ECMA/Java: how to fetch a value from mqtt trigger event

Setup, Configuration and Use Scripts & Rules
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  • Platform information:
    • Hardware: QNAP Nas w. Docker OH3 image
    • openHAB version: 3.01

Dear all,

Easy task (it seems), but I’m stuck again :frowning:

I want to visualize values I retreive from mqtt.

So I set up a broker connection Thing (mqtt:broker:xxxxx) and defined a trigger channel (which seems to be the only way to subscribe to an mqtt topic?)

The event trigger fires, which is good; log:

[INFO ] [openhab.event.ChannelTriggeredEvent ] - mqtt:broker:xxxxxxxx:CO2 triggered 565

Now I want to have the value (565) somehow visualized.

First try was to define an Item following this value, which seems not possible.
Second option would be to use a rule to transfer the mqtt value into a dummy item
And here I don’t get a clue on how to do that, even reading loads of documentation and forums. Can anybody give me the right hint here?

Thanks a lot!
Peter

2

No!
Create a Generic MQTT Thing which connects to the Broker Thing (that acts as a bridge) and add channels to that Thing These Channels can subscribe to topics ( Command- and Statetopics).
However you have read about that in the documentation, haven’t you?

3

Oh… yes, sometimes you don’t see the forest for there are too many trees. I’ll try that, thanks! :slight_smile:

4

Kaum macht man’s richtig funktioniert es auch. It works, thanks!