Alternative power/recharging source?

[david at lang.hm]

On Fri, 22 Feb 2008, Ed Montgomery wrote:

> Came across this rather amazing item the other day,
> and instantly thought this might be a very, very
> useful power/recharging mechanism for the XO...
>
> A lamp powered by gravity producing 40 watts over 4
> hours...using gravity! :-) (Consider the XO using
> about 2 watts...)

this isn't producing 40 watts of power, it's producing light roughly 
equivalent to a 40 watt light bulb. super high power LEDs are about 10x as 
efficiant, lower power LEDs are even more efficiant. so this is going to 
produce <4w, possibly as low as <2w

> Not affected by weather/season/time of day (e.g.
> solar/wind) or behaviour (animal/cow) or location,
> etc.  An unlimited power source available anywhere
> anytime!
>
> Could this mechanism (which apparently is more durable
> than the LEDs in the lamp!) be modified to power
> and/or recharge the XO batteries, etc.?

the durability of this mechanism is theoretical at this point. and while 
it avoids the problems you describe above it gains it's own set (lots of 
fine cut gears, the need for smooth surfaces for the weight to slide on, 
etc)

I'm not saying that this isn't a useful concept, but it's not perfect

> A preliminary article about the gravity lamp can be
> found here (from Virginia Tech):
> http://www.vtnews.vt.edu/story.php?relyear=2008&itemno=111

an additional possible problem is the patent that they are trying to get 
on the mechanism.

David Lang