RFID sensor using pulse processing

• US 20070222583A1
• Filed: 03/24/2007
• Published: 09/27/2007
• Est. Priority Date: 03/27/2006
• Status: Active Grant

• Current Assignee: Baohua Qi
• Original Assignee: Baohua Qi
• Inventors: Qi, Baohua
• Granted Patent: US 8,013,714 B2
• Time in Patent Office: Days
• US Class Current: 340/539.100
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0716 at least one of the integrated circuit chips comprising a sensor or an interface to a sensor
• 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

Abstract

A radio frequency identification device having sensing elements incorporated in its tags, and the sensing value determines the width of a sensing pulse in its RFID code. Through a pulse-processing unit, during communication, digital sensing values are obtained by measuring the width of the sensing pulse. Since only discrete signals exist, the tag device is insensitive to the fluctuation in its power supply voltage, which is derived from a continuous wave RF carrier.

Claims

1. A radio frequency identification tag device with sensors incorporated, comprising:

a clock generator;

a sensing pulse generator with sensing elements incorporated for generating pulses the width of which changes with sensing values;

a logic circuit for generating a serial code sequence;

a signal generator that concatenates said sensing pulse and said 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 sensing pulse generator is a monostable multivibrator.

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

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

5. The radio frequency identification tag device according to claim 1, wherein said serial code sequence has an identification code and a leading code.

6. The radio frequency identification tag device according to claim 5, wherein said leading code in said serial code sequence is concatenated with said sensing pulse in said signal generator.

7. The radio frequency identification tag device according to claim 6, wherein said signal generator is an OR gate.

8. The radio frequency identification tag device according to claim 6, wherein said leading code has a series of zeros.

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

10. The radio frequency identification tag device according to claim 9, wherein said an identification code is stored in said memory array.

11. A radio frequency interrogator device, comprising

a circuit that detects RFID signals generated by a radio frequency tag device;

a pulse processing unit for measuring the width of pulses in said RFID signals;

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

a continuous wave generation circuit;

12. The radio frequency interrogator device according to claim 11, wherein said pulse processing unit includes a counter.

13. The radio frequency interrogator device according to claim 11, further comprising a microcontroller.

14. The radio frequency interrogator device according to claim 13, wherein said pulse processing unit is realized by using a routine in said microcontroller.

15. The radio frequency interrogator device according to claim 13, wherein said sensing value processing unit is a routine in said microcontroller.

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

a clock generator, a sensing pulse generator with sensing elements incorporated for generating pulses the width of which changes with sensing values, a logic circuit for generating a serial code sequence, a signal generator that concatenates said sensing pulse and said 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 RFID signals generated by a radio frequency tag device, a pulse processing unit for measuring the width of pulses in said RFID signals, a sensing value processing unit that calculates sensing values based on pulse width values 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;

17. A system for identifying and reading sensor values according to claim 16, wherein said RFID signal includes at least one sensing pulse the width of which changes with the sensing values of said sensing elements.

18. A system for identifying and reading sensor values according to claim 17, wherein said sensing pulse is generated by a monostable multivibrator.