A gravity powered lamp
A U.S. graduate student, Clay Moulton, created a gravity powered lamp as part of his Masters thesis. The entire lamp is only 4 feet high. To light it, a user moves the weights from the bottom to the top of the lamp and into a mass sled. As the sled slowly drops down, it turns a rotor that powers the LEDs that provide the light.
The light output is roughly equivalent to a 40watt bulb, and it will stay lit for up to four hours before the weights need to be moved again.
I could easily see something like this being used in locations where electricity is very expensive or unreliable. It would also be a great tool for emergency workers or for outdoor camping. And best of all, is that the device is completely green. That is it doesn’t use any fuel at all to power it. Just gravity.
It seems to be a very nice and practical invention,
even if the resetting procedure is not so very easy
http://scholar.lib.vt.edu/theses/available/etd-08292007-103115/unrestricted/resonant-frequency.pdf
(Page 42/43) – and probably less easy if you should do it in the dark (needing more than 4 hours of light)
With a mechanism like that you can almost envision the day when a self-powered perpetual-motion device is possible.
@ J.D.: ???
The energy derives from pure muscle-power! Muscles that lift the mass sled 4 foot high against gravity.
A very similar principle as old mechanical clocks runned by those weights that had to be lifted with a chain….
Far away from a “perpetuum mobile”!