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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.
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
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
ESPHome device are consistently faster and more reliable than any smart home tech I buy at 10x the price (not hard with $3 boards).
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.
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)
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.
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).
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.
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?
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.
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.
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.
“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).
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.
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.
Edit: Looking through the repo and the article I see nothing blocking you. You certainly won't break anything!
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.
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.
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)?
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.
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. ;)
I could also very easily wire my units in so no need for WiFi. Maybe I can find a wired ethernet module.
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://codeberg.org/RevK/ESP32-Faikout
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.
[1] https://github.com/DavidvtWout/esphome-matter/pull/53
There's no Internet from the IoT SSID.