SYSTEM FOR ENCODED RF AND ENCODED MAGNETIC FIELD COMMUNICATION AND METHOD THEREFOR

Abstract: A wireless security system combines encoded RF and encoded magnetic field operation into a base unit device and a remote unit device, overcoming the limitations of RF only or magnetic field only wireless security devices. The base unit is comprised of a power supply, a base processing unit, an RF receiver and a base inductor-capacitor (LC) transceiver. The base processing unit is capable of controlling both encoded RF and encoded magnetic field operation. The remote unit is comprised of a battery, a remote processing unit, an RF transmitter, a remote magnetic field converter circuit, manual control and an energy storage device. The remote processing unit, which is capable of controlling both encoded RF and encoded magnetic field operation, is implemented on a single, monolithic integrated circuit. The remote unit device can be miniaturized to relative smallness to the extent that it can be embedded, for example, within an automobile key. The remote unit device can convert magnetic field energy to DC electrical energy for the purposes of supplying power to the remote unit device, conserving battery power and re-charging the battery.

Description: SYSTEM FOR ENCODED RF AND ENCODED MAGNETIC FIELD COMMUNICATION AND METHOD THEREFOR RELATED APPLICATIONS This U.S. Patent Application is related to the following U.S. Patent Applications. U.S. Patent Application entitled "A ROBUST LC FULL-WAVE BRIDGE RECTIFIER INPUT STRUCTURE," was filed January 15, 1998, in the name of Pieter Schieke and assigned to the same assignee as the present U.S. Patent Application. U.S. Patent Application entitled "A HIGHLY EFFICIENT MULTI-FREQUENCY VOLTAGE REGULATING CIRCUIT INCORPORATING A MAGNETIC FIELD POWER SENSOR AND PROGRAMMABLE MAGNETIC FIELD DETECTION" was filed April 16, 1998, in the names of Pieter Schieke and Willem Smit and assigned to the same assignee as the present U.S. Patent Application. The disclosures of the above referenced applications are hereby incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention: This invention relates generally to wireless security systems and specifically, to transmitter, receiver and transponder devices capable of encoded operation over a wide range of the electro-magnetic spectrum. 2. Description of the Prior Art: The current state of the art describes transmitter, receiver and transponder security devices that operate in either the RF spectrum or which communicate via magnetic field. The signals transmitted by RF devices may be encoded for the purpose of enhancing security by preventing others from capturing the transmissions and making subsequent unauthorized use. Typically, magnetic field transponders operate in a non-encoded mode. There are limitations to the RF and magnetic field security systems, currently embodied as separate, independent systems, that are well known to those skilled in the art. These limitations include size, weight, operating range and power consumption. To date no wireless security system has incorporated both technologies in a single device which is capable of encoded RF and encoded magnetic field operation and that is convenient in size and efficient in operation to make the result commercially practical. Furthermore, no existing device, even if capable of both RF and magnetic field operation, combines the functions of encoding, decoding, processing and control for both RF and magnetic field on a single, integrated circuit. Thus, there exists a need to develop a wireless security system that is capable of encoded RF and encoded magnetic field operation. SUMMARY OF THE INVENTION It is the object of the present invention to combine RF operation and magnetic field operation into a single wireless security system with encoding capability. The present invention overcomes the limitations of RF only or magnetic field only wireless security devices. It is another object of the present invention that the wireless security system shall be comprised of a base unit device and a remote unit device. It is another object of the present invention that the part of the security system comprising the remote unit device can be miniaturized to relative smallness to the extent that it can be embedded, for example, within an automobile key. It is another object of the present invention that the part of the security system comprising the remote unit device can convert magnetic field energy to DC electrical energy for the purposes of supplying power to the remote unit device and for conserving battery power and for re-charging the battery. It is another object of the present invention that the processing unit for the remote unit shall be implemented on a single, monolithic integrated circuit and shall be capable of encode processing and control for both RF operation and magnetic field operation. It is another object of the present invention