Communications system and method with A/D converter

• US 7,994,922 B2
• Filed: 09/14/2007
• Issued: 08/09/2011
• Est. Priority Date: 02/10/1999
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Round Rock Research LLC
• Inventors: Hahn, Scott, Van Horn, Mark T.
• Primary Examiner(s): La; Anh V
• Application Number:
  US11/855,788
• Publication Number:
  US 20080048866A1
• Time in Patent Office: 1,425 Days
• Field of Search: 3405721-5728, 340442-447, 340 101- 104, 731/465
• US Class Current: 340/572.4
• CPC Class Codes: G01D 9/005 Solid-state data loggers
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure
• 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 communications system includes a radio frequency identification device including an integrated circuit having a single die including a microprocessor, a receiver coupled to the microprocessor, and a backscatter transmitter coupled to the microprocessor, the integrated circuit having a digital input, and the receiver being configured to receive wireless communications from a remote interrogator; and an analog to digital converter external of the single die and having a digital output coupled to the digital input of the integrated circuit, and having an analog input configured to be coupled to an analog measuring device, wherein the radio frequency identification device is configured to transmit a signal indicative of the analog input using the backscatter transmitter. A communications method includes coupling an analog to digital converter to a radio frequency identification device.

Claims

1. A system for remotely sensing, using radio frequency signals comprising:

an interrogator operable for transmitting radio frequency signals and for receiving radio frequency signals and for communicating with remotely located radio frequency identification (RFID) tags via radio frequency signals within range of the interrogator; and

a plurality of articles remote from the interrogator, each article having associated with it an RFID tag, each tag comprising;

one or more antennas,

a single monolithic integrated circuit having a digital input and comprising;

a radio frequency signal receiver configured to receive a radio frequency interrogation signal transmitted from the interrogator,

a radio frequency signal transmitter,

a microprocessor, and

a memory for persistent storage of data,

an analog to digital converter comprising an analog input and a digital output coupled to the digital input of the integrated circuit,

a power source operable to supply power, and

a measuring device coupled to the analog input of the analog to digital converter, wherein the measuring device is configured to sense a physical characteristic selected from the group of temperature, pressure, water level, voltage, magnetic field and combinations thereof, wherein a signal indicative of the sensed physical characteristic is provided to the analog input of the analog to digital converter for conversion to the digital signal;

wherein the interrogator receives radio frequency signals from one or more of the RFID tags including data indicative of a sensed physical characteristic including the digital signal from the analog to digital converter, in response to the transmitted radio frequency interrogation signal transmitted from the interrogator.

2. The system of claim 1, wherein for one or more of the RFID tags, the digital input of the single monolithic integrated circuit receives sense data indicative of the sensed physical characteristic.

3. The system of claim 2, wherein for one or more of the RFID tags, the analog to digital converter is a stand alone integrated circuit.

4. The system of claim 3, wherein for one or more of the RFID tags, the microprocessor is operable to store digital signals received from the analog to digital converter in the memory for later retrieval.

5. The system of claim 4, wherein for one or more of the RFID tags, the microprocessor is operable to retrieve the stored signals from the memory and to cause the transmitter to transmit a radio frequency signal including the retrieved stored signals, responsive to an interrogation message received by the radio frequency receiver.

6. The system of claim 4, wherein for one or more of the RFID tags, the microprocessor periodically stores data from the digital input into the memory for later retrieval.

7. The system of claim 1, wherein one or more of the RFID tags senses temperature.

8. The system of claim 7, wherein one or more of the RFID tags stores sensed temperature readings in the memory for later retrieval.

9. The system of claim 8, wherein for one or more of the RFID tags, the microprocessor determines whether the temperature reading received from the analog to digital converter is over a threshold.

10. The system of claim 9, wherein for one or more of the RFID tags, the microprocessor records additional data in the memory indicating when a temperature reading is over a threshold.

11. The system of claim 1, wherein for one or more of the RFID tags, the power supply is a passive power supply operable to supply power in the presence of radio frequency signals.

12. The system of claim 1, wherein one or more of the RFID tags communicates radio frequency signals by backscattering received radio frequency signals.

13. The system of claim 1, wherein one or more of the RFID tags transmits radio frequency signals actively.

14. The system of claim 1, wherein for one or more of the RFID tags, the power supply is a battery.

15. The system of claim 14, wherein one or more of the RFID tags communicates radio frequency signals by backscattering received radio frequency signals.

16. The system of claim 1, wherein for one or more of the RFID tags, the single monolithic integrated circuit additionally comprises an analog to digital converter coupled to the microprocessor.

