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 Pelgrine, 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 Pelgrine 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.