A hyper small vibration absorbing battery breakthrough was just announced. Toshiyuki Ueno of Kanazawa University, in Japan, was able to make the benefits of Galfenol, an alloy of iron and gallium with magnetostrictive properties developed originally by the U.S. Navy. Very similar to another vibration battery, , but at a fraction of the size it still produces 20mW or so. This according to Toshiyuki, is approximately 20 times more efficient than any other piezoelectric based generator at this scale. Two pieces of the material are placed in parallel, wrapped in wire, and due to the physical stresses placed on them, in vibration, electrical current in induced in the coil.
I’m glad to see the Japanese can still make everything more efficient. Small electronics are sure to benefit from this and similar micro-power harvesters in the near future. See more about this project at Toshiyuki's page and the Kanazawa University website.
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