Boots Made for Power Walking

Oct. 12 -- There are boots for wading, walking, hiking and skiing. But how about boots for power?

SRI International, a research firm in Menlo Park, Calif., is working with the Defense Department to create a shoe that will convert the mechanical energy of walking into electric power to charge up gadgets, batteries and other devices.

At the heart, or rather sole, of the experimental foot-ware is a heel made of a special elastic polymer. A tiny battery positively charges one side of the flexible material and the other negatively. As the material is compressed and released — such as by the foot pressure generated during walking — the distance between the positive and negative sides change, which in turn creates electricity.

According to Ron Pelrine, the director for SRI International's Advanced Transducers Program, the prototype boot generates about half a watt of power — more than enough energy to recharge the boot's built-in battery and a cell phone. But Pelrine hopes that by the end of January the boot's output could be raised to nearly two watts which is enough juice to power several small electronic devices — a cell phone, a handheld computer, and a radio — simultaneously.

And that kind of potential could be reached since the Defense Advanced Research Projects Agency, or DARPA, has funded about $2.6 million to SRI International's research under a project called Energy Harvesting.

The goal DARPA's project is to develop unconventional energy sources to power a future soldier's equipment such as radios and electronic gun sights. By harvesting power generated by walking, soliders of the future won't have carry as many batteries and have more room for other supplies such as ammunition and food.

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Pelrine says that SRI's boots would also provide for even "smarter" foot-ware for the common ground-pounder. "The power can be used for devices on the boot such as navigation aides, electronic functions that will tell you how far you've walked and monitor your health," he said.