Output Energy Evaluation of Wrist-Worn Electret Energy Harvester for Day-Long Activities of Daily Living

Power generation characteristics of a wrist-worn rotational electret energy harvester (REEH) is investigated for activities of daily living (ADL). For the day-long output power measurement, a wearable measurement system for the REEH output power is developed. With the prototype of repulsive-torque-enhanced REEH, harvested energy of 2.14 J has been obtained for 10 hours, and half of the energy was captured during ADL, showing the importance of harvester design for ADL.