Contactless data carrier, interrogator, contactless data carrier system, and method of acquiring data

• US 20050252979A1
• Filed: 05/12/2005
• Published: 11/17/2005
• Est. Priority Date: 05/14/2004
• Status: Active Grant

• Current Assignee: Oki Communication Systems Co., Ltd. (OKI Electric Industry Company Limited), OKI Electric Industry Company Limited
• Original Assignee: Oki Communication Systems Co., Ltd. (OKI Electric Industry Company Limited), OKI Electric Industry Company Limited
• Inventors: Konuma, Ryohei, Ito, Saburo, Deguchi, Fujio
• Granted Patent: US 7,604,177 B2
• Time in Patent Office: Days
• US Class Current: 235/492
• 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 contactless data carrier has a measurement port receiving an external signal to be compared, a threshold generator that generates different threshold values, a comparator that compares the external signal with the threshold values, and a controller that controls the variable threshold generator on command from an interrogator and returns the comparison results to the interrogator. The comparison results returned to the interrogator may be the results of the individual comparisons, or information derived from a threshold value at which the comparison result changes. The contactless data carrier is small, lightweight, and inexpensive, and can be used to perform an essentially unlimited variety of measurements by connecting suitable sensors to the measurement port.

Claims

1. A contactless data carrier that exchanges data by wireless communication with an interrogator, the contactless data carrier comprising:

a measurement port receiving an external signal to be compared;

a variable threshold generator generating different threshold values;

a comparator comparing the external signal received at the measurement port with the different threshold values, and producing comparison results;

a controller controlling the variable threshold generator according to a signal received from the interrogator, and returning information derived from the comparison results to the interrogator.

2. The contactless data carrier of claim 1, comprising a plurality of measurement ports, said measurement port being one of the plurality of measurement ports, and a plurality of comparators paired with the measurement ports, the comparators comparing respective external signals received at the measurement ports with which they are paired.

3. The contactless data carrier of claim 1, comprising a plurality of measurement ports receiving respective external signals, and a selector connected to the plurality of measurement ports, for providing a selectable one of the external signals to the comparator, said measurement port being one of the plurality of measurement ports.

4. The contactless data carrier of claim 1, further comprising a bridge circuit connected between the measurement port and the comparator, for expanding a dynamic range of the external signal.

5. The contactless data carrier of claim 1, wherein the controller, the comparator, and part of the variable threshold generator are enclosed in a package, and another part of the variable threshold generator comprises circuit elements external to the package.

6. The contactless data carrier of claim 1, wherein the external signal is generated from an ambient physical quantity by a sensor with a non-linear response, the contactless data carrier further comprising a memory storing data conversion information enabling the controller to compensate for the non-linear response of the sensor.

7. The contactless data carrier of claim 1, further comprising a power supply controller performing on/off control of operating power supplied to at least the comparator and the variable threshold generator.

8. The contactless data carrier of claim 1, wherein the external signal is generated from an ambient physical quantity by a sensor and the contactless data carrier obtains power from a wireless signal transmitted from the interrogator, further comprising an external power supply port for supplying power to the sensor.

9. The contactless data carrier of claim 8, further comprising an external power supply controller performing on/off control of the power supply to the sensor.

10. The contactless data carrier of claim 1, wherein the external signal is generated from an ambient physical quantity by a sensor, further comprising an operating command output port for sending commands from the controller to the sensor, commanding sensor operation to be turned on and off.

11. The contactless data carrier of claim 1, further comprising an input port for providing the controller with an enabling signal indicating whether to accept or ignore a comparison request from the interrogator.

12. The contactless data carrier of claim 1, comprising a semiconductor chip in which at least the controller is formed as an integrated circuit.

13. The contactless data carrier of claim 1, comprising a plurality of semiconductor chips in which different components among the controller, the comparator, and the variable threshold generator are formed as integrated circuits.

