Gravity Light

Aimed at developing countries, the Gravity Light requires no batteries, as it gets energy from its own weight, thus providing free light once purchased. How does it work? The light sports a gear-train, along with a DC generator, and as a heavy object pulls down on one side, it turns that force into usable electricity. A single lift to one side is good for hours of light – when one side drops, you can just lift it back up again. Continue reading for another video and more information.

“After the first campaign, GravityLight sent the device to organizations and individuals in 26 countries. Children apparently liked swinging on it, meaning it could break, and some families complained that lifting 22 pounds was too much for them. The new version, which launches next spring, has a stronger plastic housing, and a new pulley system that effectively reduces the weight by three-quarters. It also comes with auxiliary mini-lights, or ‘SatLights,’ that can be extended in series,” reports Fast Company.