publish temperature values of several DS18B20 to mqtt once a minute

[marc107]

Hello everyone,

i have connected several ds18b20 sensors to a tasmota device and would now like to write the temperature values for each individual ds18b20 to a separate mqtt telegram.

the output from tasmota looks like this:

tele/tasmota_1EE181/SENSOR = {“Time”:“2025-04-03T23:15:20”,“DS18B20-1”:{“Id”:“0416587237FF”,“Temperature”:22.6},“DS18B20-2”:{“Id”:“04165300DCFF”,“Temperature”:22.3},“DS18B20-3”:{“Id”:“04167086AEFF”,“Temperature”:14. 3},“DS18B20-4”:{“Id”:“041370AFBCFF”,“Temperature”:22.4},“DS18B20-5”:{“Id”:“041670C003FF”,“Temperature”:13.1},“DS18B20-6”:{“Id”:“0516709747CF”,“Temperature”:20.1},“TempUnit”:“C”}

I have found out that I can create a rule that delivers almost the desired result - for the first sensor

Rule1 ON DS18B20-2#Temperature!=%Var1% DO publish tele/tasmota_1EE483/DS18B20-1/temp %value% ENDON

Unfortunately, the result is then published with every calculation (approx. every second).

Is there a way to change the above rule so that this only happens once a minute? Unfortunately, I have not been able to combine the above rule with “Time#Minute”.

Does anyone have a tip for me?

Many thanks in advance

Marc

[sfromis]

If you want to have sensor data published once a minute, you can simply set TelePeriod 60, then Tasmota will do that.

If you want your own format, you can then react to the telemetry period messages by prefixing triggers like tele-DS18B20-2#Temperature and then do your publish. No Time#Minute needed.

Your DS18B20-2#Temperature!=%Var1% rule does not make sense to check for a different value unless you have the rule also update the variable with the latest value. Still could be a lot more than once a minute, unless you do it by TelePeriod. Of course, getting down to every minute, that difference-checking may not be all that useful.

[marc107]

Thanks a lot for your fast reply!

"set TelePeriod 60" should work for me 👍

If you want your own format, you can then react to the telemetry period messages by prefixing triggers like tele-DS18B20-2#Temperature and then do your publish.

If I understand you correctly, you mean the following?

Rule1 ON Tele-DS18B20-2#Temperature!=%Var1% DO publish tele/tasmota_1EE483/DS18B20-1/temp %value% ENDON

This seems to work!

[sfromis]

Well, that part with !=%Var1% still does not make sense, unless you also update the var every time. Or skip the compare if you do no longer see it as needed.

[marc107]

OK, now i get values for all six sensors! 🥳

Is it "bad style" using the following rule?

Rule1
ON Tele-DS18B20-1#Temperature DO publish tele/tasmota_1EE483/DS18B20-1/temp %value% ENDON
ON Tele-DS18B20-2#Temperature DO publish tele/tasmota_1EE483/DS18B20-2/temp %value% ENDON
ON Tele-DS18B20-3#Temperature DO publish tele/tasmota_1EE483/DS18B20-3/temp %value% ENDON
ON Tele-DS18B20-4#Temperature DO publish tele/tasmota_1EE483/DS18B20-4/temp %value% ENDON
ON Tele-DS18B20-5#Temperature DO publish tele/tasmota_1EE483/DS18B20-5/temp %value% ENDON
ON Tele-DS18B20-6#Temperature DO publish tele/tasmota_1EE483/DS18B20-6/temp %value% ENDON

[sfromis]

With the rudimentary features of rules, you can't avoid having one trigger per sensor. You could still make it a bit more generic using %topic% instead of hardcoding tasmota_1EE483.

While this is not "important", in principle I'd prefer not to make the topics "too Tasmota-like", with the tele prefix already meant to indicate Tasmota data in the usual formats.

[marc107]

You're right, that really does make sense.
Thanks again!