🤖 Line Following Robot

An Arduino-based robot that autonomously follows a black line on a white surface using two IR sensors and an L293D motor driver.

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📖 Overview

The Line Following Robot uses two infrared (IR) sensors to detect a black line against a white surface and drives two DC motors to keep the robot on track. The robot reads sensor values in real time and adjusts its movement — going forward, turning left, turning right, or stopping — based on where the line is detected.

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✨ Features

• 📡 Dual IR sensing — left and right sensors for accurate line tracking
• ⚡ Real-time response — continuous loop reads and reacts to sensor changes instantly
• 🔄 Four movement modes — Forward, Turn Left, Turn Right, and Stop
• 🛠️ Simple and extensible — clean modular code with separate functions for each movement

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🛠️ Hardware Components

Component	Quantity
Arduino UNO	1
L293D Motor Driver IC	1
DC Motors	2
IR Sensor Modules	2
9V Battery	1
Breadboard	1
Jumper Wires	As needed

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🔌 Circuit Diagram

Built and simulated in Tinkercad

Pin Connections:

Component	Arduino Pin
Left IR Sensor	Digital 2
Right IR Sensor	Digital 3
Left Motor Control 1 (LM1)	Digital 8
Left Motor Control 2 (LM2)	Digital 9
Right Motor Control 1 (RM1)	Digital 10
Right Motor Control 2 (RM2)	Digital 11

Schematic

Circuit Layout

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🚀 Getting Started

Prerequisites

• Arduino IDE (1.8.x or 2.x)
• Arduino UNO board
• All hardware components listed above

Installation

1. Clone the repository

   git clone https://github.com/deep-chatterjee/Line-Following-Robot-using-Arduino.git
   cd Line-Following-Robot-using-Arduino

2. Open the sketch

   • Open Line_Following_Robot.ino in the Arduino IDE

3. Upload to your board

   • Select your board: Arduino UNO
   • Select the correct COM port
   • Click Upload

4. Assemble the circuit

   • Wire up the components following the schematic images in the repo
   • Power the motors with the 9V battery via the L293D

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💻 How It Works

The robot continuously reads both IR sensors and decides movement based on the combination:

Left = 1, Right = 1  →  Both on white  →  Go Forward
Left = 0, Right = 1  →  Left on line   →  Turn Left
Left = 1, Right = 0  →  Right on line  →  Turn Right
Left = 0, Right = 0  →  Both on line   →  Stop

Sensor logic: 1 = white surface detected, 0 = black line detected

Movement Flow

Read Left & Right IR Sensors
          ↓
   Evaluate sensor state
          ↓
 ┌────────┬────────┬──────────┐
 │Forward │TurnLeft│TurnRight │ Stop
 └────────┴────────┴──────────┘
          ↓
  Drive motors accordingly
          ↓
      Loop again

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📁 Project Structure

Line-Following-Robot-using-Arduino/
├── Line_Following_Robot.ino          # Arduino sketch
├── Line_Following_Robot_Schematic.png  # Circuit schematic
├── Line_Following_Robot_Circuit.png    # Breadboard circuit layout
├── LICENSE
└── README.md

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🧠 What I Learned

• IR sensor interfacing and digital signal reading on Arduino
• H-bridge motor control using the L293D driver IC
• State-based control logic for autonomous navigation
• Modular code structure for embedded systems

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🔮 Future Improvements

• Add PWM speed control for smoother turns
• Implement PID control for more precise line tracking
• Add a third center IR sensor for better accuracy
• Bluetooth module (HC-05) for wireless speed/mode control
• OLED display to show sensor state in real time

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👤 Author

Deep Chatterjee
GitHub

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📄 License

This project is licensed under the MIT License — see LICENSE for details.