Self-Powered Smart Shoes with Tension-Type Ribbon Harvesters and Sensors

Abstract

This study aims to develop self-powered smart shoes that can monitor the changes in the bodyweight of a user. A tension-type energy harvester and strain sensor are fabricated using polyvinylidene fluoride-based ribbons and nanopowder containing piezoresistive ribbons, respectively. Two different conducting nanopowders (carbon black and multi-walled carbon nanotubes) are used as stretchable sensors, and the most appropriate mixing ratio of the nanopowders is determined. The energy harvesting performance of the tension-type ribbon harvesters is experimentally investigated based on the combination patterns of ribbons and gait patterns, and a method is introduced to apply the harvesting ribbon to shoes. Tension-type ribbon sensors that detect bodyweight are installed in an acrylic insole with four rectangular holes. The connecting method between the sensors, which guarantees the stability and high sensitivity of the sensor signals, is investigated. Finally, electronic circuits are designed for energy harvesting, data communication, and switching power sources. These designed circuits are implemented in smart shoes.