Introduction

This tutorial teaches you how to control a DC motor with an Arduino, a foundational skill for motorized projects in automation and robotics. DC motors are simple, affordable actuators that provide continuous rotation, making them ideal for driving wheels, fans, or pumps. In this experiment, you’ll learn how to connect a DC motor to an Arduino using an H-Bridge for speed and direction control, program it to perform specific actions, and test its functionality. This guide is perfect for beginners and hobbyists eager to explore electromechanical systems.

By using pulse-width modulation (PWM) and an H-Bridge, you can adjust the motor’s speed and reverse its direction, unlocking a wide range of practical applications. By the end of this tutorial, you’ll have a working setup to experiment with DC motor control.

Components Required

To control a DC motor with Arduino, gather the following components:

• Microcontroller (e.g., Arduino Uno): Sends control signals to the motor driver.
• DC Motor (e.g., 6V-12V): A small DC motor suited for your project’s power needs.
• H-Bridge Module (e.g., L298N): Allows speed and direction control by managing motor polarity.
• Power Supply (e.g., 9V battery or 12V adapter): Powers the motor, separate from the Arduino’s 5V.
• Connecting Wires: Jumper wires for secure connections.
• Breadboard: For prototyping the circuit without soldering.
• Optional: Capacitor (e.g., 100µF): Stabilizes power to the H-Bridge if noise occurs.

Schematic

The schematic shows how to wire the DC motor to the Arduino via an H-Bridge module:

Basic connection overview: - Connect the DC motor’s two terminals to the H-Bridge output pins (e.g., OUT1 and OUT2 on L298N). - Wire the H-Bridge input pins (IN1 and IN2) to Arduino PWM pins (e.g., D9 and D10). - Attach the power supply (e.g., 9V) to the H-Bridge’s VCC and GND, ensuring a common ground with the Arduino. - Optionally, connect a capacitor across the H-Bridge’s power terminals to reduce electrical noise.

Note: Check the motor’s voltage and current ratings (e.g., 9V, 500mA) to ensure the H-Bridge and power supply can handle the load. The L298N may require a heat sink for prolonged use.

Steps

Follow these steps to build and test your DC motor control setup:

1. Assemble the Circuit: Connect the DC motor to the H-Bridge outputs (OUT1, OUT2) and wire IN1 and IN2 to Arduino D9 and D10.
2. Power Connections: Attach a 9V power supply to the H-Bridge VCC and GND, and power the Arduino via USB, sharing a common GND.
3. Upload the Code: Load the Arduino sketch (see "Code Example" below) to control the motor’s speed and direction.
4. Test Forward Motion: Run the code to spin the motor forward at varying speeds, observing its response.
5. Test Reverse Motion: Reverse the direction and verify the motor spins backward smoothly.
6. Fine-Tune (Optional): Adjust PWM values or add a potentiometer to dynamically control speed.

Code Example

Here’s an Arduino sketch to control a DC motor’s speed and direction using an H-Bridge (e.g., L298N):

                
// Define H-Bridge pins
const int IN1 = 9;  // PWM-capable pin for forward
const int IN2 = 10; // PWM-capable pin for reverse

void setup() {
    pinMode(IN1, OUTPUT);
    pinMode(IN2, OUTPUT);
    Serial.begin(9600);  // For debugging
}

void setMotor(int speed, bool direction) {  // Speed: 0-255, Direction: true = forward, false = reverse
    if (direction) {
        Serial.print("Forward at speed: ");
        Serial.println(speed);
        analogWrite(IN1, speed);  // Forward
        analogWrite(IN2, 0);
    } else {
        Serial.print("Reverse at speed: ");
        Serial.println(speed);
        analogWrite(IN1, 0);
        analogWrite(IN2, speed);  // Reverse
    }
}

void stopMotor() {
    Serial.println("Motor stopped");
    analogWrite(IN1, 0);
    analogWrite(IN2, 0);
}

void loop() {
    setMotor(128, true);   // 50% speed forward
    delay(2000);           // Run for 2 seconds
    stopMotor();
    delay(1000);           // Pause for 1 second
    setMotor(255, false);  // Full speed reverse
    delay(2000);
    stopMotor();
    delay(1000);
}
                
            

This code runs the motor forward at 50% speed, stops, then reverses at full speed, repeating with pauses. Adjust `speed` (0-255) and `delay()` for different behaviors.

Applications

Controlling a DC motor with Arduino has practical uses in various real-world scenarios, including:

• Automation Systems: Drives fans, pumps, or conveyor belts in automated setups.
• Prototyping for Robotics: Powers wheels or arms in robotic prototypes.
• Educational Experiments: Teaches motor control, PWM, and circuit design.
• Home Automation: Operates motorized curtains or small appliances.
• Hobby Projects: Runs model cars, boats, or DIY gadgets.