Passive radio frequency data logger
View Patent ↗A radio frequency identification device is configured as a data logger. In a logging mode the radio frequency identification device logs information received from a transmitter. In an upload mode the radio frequency identification device is configured to upload to a receiver logged information and/or information identifying the radio frequency identification device. Optionally, the logging mode is used when there is insufficient power to send a readable response signal to the transmitter.
1. A method comprising:
receiving, using a passive RFID tag, a first radio frequency transmission including first identification data configured to identify a sender of the first radio frequency transmission;
using the first radio frequency transmission to generate first electrical energy;
storing the first identification data in a log data storage using the first electrical energy;
receiving a second radio frequency transmission including second identification data configured to identify a sender of the second radio frequency transmission;
using the second radio frequency transmission to generate second electrical energy;
storing the second identification data in the log data storage using the second electrical energy;
switching from a logging mode to an upload mode, where switching from the logging mode to the upload mode includes using a circuit to change a state value stored in a static storage location, the state value being a digital value indicative of the logging mode; and
uploading the first identification data and the second identification data stored in the log data storage, in the upload mode.
2. The method of claim 1 , wherein switching from the logging mode to the upload mode is responsive to a radio frequency signal.
3. The method of claim 1 , wherein switching from the logging mode to the upload mode is responsive to an identity of a received command.
4. The method of claim 1 , wherein switching from the logging mode to the upload mode is responsive to a handshaking routine.
5. The method of claim 1 , wherein switching form the logging mode to the upload mode is responsive to a radio frequency.
6. The method of claim 1 , wherein switching from the logging mode to the upload mode is responsive to receiving data identifying a data logger including the log data storage.
7. The method of claim 1 , wherein switching from the logging mode to the upload mode is responsive to a third radio frequency transmission.
8. The method of claim 1 , wherein switching from the logging mode to the upload mode is responsive to a frequency of a third radio frequency transmission.
9. The method of claim 1 , wherein switching from the logging mode to the upload mode is responsive to manipulation of a mechanical or electrical switch included in a data logger, the data logger including the log data storage.
10. The method of claim 1 , wherein switching between the logging mode and the upload mode is automatic after the step of storing the second identification data.
11. The method of claim 1 , further including sending a response to the second radio frequency transmission, receiving an acknowledgement of the response, and changing from the logging mode to the upload responsive to the acknowledgement.
12. The method of claim 1 , further including receiving a confirmation that the uploading of the first and second identification was successful and, in response, deleting the first and second identification data from the log data storage.
13. The method of claim 1 , wherein uploading the first and second identification data is performed using energy generated from a third radio frequency transmission.
14. The method of claim 1 , wherein uploading of the first and second identification data is performed using a physical connection from the log data storage to an external device.
15. The method of claim 1 , wherein connection to an external device automatically results in a change from the logging mode to the upload mode.
16. The method of claim 1 , wherein the first radio frequency transmission and the second radio frequency transmission are each not strong enough to provide a radio frequency response signal.
17. The method of claim 1 , wherein the presence of many data loggers cannot interfere with receipt of the first radio frequency transmission, and cannot interfere with uploading the first identification data and the second identification data.
18. The method of claim 1 , wherein both the second identification data and the first identification data are received and stored in the logging mode before the step of switching from the logging mode to the upload mode.
19. The method of claim 1 , wherein switching from the logging mode to the upload mode is responsive to a specific upload command.
20. The method of claim 1 , wherein receiving of the first radio frequency transmission, receiving of the second radio frequency transmission and the uploading each occurs at a different location of a shipment.
21. The method of claim 1 , wherein the step of uploading the first identification data and the second identification data does not use the first electrical energy or the second electrical energy.
22. The method of claim 1 , wherein switching from the logging mode to the upload mode is dependent on receiving an identifier of a specific logger.
23. The method of claim 1 , wherein the static storage location is a static storage location of the passive RFID tag, the state value including a digital value indicative of whether the RFID tag is in alternatively the logging mode or the upload mode.
24. The method of claim 1 , wherein the first replay signal is a wireless signal.
25. The method of claim 1 , wherein the first radio frequency signal includes time information.
26. The method of claim 1 , further comprising generating data using a sensor and the first electrical energy.
27. The method of claim 1 , wherein the first identification information is stored in the log data storage in association with time of day information.
28. The method of claim 1 , further comprising determining when communication reliability is sufficient to send a reply signal, the reply signal being a reply to the first radio frequency transmission.
29. The method of claim 1 , wherein the sender of the first radio frequency transmission and the sender of the second radio frequency transmission are different senders.
30. The method of claim 1 , wherein the sender of the first radio frequency transmission and the sender of the second radio frequency transmission is the same sender.