Energy scavenging sensors

As the widespread deployment of wireless sensor nodes continues towards the eventual ubiquitous sensing fabric of the future, there will be an increasing demand for battery-less methods of powering them.  For some technologies, such as traditional passive radio frequency identification (RFID) tags, there is no need to provide power on-board at all.  However for other technological solutions, using wireless networks such as Zigbee or WiFi, there will be a need for power without recourse to a battery.  

For situations where sensors are located on machinery, there is a more obvious solution.  Microgenerators such as Perpetuum's PMG17 are able to convert mechanical vibration into usable electrical energy.  If this is combined with a suitable storage technology such as a supercapacitor, it is possible to deliver the peak power required for indefinite regular status reports over wireless networks.  For machinery where vibration is a part of normal operation, such power harvesting is an ideal solution.