[dorkbotsea-blabber] Re: Electricity and human power

[Steve Greenfield]

Sending this a second time. Hey Seth, Yahoo says your domain is listed with Spamhaus and bounced it back at me.

Someone mentioned having to pedal like mad to get a bike light to light up. That is due to several factors, the largest one I think being the fact that you are moving the bike and yourself faster in order to get the generator to move faster. As a kid I recall turning my bike upside down and turning the pedals by hand and it wasn't that hard to turn the generator, despite the huge inefficiencies in the mechanical coupling.

The keys are going to be:
Getting the magnets as close as possible to the coils.

Winding the correct number of turns based on matching the relative speed and the load presented by the bulbs.
Matching the size of the coils to the size of the magnets.
Laying out the magnets in a way that results in the field being pushed out into the coils.

Connecting the alternator directly to the bike wheel axis is going to be fairly slow, requiring a lot of turns to the pickup coils. It would be better if you could do something like take the tire off and put a belt on it to a pulley attached to the alternator. Or set the back tire on rollers, one of them attached to the alternator.

Steve Greenfield               // Digital photography, scanning,
Polymorph Digital Photography // retouching, and photomorphing
253-318-2473 voice           // to your specs.
polymorph at polyphoto.com     // 
http://www.polyphoto.com/  // Based in Tacoma, WA, USA



----- Original Message ----
From: Seth! Leary <em----------ary.com>
To: A discussion list for dorkbot-sea <dorkbotsea-blabber at dorkbot.org>
Sent: Tuesday, July 29, 2008 5:16:29 PM
Subject: RE: [dorkbotsea-blabber] Electricity and human power

Message 
Well, far out. I learned 
all sorts of things this afternoon. Thanks!

The reason for this line 
of inquiry (besides just intellectual curiosity) is that I want to build (or 
have built) a pedal gadget that really does use human power to do...something. 
Lighting up bulbs is pretty cool because it's visual. Powering a motorized thing 
could be good because it is actual work--as opposed to a radio or some other 
thing that burns energy into heat and such without moving anything. Basically, I 
want to recreate that science center exhibit but with more authentic feedback in 
terms of human effort to output. If anyone has had a burning desire to create 
such a thing and wants to join the fun, let me know. It would be a paying 
gig.

Cheers and thank you 
again.

Seth!