Openhab & Domoticz side-by-side

Hi All, hope someone can help me getting forward with this…

I have investigated Openhab and the migration from Domoticz with the Aeontec z-wave controller stick, all fine, and I know what to do here, that is all clear.
Also, I have investigated the MQTT part of openhab, a litte bit of a struggle (since I was hoping that Openhab was doing JSON on MQTT as payload, but it does not) but now also quite clear… (using the eventbus)

However, since all my automation is based on node-red, mqtt and JSON at the moment, it will take some more time to migrate to Openhab (doing node-red reconfiguration) , so , my question is this:

Is it possible to run Openhab in parralel to domoticz (both speaking to the same USB z-wave controller) to do a “soft-migration” ?


No sorry that won’t work. The main process (java for openHAB) will lock access to the stick’s device.

Hmm ok, thanks for the fast reply…
I guess making openhab sending JSON data as payload over mqtt for every device is also not something that can be done in a simple way right ?

Well that can be done, but if it will be simple mostly depends on the devices and not necessarily on OpenHAB.
I’m just not fully understanding how you plan to send data over MQTT to a Zwave device.

It depends on whether it all has the same json format or different items have different formats. If they all have the same format it’s not do hard. Using either the MQTT1 binding plus the MQTT Action, or the MQTT2 binding and it’s built in Action:

  1. Put all your items into a group you want to publish. Let’s call it gAll.

  2. Create three Rules, one with Member of gAll received command, one with Member of gAll received update, and the last with Member of gAll changed.

  3. Inside this rule, build the topic to publish to and the json payload as desired and send the message using the action. For the received command rule, remember to publish the value of receivedCommand instead of triggeringItem.state.

Ok, sounds simple, but remeber I’m just starting with openhab and really need to find my way, so what is simple for you might not be simple for me (yet)

But, thinking out loud, as I most likely need to reconfigure quite some stuff, what would be better ? using generic mqtt nodes in node-red or using the dedicated openhab nodes in node-red ? (I think these do not using mqtt, so , they will be slower then mqtt ?)

Would be great ta hav eyour opinion on this, cause if there is no real difference in performance and stability then I think I will just go for the Openhab dedicated nodes in node-red

I don’t use NodeRed so I have no real opinion on the matter. I wouldn’t expect the MQTT or the openHAB nodes to be faster than the other. I know many NodeRed users on this forum use the openHAB nodes.

The openHAB nodes use the REST API for fetching state on demand and Server-Send-Events for Real-time state changes.

The MQTT nodes use MQTT, obviously, for fetching state and also for real-time events.

Both protocols are TCP and string based. Strings need to be parsed and are not as compact as binary data, but so far openHAB does not have a binary interface or compressed output.

  • A tcp connection handshake takes a few milliseconds and REST API calls are fresh connections each time.
  • Our server-send-events real-time interface is crap and buggy. (This will only change with OH 2.5)

All in all I’d recommend MQTT.

Thanks, that is really helpfull, can we say “recommend MQTT or move to OH 2.5 ?”

Not really. There is no OH 2.5 final release yet any my changes to the server-send-events are not yet merged in core.

Your best bet right now is openHAB 2.5 milestone 1 with the MQTT 2 addon and Node-Red.