Zigbee fire alarm MQTT message action

[HaVi]

My Zigbee fire alarm sends different MQTT status messages but if there is a fire this is one of the unique messages:

{"ZbReceived":{"0xCB76":{"Device":"0xCB76","EF00/020F":100,"Endpoint":1,"LinkQuality":87}}}

To be more precise, the part "EF00/020F:100" is unique.

Can anyone tell me how to set up a (switch?) node so that there is only action when the above message arrives?

[zenofmud]

Here is a simple flow you can use - node you will feed the switch with the mqtt-in data

[{"id":"bd8d338ef133cb1a","type":"inject","z":"47b962d7577cfddb","name":"100","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"ZbReceived\":{\"0xCB76\":{\"Device\":\"0xCB76\",\"EF00/020F\":100,\"Endpoint\":1,\"LinkQuality\":87}}}","payloadType":"json","x":230,"y":180,"wires":[["6bc9b28b0ed61f0f"]]},{"id":"8431c3d828a36f6e","type":"debug","z":"47b962d7577cfddb","name":"100","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload.ZbReceived[\"0xCB76\"][\"EF00/020F\"]","targetType":"msg","statusVal":"","statusType":"auto","x":610,"y":180,"wires":[]},{"id":"6bc9b28b0ed61f0f","type":"switch","z":"47b962d7577cfddb","name":"","property":"payload.ZbReceived[\"0xCB76\"][\"EF00/020F\"]","propertyType":"msg","rules":[{"t":"eq","v":"100","vt":"num"},{"t":"else"}],"checkall":"true","repair":false,"outputs":2,"x":410,"y":220,"wires":[["8431c3d828a36f6e"],["5e21526f57d9143b"]]},{"id":"920bd8632cb74fd6","type":"inject","z":"47b962d7577cfddb","name":"999","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"ZbReceived\":{\"0xCB76\":{\"Device\":\"0xCB76\",\"EF00/020F\":999,\"Endpoint\":1,\"LinkQuality\":87}}}","payloadType":"json","x":230,"y":240,"wires":[["6bc9b28b0ed61f0f"]]},{"id":"5e21526f57d9143b","type":"debug","z":"47b962d7577cfddb","name":"not 100","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload.ZbReceived[\"0xCB76\"][\"EF00/020F\"]","targetType":"msg","statusVal":"","statusType":"auto","x":620,"y":240,"wires":[]}]

There’s a great page in the docs (Working with messages : Node-RED) that will explain how to use the debug panel to find the right path/value for any data item.

Pay particular attention to the part about the buttons that appear under your mouse pointer when you over hover a debug message property in the sidebar.

[TotallyInformation]

In Node-RED, when trying to work out how to extract data from an object, the easiest way is to add a debug node. Here I simulate what your mqtt-in node would do

With the debug output looking like this

In this grab, the mouse was hovering over the copy path button which you can click to get payload.ZbReceived["0xCB76"]["EF00/020F"].

You can put this into a switch node

Noting that the output is a number not a string.

Now, there may be a complexity if you have >1 alarm device and want to trigger on any of them. In that case the ["0xCB76"] part will be a problem as I assume it represents a specific device.

There are various ways to get around that issue. Personally I would probably use a function node. And if doing that, there really isn't any point in also having a switch, may as well do it all in the function.

// Check if msg.payload (optionally) contains ZbReceived
if (msg.payload?.ZbReceived) {
    const zbr = msg.payload.ZbReceived
    if (zbr["EF00/020F"] && zbr["EF00/020F"] === 100) {
        return msg
    }
}

[HaVi]

When I encountered this problem and it did not solve it after a few hours of trying, I posted a message here. It is very nice that there are people to help like in this case.

My "problem" is solved, thank you both for your help!