Two teams of scientists claim to have fabricated a miniaturised energy harvester using a piezoelectric capacitor formed by a platinum electrode which generates energy from mechanical vibrations.

Research teams from IMEC and IMEC-NL, which are based in Belgium and Holland, claim that the harvester can attain a maximum output of 40 micro-watts - the power range required by wireless sensor applications.

In particular, the firms claim that the device will be of use where it is difficult to replace batteries.

The harvester consists of a piezoelectric capacitor formed by a platinum electrode, a lead zirconate titanate (PZT) layer and a top aluminum electrode, which is fabricated on a cantilever able to support mass on its tip.

As the harvester is subjected to oscillations, so the mass causes the piezoelectric layer to stretch, which, in turn, induces an electrical power when an electrical load is connected to the device.

Commenting on the research, Bert Gyselinckx, Program Director at IMEC-NL in the Holst Centre, said: "After the demonstration of a battery-less pulse-oxymeter, which is fully powered by a thermal scavenger, this is another encouraging result which brings us closer to seeing miniaturised scavengers in real-life applications.

"We believe that first of such devices will see market introduction in five years from now and will become mainstream by the end of next decade."

Sources:

Harvesting energy from vibrations, 21/06/07
http://www.edn.com/index.asp?layout=article&articleid=CA6454543

IMEC reports 40 microwatt from micromachined piezoelectric energy harvester, 21/06/07
http://www.imec.be/wwwinter/mediacenter/en/harvester_2007.shtml


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