that the processing unit for the base unit shall be capable of encode and decode processing and control for both RF operation and magnetic field operation. It is another object of the present invention that in the magnetic field mode the present invention shall typically operate within a band of the electro-magnetic spectrum of approximately 100 KHz to 100 MHz. In the RF mode the present invention shall typically operate within a band of the electro-magnetic spectrum of approximately 100 MHz to 500 MHz. In accordance with one embodiment of the present invention, a wireless security system is disclosed comprising of a base unit and a remote unit, each capable of RF and magnetic field operation. The base unit is comprised of a power supply, a base processing unit, a RF receiver and a base magnetic field converter circuit. The remote unit is comprised of a battery, a remote processing unit, a RF transmitter, a remote magnetic field converter circuit, a manual control and an energy storage device. The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiments of the invention, as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of the present invention which includes the base unit and the remote unit. Figure 2 is a block diagram of the base processing unit. Figure 3 is a block diagram of the remote processing unit. Figure 4 is a schematic diagram of the magnetic field converter circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Figure 1, a wireless security system 100 capable of encoded RF and encoded magnetic field communication is disclosed. The system 100 is comprised of a base unit 110 capable of encoded magnetic field transmission and encoded magnetic field reception and encoded RF reception and a remote unit 150 capable of encoded magnetic field transmission and encoded magnetic field reception and encoded RF transmission which communicates with the base unit. The present invention does not disclose or claim one or more methods for encoding and decoding data. There are numerous methods that perform this function which are well known to those skilled in the art. One such method can be found in U.S. Patent 5,517,187, entitled "MICROCHIPS AND REMOTE CONTROL DEVICES COMPRISING SAME" which was patented by several of the same inventors as the present invention and currently assigned to the same assignee as the present U.S. Patent Application, is incorporated by reference. The base unit 110 is comprised of a power supply 115, a base processing unit 120 coupled to the power supply 115, a base magnetic field converter circuit 130 coupled to the base processing unit 120 and a RF receiver 140 coupled to the base processing unit 120. The power supply 115 is capable of connecting to either a commercially available AC power source or to a DC power source provided by the host of the base unit 120. The power supply 115 converts or regulates the input power to low voltage DC power which is coupled to the base processing unit 120. The base processing unit 120 controls both RF and magnetic field operation. The base processing unit 120 sends signals to the base magnetic field converter circuit 130 for the purpose of communicating with the remote unit 150. The base processing unit 120 also receives signals which originated with the remote unit 150 via the base magnetic field converter circuit 130 and RF receiver 140. The base processing unit 120 is capable of decoding signals which it receives from the remote unit 150 and encoding signals which are transmitted to the remote unit 150. The base magnetic field converter circuit 130 is coupled to the base processing unit 120. The base magnetic field converter circuit 130 is capable of generating magnetic fields which are sensed by the remote magnetic field converter circuit 170. Also, the base magnetic field converter circuit 130 is capable of sensing relative weak magnetic fields which are generated by the remote magnetic field converter circuit 170. The RF receiver 140 receives RF signals generated by the RF transmitter 180 of the remote unit 150. The RF receiver 140 relays these signals to the base processing unit 120. The remote unit 150 is comprised of a battery 155, an energy storage device 195 coupled to the battery 155, a remote processing unit 160 coupled to the battery 155 and the energy storage device 195, a remote magnetic field converter circuit 170 coupled to the remote processing unit 160 and indirectly to the battery 155 and the energy storage device 195, a RF transmitter 180 coupled to the remote processing unit 160, a manual control 190 coupled to the remote processing unit 160. The battery 155 and the energy storage device 195 supply low voltage DC energy to the remote processing unit 160, the remote magnetic field converter circuit 170, the RF transmitter 180 and the manual control 190. The energy storage device 195 is charged by a rectifier- regulator within the remote processing unit 160. The energy