I want to automatically open and close a greenhouse window vent (weighs about a pound) using a motor of some sort. What I have tried is using a spare motor connected to a belt which turns a 5.5 inch diameter pulley, and a three inch long arm on the pulley shaft moves the window (see picture below). Problem is the motor just doesn't seem to have enough power once the the belt is tensioned. It is a 12v bipolar motor and I am using four MOSFETS to run it. Is there a smarter way to do this? Or perhaps a bigger motor: http://www.ebay.com/itm/160746561872?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 ? And where might I find a suitable belt?