HOWTO: MQTT Sensors

Before you start

This page describes legacy code. To find out how it is currently done, jump here.

IMPORTANT: see Current vs. Legacy Code Base

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Configuration below pertains to sensors conforming to DZ Edge Device specification. If you're just starting, you probably want to use the ESPHome or Home Assistant integration instead. Also, take a look at MQTT: Useful Tools, Bits and Pieces.

Configuration

Configuring MQTT sensors is similar to other factory based configurations (1-Wire and XBee). Here's a working example:

<!-- MQTT Device Factory. You can have more than one if you have several brokers. -->
<bean id="mqtt-device-factory"
    class="net.sf.dz3.view.mqtt.v1.MqttDeviceFactory"
    destroy-method="powerOff">
    <!-- Broker host -->
    <constructor-arg index="0" value="mqt.broker.host" />
    <!-- Root topic - publish -->
    <constructor-arg index="1" value="/hcc/instance" />
    <!-- Root topic - subscribe -->
    <constructor-arg index="2" value="/hcc/sensor" />
</bean>

<bean id="mqtt_sensor-289E0279A201039B" factory-bean="mqtt-device-factory"
    factory-method="getSensor">
    <constructor-arg value="289E0279A201039B" />
</bean>

Below is the JSON that DZ expects. mandatory fields are entity_type=sensor, name, and signal. DZ doesn't care about the topic as long as it is under ${root-topic-subscribe}/ - it parses JSON for data.

{
    "device_id": "ESP8266-00621CC5",
    "entity_type": "sensor",
    "name": "289E0279A201039B",
    "signal": 23.87,
    "signature": "T289E0279A201039B"
}

What's next?

You might want to explore hcc-esp32 if you're feeling adventurous. Or, rather, ESPHome, or, as a last resort, Home Assistant integrations.