Development of a wirelessly-powered wearable system for finger tracking

In this paper, the development of a system capable of tracking finger motion is presented. The proposed wearable tracking unit is placed on the finger and it is wirelessly powered without using cables or batteries, thus enhancing freedom of movement. The system is comprised by two sections: a measurement unit and a wireless power transfer apparatus. The measurement unit consists of an electronic board able to measure, acquire and transmit sensors signals; a stretch sensor and an inertial measurement unit are integrated on the measurement unit. Furthermore, the wireless power transfer apparatus is implemented by means of inductively-coupled resonant circuits. A prototype of the developed system is characterized by experimental tests. Results show the feasibility of the proposed approach. The measuring system can track finger movement with a sample rate of 30 Hz, while the wireless power transfer system demonstrates the capability of transferring 67.72 mW, necessary to power the measurement unit, at a maximum distance of about 8 cm.