Gravity Light Uses Dirt to Illumine the Darkness

Problem: How does one bring light into the darkness? I don’t mean metaphorically (as in religion or philosophy); I mean literally.

We Westerners are spoiled. Who thinks about the miracle that occurs every time a switch is flipped and a room is bathed in light? We take electricity so much for granted that it generally escapes notice that satellite photos from space reveal that much of the world lives in darkness akin to that known by the human race when it was in its infancy. It’s not that hard to generate electricity if–and it’s a big if–you have two things: an adequate fuel supply and a network to deliver the electro-juice you squeeze from that fuel. Wood fires (or dried dung in much of the world) are romantic for Westerners sitting around campfires and den fireplaces, but walk six feet away from these and see the darkness. Or fill lanterns with kerosene like our ancestors did. Breathe in the toxicity.

So how does one deliver low-cost electricity to parts of the world in which fossil fuels and wood are scarce and expensive? How does one light up a room if the switch isn’t attached to wires connected to a grid that’s linked to a generator? How does one make light affordable for those with few resources? So few, in fact, that batteries are prohibitively expensive? (There are also environmental disposal hazards.) Is dirt-cheap cheap enough? Martin Riddiford thinks so.

He’s a cofounder of London-based GravityLight and his firm has come up with a product that’s where high tech meets low tech. Think of an old-style grandfather’s clock, the sort that works when chained weights are drawn up to the side of the clock and then left to ascend on their own weight. As the weights fall, they turn gears and the clock keeps time. The problem, of course, is figuring out how to make a light that’s significantly smaller than the average grandfather’s clock! Here’s where high tech comes in. We can now machine-grind very small gears and we can miniaturize dynamos. GravityLight’s very bright idea is to gear a small light and attach it to a rip-proof poly bag. One fills the bag with about 20 pounds of dirt, winches it clock-style to the bottom of the light, and lets gravity do its thing. One light plus one dirt bag provides 30 minutes of light before the bag has to be hoisted anew. The cost? Under $10 for the unit and free ever after.  

I’ll happily donate money for these to be sent around the world. If this isn’t a how-cool-is-this moment, what is?

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