RFID-Based Rotary Position Sensor

The RFID-Based Rotary Position Sensor was designed for use in a hand-crank dispenser with a circular disc inside the dispenser box containing a plurality of RFID integrated circuits (ICs) around the disc's periphery. An antenna is coupled to the crank on the outside of the box, which allows a user to turn the disc and dispense items. An RFID interrogator, coupled to a processor, determines the orientation of the crank based on the RFID ICs, providing information about the rotation angle of the internal disc which can then be used to assess level of material remaining in the dispenser. This sensor can be useful for items that are too small to tag individually (e.g., pharmaceutical pills), but there are various potential applications for the sensor system including use in limit switches, position sensors, and orientation sensors. The configuration of the RFID ICs and antenna can be tailored for specific applications. For example, the system could be used in a rack-and-pinion gear system to measure the rotational or angular displacement that arises from a linear force. Furthermore, the system could be incorporated into a rotary controller to refine the rotation angle of a rotating system, like a steering systemor rotor, for example. NASA's RFID-Based Rotary Position Sensor is at a TRL 6 (system/subsystem model or prototype demonstration in a relevant environment) when used in its original application as part of a hand-crank dispenser system. For additional applications that have not been explored by NASA, the invention is at a TRL 4 (component and/or breadboard validation in a laboratory environment).