A flexible piezoresistive sensor with highly elastic weave pattern for motion detection

A flexible high-sensitive piezoresistive sensor using conductive and highly elastic woven fabric has been fabricated for detecting human motion. Different from the previously reported pressure-strain sensors, the present sensing system is prepared based on the elastic weave between conductive warp and weft yarns on a pair of interdigital electrodes, and encapsulated by PDMS elastomer. This new sensing module exhibits the comparable sensing performance with conventional strain sensor, including the ratio of compressed resistance to initial value, sensitivity, hysteresis and repeatability. The pressure-resistance relationships of various conductive weave patterns and contact area between electrodes and conductive yarns have been systematically investigated. It was found that plain woven fabric displays an inverse proportion decline of resistance with the increase of compression pressure, the similar trends was noted for the parameters of weft density, contact area of weave and electrode, and laying angles of them. Demonstrations of such sensing modules in detecting finger pressing, bending and contraction of human abdomen from breathing were performed and clear and effective signals were output for corresponding actions.