storage device 195, which can be a simple capacitor, is capable of supplying DC electrical energy to elements of the remote unit 150 requiring power, thereby conserving battery 155 power. If the energy storage device 195 is not charged, the battery 155 supplies power to the elements of the remote unit 150. A detailed description of these functions are found in the previously mentioned U.S. Patent Application entitled "A HIGHLY EFFICIENT MULTI-FREQUENCY VOLTAGE REGULATING CIRCUIT INCORPORATING A MAGNETIC FIELD POWER SENSOR AND PROGRAMMABLE MAGNETIC FIELD DETECTION." The remote processing unit 160 is implemented on a single, monolithic integrated circuit and controls both RF and magnetic field operation. The remote processing unit 160 sends signals to the remote magnetic field converter circuit 170 for the purpose of communicating with the base unit 120. The remote processing unit 160 also receives signals via the remote magnetic field converter circuit 170 which originated in the base unit 110. The remote processing unit 160 is capable of decoding signals which it receives from the base unit 110 and encoding signals which are transmitted to the base unit 110. The remote magnetic field converter circuit 170 is coupled to the remote processing unit 160. The remote magnetic field converter circuit 170 is capable of generating magnetic fields which are sensed by the base magnetic field converter circuit 130. Also, the remote magnetic field converter circuit 170 is capable of sensing the magnetic fields which are generated by the base magnetic field converter circuit 130. The remote magnetic field converter circuit 170 transmits signals generated by the remote processing unit 160 and relays signals received from the base unit 110 to the remote processing unit 160. The RF transmitter 180 transmits RF signals generated by the remote processing unit 160 to the RF receiver 140 of the base unit 110. The manual control 190 permits manual operation of the remote unit 150. Upon activation of the manual control 190, the remote unit 150 will send a predesignated encoded signal to the base unit 110 via the RF transmitter 180 and/or the remote magnetic field converter circuit 170. The manual control 190 may be embodied in a microswitch, button or similar devices known to those skilled in the art. Three modes of operation of the wireless security system 100 are disclosed. The first mode is described as the manual control mode. In this mode, the manual control 190 is asserted. The remote unit 150 sends a predesignated encoded RF signal to the base unit 110 and/or modulates a predesignated encoded magnetic field. The base unit 110 interprets the signal sent by the remote unit 150 and may acknowledge the signal by either transmitting a response to the remote unit 150 or notifying the host system. The second mode is the passive transponder mode. In this mode the base unit 110 intermittently asserts a magnetic field via the base magnetic field converter circuit 130. The remote magnetic field converter circuit 170 senses the presence of the intermittent magnetic field and alerts the remote processing unit 160. The remote processing unit 160 directs the RF transmitter 180 to send an encoded signal to the base unit 110 and/or the remote magnetic field converter circuit 170 to modulate an encoded magnetic field. The third mode is the active transponder mode. In this mode the base unit 110 interrogates the remote unit 150 by asserting an encoded magnetic field via the base magnetic field converter circuit 130. The remote magnetic field converter circuit 170 senses the interrogating magnetic field and relays the signal to the base processing unit 160. The base processing unit 160 analyzes the encoded signal sent by the base unit 110 and directs the RF transmitter 180 to send an encoded response to the base unit 110 and/or the remote magnetic field converter circuit 170 to modulate an encoded magnetic field. Referring to Figure 2, wherein like numerals represent like elements, the functional components of the base processing unit 120 are disclosed. Those skilled in the art will recognize that the base processing unit 120 may include various embodiments in which the functional components described below may be implemented either in software or in hardware. The base processing unit 120 is comprised of a plurality of I/O ports 210, encoding logic 220 coupled to at least one of the I/O ports 210, decoding logic 230 coupled to at least one of the I/O ports 210, a base magnetic field converter circuit controller 240 coupled to at least one of the I/O ports, to the encoding logic 220 and to the decoding logic 230 and a RF serial data receiver 250 coupled to at least one of the I/O ports 210 and to the decoding logic 230. The plurality of I/O ports 210 connect the base processing unit 120 with other components in base unit 110 (figure 1) and with programming devices extrinsic to the wireless security