Power Estimation of an Active RFID Device

• US 20090195356A1
• Filed: 02/01/2008
• Published: 08/06/2009
• Est. Priority Date: 02/01/2008
• Status: Abandoned Application

• Current Assignee: Round Rock Research LLC
• Original Assignee: Keystone Technology Solutions, LLC
• Inventors: Tuttle, Mark E.
• Application Number:
  US12/024,351
• Publication Number:
  US 20090195356A1
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G06K 19/0705 the battery being connected to a power saving arrangement
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H04Q 2209/47 using RFID associated with sensors
• CPC Class Codes: H04Q 2209/75 by polling or interrogating the sub-stations
• 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

Methods and apparatus, including computer program products, for power estimating of an active RFID device. A method includes, in a radio frequency identification (RFID) interrogator, interrogating a RFID device, receiving an identification code, times and temperature data from the RFID device in response to the interrogation, and estimating a remaining battery life of a battery in the RFID device. A system includes a radio frequency identification (RFID) device having a store of times and temperature data, and a RFID interrogator programmed to interrogate the RFID, receive the times and temperature data, and estimate a remaining battery life of a battery in the RFID device from the times and temperature data.

Claims

1. A method comprising:

in a radio frequency identification (RFID) interrogator, interrogating a RFID device;

receiving an identification code, times and temperature data from the RFID device in response to the interrogation; and

estimating a remaining battery life of a battery in the RFID device.

2. The method of claim 1 wherein estimating comprises:

determining a most recent temperature from the temperature data; and

predicting the remaining battery life from the most recent temperature.

3. The method of claim 2 wherein predicting the remaining battery life comprises:

matching the most recent temperature to a temperature on a battery life expectancy curve; and

determining a battery life corresponding to the matched temperature on the battery life expectancy curve.

4. The method of claim 3 wherein the battery life expectancy curve is plot of time and temperature.

5. The method of claim 3 wherein the remaining battery life is the determined battery life.

6. The method of claim 3 further comprising receiving a battery indicator from the RFID device.

7. The method of claim 6 wherein the remaining battery life is calculated from the determined battery life and battery indicator.

8. The method of claim 1 wherein estimating comprises:

determining an average temperature from the temperature data; and

predicting the remaining battery life from the average temperature.

9. The method of claim 8 wherein predicting the remaining battery life comprises:

matching the average temperature to a temperature on a battery life expectancy curve; and

determining a battery life corresponding to the matched temperature on the battery life expectancy curve.

10. The method of claim 9 wherein the battery life expectancy curve is plot of time and temperature.

11. The method of claim 9 wherein the remaining battery life is the determined battery life.

12. The method of claim 9 further comprising receiving a battery indicator from the RFID device.

13. The method of claim 12 wherein the remaining battery life is calculated from the determined battery life and battery indicator.

14. A method comprising:

in a radio frequency identification (RFID) device having a memory, temperature sensor and battery, periodically storing measured ambient temperatures; and

estimating a remaining battery life from the stored temperatures.

15. The method of claim 14 wherein estimating comprises:

loading a most recent stored temperature; and

predicting the remaining battery life from the most recent stored temperature.

16. The method of claim 15 wherein predicting comprises:

matching the most recent stored temperature to a temperature on a battery life expectancy curve; and

setting the remaining battery life to the battery life corresponding to the matched temperature.

17. The method of claim 14 wherein estimating comprises:

determining an average temperature from the stored temperatures; and

setting the remaining battery life to a battery life corresponding to the average temperature on a battery life expectancy curve.

18. A method comprising:

in a radio frequency identification (RFID) interrogator, interrogating a RFID device;

receiving an identification code, times, temperature data and battery voltage data from the RFID device in response to the interrogation; and

estimating a remaining battery charge in the RFID device.

19. The method of claim 18 wherein estimating comprises:

setting the remaining battery charge to a battery charge corresponding to a last measured battery voltage on a battery charge life expectancy curve.

20. The method of claim 18 wherein estimating comprises:

determining an average voltage from the received voltage data; and

setting the remaining battery charge to a battery charge corresponding to the average voltage on a battery charge life expectancy curve.

21. A system comprising:

a radio frequency identification (RFID) device having a store of times and temperature data; and

a RFID interrogator programmed to interrogate the RFID, receive the times and temperature data, and estimate a remaining battery life of a battery in the RFID device from the times and temperature data.

22. The system of claim 21 wherein estimating comprises:

determining a most recent temperature from the temperature data;

matching the most recent temperature to a temperature on a battery life expectancy curve; and

determining a battery life corresponding to the matched temperature on the battery life expectancy curve.

23. The system of claim 21 wherein estimating comprises:

determining an average temperature from the temperature data;

matching the average temperature to a temperature on a battery life expectancy curve; and

determining a battery life corresponding to the matched temperature on the battery life expectancy curve.

24. A system comprising:

a radio frequency identification (RFID) device having a store of times and temperature data; and

a RFID interrogator programmed to interrogate the RFID, receive the times and temperature data, and estimate a remaining battery voltage of a battery in the RFID device from the times and temperature data.

25. The system of claim 24 wherein estimating comprises:

determining a most recent temperature from the temperature data;

matching the most recent temperature to a temperature on a battery voltage expectancy curve; and

determining a battery voltage corresponding to the matched temperature on the battery voltage expectancy curve.

26. The system of claim 24 wherein estimating comprises:

determining an average temperature from the temperature data;

matching the average temperature to a temperature on a battery voltage expectancy curve; and

determining a battery voltage corresponding to the matched temperature on the battery voltage expectancy curve.