Laser Detection App

A lightweight, sensor-free Laser Detection & Monitoring System built using Python, Flask, and OpenCV. This project creates a simple, effective security or monitoring system without requiring any Arduino, Raspberry Pi, or additional sensors.

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Table of Contents

1. Overview
2. Features
3. Minimal Setup
4. Installation & Setup
5. Project Structure
6. Usage
7. Screenshots
8. Coding Documentation
9. License

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Overview

This project leverages a camera and a laser pointer to detect interruptions in a laser beam. The system works purely in software:

• A laser is aimed at a fixed point on a wall or board.
• A camera captures the laser dot in real-time.
• OpenCV detects the presence or absence of the laser dot.
• A Flask dashboard shows live camera feed, status, and dot position.
• Security mode triggers an alarm immediately when the laser is interrupted.

The system is highly flexible and can cover large areas using mirrors to redirect the laser.

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Features

• Real-time laser detection without extra sensors.
• Flask-based web dashboard with:
  • Live video feed.
  • Laser status (ON / OFF) and position.
  • Security mode to trigger alarm on interruption.
• Alarm (alarm.mp3) triggers for any laser interruption.
• Minimal latency (adjustable polling interval & threshold).
• Supports multiple monitoring points via mirrors.
• Logs all laser activity to logs.txt.

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Minimal Setup

This system does not require any microcontrollers or sensors. Minimal hardware needed:

1. Laser pointer – Aim it at a clean, visible surface.
2. Camera – Place so that the laser dot is visible in its frame.
3. Optional mirrors – Increase coverage area by reflecting the laser beam.

Setup is as simple as:

• Put the laser in the region you want to secure.
• Place the camera so it captures the laser dot.
• Adjust mirrors to cover additional areas if needed.
• Run the Flask app, open the dashboard, and activate security mode.

No Arduino, Raspberry Pi, or external sensors are required.

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Installation & Setup

1. Clone the repository:

   git clone https://github.com/DevLord-Avijit/LDR
   cd LDR

2. Install dependencies:

   pip install -r requirements.txt

3. Configure camera & laser detection settings in config.py:

   • CAMERA_INDEX – camera port (default 0)
   • FRAME_WIDTH, FRAME_HEIGHT – capture resolution
   • RED_LOWER, RED_UPPER – laser color range
   • DETECTION_RADIUS – dot detection radius

4. Start the Flask app:

   python app.py

5. Access dashboard:

   http://127.0.0.1:5000
   

Activate Security Mode to trigger alarms on any laser interruption.

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Project Structure

LDR/
│
├── app.py                        # main Flask app entrypoint
├── camera_thread.py              # handles camera capture + OpenCV detection
├── detection_utils.py            # helper functions for color filtering, centroid calc, etc.
├── config.py                     # all tunable settings (radius, color range, camera index, etc.)
│
├── static/                       # CSS, JS, images for Flask
│   ├── css/
│   │   └── style.css
│   ├── js/
│   │   └── dashboard.js
│   └── alarm.mp3
│
├── templates/                    # Flask HTML templates
│   ├── index.html                # main dashboard (shows status, feed, stats)
│   └── settings.html             # optional config UI
│
├── data/
│   └── logs.txt                  # detection logs (timestamped)
│
└── requirements.txt              # dependencies

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Usage

1. Run the app:

   python app.py

2. Open the browser and go to:

   http://<your-ip>:5000
   

3. Dashboard features:

• Live camera feed.
• Laser status: ON (detected) / OFF (interrupted).
• Laser dot position displayed in coordinates.
• Security Mode button:
  • When ON, any laser interruption triggers alarm.mp3.
  • Alarm modal pops up; click anywhere or press any key to stop alarm.
• Logs are recorded automatically in data/logs.txt.

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Screenshots

Monitor Tab:

Alarm Triggered:

Screenshots illustrate the laser dot detection and alarm modal on security breach.

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Coding Documentation

camera_thread.py

• Handles continuous camera capture in a separate thread.
• Uses detect_laser_dot() from detection_utils.py to find the laser dot.
• Updates status (ON/OFF) and position.
• Provides get_frame() for Flask video streaming.

detection_utils.py

• Color filtering, centroid calculation, and radius detection.
• Returns laser dot coordinates if detected.

config.py

• Camera index and frame dimensions.
• Color ranges for detection.
• Dot detection radius.

app.py

• Flask app serving:
  • / → dashboard.
  • /video_feed → live JPEG stream.
  • /api/laser_status → JSON laser status for frontend.
• Integrates CameraThread for continuous detection.

Frontend (JS)

• Polls /api/laser_status every 50–100ms.
• Handles security mode and triggers alarm.mp3.
• Alarm modal stops on click or key press.
• Display updates in real-time.

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License

MIT License

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This project demonstrates a minimal, software-based LDR (Laser Detection & Response) system without additional hardware, perfect for DIY security or monitoring experiments.