system 100 (figure 1). Each of the plurality of I/O ports 210 may contain a unique plurality of control lines. Power and ground reference are supplied to the base processing unit 120 via at least one of the plurality of I/O ports 210. The encoding logic 220 is coupled to at least one of the plurality of I/O ports 210. The encoding logic 220 is responsible for preparing an encoded digital serial bit stream for transmission to the remote unit 150 (figure 1) via the base magnetic field converter circuit controller 240. The encoding logic 220 may be accessed by a programming device extrinsic to the wireless security system 100 (figure 1 ) via at least one of the plurality of I/O ports 210. The decoding logic 230 is coupled to at least one of the plurality of the I/O ports 210. The decoding logic 230 is responsible for decoding the encoded digital serial bit stream received from the remote unit 150 (figure 1) via the base magnetic field converter circuit controller 240 or the RF serial data receiver 250. The decoding logic 230 may be accessed by a programming device extrinsic to the wireless security system 100 (figure 1) via at least one of the plurality of I/O ports 210. The base magnetic field converter circuit controller 240 is coupled to at least one of the plurality of the I/O ports 210, to the decoder logic 230 and to the encoder logic 220. The base magnetic field converter circuit controller 240 sends and receives encoded magnetic field signals via the base magnetic field converter circuit 130 (figure 1). Referring to Figure 3, wherein like numerals represent like elements, the functional components of the remote processing unit 160 are disclosed. As previously stated, the remote processing unit 160 is implemented on a single, monolithic integrated circuit, thus resulting in various embodiments in which the functional components described below may be implemented either in software or in hardware. The remote processing unit 160 is comprised of a plurality of I/O ports 310, encoding logic 320 coupled to at least one of the plurality of I/O ports 310, a remote magnetic field converter circuit controller 340 coupled to at least one of the plurality of I/O ports 310 and to the encoding logic 320 and a RF serial data transmitter 340 coupled to at least one of the plurality of the I/O ports 310 and to the encoding logic 320. The plurality of I/O ports 310 connect the remote processing unit 160 with other components in remote unit 150 (figure 1) and with programming devices extrinsic to the wireless security system 100 (figure 1). Similar to the base processing unit 120 (figure 2), each of the plurality of I/O ports 310 may contain a unique plurality of control lines. Power and ground reference are supplied to the remote processing unit 160 via at least one of the plurality of I/O ports 310. The encoding logic 320 is coupled to at least one of the plurality of I/O ports 310. The encoding logic 320 is responsible for preparing an encoded digital bit serial stream for transmission to the base unit 110 (figure 1) via the remote magnetic field converter circuit controller 340 or the RF serial data transmitter 350. The encoding logic 320 may be accessed by a programming device extrinsic to the wireless security system 110 (figure 1) via one of the plurality of I/O ports 310. The remote magnetic field converter circuit controller 340 is coupled to at least one of the plurality of the I/O ports 310 and to the encoder logic 320. In addition to transceiving encoded magnetic field signals, the remote magnetic field converter circuit controller 340 contains a rectifier-regulator 345 which converts magnetic field energy to regulated, low voltage DC electrical energy. The resulting regulated DC electrical energy may be used to charge the energy storage device 195 and to re-charge the battery 155 (figure 1). Referring to figure 4, wherein like numerals represent like elements, one embodiment of the magnetic field converter circuit 400 is shown. The magnetic field converter circuit 400 is shown as comprised of an inductor 410 coupled to a capacitor 420 in parallel. Those skilled in the art will recognize that many inductor-capacitor combinations of various forms, configurations and characteristics perform substantially the same function of converting magnetic field energy to electrical energy and vice versa (e.g. series coupling). The specifications for the inductor 410 and capacitor 420 are determined by the particular application of the wireless security system 100 (figure 1). Although the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims: WHAT IS CLAIMED IS: 1. A wireless security system comprising, in combination: a base unit capable of encoded magnetic field transmission and encoded magnetic field reception and encoded RF reception; and a remote unit capable of encoded magnetic field transmission and encoded magnetic field reception and encoded RF transmission which