At first I was thinking about another way of building my Cyclo-Greenhouse, much DIY, that would be more in Hack-A-Day spirit.

Prototype 1 would be the safe way of testing the concept, prototype 2 would the fun way!

It would be more interesting to build a prototype from scratch, and smart people have already tried to build pedal-powered things :

https://www.notechmagazine.com/2011/05/pedal-powered-machines.html

And this one is exactly what I am trying to achieve

https://www.lowtechmagazine.com/2022/03/how-to-build-bike-generator.html#chargingbatteries

The idea is to either build a frame or reuse a vintage exercise bike and build a generator and converter.

the idea is to reuse a vintage flywheel exercise bike, but to put an old electric bike wheel on it and generate electricity with it.