Gravity powered lights, cheaper than solar

erco

Seems like a great, simple idea for needy places. Although I've seen documentaries about kid-powered turnstile water pumps & filters for remote villages that go unused for lack of infrastructure and spare parts. Water is arguably more important than light...

But these are cheap, disposable, easy to install, and are "powered" by rocks and such. Seems likely successful if they are well made.

http://boingboing.net/2012/12/12/gravity-powered-lights-cheape.html

Heater.

I cannot check the vid now but I'm sure that is powered like my grand father's grand father clock which was powered by, my grand father.

Martin_H

It seems better than turning a crank to charge a battery. It's a whole lot easier to lift a big weight every half hour than turning a crank for a minute to get ten minutes of light.

Heater.

Can't argue with that. How long can we power a Prop and some LEDs with a nice rock lifted to head height?
Seems the problem is how to get the power released at the right rate.

ElectricAye

Finally there's a purpose in life for people like this:





And can I interest anyone in my own invention, the gravity-powered microwave oven?

Heater.

Well, we can always find a purpose in life for people like that one!

I'm still puzzling about the power delivery problem. Clocks have escapements to deal with that.
We could do it by gearing down the motion into a small generator. I mean small for a Prop and some LEDs.
Don't have to use gears of course, good old fashioned pulleys would do.
Or, have an escapement, every second or so the rock drops, turns generator a bit, which charges a capacitor which powers our project through buck/boost switched mode PSU.

Humanoido

For countries with available ocean coast lines, especially islands, electricity is sometimes generated by ocean waves with gravity and the force of the changing wave. Rising and falling ocean tides can operate a generator on a large scale. In countries with lots of rain fall, electricity is generated by the weight and flow of rapid precipitation.

Duane C. Johnson

Hi Heater;

Heater. wrote: »

Well, we can always find a I'm still puzzling about the power delivery problem. Clocks have escapements to deal with that.
We could do it by gearing down the motion into a small generator. I mean small for a Prop and some LEDs.
Don't have to use gears of course, good old fashioned pulleys would do.
Or, have an escapement, every second or so the rock drops, turns generator a bit, which charges a capacitor which powers our project through buck/boost switched mode PSU.

This design has an "escapement" of sorts.

An escapement is a way to moderate the delivery of power. Escapements slow down the release of stored energy in small discreet packets. Some of the stored energy is wasted to do this. There is only so much power the clock need to move. If extra weight is added more energy is wasted as the clock still only needs so much power to run. This shows that the escapement is a non linear device.

The gravity generators "escapement" is the LED load. This is a diode. As the voltage across the LED increases the current increases exponentially. There is a happy balance maintained and the LED will remain lit with a steady output. Of course, the gearing is chosen so the current is not excessive.

If 2 LEDs are connected in series the generator will need to spin 2 times as fast for 2 times the voltage at the same current. The weight will drop in 1/2 the time. Note! The gearing defines the current output.

Duane J

Heater.

I was suspecting the regulation is done by simple gearing or pulleys, the idea that the LED is a non-linear load helps and did not occur to me. It's not quite an "escapement" as it is not trying to regulate timing. More impedance matching.

Duane C. Johnson

Hi Heater;

Heater. wrote: »

I was suspecting the regulation is done by simple gearing or pulleys, the idea that the LED is a non-linear load helps and did not occur to me. It's not quite an "escapement" as it is not trying to regulate timing. More impedance matching.

This is true, the escapement matches impedance wasting the excess power.

Remember the early "egg" watches that had a fusee mechanism, the kind of cone shamed capstan? Since they had wound springs the force would change as it ran down. The fusee was a torque converter and much more efficient so the escapement didn't have to waste as much excess power. Of corce, the gravity pendulum doesn't have to do this as the delivered force is pretty constant.

I remember an interesting escapement that performed impedance matching, however I can't find the reference. Basically, the escapement caught less teeth as it moved further and more teeth as it wound down. Apparently this never was practical.

Duane J