DC motor control using PIC

 When using PIC to control DC motor, the motion of motor such as forward, reverse,and speed of rotation can be programmed. If the motion of motor only required forward and reverse without considering the speed of rotation, motor can be control through relay module. the are two example of relay module which can be use by PIC to control DC motor. First figure is to control only On and OFF of motor which also compatible to other devices that are using switch. Second figure can be used to control forward and reverse motion of DC motor.

 

By using relay module, it is very easy to control the motion of motor. The programming part only require ON and OFF of output PORT.

Example of simple forward reverse motor control using 2 switches connected to RD0 and RD1:

main()

{

while (1)

{

TRISD = 0b00000011;

PORTB = 0b00000000;

TRISB = 0b00000000;

PORTB = 0b00000000;

if (PORTDbits.RD0 == 1 && PORTDbits.RD1 == 0)

 PORTB = 0b00000010;

if (PORTDbits.RD0 == 0 && PORTDbits.RD1 == 1)

 PORTB = 0b00000010;

else

PORTB = 0b00000000;

 }

}

 When DC motor require speed control, the speed of DC motor can be control by various techniques including Pulse Width Modulation (PWM), power transistor, driver IC etc. The diagram below is example of DC motor controlled by transistor and PWM.

 

Whenever there is input voltage supplied to Base pin of the transistor, the transistor will turned ON and let the current flow through. with different speed of PWM provided, the speed of motor can be adjusted. The faster the PWM signal, the faster the motor will rotate.