This is great. Thanks for posting it.
Mrs. Phil has a beater stationary bike I found for her on FreeCycle (a yahoogroup junque swap). She has put 3000 miles on it and I have been threatening to do something like your generator or maybe this (bicycle blenders):
http://www.makezine.com/blog/archive/2006/06/bicycle_blenders.html
Any tips or Do Not Do list to consider before hacking? The automobile alternator is the place I would start. I have all the part laying around, and can frame it up with unistrut. (I love that stuff -- erector set for electricians). But your plywood board looks very stable and probably safer around toes, as well.
I guess with the automobile alternator you use the matching voltage regulator? And I guess you do not use a battery to make the voltage stable? I would sort of tempted to put a battery in it, or at least add a large capacitor.
What RPMs do target the alternator to turn at? Typical automobile apps are something like 500 rpm minimum up to 2000 rpm at nominal running speed? Does that sound correct?
Thanks.