What a great idea - good luck!
Please have a think about those who get a living from the small scale distribution of kerosene. They may be out of work and struggling to feed their families.

OMG It's brilliant ! Cheap, green, simple idea! I would love to have it myself for hiking or whatever! wow.

Maybe they could be recruited as distributors of the GravityLight, in parallel with their kerosene business? Brilliant ('scuse the pun) idea, based on the ancient weight-driven clock drive system. It needs to be made tough though, as repairs or replacement would probably be prohibitively expensive.

This is a great idea. It should be on Dragon's Den to help people in third world countries. It should be set up that everyone who buys one in the western world adds an extra $5 so that a free one can be given out in Africa. That way in the west it is a profitable sustainable business and in other parts of the world they have safe light for the first time.

@999 Hot
Great Idea!
You are right about the distributors of Kerosene - but maybe we could get them to distribute & service these and other eco-friendly lights.
What would really make a difference is if we could carry out the production in the developing world as well.
Any volunteers to see it it could be done?

This is a very cool idea, but I'm bothered by the assumption that it is a good idea to replace a mostly automated lighting system with a labor intensive one.
I sure would be more likely to buy one to replace another light source if I could get at least 2+ hours of light from a single "charging" but 30 minutes is almost a joke compared to a lamp.

Rather than aim it at the 3rd world, they should just sell it in the US for disaster preparedness. After they have sold 10 thousand at $10 the cost per unit should be enough to sell in the 3rd world for $5.
I would also like to see an accessory that lets a rocking chair drive the generator.

Anyone who can distribute kerosene can distribute other things and increases in productivity yielded by light at night will provide families with extra spending power to provide markets for things they can distribute.

This reminds me of those hand-crank LED flashlights that are used for emergencies. Probably more robust, though. Excellent idea.

Great work gentleman! The world has become one step closer to being a better place… Keep it up!