Science Friday: power from gravity, deciwatt

smithbone at smithbone at
Sun Jan 20 10:25:12 EST 2013

On 01/19/2013 02:39 AM, Hal Murray wrote:

> Their target is light in Africa.   They are only getting 30 mW to 1/2 W so
> the name is appropriate.  That's enough for illumination from LEDs.
> It's not likely to be useful for OLPC any time soon.  It might be something
> to keep an eye on.

The crowd sourcing link was posted on in the IRC devel channel a few 
months ago and we were debating how much power you could really extract 
out of it.  We came up with some really low numbers.  Low enough that I 
was questioning the usefulness but it seems that we were right on.  Just 
enough to light a low power LED.  Which he said was possible due to 
todays really efficient LEDs.

The 1/2W upper end required an adjustment in the descend rate for a much 
faster drop and he didn't give the time or weight used so difficult to 
make a guess at the actual energy available.

I think the most interesting thing was said just at the end of the 
interview where they were going to use some of the money they raised to 
research a very low power satellite receiver coupled with some sort of 
low power display to try and be able do download a wikipedia page.

Richard A. Smith
smithbone at

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