How to Make a Line Follower Robot Using Arduino – Connection & Code

To make a line follower robot using Arduino, you’ll need a few components:

1. Arduino board (e.g., Arduino Uno)
2. Motor driver module (e.g., L293D)
3. Two geared DC motors
4. IR sensors (e.g., TCRT5000)
5. Chassis and wheels for the robot
6. Jumper wires
7. Power supply (e.g., batteries)

Here’s a basic connection diagram and example code to get you started:

Connection:

1. Connect the VCC and GND pins of the IR sensors to the 5V and GND pins of the Arduino, respectively.
2. Connect the OUT pins of the IR sensors to the digital pins of the Arduino (e.g., pins 2 and 3).
3. Connect the IN1, IN2, IN3, and IN4 pins of the motor driver module to the digital pins of the Arduino (e.g., pins 4, 5, 6, and 7).
4. Connect the motor terminals to the motor driver module (M1 and M2).

Here’s a sample code that demonstrates a basic line-following behavior:

// Pin definitions
const int leftSensorPin = 2;
const int rightSensorPin = 3;
const int leftMotorPin1 = 4;
const int leftMotorPin2 = 5;
const int rightMotorPin1 = 6;
const int rightMotorPin2 = 7;

// Constants
const int threshold = 500; // Adjust this threshold according to sensor readings
const int speed = 150; // Adjust motor speed as needed

void setup() {
// Configure motor pins as output
pinMode(leftMotorPin1, OUTPUT);
pinMode(leftMotorPin2, OUTPUT);
pinMode(rightMotorPin1, OUTPUT);
pinMode(rightMotorPin2, OUTPUT);

// Configure sensor pins as input
pinMode(leftSensorPin, INPUT);
pinMode(rightSensorPin, INPUT);
}

void loop() {
int leftSensorValue = analogRead(leftSensorPin);
int rightSensorValue = analogRead(rightSensorPin);

// Adjust motor speeds based on sensor readings
if (leftSensorValue < threshold && rightSensorValue < threshold) {
// Both sensors see the line, move forward
move forward();
} else if (leftSensorValue > threshold && rightSensorValue < threshold) {
// Only the right sensor sees the line, turn left
turnLeft();
} else if (leftSensorValue < threshold && rightSensorValue > threshold) {
// Only the left sensor sees the line, turn right
turnRight();
} else {
// Both sensors are off the line, stop
stop motors();
}
}

// Helper functions for motor control
void move forward() {
digitalWrite(leftMotorPin1, HIGH);
digitalWrite(leftMotorPin2, LOW);
digitalWrite(rightMotorPin1, HIGH);
digitalWrite(rightMotorPin2, LOW);
// Set motor speeds
analogWrite(leftMotorPin1, speed);
analogWrite(rightMotorPin1, speed);
}

void turnLeft() {
digitalWrite(leftMotorPin1, LOW);
digitalWrite(leftMotorPin2, HIGH);
digitalWrite(rightMotorPin1, HIGH);
digitalWrite(rightMotorPin2, LOW);
// Set motor speeds
analogWrite(leftMotorPin2, speed);
analogWrite(rightMotorPin1, speed);
}

void turnRight() {
digitalWrite(leftMotorPin1, HIGH);
digitalWrite(leftMotorPin2, LOW);
digitalWrite(rightMotorPin1, LOW);
digitalWrite(rightMotorPin2, HIGH);
// Set motor speeds
analogWrite(leftMotorPin1, speed);
analogWrite(rightMotorPin2, speed);
}

void stopMotors() {
// Stop both motors
digitalWrite(leftMotorPin1, LOW);
digitalWrite(leftMotorPin2, LOW);
digitalWrite(rightMotorPin1, LOW);
digitalWrite(rightMotorPin2, LOW);
}

Upload this code to your Arduino board, ensuring that the connections are correctly made. The robot will follow a black line on a light-colored surface. Adjust the threshold value to fit your specific setup, as it determines the sensitivity to the line.

Note:

This is a basic implementation, and you can further enhance the line follower robot with additional features and improvements based on your requirements and creativity.