I added a non-wi-fi Mitsubishi AC to Home Assistant
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I also built a web flasher with firmware configured for those boards, so you can install directly from your browser without any fiddling or configuring. The ESPHome option uses the same echavet/MitsubishiCN105ESPHome project mentioned in the article. I also included a YAML generator for that project so you can more simply customize the config. There are also separate firmware options for HomeKit and Matter. https://serin-labs.com/flash.html https://serin-labs.com/esphome/generate-yaml.html
I run Serin Labs and sell assembled kits and the cable separately.
For anyone with City Multi, P series, or M series systems with a branch box, you may also be interested in a multi zone controller I’m developing: https://serin-labs.com/multi-zone-controller.html. It connects to the system’s communication bus, allowing one device to control all zones without needing a CN105 adapter at each indoor unit. It also exposes operating data such as refrigerant pressures, temperatures, power, compressor frequency, and fault codes, with everything running locally. Software is still in development.
wiring:
1. Mini split black (GND) → ATOM G
2. ATOM spare G → shifter GND (either row)
3. Mini split red (5V) → ATOM 5V
4. ATOM spare 5V → shifter HV ref
5. ATOM 3V3 → shifter LV ref
6. Mini split yellow → shifter HV1
7. Shifter LV1 → ATOM (G2 / GPIO2)
8. Mini split white → shifter HV2
9. Shifter LV2 → ATOM (G1 / GPIO1)
if the gpio ends up being reversed you can handle it in software
Is it possible to flash them from Google home firmware to esphome without USB? I might move away from Google home soon but I'd hate to have to reopen up my ACs again.
It's not possible to cross-flash a different firmware track over the air but since you're already using the Matter-compatible firmware, you can pair it directly with Home Assistant, fully local. It won't be as configurable as the ESPHome firmware, but it'll get you the controls you need.
Awesome
I've got my own devices and can make my own cables, if you're looking for someone to test things out
I got around this by disabling the fan from blowing when the indoor unit isn't actively calling for refrigerant. The refrigerant still flows through the indoor unit but since the fan isn't running, it isn't dumping conditioned air into the room. Every unit has a different way to disable the fan when it's not heating or cooling. My mini splits needed a jumper cut on the indoor control board but my air handler was configurable via a thermostat.
This raises the issue of getting a proper temperature reading of the room. Without the air flowing over the thermistor in the indoor unit, the reported indoor temperature becomes wildly inaccurate. To get around this, a thermostat with a temperature sensor is needed. Mitsubishi has a few off the shelf options. I went with the popular route of adding a Bluetooth sensor to my ESPHome builds and I sell a bundle including the controller and remote temperature sensor. More information here: https://serin-labs.com/controller/room-sensors.html
I have an airtouch which I love but my parents have a Mitsubishi system that I’m fairly sure would be compatible, and a large floor space to manage.
Apologies for the question, but for multi zone, you mention that the controller can pick up temperature. My understanding was that temperature is only captured at the intake, not in zones? (I’m familiar with airtouch where I have ?BTLE temperature sensors in the rooms/zones that are paired to my system). But how does this work with a Mitsubishi zoned system? Or am k over-reading the capabilities. (Or is it a similar deal, I just haven’t seen where to acquire these zone temp sensors from)
I use the word zones on the Serin Multi Zone product page but it's interchangeable with indoor units. One indoor unit equals one zone.
You can override the room (intake) temperature per indoor unit/zone using a controller plugged into the CN105 port (like the OP wrote about). Depending on the controller, it can pair with a Bluetooth sensor or listen to any other type of sensor from Home Assistant. By going the ESP32 path, you can use simple, off the shelf $10 BLE sensors.
The Serin multi zone controller uses the centralized communication bus which isn't capable of overriding the indoor unit's room (intake) temperature. But if that is a must (which it is for ducted units), you can have both the multi-zone controller and a controller at every indoor unit without issue. So if you have an MHK2 thermostat on the wall and don't want to use their Kumo app anymore, the Serin multi zone controller will give you local control and you'll be able to retain the remote temperature sensor from the MHK2 thermostat.
[1] https://theairstore.com.au/product/airtouch-gateway-mitsubis...
As a small hack, I used the Python scripting interface in Home Assistant to replicate this [1] feature from Panasonic HVAC that gradually raises the cooling set point towards the morning. It is quite comfortable during the summer.
