Remote H-Bridge motor control

The assortment of wires cascading over the robots arms as I work in this H-bridge.

I have been trying to solve a control issue over the past few days involving controlling the robot's left arm which uses a 12 volt windshield wiper motor. The motor does not receive enough power from the small, temporary RF controller I am using to test the connections to all the motors. I want to have the robot ready for a full mobile demonstration before this June but at this point I will be cutting a few corners to get it to work. Then again the whole point of this robot is to be able to do what you can with whatever is available.

Anyway, today I am figuring out how to set up some sort of control that will allow me to control the 12 volt motor with a very low voltage controller. I am using two relays and I plan on setting up some sort of an H-bridge setup so that the motor's polarity can be reversed. Unfortunately this has turned out to be more difficult than I had originally thought it was going to be. The controller I am using is designed to control one motor with forward and reverse polarities. I need to use the controller to close each relay based on polarity so I will probably also need a few diodes as well (big ones to handle the voltage). Next the relays will have to close one at a time to switch between two sets of wires that will be wires to opposite sides of the battery so that when the opposite relay goes on the motor will reverse.

This all seemed simple enough to me at first but then I realized that I needed the power to the motor to be able to be turned off as well so that the arm could stop moving! I still want to try to stick with only two relays so I will post an update in a few days when I figure out how exactly I am going to do this.