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[aprssig] Re: now, 1.5 Lptops Per Child : power options?

Mark A. Lewis mark at siliconjunkie.net
Mon Dec 31 23:46:47 UTC 2007


Remember, you are also using a VERY short lever. If you were to replace
the crank with one that was say, 3 feet long you wouldn't even notice
the load. Add a flywheel with some mass and you could keep it running
with a little creative gearing and a modest power source like wind or
water. Lots of alternative energy folks are using home brew contraptions
in streams with car alternators to run bunches more than a laptop.

-----Original Message-----
From: aprssig-bounces at lists.tapr.org
[mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Scott Miller
Sent: Monday, December 31, 2007 6:40 PM
To: TAPR APRS Mailing List
Subject: Re: [aprssig] Re: now, 1.5 Lptops Per Child : power options?

> One thing you forgot .. when you are generating electricity with a
crank 
> generator .. you are doing *work*.

Yeah, I learned that as a kid, with an old field telephone dynamo, a 
knife switch, and some light bulbs.  You can crank like crazy until 
someone closes the circuit, and you'd just about break your arm if you 
were going fast enough.

> My point is that a windmill or anemometer needs to overcome this 
> resistance to generate electricity .. and it is a considerable amount
of 
> resistance believe me. Unless your windmill or anemometer has 15 or 20

> foot arms .. or you plan on waiting for a hurricane .. I don't think
it 
> will work.

It doesn't scale down to small sizes well, you're right.  I was hoping 
it'd be feasible for low-power devices, even if it wasn't very 
efficient, but it's not looking good.

Scott
N1VG





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