communicates with the base unit. 2. The wireless security system in accordance with Claim 1, wherein the base unit comprises: a power supply; a base processing unit coupled to the power supply; a base magnetic field converter circuit coupled to the base processing unit; and a RF receiver coupled to the base processing unit. 3. The wireless security system in accordance with Claim 2, wherein the base processing unit comprises: a plurality of I/O ports; an encoding logic coupled to at least one of the plurality of I/O ports; a decoding logic coupled to at least one of the plurality of I/O ports; a base magnetic field converter circuit controller coupled to at least one of the plurality of I/O ports, to the encoding logic and to the decoding logic; and a RF serial data receiver coupled to at least one of the plurality of I/O ports and to the decoding logic. 4. The wireless security system in accordance with Claim 1, wherein the remote unit comprises: a battery; an energy storage device coupled to the battery; a remote processing unit implemented on a single, monolithic integrated circuit coupled to the battery and the energy storage device; a remote magnetic field converter circuit coupled to the remote processing unit; a RF transmitter coupled to the remote processing unit; and a manual control coupled the remote processing unit. 5. The wireless security system in accordance with Claim 2 wherein the base magnetic field converter circuit comprises: an inductor; and a capacitor coupled to the inductor. 6. The wireless security system in accordance with Claim 4 wherein the remote magnetic field converter circuit comprises: an inductor; and a capacitor coupled to the inductor. 7. The wireless security system in accordance with Claim 4, wherein the electrical storage device is capable of providing low power DC electrical energy to the remote unit. 8. The wireless security system in accordance with Claim 4, wherein the remote processing unit comprises: a plurality of I/O ports; an encoding logic coupled to at least one of the plurality of I/O ports; a remote magnetic field converter circuit controller coupled to at least one of the plurality of I/O ports and to the encoding logic; and a RF serial data transmitter coupled to at least one of the plurality of I/O ports and to the encoding logic; wherein the remote processing unit is implemented on a single, monolithic integrated circuit. 9. The wireless security system in accordance with Claim 8, wherein the remote magnetic field converter circuit controller comprises a rectifier-regulator coupled to the remote magnetic field converter circuit, to the battery and to the energy storage device. 10. The wireless security system in accordance with Claim 9, wherein the rectifier-regulator is capable of converting magnetic field energy to low power DC electrical energy for charging the electrical storage device and for re-charging the battery. 11. A method for operating a wireless security system comprising, the steps of: providing a base unit capable of encoded magnetic field transmission and encoded magnetic field reception and encoded RF reception; and providing a remote unit capable of encoded magnetic field transmission and encoded magnetic field reception and encoded RF transmission which communicates with the base unit. 12. The method of operating the wireless security system in accordance with Claim 11, wherein providing the base unit comprises the steps of: providing a power supply; providing a base processing unit coupled to the power supply; providing a base magnetic field converter circuit coupled to the base processing unit; and providing a RF receiver coupled to the base processing unit. 13. The method of operating the wireless security system in accordance with Claim 12, wherein providing the base processing unit comprises the steps of: providing a plurality of I/O ports; providing an encoding logic coupled to at least one of the plurality of I/O ports; providing a decoding logic coupled to at least one of the plurality of I/O ports; providing a base magnetic field converter circuit controller coupled to at least one of the plurality of I/O ports, to the encoding logic and to the decoding logic; and providing a RF serial data receiver coupled to at least one of the plurality of I/O ports and to the decoding logic. 14. The method of operating the wireless security system in accordance with Claim 11, wherein providing the remote unit comprises the steps of: providing a battery; providing an energy storage device coupled to the battery; providing a remote processing unit implemented on a single, monolithic integrated circuit coupled to the battery and the energy storage device; providing a remote magnetic field converter circuit coupled to the remote processing unit; providing a RF transmitter coupled to the remote processing unit; providing a manual control coupled the remote processing unit. 15. The method of operating the wireless security system in accordance with Claim 12 wherein the base magnetic field converter circuit comprises the steps of: providing an inductor; and providing a capacitor coupled to the inductor. 