by Martin Riddiford and Jim Reeves (Therefore Ltd)
GravityLight is a revolutionary and sustainable approach to generating power and light. GravityLight can eliminate the need for kerosene lamps, offering huge health, economic and environmental benefits.
It takes around 3 seconds to lift the weight that charges GravityLight, which will provide up to 30 minutes of constant light, as the weight drops under the force of gravity. The weight is a bag (which doubles as the product packaging) that the user fills with 9 – 12.5kg of material (earth, rocks or sand). This connects to GravityLight via a plastic strap, which passes through the generating mechanism. A series of gears and a generator inside translates this slow falling mass into electrical energy. The system can be varied, to provide either task or ambient lighting, or both simultaneously at a lower level. It has terminals on the front to allow it to be used purely as a generator to top up batteries, or to power various low voltage devices, such as FM radios.
GravityLight has no batteries to run out, replace or dispose of, and has no reliance on the external environment, time of day, season or weather. As there are no running costs after the initial low-cost purchase, GravityLight has the potential to help lift people out of poverty, who otherwise spend large proportions of their income on kerosene for lighting.