14. A contactless data carrier system, comprising

the contactless data carrier of claim 1;

an interrogator, which exchanges data with the contactless data carrier by wireless communication; and

a signal source connected to the measurement port of the contactless data carrier, the signal source generating the signal to be compared according to an ambient physical quantity.

15. The contactless data carrier system of claim 14, wherein the interrogator commands the controller in the contactless data carrier to have the comparator execute repeated comparisons with different threshold values, and obtains information about the ambient physical quantity by finding a boundary value at which the comparison results change.

16. The contactless data carrier system of claim 15, wherein the interrogator supplies the different threshold values to the contactless data carrier and the contactless data carrier communicates individual comparison results to the interrogator.

17. The contactless data carrier system of claim 15 wherein the controller in the contactless data carrier changes the threshold value autonomously and communicates the boundary value to the interrogator.

18. The contactless data carrier system of claim 14, wherein one interrogator communicates with a plurality of contactless data carriers.

19. The contactless data carrier system of claim 18, wherein:

the interrogator broadcasts a command to the controllers in the plurality of contactless data carriers to have the comparators execute repeated comparisons with different threshold values;

the controllers store information about a boundary value at which comparison results change; and

the interrogator then polls each contactless data carrier individually to acquire information about the stored boundary value.

20. An interrogator controlling the contactless data carrier of claim 1, the external signal being generated by a signal source according to an ambient physical quantity, wherein the interrogator commands the controller in the contactless data carrier to have the comparator execute repeated comparisons with different threshold values, and obtains information about the ambient physical quantity by finding a boundary value at which the comparison results change.

21. The interrogator of claim 20, wherein the interrogator supplies the different threshold values to the contactless data carrier.

22. The interrogator of claim 20 wherein the interrogator commands the controller in the contactless data carrier to begin the repeated comparisons, and to change the threshold values autonomously.

23. The interrogator of claim 20, wherein the initial threshold value used in the repeated comparisons is determined from a threshold value at which the comparison result changed in a previous series of repeated comparisons.

24. The interrogator of claim 20, wherein the interrogator controls a plurality of contactless data carriers.

25. The interrogator of claim 24, wherein the interrogator broadcasts a command to the controllers in the plurality of contactless data carriers to have the comparators execute the repeated comparisons with different threshold values and store information about a boundary value at which comparison results change, then polls each contactless data carrier individually to acquire information about the stored boundary value.

26. A method of acquiring data from the contactless data carrier of claim 1, wherein the external signal to be compared is generated by a signal source according to an ambient physical quantity, the method comprising:

sending the contactless data carrier a command to have the comparator execute repeated comparisons with different threshold values;

recognizing a boundary value at which results of the comparisons change; and

converting the boundary value to a value of the ambient physical quantity.

27. The method of claim 26, further comprising sending the different threshold values to the contactless data carrier.

28. The method of claim 26, wherein the controller in the contactless data carrier changes the threshold values autonomously.

29. The method of claim 26, further comprising:

using the boundary threshold value to determine an initial threshold value; and

sending the contactless data carrier another command to have the comparator execute repeated comparisons with different threshold values, the repeated comparisons starting from the initial threshold value.

30. The method of claim 26, wherein the method is applied simultaneously to a plurality of contactless data carriers.

31. The method of claim 30, wherein:

the command to have the comparator execute repeated comparisons is broadcast to the plurality of contactless data carriers;

the boundary threshold value is recognized and internally stored by the controller in each contactless data carrier; and

the boundary value is obtained by polling the contactless data carriers individually.

32. A machine-readable medium storing code executable by a computing device for acquiring data from the contactless data carrier of claim 1, the code comprising:

a first program, installable in the interrogator, for sending the contactless data carrier a command to have the comparator execute repeated comparisons with different threshold values, and converting a boundary threshold value at which results of the comparisons change to a value of the ambient physical quantity; and

a second program installable in the contactless data carrier, for executing said command.