This Ingenious $20 Lamp Gets All Its Energy From Gravity

The ingenious GravityLight-a light that gets all its energy from its own weight-first appeared about three years ago. We wrote about it as it was launching on Indiegogo and went on to raise $399,590.

It provides free light (after you’ve bought it). It’s cheap. And it has none of the environmental or health side-effects as do other light alternatives in the developing world. But even all those things aren’t necessarily enough if it’s to reach its potential. If the company and foundation behind the device are to make it a success, they need a reliable product; they need to distribute it in places where distribution can be difficult; and, more fundamentally, they need to explain why someone should buy a GravityLight when there’s plenty of good, cheap solar on the market today.

Thankfully the company seems to have most of the questions answered, as least so far.

The light has a gear-train and DC generator. As a heavy object pulls down on one side, it creates a force that’s converted into electricity. The lamp can last for hours on a single lift to one side, and, of course, that lift is renewable: When one side drops to balance, you just hoist it up again. With a string of mini-lights attached, it can illuminate a small room. And, importantly, without the problems that come with kerosene lamps (fumes, fire), which are still widely used in off-grid places.

After the first campaign, GravityLight sent the device to organizations and individuals in 26 countries. They tested it and reported back about what they liked and didn’t-feedback that’s now been incorporated into a version two. Children apparently liked swinging on it, meaning it could break, and some families complained that lifting 22 pounds was too much for them. The new version, which launches next spring, has a stronger plastic housing, and a new pulley system that effectively reduces the weight by three-quarters. It also comes with auxiliary mini-lights, or “SatLights,” that can be extended in series.

“The SatLights have really revolutionized the experience,” says commercial director Caroline Angus. “Now someone can be reading while someone else is cooking, rather than there just being this one light on that one person, or a narrow part of the room.”

This story is part of our series, How’s That Working Out For You, where we check in on projects we’ve covered in the past to see if they’ve come to fruition, or turned out to just be vaporware.

With the proceeds from a second Indiegogo campaign, GravityLight is now setting up an assembly line in Kenya. The lamp will cost $20 and be distributed through door-to-door ( Avon Lady-type) networks, farmer groups, and more traditional market stalls.

Angus sees a wide range of people buying the product, from families who currently use kerosene lamps, to people who have have grid power but are afraid of blackouts. “It’s everyone from people on $2 a day to the slightly more affluent who are just conscious of the next power cut because maybe they haven’t already charged a solar light,” she says. The GravityLight is more dependable than a solar lamp, she says. It’s on-demand, whereas solar power is dependent on the weather, or your foresight in charging up a battery ahead of time.

It certainly sounds like GravityLight has answers to the big questions. But, it’s still early days, and we won’t know for sure until the new product hits the streets next year.

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