Mitsubishi AC mqtt temperature

Hi, I was hoping someone could help me out. I have successfully installed a wemos mini into the cn105 port of a Mitsubishi cassette and integrated it into HA using the gysmo38 library. I have also set up a bme 280 sensor on a separate wemos in the same room. My question is, how do I get the wemos in the Mitsubishi to read the temperature of the bme280 sensor instead of the built in Mitsubishi sensor?


Ask the developer for external sensor support here:

Thanks for the response Tom. Yes I had looked at the GitHub page and the developer specifically mentions node red. I have no experience with node red but with my limited understanding it allows someone to setup mqtt messages. I was wondering if there is a simpler way to send out a mqtt message from the temperature sensor to the HVAC wemos within home assistant.

Home assistant has an mqtt publish service but I don’t see how that is going to help you unless the gysmo38 library supports external sensors.

Sorry to bump an old thread, but I think I just got this working using the Mitsubishi2MQTT code installed on a Wemos D1 mini clone, connected to CN105, and I hadn’t seen an explicit example of how to do this elsewhere.

Once Nodered is installed you can create an MQTT out node and push the temperature you want (a number or string containing a number) to the topic: mitsubishi2mqtt/xxxxxx/remote_temp/set
where xxxxxx is the name of your heat pump entity.

You can even discover what your heat pump entity name is by creating a global MQTT listener: Create an MQTT in node, set the topic to +/+/+ and link it to a debug node. This is also useful for debugging.

Then, to regularly update the temperature, you can create an inject node, set it to repeat as often as you like, link it to a current state node that queries any entity you like, and then link the result to your MQTT out node.

I also added a 2nd inject node to manually override the temp to 88 deg just to test if everything was working. If you set this 2nd inject node to send a value of 0, it disables the remote_temp, and the heat pump goes back to using its own temp sensor.

Here’s an example:

Thank you!

I have a number of MQTT devices now, and it seems they all have their own way of defining their topics. I get them set up but can’t figure out the syntax

…enter the +/+/+ node…fantastic! Now I can see all the nodes connected to my broker in node-red and start to filter them down to the one I’m interested in.

Just used it to figure out the connection to the mitsubish2mqtt code for my Mitsubishi mini-split HVAC units.

Thanks again!

Slightly off topic, since this may not apply to HASS folk, but I am not sure if the /temp topic is just used to set a new target temperature, e.g. /temp/set 65 (I am working in Fahrenheit) , or if it can be used to monitor what the Mitsubishi thinks the current temperature is e.g. temp/ without the /set.
When I use the /set version, it returns a /settings topic confirming the new “temperature”, and from then on the /state topic comes back every 30 seconds with the set “temperature”, but not the current temperature.

Does that make sense?


@tonylane26 you can change the Mitsubishi’s idea of the current temperature by posting to mitsubishi2mqtt/<heat_pump_id>/remote_temp/set:

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As floatplane has commented above, the mitsubishi2mqtt/xxxxxx/remote_temp/set is used to provide the Mitsubishi a reading from an external remote temperature sensor in the room. It updates the Mitsubishi unit’s current temperature.

It does not set a new target temperature.

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Thanks @floatplane and @jgroeli. I simplified things by parsing the regularly broadcast /state topic, which returns elements “temperature” and “roomTemperature”. These represent the Set temperature and the Room temperature observed by the Mitsubishi infra-red sensor, respectively.