I am building a motorized vehicle for an engineering project that will operate on 12V of DC current. I need to be able to flip a regular light switch that is mounted on a platfrom. I wanted to use a paddle type arm attached to a 12V DC gear motor. How can I tell what type of RPM's I need? Some of the motors are 65RPM, 490 RPM, 162 RPM... HELP!!

The RPMs for the motor will depend on the gear set that you are building to operate the arm that will flip the switch - tell us about that. You may find that your choice of motor is driven by the torque you need - have you determined that yet?

I don't know what torque I need and I guess that I thought with a gear motor I would not need to build a gear set. Some of the motors that I was looking at said that the gear ratio was 1:10 and the torque was 0.7 Lb -Inch. I'm not sure what to do next.
Thanks!