Getting values from temperature-humidity sensor

[GammaKappa]

I have a Z-wave temperature-humidity sensor (Heiman).
The sensor works fine and in Node-Red I can query the device every minute, but the values change only after 5 min.

I know the Heiman sends out values at shorter intervals.

How can I capture the Temp/Hum values in 'real time' and send them to MQTT ?

The values of the Temperature and Humidity 'devices' in Blockly seem to be updated faster, but I cannot get the values out via a script.
The only method I have found is using a long chain of 'if' commands and a script to send out a MQTT message, but there must be a more efficient way to do this.

[FireWizard]

Hello @GammaKappa,

How do you query the Heimann Z-Wave sensor in Node Red?

They have: node-red-contrib-zwave-js (https://flows.nodered.org/node/node-red ... b-zwave-js), but also node-red-contrib-zwavejs2mqtt (https://flows.nodered.org/node/node-red ... avejs2mqtt), and also nodes for openzwave.

If you have them in MQTT it is easy to send the values to Domoticz.

Regards

[GammaKappa]

After inclusion in Z-wave the Heiman created device #1282 in Domoticz and it appears under the 'Temperature' tab.

I use the following flow :

flow1.jpg (23.17 KiB) Viewed 1221 times

The 'inject' node triggers every minute
The 'exec' node request the values of #1282 using

Code: Select all

curl -s 'http://192.168.1.xxx:8080/json.htm?type=devices&rid=1282'

The 'json' node nicely formats the output so it can be used further on.

My problem is that this seems to query the log file which updates only every 5 min. So I miss the intermediate values.

[FireWizard]

Hi, @GammaKappa,

Okay I understand.

I do not know the internal details of Domoticz that much, that I can confirm that if you query a specific sensor fromDomoticz, that the value is taken from the Domoticz log.

As you have Node Red installed, I assume you have also installed Mosquitto.

Why not use MQTT, instead of html? This will send a message every update of the value.

It is just a MQTT input node, and a switch node as a filter on msg.payload.idx, so that only messages with IDX 1282 may pass.

Regards.

[GammaKappa]

Can I publish the value of just one device to MQTT ? I don't want to flood my MQTT broker with all updates of all devices.

[FireWizard]

Hi @GammaKappa,

You asked:

Can I publish the value of just one device to MQTT?

No, you cannot, but in my opinion, you should not be worried about that.

I do not think that you will publish more than 1000 messages/second, which can easily be handled by a Raspberry Pi,

You can publish the MQTT messages under the topic domoticz/out/$idx without retain.
This will save you a switch node, if you subscribe to domoticz/out/$idx, as you don't need to filter.
Try it, and see if you get the result.

Regards

[GammaKappa]

@FireWizard

Publishing via MQTT does indeed give me the 'real time' values of the sensor.
Thanks !

[FireWizard]

Hi @GammaKappa,

In this case, if you leave it this way, mark the issue as solved.

Regards

[GammaKappa]

Indeed solved.
Thanks again FireWizard.