A knee brace that generates enough electricity to power 10 cellphones was demonstrated by scientists recently. The brace harvests the energy of a person's knee braking after taking a step, similar to the way hybrid car brakes collect energy to charge their batteries. The device only weighs 1.6kg, and does not need the intense effort that other human-powered energy generators such as hand cranks require. And while the mobile phone measurement given by the creators is pretty useless, they do have several practical applications in mind.
Scientists suggest that the brace could be used by campers and soldiers to power GPS locators and satellite phones in areas with limited access to electricity. It could also charge prosthetic knees, eliminating the need for periodic surgery to replace the batteries in the joint.
The current version of the knee brace is just a proof-of-concept; the team plans to make the device less bulky while still retaining its energy harvesting capabilities. We think this is a great idea with lots of potential (even if it was created in part by a University of Michigan professor). Hopefully we can get a working model before CES next year so we'll never need to worry about our laptop running out of juice. [Science via Science Daily, Reuters, BBC]