RFID sensor device based on pulse-processing

• US 20070182549A1
• Filed: 01/27/2007
• Published: 08/09/2007
• Est. Priority Date: 01/30/2006
• Status: Active Grant

• Current Assignee: Baohua Qi
• Original Assignee: Baohua Qi
• Inventors: Qi, Baohua
• Granted Patent: US 8,018,323 B2
• Time in Patent Office: Days
• US Class Current: 340/539.260
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A radio frequency identification device having sensing elements incorporated in the clock generators of its tags, which generate a leading code and an identification code. In the interrogator, the leading code is detected and its pulse width is measured for calculating sensing values and the baud rate in receiving the identification code. No analog to digital converter is needed in digitizing sensing values and only discrete signals exist in sensing signal generation and communication. The tag device is insensitive to variations in its power supply voltage obtained from a continuous wave RF carrier.

Claims

1. A radio frequency identification tag device, comprising:

a clock generator with sensing elements incorporated;

a logic circuit for generating a serial code sequence;

a radio frequency tuned circuit;

a circuit for loading and unloading said radio frequency tuned circuit;

a circuit for providing power for said radio frequency identification tag device by converting radio frequency continuous wave signals into direct current power.

2. The radio frequency identification tag device according to claim 1, wherein said clock generator is an RC generator.

3. The radio frequency identification tag device according to claim 2, wherein said RC generator includes a resistive sensor.

4. The radio frequency identification tag device according to claim 2, wherein said RC generator includes a capacitive sensor.

5. The radio frequency identification tag device according to claim 1, wherein said clock generator is an LC generator.

6. The radio frequency identification tag device according to claim 5, wherein said LC generator includes an inductive sensor.

7. The radio frequency identification tag device according to claim 5, wherein said LC generator includes a capacitive sensor.

8. The radio frequency identification tag device according to claim 1, wherein said code sequence has at least one pulse the width of which is determined by said sensing elements.

9. The radio frequency identification tag device according to claim 8, wherein said code sequence has an identification code and a leading code which has at least one pulse the width of which is determined by said sensing elements.

10. The radio frequency identification tag device according to claim 1, wherein said logic circuit includes a memory array.

11. The radio frequency identification tag device according to claim 10, wherein said an identification code is stored in said memory array.

12. A radio frequency interrogator device, comprising

a circuit that detects a code sequence generated by a radio frequency tag device;

a pulse processing unit for measuring the width of the pulses in said code sequence;

a sensing value processing unit that calculates sensing values based on the pulse width measured by said pulse processing unit;

a continuous wave generation circuit;

13. The radio frequency interrogator device according to claim 12, wherein said pulse processing unit includes a counter.

14. The radio frequency interrogator device according to claim 12, further comprising a microcontroller.

15. The radio frequency interrogator device according to claim 14, wherein said pulse processing unit is realized using a routine in said microcontroller.

16. The radio frequency interrogator device according to claim 14, wherein said sensing value processing unit is a routine in said microcontroller.

17. A system for identifying and reading a sensor value, comprising:

a radio frequency identification device including a clock generator with sensing elements incorporated, a logic circuit for generating a serial code sequence, a radio frequency tuned circuit, a circuit for loading and unloading said radio frequency tuned circuit, and a circuit for providing power for said radio frequency identification tag device by converting radio frequency continuous wave signals into direct current power;

a radio frequency interrogator device having a circuit that detects a code sequence generated by a radio frequency tag device, a pulse processing unit for measuring the width of the pulses in said code sequence, a sensing value processing unit that calculates sensing values based on the pulse width measured by said pulse processing unit, and a continuous wave generation circuit;

said continuous wave generated by said radio frequency interrogator device has a frequency compatible with said tuned circuit;

18. A system for identifying and reading a sensor value according to claim 17, wherein said serial code sequence includes at least one pulse with its width determined by the sensing values of said sensing elements.

19. A system for identifying and reading a sensor value according to claim 18, wherein the serial code sequence has an identification code section and a leading code, which has at lease one pulse the width of which is determined by the sensing values of said sensing elements.

20. A system for identifying and reading a sensor value according to claim 19, wherein the pulse width measured for said leading code is used to determine the baud rate of the communication for said identification code.