---
title: "HomematicIP + MQTT"
section: "smarthome"
parent: "/"
description: "How HomematicIP room sensors are bridged into MQTT and stored in InfluxDB for dashboards."
layout: base.njk
---
<h1>HomematicIP + MQTT</h1>
<div class="detail-content">

<p>HomematicIP room thermostats (living room, bedroom, home office) report
temperature and humidity into the smart home dashboard via a small,
deliberately low-tech bridge: <strong>Home Assistant → MQTT → InfluxDB</strong>.</p>

<h2>Why this path, and not a direct integration</h2>
<p>A dedicated HomematicIP-to-MQTT exporter used to run as a standalone
Docker container, but the underlying Python library lost compatibility
with HomematicIP's cloud API and hasn't been maintained since 2022. Home
Assistant, on the other hand, ships an actively maintained HomematicIP
Cloud integration — so instead of chasing a broken exporter, the bridge
now runs as native Home Assistant automations that simply republish
sensor state changes to MQTT.</p>

<h2>How it works</h2>
<ol>
<li>Home Assistant automations trigger on thermostat state changes.</li>
<li>Each automation publishes the current temperature and humidity to a per-room MQTT topic.</li>
<li>A small .NET background service subscribes to those topics and writes the values into InfluxDB, tagged by room and sensor type.</li>
<li>Grafana reads from InfluxDB for the temperature/humidity dashboards.</li>
</ol>

<h2>Why this is worth documenting</h2>
<ul>
<li>No extra Docker container or unmaintained library dependency.</li>
<li>Cloud-API changes are absorbed by Home Assistant's own maintainers, not by custom code.</li>
<li>The MQTT bridge is just configuration (automations), not a service that needs its own uptime monitoring.</li>
</ul>

</div>