David, in the past for robotics applications I have used a Worm drive or threaded rod to achieve things very similar to what you are trying to accomplish. Although you certainly could drive the gate directly from a motor, generally using a threaded arrangement provides much more torque and won't spin freely (aka droop due to gravity) when you stop the motor. http://commons.wikimedia.org/wiki/File:Worm_Gear.gif http://en.wikipedia.org/wiki/Worm_drive Oh, it looks like Denny beat me to it. Anyways, Good Luck! On Fri, Jan 9, 2015 at 6:10 PM, David C Brown wrote: > See my answer to Denny. > > A major problem is actually sourcing motor of correct torque *and* speed= .. > I originally envisaged a geared DC motor but I am wondering if a stepper > motor might be better as there seems to be a much wider range available a= nd > speed can be more easily controlled. --=20 Jason White --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .