An electromagnetic in-shoe energy harvester using wave springs

This paper reports an compact electromagnetic in-shoe energy harvester using wave springs. Such a device is able to generate electrical energy from footsteps during walking and running. Existing solutions for energy harvesting from footstep suffer from short lifespan or complex structures. The proposed solution uses wave springs that have the same performance compared to coil springs but within a much smaller space. Therefore, the proposed structure is simple and compact, thus can be integrated into the shoe heel. A prototype was built and tested under normal walking conditions. In the test, the peak power of 1.6 mW and an average energy of 55.6 J per step were recorded.