More than 780 million people rely on kerosene to light their homes. But the fuel is pricey and is toxic when burned—not to mention a fire hazard. In 2008, London-based product designer Martin Riddiford and his colleague Jim Reeves decided to create a cheap, safe alternative.
Riddiford knew a falling weight could produce enough energy to run a grandfather clock, so why not a light? To find out, he attached the crank of a wind-up flashlight to a bicycle wheel. He hung a weight from the wheel to cause it to spin; the wheel cranked the flashlight, and the device lit up.
Over the next four years, Riddiford, Reeves, and a small team spent their downtime between projects in a basement, refining the GravityLight. To use it, a person hangs the device and fills an attached fabric bag with up to 28 pounds of rocks, dirt, or other material. Lifting and releasing the bag steadily pulls a notched belt through GravityLight's plastic hub; the belt spins a series of gears to drive a small motor, which continuously powers an LED for about 30 minutes.
The team used crowdfunding to manufacture 1,000 GravityLights, which it plans to send to developing countries for field testing—plus 6,000 more for backers. "It's exciting to witness so much positive reaction to what we're doing," Riddiford says. Besides remote villages, the lamp could prove handy in campsites, closets, and any dark nook far from a socket, so Riddiford also hopes to license a retail version for less than $10.
HOW IT WORKS
1) As a weighted bag descends, it tugs a belt to turn a series of plastic gears.
2) The gears work in unison to spin an electric motor.
3) The motor powers a small yet bright LED, providing continuous illumination for about 30 minutes—the maximum amount of time that the bag can take to descend.
4) External connectors can power low-voltage devices, and the entire system is designed to work for thousands of lift-and-drop cycles.
Jim Reeves, Martin Riddiford
COST TO DEVELOP
More than $300,000
100 pounds of weight, a few more LEDs and this thing could really be useful.
who says you cant have a longer belt with weight haingign down from 2nd floor :D Can power for hours instead.
Alternative option (with extra connectors) would be also as a phone or battery charger in remote areas.
Lighting up the world, allows people to educate themselves at night, which reduces violence via being educated.
I LIKE IT!
Hopefully they market to developed countries as well for emergency lighting. I would love one in my storm shelter.
uptil I saw the bank draft which said $7814, I did not believe ...that...my neighbours mother woz like really erning money in there spare time on their computer.. there aunts neighbour started doing this for only about six months and resantly took care of the mortgage on their villa and purchased a top of the range Subaru Impreza. I went here........>>>>>>> http://xurl.es/zeq3r
@wonder: via education*
Nice way to reduce violence.
Come on let's picture the possibilities.
Statistics prove higher education reduces violence.
Sure picture the possibilities!!!! Absolutely!!!!!
Really? Seems that a solar powered battery and light would be less cost and easier!???
Mechanical is almost always easier to fix than electronic. Batteries and solar panels in 3rd world countries? Stamping or molding simple gears is must easier anc cheaper.
And everyone calling for a longer belt, think about it, where is it going to go? Are you going to have a 20ft hole in your room to power your light? Doable but reseting it twice and hour is much simpler.
I would think you could have 2 belts, with the weights on either side. Then you could get more power over the 30 minutes.
Wouldn't a 28lb weight dropping a couple feet (say 10 ft.) over 30 minutes produce only a tiny amount of work (ie. 9.3 ft-lb/min or about .009 hp)?
You don't need to dig a hole to make it last longer. What is needs is a high place, like a tree. Mount a pully high with the light low.
Very cool idea. It would be fun to do the math.
Potential energy due to gravity:
m=20 lb=9.072kg, g=9.81m/s^2(42.2ft/s^2), h=10ft=3.05m
W(weight)=0.151 watts over 30 minutes(1800 sec)
multiply by the efficiencies: n(gears)~0.9 and n(alternator) ~0.8 (these are estimated)
a standard LED bulb pulls around 0.04-0.09 watts, so this is plenty for one or two bulbs
Maybe a good idea would be to supply a longer belt and light w/ long wires that can be plugged in to the given connections, and let the owner figure out how to set it up. if they don't have enough height for the whole belt, it could be cut or just dangled from the back of the device
Why not use a Chinese Windlass or Differential Chain Hoist- Two drums or wheels of different diameters mounted togather on the same axel?
At the start the chain is wound around the large drum or wheel, and as it revolves the end of the chain winds up on the smaller drum or wheel leaving a lengthening loop of chain between them. The weight hangs from a pulley on the loop.
Its a common grandfather clock drive.
I still think my perpetual motor is way better!
I was a contributor for this product on their kickstarter campaign, a year later and no one has received a light yet! dissapointing