A sub-cm3 energy harvester for in-vivo biosensors

Abstract

The development of a kinetic energy harvester for in-vivo applications is reported. Consisting of an untethered magnetic platform encased by two stators, the device converts normal body movements into electrical power. A combination of microfabrication technologies, conventional manufacturing and 3D printing techniques were used to fabricate and package the harvester, measuring 0.27 cm3 in total volume. The device was initially tested on a linear shaker, yielding an RMS and instantaneous output power of 0.33 μW and 0.65 μW, respectively, on a 20 Ω matched load at 7.17 Hz actuation frequency. The device was then embedded on a wrist band to characterize its power conversion capability on human body, and tested during walking and running activities. Instantaneous output power measured during these activities were 0.28 μW and 0.61 μW for walking and running, respectively. The findings reported in this work demonstrate the potential of this energy harvester to continuously recharge the batteries of in-vivo biosensors, when implanted together in the body.