Dueling Openhabs (feeding from a 2nd with zwave)

[Dim (Angelos)]

@psyciknz

how does this differ from mqtt-eventbus: and do I have to install something to get access to mqtt-eventbus?

The MQTT Binding bundle includes 3 main components:

1. The MQTT Client, which allows you to configure items that subscribe or publish to MQTT some telegrams (OH2 associated file: mqtt.cfg)
2. The MQTT Transport, which is essentially the fundamental support for the MQTT messaging protocol (no config file)
3. The MQTT Event bus, which links the entire openHAB (2) Event Bus to the MQTT Broker (OH2 associated file: mqtt-eventbus.cfg)

There are also the MQTT Persistence & MQTT action Add-Ons but we don’t need them for your goal.

To get access to the mqtt-eventbus, you need to configure the OPENHAB_CONF/services/mqtt-eventbus.cfg file.
Check MQTT Binding · openhab/openhab1-addons Wiki · GitHub (watch out… this is from the openHAB 1 world)
and one example here:
[OH2] Control ESP8266 Relay using MQTT Eventbus

I see that you are using config references to openHAB 1 (openhab.cfg file). This will work but if you are using OH2, you need to use the files mentioned above.

@psyciknz

But how do I get the zwave sensor on the slave (raspberry pi) to then push that temp value received from the zwave device to the mqtt bus that the master can read?

One way would be to set up the MQTT ↔ OH Event Bus connection on the slave rPi (with Z-Wave) and use a new item that is MQTT bound on the master rPi that subscribes to the status updates as they are published by the slave rPi via MQTT-Event Bus.

Or you could deploy in both rPis the MQTT-Event Bus and mirror the settings (out from slave = in to master, etc). I haven’t tried this setup yet, so I don’t know how it works in detail.