"Mini-muscles" could fuel smartphones

Flexible membrane could extend battery life for mobile gadgets

Stewart Mitchell
7 Apr 2011

Scientists in New Zealand hope to overcome the perpetual shortage of battery life in smartphones with a system that harnesses power from human movement.

This idea of user-generated power for devices has been around for several years, with researchers touting wearable micro generators woven into fabric, but the beauty of the New Zealanders' approach is its simplicity.

They have developed a variable capacitor generator that harvests energy from the action of flexing and unflexing a rubber-like substance.

"Imagine soft generators that produce energy by flexing and stretching as they ride ocean waves or sway in the breeze like a tree," said Thomas McKay of the Auckland Bioengineering Institute's Biomimetics Lab."We've developed a low-cost power generator with an unprecedented combination of softness, flexibility, and low mass.”

The muscle-like materials used in these “dielectric elastomers” are capable of producing energy when deformed, but had previously relied on bulky external electronics to process the electricity.

"Our team eliminated the need for this external circuitry by integrating flexible electronics directly onto the artificial muscles themselves,” said McKay.

“One of the most exciting features of the generator is that it's so simple; it simply consists of rubber membranes and carbon grease mounted in a frame."

According to the scientists, their prototype device could be incorporated into clothing and harvest electricity from human movement, with the power fed into a mobile phone battery for storage.

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