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lamp fueled by gravity

Posts: 769
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By Susan Trulove

Gravia lamp

BLACKSBURG, Va., February 19, 2008 -- A Virginia Tech student has created a
floor lamp powered by gravity.

Clay Moulton of Springfield, Va., who received his master of science degree
in architecture (concentration in industrial design) from the College of
Architecture and Urban
Studies in 2007, created the lamp when he was an industrial design graduate
student. The light-emitting diode (LED) lamp, named Gravia, has just won
place in the Greener Gadgets Design Competition as part of the Greener
Conference in New York City.

Concept illustrations of Gravia depict an acrylic column a little over four
feet high. The entire column glows when activated. The electricity is
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 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
in the mass sled near the top of the lamp. The sled begins its gentle
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
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 LEDs, which are generally
considered long-life devices, become short-life components in comparison
to the
drive mechanisms," he said.

The acrylic lens will be altered by time in an attractive fashion, Moulton
said. "The LEDs produce a slightly unnatural blue-ish light. As the acrylic
ages, it becomes slightly yellowed and crazed through exposure to ultraviolet
light," he said. "The yellowing and crazing will tend to mitigate the
blue hue of the LED light. Thus, Gravia will produce a more natural color of
light with age."

He predicted that the acrylic will begin to yellow within 10 to 15 years when
Gravia is used in a home's interior room.

A patent is pending on the Gravia. To learn more, contact Jackie Reed of
Virginia Tech Intellectual Properties Inc. (http://www.vtip.org) at
jreed@vtip.org or call (540) 443-9217.

Learn more about the lamp and the designer's philosophy at

PHOTO INFORMATION: The Gravia LED lamp will be powered by gravity. The entire
column will glow.

Contact Susan Trulove at strulove@vt.edu or (540) 231-5646.

© 2008 Virginia Polytechnic
Institute and State University
Posts: 131
Location: Bellevue, WA
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Sigh. I always seem to be the one on the alternative energy forums taking the wind out of people's sails. Sorry everybody (especially Kelda), but the gravity lamp can't work the way the inventor claims. It's founded on faulty math.

I'm as disappointed as everyone else - I excitedly covered the gravity lamp on my blog a few weeks back, but as a result, I've also tracked the aftermath of the announcement.

Basically, the math involved in the gravity lamp is just wrong.  In summary:

  • [li]In the schematics, the weight is defined as 50 pounds. Let's ignore for the moment the fact that 50 pounds is too heavy for most humans to reasonably lift.[/li]
    [li]Next, 50 pounds falling 1.22m in gravity of 9.8m/s2 gives you 271.4 joules.[/li]
    [li]If you ignore energy losses, which are probably going to be considerable, 271.4 joules can power a 1 watt light for four and a half minutes.[/li]
    [li]If you reduced the bulb to a little .1 Watt LED, like a Christmas light, you could get 45 minutes of light out of it.[/li]

  • Since his math was incorrect, the inventor has announced a statement of apology.

    I still think it's wonderful to look for devices like this that take advantage of unconventional energy sources. Personally, I've transformed my tv remote control so that it's powered by shaking. All of my flashlights are wind-ups, and our elliptical machine is hooked up to power the tv we watch when we're exercising. So I hope we find more cool stuff like this that actually pans out...
    Opportunity is missed by most people because it is dressed in overalls and looks like work - Edison. Tiny ad:
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