Hello everyone, I am a music composer and total noob. So please excuse my lack of engineering knowledge. I am attempting to build a music box that can play without having to turn the gear's crankshaft manually. Here is a picture of the music box: I have been doing some research and think I have a rough plan. Please correct me if I am wrong, I think I need a DC motor like this one: http://www.sciplus.com/itm_photos/web40663.jpg [Broken] Do you guys think this is a good motor to turn the gears? I also want to be able to change the speed so I guess I'll need a rheostat or potentiometer. Which is better and what specs do I need? Will I need to match the voltage of my motor? What batteries are good for this? I would like to save space so if I get two 9 volts = 18V will this be too much for my little 12V motor? Is there a good package kit that has a motor and speed control together? thanks ahead of the help and advice!