Hi, I am attempting at making a simple device that will run on dc power that just spins a item i place vertically in the air. I am trying to do it without having to by any of the parts being i could just buy a new one for around 250 bucks. My first question is how to you determine the amount of torque i need to turn the object with a given motor? (trying to decide between a 6V or 12V motor) What is the simplest (and cheapest) way of regulating the speed of the motor? (i only need to run the motor from 5-15 rpm unless i use gears to reduce the rotational speed of my object) I also have roughly 8 6V 4.5aH rechargeable batteries to use, is it possible to hook those in series and run the 6V motor off of them? If so, what would be the potential drawbacks to doing so as opposed to buying a higher capacity battery?