A sub-cm(3) energy harvester for in-vivo biosensors

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 cm(3) in total volume. The device was initially tested on a linear shaker, yielding an RMS and instantaneous output power of 0.33 mu W and 0.65 mu W, respectively, on a 20 Omega 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 mu W and 0.61 mu W 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.