CO2 Monitor MQTT Bridge

This Node.js application bridges a TFA-Dostmann AirCO2ntrol Mini CO2 monitor to MQTT, making it compatible with Home Assistant through MQTT discovery.

Features

• Connects to TFA-Dostmann AirCO2ntrol Mini CO2 monitor
• Publishes CO2 and temperature readings to MQTT
• Supports Home Assistant MQTT discovery
• Configurable through environment variables
• Automatic reconnection to MQTT broker
• Debug logging capability

Installation

1. Clone this repository:

git clone https://github.com/yourusername/co2-mqtt.git
cd co2-mqtt

2. Install dependencies:

npm install

Configuration

The application is configured through environment variables. Copy the .env.example file to .env and modify the values as needed:

cp .env.example .env

Environment Variables

• MQTT_BROKER: MQTT broker URL (default: mqtt://localhost)
• MQTT_USERNAME: MQTT username (optional)
• MQTT_PASSWORD: MQTT password (optional)
• MQTT_TOPIC_PREFIX: MQTT topic prefix for Home Assistant discovery (default: homeassistant/sensor/co2_monitor)
• DEVICE_ID: Unique identifier for the device (default: co2_monitor_1)
• DEVICE_UUID: Unique UUID for the device
• DEBUG: Enable debug logging (default: false)

Usage

1. Ensure your CO2 monitor is connected to your computer
2. Start the application:

node index.js

The application will:

• Connect to the CO2 monitor
• Connect to the MQTT broker
• Publish Home Assistant discovery messages
• Continuously publish sensor readings

Home Assistant Integration

The application automatically publishes Home Assistant MQTT discovery messages for:

• CO2 concentration (in ppm)
• Temperature (in °C)

These sensors will automatically appear in Home Assistant if MQTT discovery is enabled.

Troubleshooting

• If the application fails to connect to the MQTT broker, check:
  • The broker is running
  • The broker address is correct
  • The port is correct
  • The credentials are correct (if required)
• Enable debug logging by setting DEBUG=true in your .env file
• Check the console output for error messages

Dependencies

• co2-monitor: For communicating with the CO2 monitor
• mqtt: For MQTT communication
• dotenv: For loading environment variables