17. The system of claim 1, wherein for one or more of the RFID tags, the memory further comprises unalterable indicia.

18. The system of claim 1, wherein for one or more of the RFID tags the memory is readable, writeable and re-writeable.

19. The system of claim 1, wherein for one or more of the RFID tags the memory is non-volatile.

20. The system of claim 1, wherein for one or more of the RFID tags the radio frequency receiver is operable to receive spread spectrum modulated signals.

21. The system of claim 1, wherein for one or more of the RFID tags the radio frequency transmitter is operable to communicate spread spectrum modulated signals.

22. The system of claim 14, wherein for one or more of the RFID tags the single monolithic integrated circuit further comprises a voltage sensor coupled to the battery.

23. The system of claim 1, wherein for one or more of the RFID tags, periodically the microprocessor receives digital data from the analog-to-digital converter that is indicative of a sensed characteristic from the measurement device and stores the data in the memory.

24. The system of claim 23, wherein for one or more of the RFID tags, and responsive to a received radio frequency signal that includes a command, the microprocessor retrieves stored data indicative of the sensed characteristic from the memory and subsequently configures the radio frequency transmitter to communicate the data using radio frequency signals.

25. A method for remote sensing characteristics of an article comprising:

providing an RFID tag affixed to the article, the RFID tag comprising;

a substrate,

one or more antennas disposed on the substrate,

a radio frequency transceiver circuit coupled to the one or more antennas comprising;

a single monolithic integrated circuit having a digital input and comprising a radio frequency receiver, a radio frequency transmitter, a microprocessor, a memory for persistent data storage,

a power supply coupled to the radio frequency transceiver circuit, and

a measuring device for sensing a physical characteristic selected from the group of temperature, pressure, water level, voltage and combinations thereof and outputting an analog signal indicative of the sensed characteristic, and

an analog-to-digital converter for receiving the analog signal from the measuring device at an analog input, converting the received signal to a digital signal, and outputting the digital signal to the radio frequency transceiver circuit via the digital input of the integrated circuit;

receiving a radio frequency signal including an interrogatory message in the radio frequency receiver;

collecting data from the digital signal resulting from the analog-to-digital converter converting voltages from the measuring device, wherein the collected data is indicative of the characteristic sensed by the measuring device; and

transmitting the collected data by communicating a radio frequency signal from the radio frequency transmitter to a radio frequency interrogator within range of the transmitter.

26. The method of claim 25 and further comprising:

providing the radio frequency interrogator configured to transmit radio frequency signals and to receive radio frequency signals and operable to communicate with RFID tags in remote proximity to the interrogator;

transmitting from the interrogator the radio frequency signal including the interrogatory message comprising a command to respond with the collected data; and

receiving a radio frequency signal from at least one RFID tag including the collected data.

27. The method of claim 25, wherein the sensed physical characteristic is temperature.

28. The method of claim 27, wherein the article is perishable.

29. A method for remotely determining the temperature of an article, comprising:

providing a radio frequency identification (RFID) device affixed to the article, the RFID device comprising;

a substrate,

one or more antennas disposed on the substrate,

a single monolithic integrated circuit having a digital input and comprising;

a radio frequency receiver coupled to the one or more antennas,

a radio frequency transmitter coupled to the one or more antennas,

a microprocessor, and

a memory coupled to the microprocessor,

a measuring device for sensing temperature coupled to the microprocessor via an analog to digital converter circuit, wherein the measuring device outputs an analog signal indicative of the sensed temperature to the analog to digital converter circuit, the analog to digital converter circuit converting the analog signal to a digital signal and outputting the digital signal to the integrated circuit via the digital input, and

a power supply;

receiving in the radio frequency receiver a radio frequency signal including an interrogatory message requesting transmission of data indicative of temperature sensed by the measuring device;

collecting digital data indicative of temperature sensed by the measuring device; and

transmitting a radio frequency signal from the radio frequency transmitter including the collected data.

30. The method of claim 29, wherein the article is perishable.

31. The method of claim 30, wherein the microprocessor is operable to periodically collect temperature data and store the data in the memory for later retrieval.

32. The method of claim 31 and further comprising providing a counter coupled to the microprocessor, wherein the microprocessor is operable to configure the counter responsive to a command received in the radio frequency signal receiver to contain a predetermined count, and further to collect the number of temperature samples equal to the predetermined count, and to store the digital data corresponding to the samples in the memory for retrieval.

33. The method of claim 32, wherein the microprocessor receives a command to transmit data as a portion of a radio frequency signal received in the radio frequency receiver and in response configures the memory to retrieve stored temperature data and configures the transmitter to communicate the stored data via radio frequency signals from the radio frequency transmitter.

