A battery-free wearable system for on-device human activity recognition using kinetic energy harvesting

Abstract

Wearable devices are increasingly prevalent in daily life, especially for activity recognition, health monitoring, and fitness management. However, their reliance on batteries poses inconveniences, expenses, and environmental issues. To address these concerns, we present a battery-free wearable system that utilizes kinetic energy from human activities as both the energy source and a sensing signal for on-device activity recognition. With a carefully designed hardware and software, our system achieves real-time activity recognition on an ultra-low-power micro-controller, including on-board classification and wireless transmission. Real-world experiments demonstrate that our system operates the wearable device up to 95.2% of the time, inferring and reporting ongoing activities within 8 seconds with up to 87% accuracy