Arduino Controlled Robotic Arm

I made an OWI robotic arm and controlled it with an arduino. Because I only had one dual h-bridge left over from the start here project I had to make switches to control the robotic arm with servos. The switch to control the base rotation motor looks like this when the arm is rotating clockwise: and like this when the arm is rotating counterclockwise: here is a picutre of the motor driver and the switches: I am thinking of adding potentiometers to make the arm movement more precise.