How to Build a Line-Following Robot Using an Arduino Board

Creating a line-following robot using an Arduino board is a popular project for beginners in robotics and programming. This guide takes you through the step-by-step process of building your own line-following robot. Whether you are a tech enthusiast, a student, or a hobbyist, you can easily follow these instructions to get your robot up and running.

Components Needed

Arduino Board: e.g. Arduino Uno Chassis: robot car kit or custom-built Motors: DC motors or servo motors Motor Driver: e.g. L298N or L293D Line Sensors: IR sensor module or reflectance sensors Wheels: 2 or more wheels Caster Wheel: for balance Power Supply: battery pack Jumper Wires: Breadboard: optional for prototyping

Step-by-Step Instructions

1. Assemble the Chassis

Build the Robot Frame: Attach the motors to the chassis and fix the wheels. Ensure a stable structure for the robot to maintain balance and avoid tipping.

2. Connect the Motors

Motor Driver Connection

Connect the motors to the motor driver. The motor driver allows the Arduino to control the speed and direction of the motors.

For L298N: Connect motor A to output terminals e.g. Out1 and Out2. Connect motor B to output terminals e.g. Out3 and Out4. Connect the input pins of the motor driver to Arduino digital pins e.g. pins 4, 5, 6, and 7.

3. Connect the Line Sensors

Sensor Placement

Place the IR sensors in front of the robot close to the ground to detect the line black tape on a white surface. This ensures accurate line tracking.

Wiring

Connect the output of the sensors to the Arduino. For example:

Connect the left sensor to pin 8 Connect the right sensor to pin 9

4. Power the Components

Power Supply

Connect the battery pack to the motor driver and ensure the Arduino is powered appropriately. You can power the Arduino either from the battery or USB.

5. Write the Arduino Code

Below is a simple example code to get you started:

// Define motor pins
#define ENA 5       // Enable pin for motor A#define IN1 4       // Input pin 1 for motor A#define IN2 3       // Input pin 2 for motor A#define ENB 6       // Enable pin for motor B#define IN3 7       // Input pin 1 for motor B#define IN4 8       // Input pin 2 for motor B
// Define sensor pins
#define LEFT_SENSOR 9#define RIGHT_SENSOR 10void setup() {  // Set motor pins as outputs  pinMode(ENA, OUTPUT);  pinMode(IN1, OUTPUT);  pinMode(IN2, OUTPUT);  pinMode(ENB, OUTPUT);  pinMode(IN3, OUTPUT);  pinMode(IN4, OUTPUT);  // Set sensor pins as inputs  pinMode(LEFT_SENSOR, INPUT);  pinMode(RIGHT_SENSOR, INPUT);}void loop() {  int leftState  digitalRead(LEFT_SENSOR);  int rightState  digitalRead(RIGHT_SENSOR);  if (leftState  LOW  rightState  LOW) {    // Move forward    moveForward();  } else if (leftState  LOW  rightState  HIGH) {    // Turn right    turnRight();  } else if (leftState  HIGH  rightState  LOW) {    // Turn left    turnLeft();  } else {    // Stop    stop();  }}void moveForward() {  digitalWrite(IN1, HIGH);  digitalWrite(IN2, LOW);  digitalWrite(IN3, HIGH);  digitalWrite(IN4, LOW);  analogWrite(ENA, 255); // Full speed  analogWrite(ENB, 255); // Full speed}void turnRight() {  digitalWrite(IN1, HIGH);  digitalWrite(IN2, LOW);  digitalWrite(IN3, LOW);  digitalWrite(IN4, LOW);  analogWrite(ENA, 255); // Full speed  analogWrite(ENB, 0);   // Stop}void turnLeft() {  digitalWrite(IN1, LOW);  digitalWrite(IN2, LOW);  digitalWrite(IN3, HIGH);  digitalWrite(IN4, LOW);  analogWrite(ENA, 0);   // Stop  analogWrite(ENB, 255); // Full speed}void stop() {  digitalWrite(IN1, LOW);  digitalWrite(IN2, LOW);  digitalWrite(IN3, LOW);  digitalWrite(IN4, LOW);}

6. Upload the Code

Connect your Arduino to your computer and upload the code using the Arduino IDE.

7. Testing

Place the robot on a line black tape on a white surface and observe its behavior. Adjust the sensor positions or code logic as necessary for better performance.

8. Troubleshooting

If the robot does not follow the line properly, check:

Sensor alignment and sensitivity Motor connections and power supply Code logic for controlling the motors

Conclusion

With this setup, you should have a basic line-following robot using an Arduino. You can expand the project by adding features like speed control, obstacle avoidance, or more sophisticated algorithms for line detection. Happy building!