Rotational energy harvester for body motion

This paper presents a micro-rotational energy harvester topology for extracting electric energy from human body motion at joint locations. This was accomplished using an inertial-based axial flux machine constructed with multiple permanent magnet poles and stacked microfabricated planar coils. Several body locations were tested while walking and running on a motor-driven treadmill. An average power of 472μW was obtained when the 2cm³ device was placed on the ankle while walking at 4mph.