NextBillion - An Initiative of the William Davidson Institute at the University of Michigan

Monday, January 7, 2013

The problem of bringing light to remote parts of the developing world has been tackled in the past with everything from solar-powered lamps to wind-up devices and rechargeable batteries – all of which require relatively expensive kit or physical effort by the user.

But two London-based designers have now developed a light source that operates on the stuff that surrounds you – earth, rocks or sand – with the helping hand of gravity.

Developed by Martin Riddiford and Jim Reeves over the last four years, the GravityLight is simply charged by a bag that is filled with around 9kg of material and hung from a cord below the light. As the bag descends, a series of gears inside the device translates this weight into energy, providing 30 minutes of light. The light strength can be adjusted, from strong task lighting to a longer-lasting low-level glow, and two terminals on the front allow it to be used as a generator so it can recharge other devices including radios and batteries.