The kerosene lamp is widely used in developing countries to provide light. Jim Reeves and Martin Ridiford have been looking for a better solution. Initially they set out to create a light powered by solar energy, buy they discovered something even better. The light powered by gravity that they created will cost under $10 and have no running costs. A village’s investment will be payed off within 3 months of using the light instead of purchasing kerosene and will have no cost from that moment into the future.
How does Gravitylight work? A plastic belt hangs from the device and attaches to a bag, filled with something like dirt or rocks. When the bag is lifted up to the device it slowly lowers the bag to power the LED bulb. It can provide up to 30 minutes of light before the bag needs to be raised up again. See the video for a demonstration. Learn more on their successful Indiegogo project page or deciwatt.org.