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geiger2mqtt

License: MIT Python cosalette

GPIO geiger counter to MQTT bridge

geiger2mqtt counts the pulses of a Geiger-Müller counter board on one GPIO pin of a Raspberry Pi. Every 30 seconds it publishes the counts per minute (CPM), the dose rate derived from them and an average dose rate over the last 15 minutes as one JSON message. Home Assistant discovers the three values as sensors.

Features

  • Exact counts. CPM is the number of pulses in the last 60 s, and the average covers the last 15 minutes (ADR-001).
  • Any tube. Set the conversion factor for your tube; the default suits an SBM-20.
  • Dead-tube detection. Five minutes without a pulse mark the sensor offline. The next pulse brings it back online, without a restart.
  • Home Assistant discovery. Three sensors with units and icons.
  • Unprivileged container. Only /dev/gpiochip0 is passed in, on every Raspberry Pi from the Zero 2 W to the Pi 5 (ADR-002).

Hardware

Component Requirement
Counter Geiger counter board with a pulse output (SBM-20, J305, ...)
Interface One GPIO input; the board pulls its output low for each pulse
Platform Raspberry Pi with Docker

  • Getting Started

    Install geiger2mqtt and see your first MQTT messages.

    Get started

  • Configuration

    All settings — environment variables, .env files, and CLI flags.

    Configure

  • MQTT Topics

    Topic reference with payload schemas, directions, and retain flags.

    Topics

  • ADRs

    Architecture decision records documenting design choices.

    Decisions