Local control for Mr Cool Smart Hvac Products

Hi Guys,

Just got done installing a 4 zone Mr Cool Mini-split system a couple days ago. These things come with wifi usb dongles featuring ESP chips to allow remote control and interfacing with google alexa etc. ESP-12-F on the chips.

Has anyone done any research or work on getting tasmota onto these controllers, or getting a way to control them locally without the cloud be it via NR, HE, HA etc?

If there are no local options or a tasmota hack currently available would anyone be interested in helping me out on getting these things 100% local in my spare time?


I have been looking to get a mini split system for my secondary home and Mr. Cool has been at the top of my list but in regards to connecting them, I have contacted support multiple times and they have not been the most forthcoming is probably the best way to put it.

I have not pulled the trigger yet but my plan was to do IR controls via Z-Wave or broadlink, but that has its own issues, blocked signals and no 2 way sync so I would be super interested in helping in any way I can. Another hacky way would be probably to use Alexa custom actions, but again no 2 way sync and cloud dependent as well.

After doing some research it seems they operate on the same platform and the cielo breeze platform while have an open cloud API that has already been interfaced with Smart things, so someone should be able to port that over to node red etc for cloud interfaced control, and possibly analyze the API to figure out a local control option.

Love the Mr. Cool system btw… The DIY versions really can all be done without any contractors if your comfortable putting in a breaker or already have one available, and it is managing to keep my 2 story 1600 sqft farmhouse built in 1903 warm for less than $150 a month!!!

Great to hear, yeah we have a 2-story 1500 sqft 1920’s I think Spanish Style home that we just renovated from the studs, but somehow forgot to plan for heating and cooling, probably because we haven’t had it for the last 30 years, but 1500W space heaters don’t really cut it anymore. If you don’t mind me asking how much did it cost you? My research has come out to about $6k for a 3-zone 36K BTU system. My biggest worry is running the lines from the outdoor to indoor units so that it does not look terrible.

I did a little bit of research as well and it appears the ESP-12-F is a WiFi module based on ESP8266, and there appear to be a few ESP-12-F devices that have been successfully flashed with tasmota, just relays from what I have found but I wonder if they can be adapted. I saw on the backside of the chip it has the normal contacts, not through holes but that should not be that big of a deal, for flashing associated with the ESP8266 devices I have seen at least.


ESP-12F plug being flashed:


ESP-12F 4 Relay Template:

Configuring Unknown Device once Tasmota is flashed (likely will be needed in this case):


This is potentially going to be a stumbling block however:

“Some smart devices have additional functionality which may be handled by codes sent to a separate MCU in the device. Devices with functions offloaded to a separate MCU require additional coding in the software or via rules. Certain supported Tasmota BASE devices have built-in code to handle MCU controlled devices. Using a template with an appropriate BASE device may have the programming logic required to manage the MCU commands for your device. If an existing BASE device with the logic for your device is not available, a modified device driver will be required. This case is outside of the scope of this article.”

This is my current thought process:

Option 1 - Cloud API: Saw that SmartThings support Cielo as an integration but it seems to be first party and I have not been able to find any API listed and I have never had a SmartThings so I have no clue if you can see the underlying code for the first party integrations.

Option 2 - Network Sniffing: Depending on the security Cielo put into their system I wonder if we could just sniff various packets being sent to the dongle/adapter while in operation and reverse engineer from there.

Option 3 - Tasmota: I am guessing flashing the ESP-12F is going to be the easy part, the hard part is going to interface with that ARM chip, which unless we can find firmware binaries or be able to extract a firmware binary, I am not sure how we can reverse engineer. I spent a little bit of time trying to find patents or FCC filings or WiFi filings and came back with nothing so far.


I just found this which may be promising:

It looks like that is mimicking the website control via websocket as he has not found any public API:

Let me stop you right there… thats 2500-3000 too much to be paying! Here you are… My 4 zone system cost me less than $3500.

