Aircraft maintenance can be time consuming and expensive. With suitable sensors connected directly to the body of the aircraft, tiny cracks and material fatigue could be constantly monitored. Ulrich Schmid and co-workers, Vienna University of Technology, Austria, have developed a thermoelectric energy-harvester module sufficiently small and powerful that it can power a sensor network.

The generator consists of a small water tank connected to the outside of an aircraft via a thermoelectric generator. The temperature change on landing and take-off produce a thermal gradient between the water tank and aircraft body, which can be used to generate a current. During one flight, the energy harvester can provide the energy of eight to ten milliwatt hours — which is sufficient for a wireless sensor node.

This wireless and battery-less sensor set up reduces the weight of the aircraft and does not create the unnecessary waste of a battery-powered sensor network.

• Miniaturized Power Modules for Aircraft Bodies
  Vienna University of Technology, Austria, 14 June 2011
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