Radio frequency identification tags adapted for localization and state indication
View Patent ↗An embodiment of the present invention provides a radio frequency identification (RFID) tag, comprising at least one light emitting diode (LED) that is controlled by the RFID's logic and powered by the RFID's power harvesting circuit, wherein the RFID tag is capable of being interrogated by an RFID reader and reporting its unique identification number by RF backscatter and/or controlling the illumination state of the at least one LED.
1. An apparatus, comprising:
a wirelessly-powered radio frequency identification (RFID) tag with at least one light emitting diode (LED) that is powered by said RFID's power harvesting circuit in response to a tag specific illumination command;
controllers to control the illumination state of said at least one LED and to automatically localize the RFID tag associated with a blinking LED by performing the action of filtering to accentuate intensity discontinuities and deemphasizes linear or flat regions, thresholding to ensure that only bright red light sources are considered, K-means clustering to ensure that only sufficiently large regions are considered, and selecting pixels whose on-off rate is within a given range;
wherein said wirelessly-powered RFID tag powers said LED to provide bright duty-cycled illumination by discharging a storage capacitor when a sufficient operating voltage is reached.
2. The apparatus of claim 1 , wherein said wirelessly-powered RFID tag is interrogated by an RFID reader and reporting a unique identification number by RF backscatter and/or controlling the illumination state of said at least one LED.
3. The apparatus of claim 2 , wherein said illumination is controlled either by an explicit LED-control command from said RFID reader, or locally by said wirelessly-powered RFID tag.
4. The apparatus of claim 3 , wherein said LED is configured to provide visual feedback to a human operator.
5. The apparatus of claim 1 , wherein when the minimum operating voltage is reached, the LED is turned off, at which point the storage capacitor recharges.
6. An apparatus, comprising:
a wirelessly-powered radio frequency identification (RFID) tag with at least one light emitting diode (LED) that is powered by said RFID's power harvesting circuit in response to a tag specific illumination command and is to light up when the tag is in the range of an RFID reader;
controllers to control the illumination state of said at least one LED and to automatically localize the RFID tag associated with a blinking LED by performing the action of filtering to accentuate intensity discontinuities and deemphasizes linear or flat regions, thresholding to ensure that only bright red light sources are considered, K-means clustering to ensure that only sufficiently large regions are considered, and selecting pixels whose on-off rate is within a given range;
wherein said wirelessly-powered RFID tag powers said LED to provide bright duty-cycled illumination by discharging a storage capacitor when a sufficient operating voltage is reached.
7. The apparatus of claim 6 , wherein said wirelessly-powered RFID tag is interrogated by an RFID reader and reporting a unique identification number by RF backscatter and controlling the illumination state of said at least one LED.
8. The apparatus of claim 7 , wherein said illumination is controlled either by an explicit LED-control command from said RFID reader, or locally by said wirelessly-powered RFID tag.
9. The apparatus of claim 8 , wherein said LED is configured to provide visual feedback to a human operator.
10. The apparatus of claim 6 , wherein when the minimum operating voltage is reached, the LED is turned off, at which point the storage capacitor recharges.
11. An apparatus, comprising:
a wirelessly-powered radio frequency identification (RFID) tag with at least one light emitting diode (LED) to be powered by a power harvesting circuit for the wirelessly-powered RFID tag, wherein the LED is powered in response to a tag specific illumination command and wherein said wirelessly-powered RFID tag powers said LED to provide bright duty-cycled illumination by discharging a storage capacitor when a sufficient operating voltage is reached, and
controllers to control the illumination state of said at least one LED and to automatically localize the RFID tag associated with a blinking LED by performing the action of filtering to accentuate intensity discontinuities and deemphasizes linear or flat regions, thresholding to ensure that only bright red light sources are considered, K-means clustering to ensure that only sufficiently large regions are considered, and selecting pixels whose on-off rate is within a given range;
wherein localizing the RFID tag is done with a blink detection algorithm or a stereo triangulation algorithm.
12. The apparatus of claim 11 , wherein said wirelessly-powered RFID tag is interrogated by an RFID reader and reporting a unique identification number by RF backscatter and controlling the illumination state of said at least one LED.
13. The apparatus of claim 12 , wherein said illumination is controlled either by an explicit LED-control command from said RFID reader, or locally by said wirelessly-powered RFID tag.
14. The apparatus of claim 13 , wherein said LED is configured to provide visual feedback to a human operator.
15. The apparatus of claim 11 , wherein when the minimum operating voltage is reached, the LED is turned off, at which point the storage capacitor recharges.