Wearable electronics are demonstrating great potential in many areas, but finite capacity of chemical batteries become a bottleneck of their applications. We develop three kinds of wrist-worn energy harvesters that have different power enhancement mechanisms to address this issue. A compact energy harvester with magnetic frequency-up converter is developed to increase energy conversion capacity while a tiny repulsive magnetic spring is introduced to enhance response motion. Besides, a proof-massless energy harvester is investigated to improve motion capture capacity of wrist-worn energy harvester. A general model is constructed to predict the performances of these energy harvesters. The experimental results show that these energy harvesters achieve significant power improvement and their power output and power density can reach ten times that of the counterparts.
Keywords self-powered wearables, energy harvesting, arm swing, wrist-worn, electromagnetic transducer