Hello World Plugin

A simple test plugin for the LEDMatrix plugin system. Displays a customizable greeting message with optional time display.

Purpose

This plugin serves as:

• Test plugin for validating the plugin system works correctly
• Example plugin for developers creating their own plugins
• Simple demonstration of the BasePlugin interface

Features

• ✅ Customizable greeting message
• ✅ Optional time display
• ✅ Configurable text colors
• ✅ Proper error handling
• ✅ Configuration validation

Installation

This plugin is included as a test plugin. To enable it:

1. Edit config/config.json and add:

{
  "hello-world": {
    "enabled": true,
    "message": "Hello, World!",
    "show_time": true,
    "color": [255, 255, 255],
    "time_color": [0, 255, 255],
    "display_duration": 10
  }
}

2. Restart the display:

sudo systemctl restart ledmatrix

Configuration Options

Option	Type	Default	Description
enabled	boolean	true	Enable/disable the plugin
message	string	"Hello, World!"	The greeting message to display
show_time	boolean	true	Show current time below message
color	array	[255, 255, 255]	RGB color for message (white)
time_color	array	[0, 255, 255]	RGB color for time (cyan)
display_duration	number	10	Display time in seconds

Examples

Minimal Configuration

{
  "hello-world": {
    "enabled": true
  }
}

Custom Message

{
  "hello-world": {
    "enabled": true,
    "message": "Go Lightning!",
    "color": [0, 128, 255],
    "display_duration": 15
  }
}

Message Only (No Time)

{
  "hello-world": {
    "enabled": true,
    "message": "LED Matrix",
    "show_time": false,
    "color": [255, 0, 255]
  }
}

Testing the Plugin

1. Check Plugin Discovery

After adding the configuration, check the logs:

sudo journalctl -u ledmatrix -f | grep hello-world

You should see:

Discovered plugin: hello-world v1.0.0
Loaded plugin: hello-world
Hello World plugin initialized with message: 'Hello, World!'

2. Test via Web API

Check if the plugin is installed:

curl http://localhost:5001/api/plugins/installed | jq '.plugins[] | select(.id=="hello-world")'

3. Watch It Display

The plugin will appear in the normal display rotation based on your display_duration setting.

Development Notes

This plugin demonstrates:

BasePlugin Interface

class HelloWorldPlugin(BasePlugin):
    def __init__(self, plugin_id, config, display_manager, cache_manager, plugin_manager):
        super().__init__(plugin_id, config, display_manager, cache_manager, plugin_manager)
        # Initialize your plugin
    
    def update(self):
        # Fetch/update data
        pass
    
    def display(self, force_clear=False):
        # Render to display
        pass

Configuration Validation

def validate_config(self):
    # Validate configuration values
    return True

Error Handling

try:
    # Plugin logic
except Exception as e:
    self.logger.error(f"Error: {e}", exc_info=True)

Troubleshooting

Plugin Not Loading

• Check that manifest.json is valid JSON
• Verify enabled: true in config.json
• Check logs for error messages
• Ensure Python path is correct

Display Issues

• Verify display_manager is initialized
• Check that colors are valid RGB arrays
• Ensure message isn't too long for display

Configuration Errors

• Validate JSON syntax in config.json
• Check that all color arrays have 3 values (RGB)
• Ensure display_duration is a positive number

License

GPL-3.0 License - Same as LEDMatrix project

Contributing

This is a reference plugin included with LEDMatrix. Feel free to use it as a template for your own plugins!

Support

For plugin system questions, see:

• LEDMatrix Plugin Documentation
• Plugin Architecture Spec