fit with the housing  136  or may include a positive mechanical latch to support the button housing  156  at a desired one of the button positions  148 . 
   When the switch  152  is in a closed state, an antenna circuit  158  is formed that includes the RFID encoder  150  and the button coil  154 . When the switch  152  is closed, the antenna circuit  158  allows the RFID encoder  150  to be energized. When energized, the RFID encoder  150  generates an RF data signal that is transmitted from the button coil  154 . The RF data signal contains data stored by the RFID encoder  150 . 
   The controller  130  runs software configured to operate the multiplexer  144  to connect a selected one of the reader coils  146  to the RFID decoder  142 . The computing device  122  further operates the RFID decoder  142  to energize the selected reader coil  146 . Typically, the computing device  122  will operate the multiplexer  144  to cycle among the plurality of reader coils  146  if more than one reader coil  146  is used. 
   When the selected reader coil  146  is energized by the RFID decoder  142  as described above, the selected reader coil  146  transmits an RF power signal. If the button coil  154  of any one of the button assemblies  24  is within range of the RF power signal generated by the selected reader coil  146 , any button coil  154  adjacent to the selected reader coil  146  converts the RF power signal into a current capable of energizing the RFID encoder  150  connected to the adjacent button coil  154 . 
   If the switch  152  connected to the button coil  154  that receives the RF power signal is open, the antenna circuit  158  is not formed, and the RFID encoder  150  is not energized. If, however, the switch  152  connected to the button coil  154  that receives the RF power signal is closed, the antenna circuit  158  is formed, and the adjacent button coil  154  generates a current that energizes the RFID encoder  150 . As described above, the RFID encoder  150  generates the RF data signal when energized. The adjacent button coil  154  thus transmits the RF data signal to the selected reader coil  146  adjacent thereto. 
   The selected reader coil  146  receives the RF data signal and converts the RF data signal into a current that is received by the RFID decoder  142  through the multiplexer  144 . The RFID decoder  142  extracts from the RF data signal the data stored by the RFID encoder  150  connected to the adjacent button coil  154 . 
   The RFID encoder  150  then passes the extracted data to the computing device  122 . In the example data exchange system  120 , the extracted data may be any data capable of storage in digital form. One example of data that may be stored by the encoder  150  will be described in further detail below. 
   The RFID decoder  142  and RFID encoder  150  are or may be conventional. The RFID system formed by the decoder  142  and encoder  150  can be used both to transmit data from the button assemblies  24  to the button reader system  140  and, under appropriate conditions, form a conventional RFID programming system to allow programming of the RFID encoder  150  of the button assemblies  24 . Alternatively, data may be stored directly onto the RFID encoder  150  using electrical contacts (not shown). 
   The power to the button assemblies  24  is provided by the power supply  132  through the RFID decoder  142 . Typically, the power supply  132  will comprise a power management system to minimize power consumption when the computing device  122  is operating under battery power. As part of this power management system, the computing device  122  may be programmed to controller the RFID decoder  142  and multiplexer  144  to minimize power consumption by the button reader system  140 . 
   III. Tracking Systems 
   As described above, the buttons  24  may store any type of data capable of being stored electronically. One example of a use of such buttons is depicted in  FIG. 5 .  FIG. 5  depicts a dog  220  wearing a collar  222 . Attached to the collar is a button  24   d  containing data associated with the dog  220 , such as the dog&#39;s name and contact information for the dog&#39;s owner. Someone finding the button  24   d  associated with the dog  220  could thus place the button in a button position  48  such as those associated with the cell phone device  22  to call the dog&#39;s owner and/or in a button position  148  such as those associated with the computing device  22  to extract data from the button  24   d.    
   This same principle may be applied to objects other than pets, such as electronic equipment and the like. Buttons like the button  24   d  may thus be used as part of a larger tracking system to notify finders of objects of how to return the found object. 
   IV. Summary 
   In general, the present invention allows the user of the button assemblies  24  to control when the data stored thereon is downloaded by requiring that the switch  52  be closed to allow the antenna circuit  58  to be formed. The button assemblies may be discrete or may be incorporated as part of another structure such as a business card, credit card, identification card, or the like. To this end, security can also be enhanced by designing the antenna circuit such that the button assembly must be within a first range of less than approximately three inches, within a second range of less than approximately one inch, and in the preferred embodiments approximately one-half inch. 
   In addition, the button assemblies  24  may be constructed to operate as part of a larger system such as those described in the Applicant&#39;s issued U.S. Pat. Nos. 6,940,974 and 6,961,425 and copending patent application Ser. Nos. 11/253,108, 11/583,461, and 11/583,523. The disclosures of those patents and patent applications are hereby incorporated herein by reference. 
   The present invention may thus be embodied in many forms other than those depicted and described herein. The scope of the present invention should be determined based on the claims appended hereto and not the foregoing detailed description.