Wireless device configured for powering transmissions with harvested energy
Embodiments of the present disclosure generally relate to a wireless identification tag configured to harvest ambient energy and transmit an identification signal intermittently, and system and methods for use thereof. In one implementation, the tag may include an antenna configured to receive ambient energy. The tag may also include an energy storage component configured to aggregate and store the received ambient energy. The tag may also include a transmitter electrically connected to the energy storage component and configured to transmit the identification signal. The tag may also include a circuit connected to the transmitter and configured to implement an identification transmission rule, to cause the transmitter to delay sending the identification signal even when sufficient energy for transmission of the identification signal is aggregated and stored in the energy storage component.
1. A wireless identification tag configured to harvest ambient energy and transmit an identification signal intermittently, the tag comprising:
at least one antenna configured to receive ambient energy;
at least one energy storage component, electrically connected to the at least one antenna, configured to aggregate and store the received ambient energy;
at least one transmitter electrically connected to the at least one energy storage component, configured to transmit the identification signal; and
at least one circuit connected to the at least one transmitter and configured to implement an identification transmission rule, to cause the transmitter to delay sending the identification signal until an amount of energy stored in the energy storage component is equal to or greater than a sum of a first amount of energy required for identification signal transmission and a second predetermined amount of reserve energy.
2. The wireless identification tag of claim 1 , wherein the at least one circuit is configured to implement the identification transmission rule to cause the transmitter to send the identification signal in a predetermined time interval.
3. The wireless identification tag of claim 1 , wherein the at least one circuit is configured to implement the identification transmission rule to define a time interval between transmission of two consecutive identification signals.
4. The wireless identification tag of claim 1 , wherein the at least one circuit is configured to implement the identification transmission rule to randomly select a time interval between two consecutive identification signal transmissions.
5. The wireless identification tag of claim 1 , wherein the at least one antenna is configured to receive energy transmitted at a frequency within at least one of a first frequency band around 900 MHz or a second frequency band around 2.4 GHz.
6. The wireless identification tag of claim 5 , wherein the at least one circuit is configured to cause the transmitter to transmit the identification signal in the second frequency band using energy received in at least one of the first frequency band or the second frequency band.
7. The wireless identification tag of claim 1 , wherein the at least one energy storage component is configured to power the wireless identification tag with the stored received ambient energy.
8. The wireless identification tag of claim 7 , wherein the at least one energy storage component includes at least one capacitor configured to power the wireless identification tag without a battery.
9. The wireless identification tag of claim 1 , wherein the at least one circuit is configured to implement the identification transmission rule when the at least one antenna receives ambient energy of a first predetermined frequency.
10. The wireless identification tag of claim 9 , wherein the first predetermined frequency is a frequency of about 900 MHz.
11. The wireless identification tag of claim 9 , wherein the at least one circuit is further configured to cause the transmitter to send the identification signal less than ten seconds after the at least one antenna receives ambient energy in a second predetermined frequency.
12. The wireless identification tag of claim 11 , wherein the second predetermined frequency is about 2.4 GHz.
13. The wireless identification tag of claim 1 , wherein the predetermined amount of reserve energy includes energy for powering at least one portion of the wireless identification tag, apart from the at least one transmitter, for a predetermined time period.
14. The wireless identification tag of claim 1 , wherein the predetermined amount of reserve energy includes a minimum amount of energy for the energy storage component to power the at least one transmitter.
15. The wireless identification tag of claim 1 , wherein the predetermined amount of reserve energy includes energy for powering the at least one transmitter to send a predetermined number of transmissions of the identification signal.
16. The wireless identification tag of claim 1 , wherein the at least one circuit is configured to monitor energy stored in the energy storage component, and cause the at least one transmitter to transmit an additional identification signal, the additional identification signal requiring less energy to transmit than the delayed identification signal, when the ambient energy stored in the energy storage component is determined to be below a predetermined threshold level.
17. The wireless identification tag of claim 1 , wherein the delayed identification signal includes unique identifier data of the wireless identification tag.