Years ago I became acquainted with one of our librarians, who was from Germany. He told me he lived in Dresden during World War 2, and he had a flashlight that had a handle which he could squeeze and it would light the bulb. But he said he lost it and everything else when the Allies firebombed Dresden and the city burned.
My point about relating this story is that the idea of using human energy to power a light is not new. For many decades, the electric generators have been using human and animal muscle to convert sweat into electricity.
This time. a few inventors have developed the Gravity Light. This device uses a weight that is periodically lifted to store enough energy to power the light for tens of minutes. In their video, they do not show the actual unit in operation, but I assume that it uses a series of gears to turn the very slow moving weight’s downward travel into a much higher speed of rotation of the generator’s rotor. This was essentially what the hand powered light did, except it had to be squeezed constantly to keep the light lit. But instead it requires the user to lift the weight up, and over time this weight slowly drops as it powers the generator.
When you think about it, you will realize that this is the same thing that the hydroelectric power stations do at the dam at the reservoir. The generating station converts the falling water to electricity, by using it to turn a turbine, which turns the generator. The water must fall from a high to a lower place in order to release the energy.
The website said that the first production run of the Gravity Lights won’t be available until March, 2013. People don’t realize what a health hazard fires are, whether from cooking or from a kerosene lantern. I think this product would make a good investment. If the price could be kept low, it would be usable in many more places than the solar lights, because it doesn’t depend on sunlight.
Thanks to Quantsuff for sending me the link to this project. Check out some more LED projects on his website.
Update Dec 12 – Mark commented:
Such a clever idea, seems incredible that clocks have used this principle since the 17th century and yet no one thought of this before.
Clocks have used this weight system for power for centuries, but they thought up a better way to power electrical appliances long ago. They had the rotating wheel, just like this Gravity Light has, connected with gears to a generator, just like this Gravity Light. And they added some weight, just like this Gravity Light, in the form of water. They put some buckets, just like this Gravity Light has, on the wheel, and BINGO! They had a water wheel, capable of generating enough electricity for a small village.
The company has surpassed their $55,000 goal by a sizeable amount. You can read more about it here.