@nvschilleman i think you have logger enabled??
And yes, unit is updating frequently (during which the blue led blinks)
For the beeping i do not have any clues…sorry
I suspect it is related to
frame check failed
Maybe you can ask on the Telegram group Midea-msmart, as most devs are on there 
Just a last update from me as everything seems to be finally working fine!
I gather the connection issues were due to the lease of the router and the fact I had two different ESP8266 for my two splits and, pretty dumbly I have to say, I’ve been juggling around with firmware and such on both.
I did some checks and even after disconnecting and reconnecting them after some minutes or hours, they connect to internet in a matter of few seconds.
So yeah, thanks again for all the help, really!
Should you even need IT or ES translations for your projects, just let me know 
Good to hear everything works as you wanted and glad to help 
I am running Home Assistant 2021.2.3 on a Raspberry PI. I have installed ESPHome 1.16.2 and am able to flash the ESP-01 boards. When the ESP-01 board is powered up it connects to the network and in the ESPHome UI the red bar above the relevant turns green. I couldn’t get the https://github.com/dudanov/esphome repository to install in HACS - custom repository and get the error “Repostitory structure for dev is not compliant” to make the Midea-ac component available in ESPHome.
Using my Mac I was able to follow the instructions for flashing the ESP-01 on another computer with the Midea-ac component included however, the board doesn’t then appear in ESPHome on the home assistant.
Do I need to find a way to get the Midea-ac component onto my home assistant PI? If so, does anyone have any ideas on how to do that?
Sorry, just read again your message and I think your issue is what I had at the beginning.
You have to install the ESPHome dev addon, not the regular one, as in the dev version you can actually modify the configuration in the supervisor > addon part adding the dudanov repo. @aceindy explained this to me just a few post above
Thanks. I hadn’t realised that I needed to type the version in on that page. The steps for getting the dev version of ESPHome was what tripped me up.
I must say I’m slightly confused by the more recent posts.
My board setup looks the same as @nvschilleman’s boards, CN3 is 5-pin, connected to an adapter board that says 2.4G(WIFI) on it.
Can I connect directly to the CN3 as @kokuo81 did with their 4-pin, or do I need to use a modified USB port?
Thanks!
the usb and 4 pin connector(cn3) are the same; I also used the 4 pin plug myself
(as shown in the picture in the first post)
However, nvschilleman did have some issues, never heard if they got resolved…
You said that your AC had both the 4pin and usb style plugs. Do you have one of these interface adapters for the USB?
Good evening everyone,
@vilord, my indoor unit became unresponsive when I plugged out the wifi board (even the IR remote didn’t do anything), the pinout of the 5 pin connector is different from the 4 pin connector. I’d say you’ll have a bigger chance of getting this to work with the board plugged in.
My AC does respond to commands from the ESP, however I dont get a response from the AC to Home Assistant. I also did not subscribe to the Telegram group yet, I Will do that when I have some spare time, I Just work to much at this moment 
I’m using a Wemos D1 instead of an esp01, because that’s what I already have a bunch of.
Soldered it all up, it powers up just fine.
I was able to communicate through esphome to see the logs, but it is only transmitting, never getting any responses.
Can’t see or control the AC through the esp.
Hmmm.
This worked okay on the mitsubishis, but perhaps the uart in the AC is not willing to listen to 3.3v serial data. I’ll see if I have the supplies to level shift this up to 5v, and hope that’s the problem…
I just wanted to say to all of you a huge thank you! I just flashed a Wemos D1 Mini, and it’s working perfectly!
This is the config (if you’re interested in it):
esphome:
name: d1_mini_03
platform: ESP8266
board: d1_mini
wifi:
ssid: !secret wifi_name_1
password: !secret wifi_password_1
manual_ip:
gateway: !secret wifi_gateway
subnet: !secret wifi_subnet
static_ip: !secret wifi_ip_d1_mini_03
ap:
ssid: d1_mini_03
password: !secret wifi_password_1
captive_portal:
logger:
baud_rate: 0
api:
ota:
uart:
rx_pin: RX
tx_pin: TX
baud_rate: 9600
midea_dongle:
climate:
- platform: midea_ac
name: "Midea AC"
beeper: true
binary_sensor:
- platform: status
name: status_d1_mini_03
id: status_d1_mini_03
For those who are using windows 10 and because the PR is still open, and you want to try it out:
docker build -t esphome:local -f ./docker/Dockerfile .
docker run -d --net=bridge -p 6052:6052 -p 6053:6053 --name=espHome -v YOUR_CONFIG_PATH:/config esphome:local
That’s it, and you can flash the ESP with a USB cable or with OTA.
I have made a test setup with a nodemcu esp8266. See if i could get this to work with my Mr. Cool minisplit. The wifi boards are identical as shown by nvschilleman
Unfortunately i did not have a 3.3/5.0v converter. I tried messing around with some resistor and such but not luck. I did however connect only the RX line and had the USBwifidongle from mr cool plugged in. And was able to read out the current settings every time something changed.
The TTL converter is ordered and should be here tmrw. Hopefully all will work and this will make alot of Mr. Cool owners happy! I am sure since there is no solution, and these units are very popular here in the US since they are sold as complete DIY ac minisplits.
Will provided update in next few days with some photos of the units.
I can confirm it works with Mr. Cool units. Ill post some picture of the units tmrw.
This is really awesome thanks so much!
Thanks go all to:
Mac-Zhou, Rene Klootwijk and Sergey Dudanov 
Here are some pictures of the Mr cool unit. Also my integration of the board.
Cut the blue board a little smaller then directly soldered the ESP01 on top. Soldered some wire directly to the green board. The usb connector is different then the norm as described by someone else.
Does anyone know if there is a way to turn the AC display on and off? I can do this with the infrared remote but was hoping i can do the same from esphome?
As far as i know, not.
They have looked into it, but it seems this command is not available on uart, IR only
Following up on my post earlier, the 3.3v->5v level shift was all I needed. Plugged it in and a few seconds later the current temp popped up in home assistant, all working perfectly. Think I’ll reflash OTA to turn off the beeper. Thanks! This is with a Mr. Cool DIY 12k
I was experiencing the same problem you have.
Following @aceindy 's advice I joined the Telegram group, thanks to the developers its working for me now!
Install ESPHome using custom repository dudanov:midea-climate-support-wo-integrity-check.
You can use the same yaml format.
I Just finished soldering 3 dongles, 2 to go! 
