Example Code for Arduino-DC Motor Control

Last revision 2026/01/08

Explore the setup and programming of DC motor control using Arduino, featuring detailed example code, wiring diagrams, and instructions for setting motor speed and direction.

Hardware Preparation

Software Preparation

Wiring Diagram

Sample Code

  1. Open Arduino IDE
  2. Upload the code to UNO

/**set control port**/
const int E1Pin = 10;
const int M1Pin = 12;
const int E2Pin = 11;
const int M2Pin = 13;

/**inner definition**/
typedef struct {
  byte enPin;
  byte directionPin;
} MotorContrl;

const int M1 = 0;
const int M2 = 1;
const int MotorNum = 2;

const MotorContrl MotorPin[] = { {E1Pin, M1Pin}, {E2Pin, M2Pin} } ;

const int Forward = LOW;
const int Backward = HIGH;

/**program**/
void setup() {
  initMotor();
}

void loop() {
  int value;
  /**test M1 **/
  setMotorDirection( M1, Forward );
  setMotorSpeed( M1, 100 );
  delay(1000);
  setMotorSpeed( M1, 0 );
  delay(100);

  setMotorDirection( M1, Backward );
  setMotorSpeed( M1, 50 );
  delay(1000);
  setMotorSpeed( M1, 0 );
  delay(100);

  /**test M2**/
  setMotorDirection( M2, Backward );
  for (value = 0 ; value <= 100; value += 5) {
    setMotorSpeed( M2, value );
    delay(100);
  }
  setMotorSpeed( M2, 0 );
  setMotorDirection( M2, Forward );
  for (value = 0 ; value <= 100; value += 5) {
    setMotorSpeed( M2, value );
    delay(100);
  }
  setMotorSpeed( M2, 0 );
}

/**functions**/
void initMotor( ) {
  int i;
  for ( i = 0; i < MotorNum; i++ ) {
    digitalWrite(MotorPin[i].enPin, LOW);

    pinMode(MotorPin[i].enPin, OUTPUT);
    pinMode(MotorPin[i].directionPin, OUTPUT);
  }
}

/**  motorNumber: M1, M2
direction:          Forward, Backward **/
void setMotorDirection( int motorNumber, int direction ) {
  digitalWrite( MotorPin[motorNumber].directionPin, direction);
}

/** speed:  0-100   * */
inline void setMotorSpeed( int motorNumber, int speed ) {
  analogWrite(MotorPin[motorNumber].enPin, 255.0 * (speed / 100.0) ); //PWM
}

Result

M1 will forward at full speed, and then half speed inversion; M2 velocity from fast to slow, reverse first, and then forward.

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