Develop a speed controller for the robot drive motors by pulsing the drive motors on and off. The motors are sent a pulse of 1ms for reverse and 2ms for forward at full speed. If no pulse is sent for 20ms, the motor stops. If a motor is sent a 1 or 2ms pulse followed by no pulse in a repeating pattern, it will move slower. To move even slower use pulse, no pulse, no pulse in a repeating pattern. To move faster use pulse, no pulse, pulse in a repeating pattern. Using this approach, develop a speed controller for the robot with at least five speeds and direction. Send no pulse for the stop speed. Some additional mechanical noise will result from pulsing the motors at slow speeds. See if the robot will move in a straight line at a slow speed.