[1]: http://getnavi.jp/appliances/681340/ (ja)
PID control seems to be lacking overall, the control laws seem to be more basic. In particular, my unit waits until temperature deviation from setpoint exceeds 1C before cycling on. If I want finer control, there are a few options I can think of: 1. Spoof the temperature, add a TEC , heater, cooler or something to the sensor on the remote 2. Manipulate the controller buttons, change the setpoint down or up by 0.5 degrees so the unit kicks on after a 0.5 degree change instead of a 1 degree change 3. Spoof the temperature sensor itself, hack into the wiring with some transistor based circuit 4. Hack into the actual unit, fully take over the compressor and fan control 5. Buy a better unit or off the shelf controller 6. Spoof the remote control, reverse engineer the IR communication temperature signal
This last option seems the least intrusive and cleanest, I see other people have done it, it's definitely a lot of work even with AI.
If so, you're right, the easiest way is to build/buy an IR blaster module for a microcontroller (ESP32 if you want wifi) and connect a temperature sensor. HA/EspHome is overkill for this, but can be useful for the large catalog of pre built integrations. Most of them are built using/on IR libraries for 'Arduino' anyway, so you can easily roll your own with a half dozen lines of C++.
Mapping out your own PID correction algorithm (esp says the room is 72 F when it's really 70 F to get it to cool sooner), but usually just having the remote room temp sensor near where you'd be sitting instead of near the ceiling or in the return air stream gets you close enough.
My biggest worry is the heat from the microcontroller affecting the temperature on the temperature sensor. I want to use a Sensirion SHT45, it has 0.01 degree temperature resolution and is supposed to be accurate to 0.1 C. But I need to locate the temp sensor far enough away from the microcontroller to make the overall remote controller form factor awkward. I have a Raspberry Pi 4 that does the temperature data logging and web server, but that runs pretty hot.
I want to do this but I'm worried about stressing the compressor with extra start/stop cycles would shorten its lifespan. Maybe they are programmed to overshoot/undershoot the set temp to prolong lifespan?
Disclaimer: I know next to nothing about how ACs work beyond the very basics.
Short cycling would be bad in the sense that the motor frequently turns on. The maximum current is during motor start and the maximum motor coil cooling is when the fan is running at high speed steadily. So if it starts a lot and doesn't run much at high speed you might tend to overheat, sure. That would definitely drastically reduce the motor lifespan.
If you are still starting periodically and running for awhile, you can see where this goes.
I think it's not overshoot/undershoot that is happening so much as delayed kick on.
That said, it's still a mechanical device that can experience stresses caused by cycles. Refrigerant systems also deal with gas/liquid phase changes and high pressures, so most units I've worked with do have a compressor lockout timer that allows a few minutes for temps/pressures to stabilize before kicking the compressor back on.
Apologies for the Claudish, especially if anyone wades through the blog posts. I cringe when I reread them, but having some documentation on a working system is better than the ~none I was publishing before.
Dead simple. Cracked it open, chucked an ESP32 in there connected to the soft power button, and to the “machine is on” indicator on the display, which was conveniently on its own pin. No need for any thermal protection cleverness as the machine does that itself.
Now I just turn it back on when I’m heading home, and no longer have to wait for the pot to warm up again.
I then decided to stop using the “make coffee at time” functionality baked into the machine, as the kid gets up when the kid gets up, and the machine would either start early and wake her, or she’d get up before it and I’d have to go start it. Now, she opens her bedroom door, I get “kid is awake” alert on my phone, and the machine brews the coffee.
Out of all of the smart home threads and articles I've read over the years this is the only sentence that made me wish I had it. It's genius
Exceptions like the above make automations hard.
So... just make sure the automation only becomes available from ~6 AM to 8 AM. ;)
In most cases, there's nothing wrong with the switch on the wall. I don't need a complex home automation. I do have Home Assistant. It isn't very useful. It's kind of nice to have a couple of lights on from dark until 9 p.m. but with the efficiency of modern LEDs, it's probably cheaper to just leave those lights on 24-7 than to leave my home assistant machine on 24-7.