16. The method of operating the wireless security system in accordance with Claim 14 wherein the remote magnetic field converter circuit comprises the steps of: providing an inductor; and providing a capacitor coupled to the inductor. 17. The method of operating the wireless security system in accordance with Claim 14, wherein the electrical storage device is capable of providing low power DC electrical energy to the remote unit. 18. The method of operating the wireless security system in accordance with Claim 14, wherein providing the remote processing unit comprises the steps of: providing a plurality of I/O ports; providing an encoding logic coupled to at least one of the plurality of I/O ports; providing a remote magnetic field converter circuit controller coupled to at least one of the plurality of I/O ports and to the encoding logic; and providing a RF serial data transmitter coupled to at least one of the plurality of I/O ports and to the encoding logic; wherein the remote processing unit is implemented on a single, monolithic integrated circuit. 19. The method of operating the wireless security system in accordance with Claim 18, wherein the remote magnetic field converter circuit controller comprises a rectifier-regulator coupled to the remote magnetic field converter circuit, to the battery and the energy storage device. 20. The method of operating the wireless security system in accordance with Claim 19, wherein the rectifier-regulator is capable of converting magnetic field energy to low power DC electrical energy for charging the electrical storage device and for re-charging the battery. 21. The method of operating the wireless security system in accordance with Claim 11 further comprising the steps of: providing for a manual control mode; providing for a passive transponder mode; and providing for an active transponder mode. 22. A base unit capable of encoded magnetic field transmission and encoded magnetic field reception and encoded RF reception. 23. The base unit in accordance with Claim 22 wherein the encoded magnetic field transmission and the encoded magnetic field reception and the encoded RF reception are controlled by a single processing unit. 24. The base unit in accordance with Claim 22, wherein the base unit comprises: a power supply; a base processing unit coupled to the power supply; a base magnetic field converter circuit coupled to the base processing unit; and a RF receiver coupled to the base processing unit. 25. The base unit in accordance with Claim 24, wherein the base processing unit comprises: a plurality of I/O ports; an encoding logic coupled to at least one of the plurality of I/O ports; a decoding logic coupled to at least one of the plurality of I/O ports; a base magnetic field converter circuit controller coupled to at least one of the plurality of I/O ports, to the encoding logic and to the decoding logic; and a RF serial data receiver coupled to at least one of the plurality of I/O ports and to the decoding logic. 26. A remote unit capable of encoded magnetic field transmission and encoded magnetic field reception and encoded RF transmission. 27. The remote unit in accordance with Claim 26 wherein the encoded magnetic field transmission and encoded magnetic field reception and encoded RF transmission are controlled by a single processing unit implemented on a single, monolithic integrated circuit. 28. The remote unit in accordance with Claim 26, wherein the remote unit comprises: a battery; an energy storage device coupled to the battery; a remote processing unit implemented on a single, monolithic integrated circuit coupled to the battery and the energy storage device; a remote magnetic field converter circuit coupled to the remote processing unit; a RF transmitter coupled to the remote processing unit; and a manual control coupled the remote processing unit. 29. The wireless security system in accordance with Claim 28, wherein the remote processing unit comprises: a plurality of I/O ports; an encoding logic coupled to at least one of the plurality of I/O ports; a remote magnetic field converter circuit controller coupled to at least one of the plurality of I/O ports and to the encoding logic; and a RF serial data transmitter coupled to at least one of the plurality of I/O port and to the encoding logic; wherein the remote processing unit is implemented on a single, monolithic integrated circuit.

Inventors: BRUWER FREDERICK J, SMIT WILLEM, VAN NIEKERK JOHANNES A, BRUWER, FREDERICK, J., SMIT, WILLEM, VAN NIEKERK, JOHANNES, A.
Applicants: MICROCHIP TECH INC, MICROCHIP TECHNOLOGY INCORPORATED
Application year: 1999
Main classification: G06K7
IPC codes: G06K7, G06K17, G06K19, G07C9, G08B25, H02J17, H04B1, H04B5