For outdoor to indoor unit connections they make enclosures to cover the lines so they dont look tacky on the outside of your home. Personally I am 3d printing my own covers and running an led strip inside with the lines. If im going to add something to the outside of my house it might as well have some form of visual appeal :wink:

I came across that earlier and have it on my list of things to analyze. We’ll get integration for sure, even if I have to wait for Markus to have time to implement it into the core for me lol

Interesting, I was looking on HomeDepot and my notes state $5-5.5K pre-tax but when I just clicked the link again it lists $3500,
MRCOOL DIY 36,000 BTU 3-Ton 3-Zone Ductless Mini-Split Air Conditioner Heat Pump, 230-Volt/60Hz-DIYM336HPW03B08 - The Home Depot
I wonder why it was so high when I was originally doing the research. I liked the listings on HomeDepot since they allow you to select your line set length, something basically all other listings gloss over or provide limited options for.

I was also looking into Daikin or Mitsubishi, but neither of those lines comes pre-charged, however, they do seem to both support HA much better including local integrations, polling only though I think.

Little more research:
Great little thread here that may come in handy.

On another note, anyone know what happened to codahq? I know he had a falling out with HE which resulted in him pulling a lot of his code, but I wonder if he knows about what you guys are doing over here.

The only downside there is needing to either hire a professional or vaccum and then charge the lines yourself, which requires special tools and if you mess up you might be buying another outdoor unit.

I have no idea… @markus or @april.brandt might talk to him and know more though

I do know the true story, but I don’t know where he ended up. I’m sure someone stays in contact with him. He’s still got an active git… Maybe he’s floating or just using HE quietly. If someone wanted to reach out to him that would probably be the place to start.

That’s what I know.

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So found a solution allowing fully local interfacing and control of not just Mr Cool systems but a slew of others as well…

For those interested here is a link, beware you will need to be comfortable with soldering and either using esphome or coding.

GitHub - nicholasrobinson/node-smartcielo: NodeJs interface for interacting with smartcielo remote AC control API (MRCOOL)

If there’s any interest in details on actually building the dongles let me know and ill do a write up… Its ALOT easier than it seems


Not to burst your bubble or anything but I thought you were already aware of this. :wink:

That being said, I would be extremely interested in a write up guide for getting it to work. I really appreciate the OLL team keeping projects like these alive on the forums, it genuinely creates a great atmosphere despite the lull of activity here recently.

Also I have one question regarding the installation of the mini split itself. What exactly comes with the unit and what does the installer have to provide?

Based on the manual and reviews, it seems like they provide everything except the input electricity line and associated air gap breaker. The unclear part is how the indoor units are powered. I see that the refrigerant lines come in sets of 25? ft and you can bridge up to a total of 75ft for a single unit, but what about the “signal cable”, is that also the power cable? And if so, how does that work with the 25ft line sets? Are there plugs that extend the signal cable as well or does the installer have to provide their own signal cable altogether?

Also I have a feeling these units are going to surge in popularity, they now even have the 12k, 18k, and 24k BTU single zone units at Costco, so getting an official integration may actually be worth while.

Everything is included except the power line from your breaker to the outdoor unit and the emergecy/safety breaker many areas require between the breaker panel and outdoor unit.

The signal cables are also the power cables and run right along with your coolant lines to the central unit.

As to line length… this is why you want to shop around… places like lowes and home depot tend to only have 16 and 25 foot line sets. when you are extending a line set you also need to buy a signal cable extension to match.

with these systems having a few/several extra feet of coolant line is not actually an issue and will not negatively impact the system or performance, as long as you can properly coil the excess line somewhere in your setup.

If your doing a single room unit direct through external wall then go with the shortest length that will reach your unit. If your going to be going under the house to an internal wall, to another floor, or through the attic always go a bit longer than you think you will need. Its far easier and cheaper to get a system with longer default lines and coil than it is to add a line and cable set…a 16ft extenion set for those damned things will usualy set you back more than what an extra indoor air handler will for a a multi zone unit!!!

I was but the code for it was a mess and didnt work properly and was below my skill set at the time to make work, it also wasnt confirmed to work with any of the mr cool systems yet so at that time waste of money. Now however is another story :slight_smile: Granted i went a bit overboard and added a smoke and gas leak sensor and a piezo buzzer to my ac units, and I am about to add Particulate matter and C0 sensors to them as well so each unit will also provide full air quality reporting.

There are a couple ways to get it to work. ill write up the easiest way and ill also take some pictures showing actual wiring of the parts together (each dongle cost me a total of 3.75 to make) in the next day or so, and then ill look into writing up the more complex ways to set it up.

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