I literally couldn’t do without HA - I live off-grid, and it manages everything from monitoring water tank levels & running pumps to a power grid distributed over three independent and geographically distributed battery banks. Monitors for anomalies and tells me what is acting up - for instance today I got sent on a mission to find out why an array of PV was underproducing by 33%. Wouldn’t have noticed until it started having energy budget impacts otherwise. Makes decisions on whether today is a passive cooling/heating day or whether we have the energy budget to run climate control, when windows should be opened/closed to maximise efficiency, which blinds to close when depending on where the sun is to prevent or encourage passive solar gain, when to run the partially pumped storage hydro and in which direction, when to pull the pin on the deluge system and where if it’s set to wildfire mode. It has literally saved the house - not our lives, as we’d already evac’d and left it in charge of firefighting.
Stuff like the coffee machine and opening the blinds in the morning are just easy quality of life improvements, something less to have to manage manually, as my days are full enough that removing any point of friction is useful.
And yeah, I’ll take slightly stale coffee now over fresh coffee in ten minutes.
In the USA, wired thermostats tend to use standardized 24V wiring schemes, or 208V/240V for mains voltage heaters (electric heat, common on the west coast, especially in shitty apartments, central hot water/steam heating with 24V controls is more common on the east coast).
It's a tradeoff I'm willing to make for simple, open I/O. It's not PWM but rather a "call" for heat, cooling, or fan. If I'm refinishing the wall I can (and have) put in a $3 thermostat in its place so I don't destroy the $300 one with paint and dust.
It's also very easy to debug and repair, as I experienced on a day when the temperatures exceeded 100F and was able to execute an emergency repair myself.
If companies like Nest and Ecobee were not allowed to exist, we would all be stuck with the overwhelmingly universally overpriced, proprietary garbage the OEMs put out.
The difference can be as extreme as 10+ years of service life. There are residential systems that were installed in the 80s and 90s that are still running fine today. The hermetically sealed scroll compressor is an engineering marvel. The electronics will generally fail before any meaningful mechanical wear is incurred.
Why?
Semiconductors wear faster than copper wires and contactors and are much harder to replace. I can take a part from my neighbor's condensing unit and it would almost certainly work in mine. The make/model is largely irrelevant. I can go on Amazon, search "Start+Run Capacitor" and buy the first thing I find.
The system never catches up, even at night?
I've only observed ductless systems like this in retrofitted, older homes in Canada. And at that point they're usually not integrated with the home's existing heating system / thermostat.
Off the top of my head, Mitsubishi, Rheem, Lennox, and Carrier all have similar default options, with converter boxes for retrofits to 24V controls.
I live in an NYC apartment with a similar Mitsubishi ducted split system - very short run ductwork just because the apartment itself is small, but takes up way less space than traditional American-style air handlers, even the apartment sized ones. The entire air handler is suspended above my bathroom ceiling, in between the drywall and the slab above.
My system was originally installed with the 2-wire serial wall thermostat but I converted it to one of Mitsubishi's Redlink wireless units because I needed to relocate the thermostat. But since Redlink isn't wifi, and the Mitsubishi networked thermostats and cloud platform get pretty poor reviews... this project is super interesting to me.
I could also very easily wire my units in so no need for WiFi. Maybe I can find a wired ethernet module.
There's no Internet from the IoT SSID.
Since it's running ESPHome you can easily verify everything it's doing.
Thread would be even better but this is good enough for me. 100x better than the original cloud app it came with. Still no proprietary app required, works on every platform.
The manufacturer documentation [0] for everything is great and it was perfect for my goal of getting them to show up in Savant as native thermostats [1] (likely beyond typical scope for split units).
[0] https://protoart.net/knowledgebase/me_cn105_ata_wifi_http_ap... [1] https://github.com/samstevenm/minisplit-local-public
Their official service needs an app and cloud access to control it. And I absolutely refuse to do that.
https://github.com/DomiStyle/esphome-panasonic-ac/blob/maste...
ESPHome device are consistently faster and more reliable than any smart home tech I buy at 10x the price (not hard with $3 boards).
At least that’s how I use the mini split in my garage. I have to remember to give it 15-20 minutes headstart before I use the garage or will be really hot.
All "smart" t-stats can be used in "dumb" mode but the remote control and monitoring is really the killer feature. Scheduling and presence is meh, if you're obsessed with energy savings I guess.
I'd rather know if the system has failed when I'm 500 miles away before the pipes freeze.
