The Gravity Light is designed to offer a safer alternative to kerosene lamps in developing countries. For the rest of the world, it is a safe, clean and affordable source of light. No batteries, no electrical grid, no kerosene/fuel.
The use of kerosene results in vastly higher cancer rates due to smoke inhalation. And regular purchase of kerosene is already a significant part of the family income in developing countries.
Gravity Light takes advantage of the unlimited force on earth - Gravity. It uses that Earth’s gravity to drive a drive a gear-train enough to generate electricity to power an LED bulb. An LED bulb light enough for nightly activities.
Watch this video to see how it works
It works by hanging a bag filled with weights (or simply rocks or sand) up, and gravity does it job. The bag descends slowly. The pull of the weighted bag turns a low-speed high-torque gear, which drives a DC generator. The bag falls around 1mm per second (depending on the weight) and the DC motor is driven at a thousand rotation per minute.
When the bag touches the ground, simply hoist the bag up again and gravity continues to provide light. It takes around 30 to 45 mins for the process to repeat.
Here’s another video from the creators of Gravity Light.