Hi, I am thinking of making a mechanical timer to control a pedestal fan. I want do a completely mechanical one, just for the feel of it. For the energy storage method, I have two options, either a spiral spring or a counterweight. Which one should I use? Any good reading material on this? I can take care of gearing. The fan's plug is connected to a 3 pin socket beside the switch. How do I cut off the supply (turn off the switch) when the timer stops? Thanks, Chaitanya.