(There is a case where if your house is well insulated enough, then it can be worth avoiding cycling your AC during the day, because it is both less efficient and will wear more while pulling the temperature down and this can be worse than just leaving it running in a sufficiently insulated house. It still is probably worth turning it off if you're away for a week, though)
That's just not true. Aircon is a heat pump. It pumps heat more efficiently when more heat is available to be pumped.
Warmer indoor air increases evaporator temperature. A higher evaporator temperature means that the system operates with less temperature lift. This means that the system does less work (per BTU pumped) to cool a house that is hot inside, than one that is already conditioned inside.
Equipment longevity also tends to be increased with less-frequent, longer runtimes than with more-frequent, shorter runtimes. There's less temperature cycling, fewer in-rush current events, and the lubricating oil in a running compressor is actively circulated to the parts that need lubricated. Reducing the number of compressor start-ups is a good thing; these machines like to run.
So even if same number of BTUs enter the home and need pumped out whether the aircon is running or not, then: Letting things warm up inside when there's nobody home to care about that constitutes an improvement in a broad number of ways.
Reality is even better: On a hot day, a house that is hot inside takes in fewer BTUs than one that is cool inside, due to the reduced temperature delta between indoors and out. When we have fewer BTUs coming in, then we have fewer BTUs that we must ultimately pay to pump back out.
All of the material thermal failures I can think of come from localized and more extreme sources: electronics, lightbulbs, washing/drying clothes, washing dishes in a dishwasher. Water below freezing point too, but that's because the temperature fell below a threshold. None of these are from heating or cooling rooms directly with HVAC.
What's the baseline and what's the safe delta?
“HVAC” is essentially not a thing in houses in South Africa likely due to having a mild climate, this also makes insulation in houses optional and mostly not done.
So most people with AC here are probably using it as a luxury and will happily have it be off a little if it meaningfully reduces energy usage while still making their house noticeably more comfortable.
I am enamoured by making dumb AC's smart by this method, since you probably have a lot less IT risks than by using the suppliers app. I think the trade off is between IT risk and mechanical / technical risk, since adding your own parts have an effect on warranty (or at least: willingness to repair by the supplier).
Some AC can go ridiculously low (http://news.bbc.co.uk/2/hi/uk_news/england/3144803.stm). I do not want to change the temperature remotely, I just want to not have the AC used to extremely cold temperature. I am fine to advertise it to weed of people who like it very cold.
Most programmable thermostats in the US do have built-in limits for device protection.
I've never met anyone who sets AC in a home to lower than 68F and that is an absolute extreme. Most central AC systems are designed for ~20 degree temperature differential so on really hot days you'd have trouble getting it that low anyway unless the system is oversized.
Yeah, why set the upper limit to 22 and not like 24-25? It will save you even more power for those that don't sit in your airbnb in a 3 piece business suit...
18C is not uncommon in the UK. They seem to like it colder. Italy is down south so 25C may already be getting cold for them. Then there's the Indians who like it closer to 30C...
Did you just post a link to a 23 year old news article with no sources on an http-only site as supporting evidence that your airbnb unit's AC unit can go dangerously low?
You really think your guests will get frostbite if you don't do them the favor of limiting the AC temperature (with the unintended side-effect of saving you some money)?
Of course any guest is free to write in their review “can’t make temperature lower than 18°!” but the number of people choosing not to book for that reason in any given year is likely 0 or very close to it.
There are a lot of people who don’t “get” thermostats and their intuitive model of ACs is like that of getting a bath to a particular temperature by turning a faucet to full hot or cold to get what they want.
And if these people are out of the room when it reaches the actual temperature they want (and would change it), then the AC is left possibly for hours working full time, burning maximum energy and related wear and tear by trying to hopelessly achieve an unattainable temperature.
Edit: Looking through the repo and the article I see nothing blocking you. You certainly won't break anything!
Or multiple AC units can be networked and managed over Ethernet: https://www.mitsubishielectric.co.jp/ldm/control/function/
People do start placing hand warmers on the panel if you lock them down too much, but what you asked should be possible in principle.
However, the Mitsubishi Pencil company is entirely unrelated to the Mitsubishi Group. Ironically, they share a very similar three diamond logo, which they registered and used years before Mitsubishi Group.