Wireless personal information carrier having logic for connecting a battery only during data transfers
View Patent ↗An information carrier in a preferred embodiment is worn like a dog-tag and carries data such as medical information. The tag operates wirelessly, communicating with a nearby reader which interrogates the tag with a selected combination of RF signal frequencies. Extremely long term battery usage is achieved by connecting the battery in the tag only when the proper combination of RF signals, each at least at a minimum threshold power level, is received at the tag to produce a trigger voltage in activation logic to close a solid state switch. After a sequence of communications between the reader and the tag is then completed to transfer selected data from the memory, the battery is again disconnected to preserve battery energy for very long periods of time. The battery may be slowly recharged by ambient energy using a scavenging antenna array.
1. A method for a wireless information storage to be interrogated by a proximate reader; the method comprising the steps of:
receiving a trigger signal at a first frequency using a first radio circuit;
activating a decoding circuit of the first radio circuit in response to receiving the trigger signal;
receiving a coded signal at the first frequency using the first radio circuit;
decoding and validating the coded signal using the first radio circuit; and
if the coded signal is validated, activating a second radio circuit by closing a solid state switch interposed between the battery and the second radio circuits; and
performing a wireless information transfer at a second frequency from the storage device to the reader using the second radio circuit.
2. The method of claim 1 , wherein the coded signal is a bit code modulated RF signal.
3. The method of claim 1 , wherein:
the step of activating the decoding circuit is performed passively using energy from the trigger signal; and
the step of decoding and validating the coded signal is performed actively using energy from the battery.
4. The method of claim 1 , wherein:
the step of receiving the trigger signal is performed using a first antenna; and
the step of performing the information wireless transfer is performed using a second antenna.
5. The method of claim 1 , further comprising:
receiving an index signal at the second frequency from the reader; and
receiving an acknowledgement signal from the reader;
wherein the information wireless transfer comprises transmitting data corresponding to the index signal to the reader.