34. A radio frequency identification (RFID) device for transmitting sensed conditions to a remote receiver, comprising:

a substrate;

one or more antennas disposed over the substrate;

radio frequency transceiver circuitry coupled to the one or more antennas and disposed adjacent the substrate, the radio frequency transceiver circuitry comprising a single monolithic integrated circuit comprising;

a digital input,

a radio frequency signal receiver,

a radio frequency transmitter for communicating radio frequency signals,

a memory for persistent storage of data, and

a microprocessor;

a power source for supplying power to the radio frequency transceiver circuitry;

a measuring device for measuring a condition and generating an analog signal indicative of the measured condition; and

an analog to digital converter coupled to the microprocessor, wherein the analog to digital converter is configured to receive the analog signal from the measuring device, convert the analog signal to a digital signal, and output the digital signal to the digital input of the integrated circuit.

35. The device of claim 34, wherein the analog signal is indicative of at least one condition selected from the group of temperature, pressure, magnetic field, voltage, water level and combinations thereof.

36. The device of claim 34, wherein the memory comprises memory that is readable, writeable and re-writeable.

37. The device of claim 34, wherein the memory comprises non-volatile memory.

38. The device of claim 34, wherein the memory further comprises a non-alterable indicia.

39. The device of claim 34 wherein the analog-to-digital converter is formed on the integrated circuit.

40. The device of claim 34, wherein responsive to a received command from a remote radio frequency interrogator received by the radio frequency receiver, the microprocessor inputs data from the analog to digital converter corresponding to the input signal and the microprocessor configures the radio frequency transmitter to communicate the data by communicating radio frequency signals.

41. The device of claim 34, wherein the radio frequency transmitter communicates radio frequency signals by backscatter reflection.

42. The device of claim 34, wherein the power source is a battery.

43. The device of claim 42, wherein the radio frequency transmitter actively transmits radio frequency signals.

44. The device of claim 40, wherein the single monolithic integrated circuit further comprises a counter, and responsive to a received command from a remote interrogator received by the radio frequency signal receiver, the microprocessor configures the memory to store a plurality of data samples corresponding to a count within the counter indicative of the input signal from the analog-to-digital converter over a predetermined time period, and the microprocessor configures the radio frequency transmitter to communicate the stored data samples using radio frequency signals.

45. A method for determining the temperature and pressure of an article remotely, comprising:

providing in the article a radio frequency identification (RFID) tag comprising;

a substrate,

one or more antennas disposed on the substrate,

a single monolithic integrated circuit comprising;

a radio frequency receiver coupled to the one or more antennas,

a radio frequency transmitter coupled to the one or more antennas,

a microprocessor, and

a memory coupled to the microprocessor for the persistent storage of data,

a measuring device for sensing temperature and outputting an analog temperature signal,

a measuring device for sensing pressure and outputting an analog pressure signal,

an analog to digital converter coupled to the microprocessor and configured to receive the analog temperature signal and the analog pressure signal, convert the analog temperature signal to a digital temperature signal, convert the analog pressure signal to a digital pressure signal, and output the digital temperature signal and the digital pressure signal to the integrated circuit, and

a power supply;

receiving in the radio frequency receiver a radio frequency signal including an interrogatory message requesting transmission of data indicative of at least one of the characteristics of temperature, pressure, and the combination thereof, sensed by the measuring devices;

collecting digital data indicative of the characteristic sensed by the measuring devices, wherein the digital data comprises at least one of the digital temperature signal and the digital pressure signal; and

transmitting a radio frequency signal from the radio frequency transmitter including the collected data.

46. The method of claim 45, wherein the article is non-perishable.

47. The method of claim 45 wherein the microprocessor is operable to periodically collect sensed characteristic data and store the data in the memory for later retrieval.

48. The method of claim 47 and further comprising providing a counter coupled to the microprocessor, wherein the microprocessor is operable to configure the counter responsive to a command received in the radio frequency signal receiver from an interrogator to contain a predetermined count, and further the microprocessor is operable to collect the number of data samples equal to the predetermined count, and to store the data corresponding to the samples in the memory for later retrieval.

49. The method of claim 48 wherein the microprocessor further receives a command from an interrogator to transmit data as a portion of a radio frequency signal received in the radio frequency receiver and in response configures the memory to retrieve the stored data and further configures the radio frequency transmitter to communicate the stored data via radio frequency signals from the radio frequency transmitter.

50. The method of claim 49, wherein configuring the transmitter further comprises communicating radio frequency signals by backscatter reflection.