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Gravity Lamp, the LED lamp powered by gravity Answered

A Virginia Tech student designed an LED lamp that is powered by gravity. It is called the Gravia, and it took second place at the Greener Gadgets competition in NYC. Gravity as a renewable energy source? Amazing!

From http://pesn.com/2008/02/19/9500471_Gravity_Lamp/
Concept illustrations of Gravia depict an acrylic column a little over four feet high. The entire column glows when activated. The electricity is generated by the slow fall of a mass that spins a rotor. The resulting energy powers 10 high-output LEDs that fire into the acrylic lens, creating a diffuse light. The operation is silent and the housing is elegant and cord free – completely independent of electrical infrastructure.

The light output will be 600-800 lumens – roughly equal to a 40 watt incandescent bulb. Each drop of the gravity mechanism runs the light over a period of four hours.

To "turn on" the lamp, the user moves weights from the bottom to the top of the lamp. An hour-glass like mechanism is turned over and the weights are placed in the mass sled near the top of the lamp. The sled begins its gently glide back down and, within a few seconds, the LEDs come on and light the lamp, Moulton said. “It’s more complicated than flipping a switch but can be an acceptable, even enjoyable routine, like winding a beautiful clock or making good coffee,” he said.

Moulton estimates that Gravia’s mechanisms will last more than 200 years, if used eight hours a day, 365 days a year.

The winner of the Greener Gadgets competition was the Enerjar.


This thing only exists on paper. This device was never built.

yes, LED is a future of the field of lighting, i use led now, and enjoy it,
i find some advantages of it slowly!

led grow lights a.jpg

The numbers might be out but I read the book written by the english guy who developed the wind up radio for africa and he talked about the immense potential of using gravity, springs etc and a clockwork mechanism to extract the potential energy slowly. There is something very worthwhile in this concept, if not in this particularly application.


10 years ago

Concept illustrations, eh? And 50 pounds of weight! Sanity check:
  • 1.3m * 25kg * 9.8 = (approx) 300J (potential energy of 50lb at 4ft)
  • 300J = 300 Ws
I wonder how they expect to get "4 hours" of "40W equiv" (5-10W of LEDs?) out of it? Looks like about one minute to me :-( Did I make a mistake in my math or physics? One of us seems to be off by a factor of about 500?

It's sort of a sobering thought, that you'd have to carry that 50lb weight up something like 25 stories to get an hours worth of 40W light :-(

Looks right to me, and what I came in here to say ;-) When I read this on boingbboing or wherever last week I did the math and said "no way".

Ah. I'm not the first to see this problem, and the inventor concedes the error here.
It's sad that so many of these neat-sounding ideas turn out this way...

Grr. You know, it's sort-of acceptable that a conceptual design would have this sort of error, but I'm really saddened that it got past the judges. THAT just shouldn't happen. (and "more efficient LEDs" doesn't save the idea. Current LEDs are already approaching substantial fractions of max theoretical efficiency. A 100% efficient LED might last 2 to 4x longer than the "less than a minute" estimate. But never close to 500x. Sigh.)

awsome, everyone should have one if its marketed

Cool! I've thought of this before, but I've never seen one built.

One question...where can I get one? If this goes commercial, wuddya wanna bet that they make a survival flashlight version?

that'd be real useful, now I can see the sky at night, lol. Maybe if they employ a spring.

that's pretty smexy.