RFID sensor array and sensor group based on pulse-processing

• US 20080204198A1
• Filed: 02/20/2008
• Published: 08/28/2008
• Est. Priority Date: 02/22/2007
• Status: Active Grant

• Current Assignee: Baohua Qi
• Original Assignee: Baohua Qi
• Inventors: Qi, Baohua
• Granted Patent: US 8,026,795 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G01D 9/005 Solid-state data loggers

Abstract

An RFID device having sensor arrays incorporated in its tags. Each tag generates an ID code together with sensing pulses the width of which changes with sensing values. Conflicts between tags in communication are avoided by adding a sleep section to the code sequence. The interrogator reads the ID code and digitizes the width of sensing pulses during the communication with tags, and then calculates sensing values based on the information obtained. Since only discrete signals exist in data acquisition, and the digitization process is in parallel with data communication, the system needs neither ADC circuits nor an extra process for signal digitization.

Claims

1. A radio frequency identification tag device comprising:

a clock generator;

a logic circuit for generating a serial code sequence;

at least one sensor array that includes at least one sensing element;

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

a signal generator that concatenates said serial code sequence and said sensing pulses;

a radio frequency tuned circuit;

a circuit for emitting modulated signals through said radio frequency tuned circuit.

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 at least one resistive sensor.

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

5. The radio frequency identification tag device according to claim 1, wherein said signal generator is an OR gate.

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

7. The radio frequency identification tag device according to claim 6, wherein an identification code is stored in said memory array.

8. A radio-frequency identification tag group that includes at least one tag device with each of its tag devices comprising:

at least one sensor array which includes at least one sensing element;

a clock generator;

a logic circuit for generating a serial code sequence;

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

a signal generator that concatenates said serial code sequence and said sensing pulses;

a sleep timer that adds a sleep section to the code generated by said signal generator;

a radio frequency tuned circuit;

a circuit for emitting modulated signals through said radio frequency tuned circuit.

9. The radio frequency identification tag device according to claim 8, wherein said sensing pulse generator is a monostable multivibrator.

10. The radio frequency identification tag device according to claim 9, wherein said monostable multivibrator includes at least one resistive sensor.

11. The radio frequency identification tag device according to claim 9, wherein said monostable multivibrator includes at least one capacitive sensor.

12. The radio frequency identification tag device according to claim 8, wherein said signal generator is an OR gate.

13. A radio frequency interrogator device, comprising

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

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

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

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

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

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

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

18. A system for identifying and reading a sensing values, comprising:

at least one radio frequency identification tag device that includes at least one sensor array which has at least one sensing element, a clock generator, a logic circuit for generating a serial code sequence, a sensing pulse generator with said sensing elements incorporated for generating sensing pulses the width of which changes with sensing values, a signal generator that concatenates said serial code sequence and said sensing pulses, a radio frequency tuned circuit, and a circuit for emitting modulated signals through said radio frequency tuned circuit;

a radio frequency interrogator device having a circuit that detects the RFID signal generated by said radio frequency identification tag device, a pulse processing unit for measuring the width of pulses in said RFID signal, a sensing value processing unit that calculates sensing values based on the pulse width measured by said pulse processing unit;

19. A system for identifying and reading sensing values according to claim 18, wherein said sensing pulses are generated by monostable multivibrators.

20. A system for identifying and reading sensing values according to calim 18, wherein said ratio frequency identification tag device further includes a sleep timer that adds a sleep section in the code sequence generated by said signal generator.