This project demonstrates how to build an Autonomous Line Follower Robot using an Arduino UNO, IR sensors, and an L293D motor driver. The robot detects and follows a black line on a white surface by controlling the speed and direction of its motors based on real-time IR sensor feedback.

• Detects and follows black lines on white surfaces
• Uses dual IR sensors for left/right tracking
• Supports movement: Forward, Left Turn, Right Turn, Stop
• Powered by Arduino UNO with L293D motor driver
• Cost-effective and beginner-friendly
• Can be upgraded into a maze-solving robot

The robot uses IR sensors to detect lines based on infrared reflectivity. Black surfaces absorb IR light, while white surfaces reflect it. When the robot's sensors detect black (low signal), it interprets a line and adjusts its motors accordingly. Basic behavior includes:

• Both sensors on white → move forward
• Left sensor on black → turn left
• Right sensor on black → turn right
• Both sensors on black → stop

IR Sensor Pinout:

• IR Sensor Output → Arduino Pins 2 (Left) and 4 (Right)
• Motor Driver ENA/ENB → Arduino Pins 5 and 8
• Motor Driver IN1-IN4 → Arduino Pins 6, 7, 9, 10
• VCC (5V), GND appropriately connected
• BO Motors connected to motor driver outputs

L293D Pinout:

#define enA 5
#define in1 6
#define in2 7
#define in3 9
#define in4 10
#define enB 8
#define R_S 4 // Right sensor
#define L_S 2 // Left sensor

void setup() {
  pinMode(R_S, INPUT);
  pinMode(L_S, INPUT);
  pinMode(enA, OUTPUT);
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  pinMode(enB, OUTPUT);
  digitalWrite(enA, HIGH);
  digitalWrite(enB, HIGH);
}

void loop() {
  if ((digitalRead(R_S) == 0) && (digitalRead(L_S) == 0)) {
    forward();
  }
  else if ((digitalRead(R_S) == 1) && (digitalRead(L_S) == 0)) {
    turnRight();
  }
  else if ((digitalRead(R_S) == 0) && (digitalRead(L_S) == 1)) {
    turnLeft();
  }
  else if ((digitalRead(R_S) == 1) && (digitalRead(L_S) == 1)) {
    Stop();
  }
}

void forward() {
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  digitalWrite(in3, LOW);
  digitalWrite(in4, HIGH);
}

void turnRight() {
  digitalWrite(in1, LOW);
  digitalWrite(in2, HIGH);
  digitalWrite(in3, LOW);
  digitalWrite(in4, HIGH);
}

void turnLeft() {
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  digitalWrite(in3, HIGH);
  digitalWrite(in4, LOW);
}

void Stop() {
  digitalWrite(in1, LOW);
  digitalWrite(in2, LOW);
  digitalWrite(in3, LOW);
  digitalWrite(in4, LOW);
}

• PID algorithm for better control
• Adjustable motor speed via potentiometer
• LCD display for real-time debug info
• Ultrasonic sensor for obstacle detection
• Switch to L298N for more current capacity

• 📖 Complete Tutorial on Circuit Digest
• 📘 IR Sensor with Arduino
• ⚙️ Motor Driver L293D vs L298N
• 💡 More Arduino Robotics Projects

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