Energy scavenging for wireless sensor nodes

Most wireless sensor nodes are powered by primary or secondary (rechargeable) batteries. These take up a large proportion of the size and weight, and often the cost, of the nodes, and furthermore the need to replace or recharge them creates a significant maintenance burden. Maintenance free power provision would greatly increase the feasibility of networks with very large numbers of, or very widely distributed, nodes. Recently the scavenging of energy from the environment, in the form of heat, motion, light or other electromagnetic radiation, has been actively researched as a possible solution to this problem. In this paper the progress and ultimate potential of such power sources is reviewed, with an emphasis on motion and vibration scavenging. The power levels achievable are examined, and applications are considered in which such sources are attractive to substitute for or supplement batteries.