Line Following and Intersection Detection Robot using Raspberry Pi

This project uses a Raspberry Pi and PiCamera to follow a black line on the ground and detect intersections. Based on the detected intersection count, the robot executes predefined movements (e.g., go straight, turn left, stop) using a PID control system.

🔧 Features

• Real-time video processing using PiCamera
• Black line detection and tracking
• Intersection detection based on line width
• Predefined path control (left, right, straight, stop)
• PID control for smooth line following

📦 Hardware Requirements

• Raspberry Pi (3 or 4)
• PiCamera
• 2 DC motors
• Motor driver (e.g., L298N, BTS7960)
• Robot chassis with black line track

📌 GPIO Pin Configuration

Motor Action	GPIO Pin
Right Forward	26
Right Backward	6
Left Forward	5
Left Backward	19

🚀 Installation

1. Update packages and install dependencies:

   sudo apt update
   sudo apt install python3-opencv python3-picamera
   
   

2. Run the program with root privileges:

   sudo python3 main.py

🧠 How It Works

• Captures frames from the PiCamera.
• Converts the frame to grayscale and applies binary thresholding.
• Detects black contours using cv2.findContours.
• Identifies the largest black region and calculates its center and angle.
• Applies PID control based on line position and angle to adjust motor speeds.
• Detects intersections when line width exceeds a threshold and reacts accordingly.

🗺 Path Definition

The robot follows a predefined route based on the number of detected intersections:

rota = {
    1: "straight",
    2: "left",
    3: "left",
    4: "stop"
}

• 1st intersection → go straight
• 2nd intersection → turn left
• 3rd intersection → turn left
• 4th intersection → stop

⚙️ PID Parameters

Kp = 0.35
Ki = 0.001
Kd = 0.09
K_ang = 0.3

You can tune these values to better match your robot's behavior and environment.

🎞 Demo

🎮 Controls

• Press q to quit the program.

⚠️ Notes

• Ensure the robot is placed on a surface with high contrast black lines.
• The robot stops and GPIO pins are safely cleaned up at the end of execution.