Widely available pedal powered sewing machines will be a better solution. Just attach an electric generator instead of the sewing machine.

I have used such a sewing machine by myself, and it beats a hometrainer easily.

One can actually do productive work - like sewing or in this case computing - while powering it.

And it still doubles as a sewing machine! Beat that!

Search Google for

pedal sewing machine

for more info.

Jan, Germany