Recent progress in the design of low power VLSI circuits[1,2] and magnetic MEMS technologies[3,4,5] has led to significant reduction in the power consumption of wireless sensor networks and miniaturisation of integrated nodes. This presents an opportunity to explore practical solutions for self-powering the autonomous sensor nodes, with large expected lifetimes. Of late, power generation by scavenging energy from ambient vibrations has emerged as a promising alternative to batteries. The electromagnetic power generators have an advantage of potentially providing infinite amount of energy without depending on intrinsic coupling factor as in a piezoelectric generator[6,7]. Recently we reported[8,9], the performance of electromagnetic micro power generator using moving copper coils and stationary micro-magnets with a maximum generated load voltage and power of 950mV and 85μW respectively. In this study, the mechanical and electrical characteristics of two designs of microfabricated power generators with vibrating magnets are compared. This paper discusses design, simulation and batch-fabrication steps for two electromagnetic power generators, where design 1 consists of two oppositely polarized vibrating Co{sub}50Pt{sub}50 face centered tetragonal phase (fct) hard magnets, between two sets of copper coils electroplated on silicon wafers and design 2 consists of Co{sub}50Pt{sub}50 magnets vibrating between copper coils electroplated over a soft magnetic, Ni{sub}45Fe{sub}55, layer. The volume of the device is about 43mm{sup}3.
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