Dynamic QR Code Bus Schedule Display

A real-time bus schedule display system that uses dynamic QR codes to share information without requiring end-users to have internet connectivity. The system simulates a bus stop display where arrival times are continuously updated and shared via QR codes that contain the actual schedule data rather than URLs.

Core Concept

Traditional QR codes typically contain static URLs that require internet connectivity to access information. This project takes a different approach:

• QR codes contain the actual JSON data of bus schedules
• Updates every 2 seconds with new arrival times
• Users can scan and get real-time information without internet access
• Perfect for public displays in areas with limited connectivity

Screenshots

Note: The web interface shown above includes a table view for demonstration purposes. In production, this could be replaced with a monochrome LCD/LED display showing only the QR code, making it more suitable for outdoor bus stops and reducing power consumption.

Use Cases

• Bus stops without reliable internet connectivity
• Public transport information displays
• Event schedules in areas with poor network coverage
• Any scenario requiring offline access to frequently updated information
• Digital signage with real-time data access via QR codes

How It Works

1. Server maintains a queue of buses and their arrival times
2. Every 2 seconds:
   • Existing bus times are decremented
   • New buses may be added to the queue
   • Arrived buses (time = 0) show "Almost there!"
   • Passed buses are removed from the queue
3. Current state is encoded into a QR code and displayed
4. Users scan QR code to get instant access to the latest schedule

Features

• Real-time updates every 2 seconds
• Queue-based bus management
• Self-contained QR codes (no URL redirection)
• Automatic bus removal when arrival time reaches zero
• Responsive web interface
• WebSocket-based real-time updates
• Minimal and clean UI

Technical Stack

• Backend: Go 1.21+
  • Gin web framework
  • WebSocket support
  • QR code generation
• Frontend: Pure JavaScript & CSS
  • No external dependencies
  • Responsive design
  • Real-time WebSocket updates

Setup

1. Clone the repository
2. Install dependencies:

   go mod download

3. Run the application:

   go run main.go

4. Open http://localhost:8080/index in your browser

Project Structure

.
├── assets/
│   ├── css/
│   │   └── style.css    # Styles for the web interface
│   └── js/
│       └── script.js    # Frontend WebSocket and UI logic
├── views/
│   └── index.tmpl       # HTML template
├── main.go              # Server implementation
├── go.mod              # Go module definition
└── README.md           # This file

License

This project is licensed under the Mozilla Public License Version 2.0 - see the LICENSE file for details.