Conformal RFID sensing for assisted living

Two passive sensing designs based on UHF RFID technology are presented for assisted living application. The first tag is mounted on the hard palette of the mouth and detects tongue position, while the second is a skin-mounted strain gauge. Both designs are proposed for wheelchair or computer mouse control applications. Measurements show the sensors can communicate over short ranges comparable with the distance expected between a patent's mouth or face and a reader antenna. The mouth sensor is demonstrated to act as a tongue controlled switch, while the epidermal sensor is intended for eyebrow twitch control, tests indicate both designs have a useful and repeatable sensing function, with more than 3dB isolation in the switching case and approximately 0.25dBm per percentage stretch in the strain gauge.