Electronic identifier apparatus and method utilizing a single chip microcontroller and an antenna coil

• US 5,347,263 A
• Filed: 02/05/1993
• Issued: 09/13/1994
• Est. Priority Date: 02/05/1993
• Status: Expired due to Fees

• Current Assignee: Gallaher Group Limited (Government of Japan), Telsor Corporation
• Original Assignee: Gnuco Technology Corporation
• Inventors: Carroll, Gary T., Pauley, J. Donald
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Miller, John W.
• Application Number:
  US08/014,458
• Time in Patent Office: 585 Days
• Field of Search: 340/825.54, 340/825.31, 340/825.34, 340/572, 340/539, 235/449, 235/382, 342/42, 342/44
• US Class Current: 340/5.61
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G08B 13/14 by lifting or attempted removal of hand-portable articles

Abstract

Low cost, compact electronic identifier apparatus interrogates a passive (no external power) or active (external power) transponder. Such identifier apparatus and transponder(s) may be used, e.g., for: (1) access control, (2) animal feeding and animal health, (3) inventory control, (4) process control, and/or (5) theft/security applications. The identifier apparatus further powers the transponder if it is passive. A power carrier signal broadcast by the identifier apparatus clocks and/or synchronizes the transponder operation. In response to being interrogated, the transponder sends back identification (ID) data. The ID data is received and extracted by the identifier apparatus in the presence of the power carrier "noise", and is then demodulated and decoded to recover the ID data. The electronic identifier apparatus uses a low cost, high speed, single chip microcontroller configured to operate so as to eliminate the use of decoders, drivers and other external circuitry.

Claims

1. Electronic identifier apparatus comprising:

an antenna coil;

a single chip microcontroller, said single chip microcontroller including;

a memory circuit wherein a control program is stored, and

a multiplicity of I/O pins through which data signals are transferred into and out of said single chip microcontroller, each I/O pin being connected to a respective I/O circuit included within said single chip microcontroller, a plurality of said I/O pins being connected in parallel to said antenna coil;

extraction means connected to said antenna coil for extracting an ID carrier signal from whatever signals may be present at said antenna coil;

a band pass amplifier connected to said extraction means, said band pass amplifier being configured to pass the ID carrier signal received through said antenna coil and extraction means, any ID carrier signal that passes through said band pass amplifier being connected to said single chip microcontroller;

said single chip microcontroller being configured by said control program to (a) generate a power output signal that is applied to said antenna coil through said plurality of parallel-connected I/O pins, (b) decode any ID carrier signal that is received from said band pass amplifier, and (c) produce at least one control signal responsive to the receipt and decoding of a particular ID carrier signal; and

an interface circuit connected to said single chip microcontroller circuit through which said control signal operates to perform a specified function.

2. The identification apparatus as set forth in claim 1 wherein said interface circuit includes a relay switch.

3. The identification apparatus as set forth in claim 1 wherein said band pass amplifier comprises a multi-stage band pass amplifier utilizing an operational amplifier within each stage.

4. The identification apparatus as set forth in claim 3 wherein said multi-stage band pass amplifier comprises four stages, each stage including one of the operational amplifiers of a quad operational amplifier integrated circuit.

5. The identification apparatus as set forth in claim 1 wherein said single chip microcontroller comprises an EPROM-based 8-bit CMOS Microcontroller of the PIC16C5x series of EPROM-based 8-bit CMOS Microcontrollers.

6. The identification apparatus as set forth in claim 5 wherein said antenna coil comprises 150-180 turns of number 30 gauge wire wound in a coil having an approximate diameter of 4 to 6 cm.

7. The identification apparatus as set forth in claim 6 wherein the number of I/O pins of said single chip microcontroller that are connected in parallel to said antenna coil comprises at least four.

8. The identification apparatus as set forth in claim 7 wherein said peak detector circuit includes a diode and a capacitor that perform an amplitude demodulation function.

9. The identification apparatus as set forth in claim 1 wherein said interface circuit includes a standard RS-232 interface circuit through which digital data signals may pass in serial fashion.

10. The identification apparatus as set forth in claim 9 wherein all of the elements of said identification apparatus may be mounted on a circuit board having dimensions of about 9 cm by 4.7 cm.

11. Electronic identifier apparatus constituting:

an antenna coil;

a single chip microcontroller, said single chip microcontroller including

a memory circuit wherein a control program is stored, and

a multiplicity of I/O pins through which data signals are transferred into and out of said single chip microcontroller, each I/O pin being connected to a respective I/O circuit included within said single chip microcontroller, a plurality of said I/O pins being connected in parallel to said antenna coil;

a peak detector circuit connected to said antenna coil;

a multi-stage band pass amplifier connected to said peak detector circuit, said band pass amplifier being configured to pass an ID carrier signal received through said antenna coil and peak detector circuit, any ID carrier signal that passes through said pass amplifier being connected to a specified one of the I/O pins of said single chip microcontroller;

an interface circuit connected to said single chip microcontroller circuit through which a control signal generated by said single chip microcontroller circuit may perform a specified function; and

means for connecting an external power source to said single chip microcontroller, interface circuit, and band pass amplifier, whereby operating power is provided to said identifier apparatus;

said single chip microcontroller being configured by said control program to at least;

(a) generate a modulated output signal that is applied to said antenna coil through said plurality of parallel-connected I/O pins, (b) demodulate and decode any ID carrier signal that is received at the specified one of the I/O pins connected to said band pass amplifier, and (c) produce said control signal responsive to the receipt, demodulation and decoding of a particular ID carrier signal.

12. The identification apparatus as set forth in claim 11 wherein all of the elements of said identification apparatus are realized using two integrated circuits and no more than about 36 discrete components.

13. The identification apparatus as set forth in claim 12 wherein said single chip microcontroller comprises an EPROM-based 8-bit CMOS Microcontroller of the PIC16C5x series of EPROM-based 8-bit CMOS Microcontrollers.

14. The identification apparatus as set forth in claim 13 wherein said antenna coil comprises approximately 150-180 turns of number 30 gauge wire wound in a coil having an approximate diameter of 4 to 6 cm.

15. The identification apparatus as set forth in claim 13 wherein the number of I/O pins of said single chip microcontroller that are connected in parallel to said antenna coil comprises at least four.

16. A method of electronically identifying a transponder unit, said transponder unit having circuitry that transmits an assigned identification signal upon being powered from an external source, said method comprising the steps of:

(a) generating a square-wave carrier signal using a single chip microcontroller and outputting said carrier signal to a multiplicity of I/O pins of said single chip microcontroller;

(b) connecting a plurality of said multiplicity of I/O pins in parallel and connecting the resulting parallel connection directly to an antenna coil having an inductance, whereby said square-wave carrier signal is applied directly to said antenna coil from the I/O pins of said single chip microcontroller, and a current flows through said antenna coil that, because of said inductance, is filtered to be more or less sinusoidal;

(c) positioning said antenna coil within about 2 to 10 cm of said transponder unit so that power is induced in said transponder unit from said carrier signal, whereby said transponder unit transmits its assigned identification signal;

(d) sensing and demodulating any identification signals that may be transmitted by said transponder unit while said antenna coil remains within about 2 to 10 cm of said transponder unit; and

(e) decoding the identification signal sensed and demodulated in step (d) to determine a particular transponder unit from which said identification signal was transmitted.

17. The method as set forth in claim 16 wherein step (e) further includes verifying if the identification signal sensed and demodulated in step (d) is the identification signal assigned to a particular transponder unit, and if so generating a control signal that controls a prescribed operation that is carried out once a proper identification has been verified.