In this example, an OOPic microcontroller sends positioning signals to two modified servos that have been altered for continuous rotation.
Modified servos are effective drive motors for a small robot.
This example may provide a good starting point for a small robot project. In the above schematic, the OOPic is powered by an external 9V battery. The servos have their own supply of four NiMH AA batteries . Ni-Cad or Alkaline batteries would also work well. Servos may draw up to 1 amp of current.