These mini split inverter units seem to be good for +/- 1 C, but the 2 C swing can feel quite substantial.<p>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<p>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.
I’ve been working on a similar setup using the M5Stack NanoC6 and AtomS3 Lite, and put together a parts list and wiring guide on my site: <a href="https://serin-labs.com/parts.html" rel="nofollow">https://serin-labs.com/parts.html</a>.<p>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.
<a href="https://serin-labs.com/flash.html" rel="nofollow">https://serin-labs.com/flash.html</a>
<a href="https://serin-labs.com/esphome/generate-yaml.html" rel="nofollow">https://serin-labs.com/esphome/generate-yaml.html</a><p>I run Serin Labs and sell assembled kits and the cable separately.<p>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: <a href="https://serin-labs.com/multi-zone-controller.html" rel="nofollow">https://serin-labs.com/multi-zone-controller.html</a>. 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.
HN is awesome sometimes, I actually <i>just</i> installed 3 of your devices in my ACs to get them all wifi enabled. Worked perfectly, thank you!<p>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.
Awesome. I'm glad to hear that.<p>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.
Thanks. I’ve been looking for a clean ots solution and somehow managed to not come across your company yet. Just purchased pre-assembled module!
The Nano is fine to connect directly because it has diodes on the data pins but the S3 Lite needs a level shifter or it'll eventually stop communicating with the air handler.
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Mitsubishi AC units that support M-NET have a CN105 port. IIRC, my specific model uses a JST PA 5-pin connector rather than a JST PH 5-pin.<p>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.<p>[1]: <a href="http://getnavi.jp/appliances/681340/" rel="nofollow">http://getnavi.jp/appliances/681340/</a> (ja)
I did a similar thing, heavily aided by Claude, after seeing the protart modules posted here on HN last year. <a href="https://github.com/samstevenm/minisplit-local-public" rel="nofollow">https://github.com/samstevenm/minisplit-local-public</a><p>Apologies for the Claudish, especially if anyone wades through the blog posts. I cringe when I reread them, but having <i>some</i> documentation on a working system is better than the ~none I was publishing before.
This is kinda unrelated but I learned while researching for my new AC that there are two Mitsubishi brands/companies, one is Mitsubishi Electric and the other is Mitsubishi Heavy Industrial. And their ACs are not the same, so just saying Mitsubishi AC probably could lead to problem. The one OP has is Mitsubishi Electric by the first photo.
<a href="https://github.com/heishamon/HeishaMon" rel="nofollow">https://github.com/heishamon/HeishaMon</a>
<a href="https://archive.is/KF0iH" rel="nofollow">https://archive.is/KF0iH</a> (no annoying popups)
For anyone wondering why he would ever do this, it seems to be a type of hidden mini-split system used in euro-style shoebox flats, with a super-proprietary thermostat. Wi-Fi capability is an option at additional cost, but was not purchased.<p>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).
Most new construction with heat pumps are going to use similar thermostats, both because of improved efficiency since the outside unit wants to know how much heating/cooling load is being requested, and more importantly, because builders are lazy and would rather use a battery-powered wireless option than run thermostat wires.<p>Off the top of my head, Mitsubishi, Rheem, Lennox, and Carrier all have similar default options, with converter boxes for retrofits to 24V controls.
Is this "mini" split? This type of panels are pretty standard for office buildings in Japan. Usually networked into building management system somewhere. Most household mini splits come with an IR remote, and don't support these panels. Standalone third-party thermostats are rare.
FYI this kind of thermostat is actually better. American style thermostat put your HVAC system in either on or off state (basically PWM), whereas this kind of communicating thermostat can tell the system what the temperature is, so they adjust power accordingly. I do wish they have standardized protocol though.
In some countries there are devices supporting the OpenTherm protocol: <a href="https://en.wikipedia.org/wiki/OpenTherm" rel="nofollow">https://en.wikipedia.org/wiki/OpenTherm</a> <a href="https://www.opentherm.eu/" rel="nofollow">https://www.opentherm.eu/</a>
Single stage hvac systems tend to have better performance in the max capacity cooling cases (Texas) and last significantly longer than units that rely on non-linear electronic devices.<p>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.
The thermostat is better only because it takes advantage of the inverter modulation capabilities in the heat pump. I don't have the sense that inverter modulation is the norm for most home ducted systems, even new builds in North America.<p>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.
Depends on your definition of better.<p>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.<p>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.<p>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.
I had this same control panel in Australia. The actual AC unit was part of the strata common property and I think somehow shared between multiple units on the floor.
My idea of HVAC is that it should be "set and forget", so "smart" is the polar opposite of what I want. The round Honeywell on the wall has been doing its job for the past few decades, and will likely last many more with only an occasional cleaning.
If you have same schedule every week, don't go on vacation, your kids don't have breaks, don't have seasons, then 'set and forget' dumb thermostat will work for you without any problems. For the rest of us we need some 'smartness' in our thermostats.
