Low-profile Rotational Electret Energy Harvester for Battery-less Wearable Device

Abstract

Rotational electret energy harvester (EH) for human arm swing is developed. By using flexible print circuit boards for electrode/electret substrates and metal ball bearing for the rotational support, the maximum thickness for the rotational part including the eccentric mass is as thin as 3.3 mm. Output power up to 80 μW has been obtained from arm swing during walking at 1.45 m/s. A multi-axis robot is also employed for evaluation of power generation performance.