A silicon MEMS micro power generator for wearable micro devices

In this paper, a prototype vibration-induced micro power generator is fabricated and tested to investigate the feasibility of a wearable silicon micro power source. This prototype device consists of an energy-collecting electroplated copper coil of 0.1 mm thickness, a nickel-iron alloy (NiFe) suspension spring and a commercially available neodymium iron boron (NdFeB) magnet of dimension 2 mm x 2 mm x 1 mm. The overall size of the micro power generator is 6 mm x 6 mm x 1 mm. The average generated power is 0.32 uW when the device is tapped gently with fingers. This tapping mimics the vibration when the device is worn on a person, and demonstrates power generation feasibility by general human activity. Average power of 1.44uW was measured when the device was placed on a vibration bed excited with a sinusoidal signal of 50 mu m amplitude.