cubigato GmbH has released the project gmc-geiger-mqtt as Open Source. The project is now available on GitHub and is available to the developer community.
gmc-geiger-mqtt is a Python application that reads GMC Geiger counters via a serial interface and publishes the radiation measurement values via MQTT. The software enables seamless integration of Geiger counters into smart home systems such as Home Assistant.
The core functionality of the MQTT bridge is fully implemented and production-ready. The software reliably reads radiation values from GMC devices (tested with GMC-800), calculates moving averages and publishes the data via MQTT. Integration into Home Assistant works automatically via MQTT Discovery.
Future enhancements include a web UI for visualizing measurement values as well as additional output plugins for databases.
The project is structured as a modern Python package and uses uv for dependency management. The architecture cleanly separates between device layer (serial communication), processing layer (data processing) and MQTT layer (publishing). Automated unit tests as well as manual hardware tests document the functionality.
The software is aimed at anyone who wants to integrate radiation measurements into Home Assistant, for example. Typical use cases include monitoring background radiation, creating long-term statistics or automation based on radiation values.
The data can of course also be processed with any other MQTT client.
The complete source code is available on GitHub: