Because the motor consumes high current, MCU cannot control the motor directly. It requires a driver IC like L293 to control the motor. L293 is a most popular and less expensive built-in H-bridge in a small integrated circuit used for low current motors freewheeling diodes are used to avoid problems due to back emf. The motor speed can be adjusted in 10 levels. The 10th LED bar shows the motor speed. The Dir key is for changing the direction of motor rotation and the Fast and Slow keys are for increasing or decreasing the speed of the motor .
