An LED light that runs on rope pulls and gravity has been developed, which could be good news for developing countries without access to stable lighting.

GravityLight, a crowdfunding campaign and product created by British designers Martin Riddiford and Jim Reeves, allows a cheap LED kit to run for up to thirty minutes -- for free -- through no more than a three-second pull on a rope.

The energy source after this? Something free that everyone has access to -- gravity.

The GravityLight was built for the purpose of supplying cheap, effective lights to remote villages and areas in developing countries that often have to go without reliable power sources. Low wages and expensive light sources means that once the sun goes down, everything goes dark.. or you have to rely on biomass fuel burning. This product aims to change that.

Burning Kerosene for lighting purposes produces 244 million tonnes of carbon dioxide annually, according to the team. In addition, using biomass fuel can result in inhaling dangerous smoke, and this can cause lung cancer, eye infections and burns if something goes wrong, as well as costing money many can ill-afford.

Each GravityLight kit includes an LED lamp which works by using the gravitational pull of a weight hanging from the lamp. Every time you lift the 9kg weight -- which is a small sack that can be filled with rocks or sand -- enough power is generated to provide thirty minutes of light.

Batteries and fuel are not required, making the light clean and potentially affordable for those on low wages. The team say that this also means users can "use the money they have saved to buy more powerful solar lighting systems in the future."

But why not use solar power to light the developing world? The team cite a number of reasons, including the need to buy batteries to store energy -- often beyond the reach of the poverty-stricken -- and they deteriorate over time, requiring replacements every few years.

The first batch of 1000 gravity-powered LED lamps are going to be given to villagers in both Africa and India to use for free, in order to test and further refine the design. Once this trial is complete, the team want to be able to mass-produce the GravityLight for less than $5.

At the time of writing, with 35 days left to go, the campaign has reached $85,020 in funding, beyond the team's original goal of $55,000.

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This post was originally published on Smartplanet.com