Before we get started with connecting everything and making it all move, let's spend some time understanding some of the basics of DC motor control. Whether you choose a two or four wheeled mobile platform, or a tracked platform, the basic movement control is the same. The unit moves by engaging the motors. If the desired direction is straight, the motors are run at the same speed. If you want to turn the unit, the motors are run at different speeds. The unit can actually turn in a circle if you run one motor forward and one backwards.

DC motors are fairly straightforward devices. The speed and direction of the motor is controlled by the magnitude and polarity of the voltage applied to its terminals. The higher the voltage, the faster the motor will turn. If you reverse the polarity of the voltage, you can reverse the direction the motor is turning in.

However, the magnitude and polarity of the voltage are not the only factor that is important when it comes to controlling your...