Experiences with Mitsubishi Mini-split Systems

Has anyone done work with monitoring Mitsubishi mini-split (air-based) heatpump systems?

I have a US-based system from which I’d like to get information (temperature readings and set points off the internal units, making my head units operate as remote emonTH devices). While I can find references to Mitsubishi’s own cloud, Kumo, and some scattered references that suggest conversions to Honeywell’s RedLink protocol may be possible. It’s not at all straightforward. As the Mitsubishi converters to hook up to something like a NEST thermostate are over a hundred dollars per unit, I’m hoping someone may have investigated this in the past and figured out what is/is not possible.

I’m looking for integration at the electronics level, hopefully getting information I can read and send off to MQTT. Hooking up temp probes for the coolant level as is commonly discussed for ground-based systems is not what I’m looking to accomplish…yet.

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Following up on this thread, there’s now working Arduino interface libraries for working with Mitsubishi systems. GitHub - SwiCago/HeatPump: Arduino library to control Mitsubishi Heat Pumps via connector cn105 has the details (not my project, not yet tested, looks awesome), Do check out the terrific blog post at the end of the README in that repository.

So many projects, so little time. :slight_smile: