Kyle Toole, engineering student at Strathclyde University in Glasgow, was frustrated after running out of battery for his MP3 player while hiking. The 21 year old set out there an then to design a product that would enable hikers to use their phones or listen to their MP3 players everywhere, even far away from mains power.
For his fourth year project, Kyle created the Etive Kinetic Charger. The device uses the naturally occurring, vibrating, shock forces concentrated at the knee and ankle during walking. Using the physics behind Faraday’s law of induction (when magnet forces are changed an electric current can be created), Kyle created a device using repelling neodymium (NdFeB) magnets, suspended within a magnetic field. As the magnet bounces within the tube during motion, it induces a current within a copper wire coil, up to 3.8V of power each tube.
The Etive system is currently being further developed to stack multiple energy generators that will recharge a lithium ion battery. Kyle determined that a single person could expend an estimated 407 watts of power during hiking, all which could easily be captured by the Etive system.
A similar device in final development is the nPower PEG above, available for pre-order today. The 9″ long, 9 oz device from Tremont Electric works off of the same principle as the Etive. The kinetic energy resulting in the movement from your bag or hip while walking translates to an 80% charge for most devices from an hour of walking.
I think I may have to try one of these since I haven’t had much luck on climbs with my Powerfilm ultracompact USB + AA charger. You can always count on walking but you can’t always count on the sun!