The project is intended to control the speed of a DC motor by varying voltage across the terminal. The concept behind the project is, since the speed of DC motor is directly proportional to the voltage applied therefore the duty cycle of the pulse is varied (i.e. Pulse Width Modulation is used) to control the speed.
A microcontroller of 8051 family is used to interface two input buttons for controlling motor speed. The microcontroller programmed in assembly/Embedded C language generates PWM i.e. Pulse Width modulation at the output according to program instructions. The ON and OFF time of the pulses or the duty cycle changes the average voltage given to the motor and therefore the speed of the motor changes. The PWM signals are received by a motor driver IC interfaced to microcontroller for delivering required output in controlling DC motor speed.