For some people they may only opportunistically (perhaps they have excess PV production at that moment) run their AC or temporarily turn it off when they temporarily have other power demands at that moment (eg running dishwasher, washing machine, microwave, kettle, etc) and don’t want to pay for grid energy while doing so.<p>“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.<p>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.
This is exactly the case in my household. Excess solar is pretty much worthless here, so with a smart AC you can dump the excess solar into your house as either heat or cold. This (currently) has a lot better ROI than installing a household battery. (Battery tech and availability might change this.)<p>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).
Isn’t this is only true with central air though? Most other types of ac are not full climate solutions to leave running all the time and need some manual control.<p>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.
Check out Uncle Pennybags over here with AC in his garage...<p>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.<p>I'd rather know if the system has failed when I'm 500 miles away before the pipes freeze.
Anyone tried this on the Bosch units? Their WiFi module comes as an addon too.
my solution is to capture the irs with flipper and replay them with tasmota
Does anyone know if this could be used to "cap" the AC settings ? It could be useful in an airbnb place, where I want to limit the lowest (e.g. 18 degres Celsius) or hottest (e.g. 22 degres Celsius) the guest can set the AC.
These panels technically lets you do everything you would ever want to on an AC control panel: <a href="https://www.mitsubishielectric.co.jp/ldm/slim/remotecontrol/" rel="nofollow">https://www.mitsubishielectric.co.jp/ldm/slim/remotecontrol/</a><p>Or multiple AC units can be networked and managed over Ethernet: <a href="https://www.mitsubishielectric.co.jp/ldm/control/function/" rel="nofollow">https://www.mitsubishielectric.co.jp/ldm/control/function/</a><p>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.
To answer your question, yes you could certainly do that and override what ever the physical thermostat was set to. You could also set max hours per day (kWh)for usage or adjust for variable rate plans.
As with anything you'd need to test.<p>Edit:
Looking through the repo and the article I see nothing blocking you. You certainly won't break anything!
If you controlled the AC temperature remotely it's a great red flag to never rent that Airbnb. Some people like it cold when they sleep.
I don’t think they’re proposing remotely controlling it, just so that the guest would experience being unable to change the temperature to outside the allowed range.<p>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.<p>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.<p>And if these people are out of the room when it reaches the <i>actual</i> 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.
I understand, and I could make it clear in the description that AC is capped at 18 degres C minimum (65F), so people who like it very cold could skip my airbnb.<p>Some AC can go ridiculously low (<a href="http://news.bbc.co.uk/2/hi/uk_news/england/3144803.stm" rel="nofollow">http://news.bbc.co.uk/2/hi/uk_news/england/3144803.stm</a>). 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.
I did similar with our coffee machine a year ago - I was bored of getting home from the school run to a cold pot of coffee because the machine automatically turns off the hot plate after 30 minutes, and it seems there is no such thing as a WiFi connected drip coffee machine. Kettles, yes, coffee machines, no.<p>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.<p>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.<p>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.
> Now, she opens her bedroom door, I get “kid is awake” alert on my phone, and the machine brews the coffee.<p>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
I'm hoping to get a mini-split system installed soon and thought I might as well look for something with HA integration. It's not easy. Some manufacturers like Samsung actually want to charge you monthly for cloud integration! Completely out of the question obviously. I came across this, and Mitsubishi is supposed to be good anyway. I would prefer something that's actually supported but I can't seem to find any other options.<p>I could also very easily wire my units in so no need for WiFi. Maybe I can find a wired ethernet module.
I used this guys thing <a href="https://clima.protoart.net/" rel="nofollow">https://clima.protoart.net/</a> after someone mentioned it in an HN comment last summer, then used claude to extend it this summer. A year in, I’m very pleased. Matter or thread would be nice, but these are super straightforward out of the box and totally local.<p>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).<p>[0] <a href="https://protoart.net/knowledgebase/me_cn105_ata_wifi_http_api_mqtt_topics/" rel="nofollow">https://protoart.net/knowledgebase/me_cn105_ata_wifi_http_ap...</a>
[1] <a href="https://github.com/samstevenm/minisplit-local-public" rel="nofollow">https://github.com/samstevenm/minisplit-local-public</a>
I have a Daikin system. I use Faikout(ESP32 that controls the heads via the debug port) to control my units from home assistant. Works great!<p>Their official service needs an app and cloud access to control it. And I absolutely refuse to do that.<p><a href="https://codeberg.org/RevK/ESP32-Faikout" rel="nofollow">https://codeberg.org/RevK/ESP32-Faikout</a>
My ideal system would be something that does matter over thread with zero external internet access. Matter over thread devices are all standardized so no proprietary app required, and the newer iphones have a thread radio built in so you can control them without even a hub.
Fwiw I have a Samsung AC system and Claude was able to one-shot a custom web dashboard to control it.
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