Dual Mode Pressure Sensing for Lower-Limb Prosthetic Interface

We present an electronic sensory system capable of measuring both dynamic and static normal pressure to monitor the pain and stress felt by amputees on contact points between residual limb and prosthesis’ sockets. Monitoring the contact forces is crucial to ease the prosthesis customization process and to reduce the pain for the final user. We propose a novel design of a sensing unit that exploits jointly piezoelectric and piezoresistive materials to detect and to discriminate dynamic and static stimuli, and a digitally controlled amplification circuit that permits the signal acquisition from both kind of transducers with low cost microcontroller. Results demonstrate that our design provides valuable information at 1 ksps rate with a global power consumption lower than 25 mW.