Customize a Bicycle

The project is about to install a rubber roller chain in a bicycle (the ype with gears and change speeds). it will be installed between the front and rear tires. I recommend to use bicycle with gears. the rubber roller chain is hanging up (13 cm from groung). when I want to use the rubber rooler chain, I will press a push button, when I push that push button, the rubber roller chain will be lowered down to touch the ground and start taken the power from pedals (Pedals are what we push by our feets to move on the bicycle.).. I do not mind if the rubber chain can run without rear tire, or can run with rear tire. no problem.