GravityLight is a replacement for kerosene lamps in developing countries. Its power source? Weights pulled by gravity.

There’s no internal battery. Rather, it’s an on-demand generator, producing just enough power to make an LED glow.

That LED produces enough light to fill a 10'x10' room…

…and when it goes dark, there’s no fuel to buy. You just reset a bag of sand.

Now, the team will be testing their creation in real environments, to see if their durability concerns meet real world tolerances.

Assuming they do, a $5 lamp could light much of the world.

A $5 LED Lamp Powered By Sand And Gravity

In developing countries, light at night can be a dangerous luxury. But there may be a better solution than solar.

Kerosene lamps have a certain romantic nostalgia, but for those who rely on these lamps as their sole source of light, they’re both dangerous and expensive. The fuel can cost 10-20% of someone’s income, and even the small flame contributes to high rates of disfiguring (even deadly) burns.


The GravityLight, an Indiegogo-funded skunkworks project inside Therefore Design, wants to replace the ubiquitous kerosene lamp. But rather than using new-fangled solar and lithium ion batteries (the latter of which has a devastatingly short shelf life), they’re going with older ideas—gears and weights—to drive power to an LED.

"We wanted to make a device that could provide power for light, as and when it was required, with no limit to the run time in any given night, at a price that will be affordable," designer Jim Reeves tells Co.Design. "It’s the affordable part that has been the challenge."

Much like an old grandfather clock, the GravityLight is powered by the force of gravity, pulling on a weight that a user has positioned. So a 22-pound bag of sand attached to a rope can generate 176 joules per lift, which is enough to illuminate a 100-square-foot room via LED for half an hour. There’s no battery backup, but that’s OK. Because when the time runs out, all someone needs to do is hang the bag of sand again. And sand is in pretty unlimited supply.

"It’s a very old idea. What has changed, and continues to change, is the power requirement of LEDs and other electronics. It’s the convergence of these factors that have made GravityLight practical," Reeves explains. "Many have said it seems obvious, and wonder why it’s never been done before. One reason might be that it is trickier to get right than it might first appear, and I think the old cliche applies that most good ideas seem very simple."

Indeed, when any gadget makes its way into a developing country, durability becomes of paramount importance. GravityLight is designed with such concerns in mind—the gears need no oil, they move very slowly and run dry, and the LEDs should have a 30–50-year shelf life—but working in an environment that’s often dirtier and hotter than the 72-degree vacuumed office spaces most of us spend our days, anything can happen.

"This is why the trial we are now enabled to undertake is critical," Reeves explains. "We want to field test the design and see how well it performs with changing humidity, transit, particle ingress, and resultant wear. We have strategies that are design to cope with all these factors in the design, but the trial will be the proving ground for how well we have done."

From my limited knowledge of LED technology, it seems like a major concern will be, not how long the LEDs can last but how long they can last burning bright enough for practical use. (Heat destroys LEDs at the transistor level, even in cooler environments.) But bigger picture, if GravityLight succeeds, it will be more than a mere lamp; it will be a relatively passive generator, capable of generating a trickle of electricity for topping off batteries or any other use case resourceful people can spot. And how exciting is that?

If you’d like to support the project and score a GravityLight of your own in the process, you can donate $60 to the project on Indiegogo.

Support it here.

[Hat tip: AEI Ideas]

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11 Comments

  • paulo formanes

    how can we commercially buy one of these?

    please email me at paulo.formanes .com

  • Joel K.

    This is such a cool idea and also really great looking. I just was wondering if it would work to use spring tension instead of a weight. Like winding a watch. Maybe it could be more compact. Anyway, great work.

  • Tskumaresh

    Have you started commercial production ? Got hughe potential in India. Mail me details to tskumaresh .com  - Thanks, Kumaresh

  • Ratishsrivastava

    Please send further details at ratishsrivastava@hotmail.com thanks ratish

  • Aandrei

    i had the grandfather clock concept for powersource in my head for a long while...once again someone has acted upon an idea....great work guys...how scalable is this concept, i mean can it be scaled up to produce more energy?...please contact me aandrei@telkomsa.net i'm very interested in all renewable/innovative ideas around energy

  • Kim Miller

    That is absolutely amazing! Loved reading your article - what a helpful little device!
     

  • Sylvain Vanderhaegen

    5$ is an estimated mass production cost, it is more likely to cost around 30-40 on shelves. Be wary of this kind of bold titles, you may just hurt them in the end
    .

  • Bharat Barki

    That is precisely the thought that crossed my mind as well Sylvain Vanderhaegen. With so many innovations on the field (already market tested) and others waiting to go green and perform on the field, like this one it is not very right to have headlines such as these when the consumer has become far more intelligent now than yesteryear. I mean the consumer is aware of terms such as 'economy of scale' and their significance in the market today.