L293D Motor Driver with Arduino

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Controlling a motor from an Arduino using the L293D H-bridge

Driving a Motor with Arduino

A good way to control a motor is to use an H-bridge. This is a type of circuit that allows you to reverse the current flow of the motor, therefore giving you direction control.

An H-bridge contains four switches and a motor at the center, forming an H-like shape. Turning any two of the switches on reverses the motor’s current, which can change its direction.

H-bridge direction control H-bridge direction control

The L293D has two of these H-bridges inside it, allowing you to control up to two DC motors or one stepper motor.

L293D Pinout

Pin NumberPin Name
1Enable 1
2Input 1
3Output 1
6Output 2
7Input 2
9Enable 2
10Input 3
11Output 3
14Output 4
15Input 4

The pins with names containing the same numbers form a single channel in the L293D that can control one motor.

Each pin type has a specific function:

Controlling L293D

The Enable pins turn their motors on/off. A HIGH state enables the motor; a LOW state disables it. You can also send PWM signals to control motor speed. A duty cycle of 0% stops the motor; a duty cycle of 100% runs the motor at full speed.

The input pin pairs of the H-bridge control the direction of their motor. If input A is high and input B is low, the motor spins one direction. If input A is low and input B is high, the motor spins in the opposite direction. If the inputs’ states are the same, the motor stops.

H-Bridge control summary:

Input (Enable, In A, In B)Motor Direction/Speed
0, any, anyStopped
1, 1, 1Stopped
1, 1, 0Direction 1
1, 0, 1Direction 2
1, 0, 0Stopped
PWM, any, anyVaried speed


L293D schematic

Example Code

// Define pin constants
#define EN  5
#define IN1 4
#define IN2 3

boolean isReversed = false;

void setup() {
  // Configure pins as output
  pinMode(EN,  OUTPUT);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);

void loop() {
  for (int i = 0; i < 256; i++) {
    // Increment the speed from 0 to 255
    setMotorSpeed(i, isReversed);

  delay(3000); // Run at full speed for 3 seconds

  for (int i = 255; i > 0; i--) {
    // Decrement the speed from 255 to 0
    setMotorSpeed(i, isReversed);

  // Stop the motor and wait a little bit
  isReversed = !isReversed; // Reverse the motor

// Motor control functions

void setMotorSpeed(int speed, boolean reverse) {
  // Set the speed of the motor.
  analogWrite(EN, speed);
  digitalWrite(IN1, reverse);
  digitalWrite(IN2, !reverse);

void stopMotor() {
  // Stop the motor.
  analogWrite(EN, 0);
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);