Midea branded AC’s with ESPhome (no cloud)

BakaMonogatari · May 9, 2021, 3:44pm

Ok I’m having some trouble here. I’m using an Adafruit ESP32 with an Adafruit TXB0104 level shifter.

This is all I’m getting.

I have

 # UART settings for Midea dongle (required)
 uart:
   tx_pin: GPIO17
   rx_pin: GPIO16
   baud_rate: 9600

in the YAML file. At first I had mistakenly used pins 1 and 3 which was in the example code which according to this is incorrect and that it should be 16 and 17. Still getting nothing. Also tried using some of the other GPIO pins, same deal.

I’m not sure if I have a configuration issue or a hardware one. I tried more than one level shifter, and I’m getting 5V on the HV side and approx 3.3v on the LV side. Sometimes the TX pin coming from the A/C is low (like 2v) but I’m guessing that’s normal when checking a UART pin with a multimeter?

I also tried putting the Midea dongle back in to make sure it wasn’t an issue with the a/c itself but it seems to be fine, and I also tried more than one A/C (I have 3). Not sure what’s going on here and I’m hoping someone might have some insight.

paddy0174 · May 9, 2021, 4:13pm

As suggested in the Telegram group, change RX and TX (physically). That should solve the problem.

If not, please report back.

BakaMonogatari · May 9, 2021, 4:28pm

I think I forgot to mention, but yes I’ve tried it both ways.

iamvlanone · May 9, 2021, 4:42pm

I had the same issue and swopping resolved it. After the tx query you should get an rx frame. Check all connections. I had a bad crimp. Check continuity on all cables to the AC?

paddy0174 · May 9, 2021, 4:52pm

Please show a picture of your connection to the A/C (to see the cable colors and how/where the are connected). Like the other end of the cable from the pic above.

EDIT: and the complete yaml from ESPHome.

BakaMonogatari · May 9, 2021, 5:03pm

The other end is just a USB cable (it’s one of the window units that uses a regular USB female) but I removed the electrical tape so you can see which wire is soldered to what.

The YAML file is here:

esphome:
  name: mideatest1
  platform: ESP32
  board: featheresp32

wifi:
  ssid: "NERV24"
  password: "[redacted]"

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Mideatest1 Fallback Hotspot"
    password: "DLlwng3yji0R"

captive_portal:


# Enable Home Assistant API
api:

ota:

# Example configuration entry

# Disable logging over UART (required)
logger:


# UART settings for Midea dongle (required)
uart:
  tx_pin: GPIO17
  rx_pin: GPIO16
  baud_rate: 9600

# Optional (if you want modify settings)
midea_dongle:
  strength_icon: true

# Main settings
climate:
  - platform: midea_ac
    name: "My Midea AC"
    visual:
      min_temperature: 18 °C
      max_temperature: 25 °C
      temperature_step: 0.1 °C
    beeper: false
    swing_horizontal: true
    swing_both: true
    outdoor_temperature:
      name: "Temp"
    power_usage:
      name: "Power"
    humidity_setpoint:
      name: "Hum"

paddy0174 · May 9, 2021, 5:09pm

You have to disable the logger component:

logger:
  baud_rate: 0

BakaMonogatari · May 9, 2021, 5:21pm

Ok just tried that. Same thing.

paddy0174 · May 9, 2021, 5:27pm

The logger baud rate set to zero is necessary, so leave it in.

Now change TX/RX

I know, tedious, but with the logger enabled it can’t work, so we have to disable the logger and start again with all the other possible things.

When you changed that, what is the output in ESPHome (the pic you already took)?

~~EDIT: Wait, are you sure, that is a feather board? It looks way more like a NodeMCU…~~

BakaMonogatari · May 9, 2021, 5:43pm

Ok tried switching TX/RX again. Same thing. The output in ESPhome is the same as the pic I took earlier.

Just out of curiosity, would connecting TX/RX of the ESP32 together (doing this on the bench, disconnected from the A/C entirely) be a valid loopback test? Because I just tried it and I’m seeing this sporadically:

[13:41:41][D][midea_dongle:094]: TX: AA 22 AC 00 00 00 00 00 03 03 41 00 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 84 68 
[13:41:42][D][midea_dongle:029]: RX: AA 20 02 05 45 44 68 69 41 49 A8 04 44 2B B3 BE 81 A1 52 45 95 35 B3 0A 91 98 52 35 49 4B 0B 60 91 
[13:41:42][W][midea_dongle:031]: RX: frame check failed!

Even though it’s not repeating back every single TX string can I at least assume the ESP32 as it’s configured is capable of receiving?

BakaMonogatari · May 9, 2021, 11:35pm

Ok loopback test is working fine. Verified that TX/RX pins on the Feather map to GPIO16 and 17. I also ran the loopback through level shifter and it’s working fine there too. Not sure what the problem is at this point. I ordered an oscilloscope from Amazon and it should be here tomorrow.

BakaMonogatari · May 12, 2021, 2:50am

Ok it works! Turns out the issue was the Adafruit TXB0104 based level shifter I was using. Either they were defective (I tried two!) or they don’t work for this application for reasons I don’t understand yet. I actually needed to buy an oscilloscope to figure this out. Fortunately I was able to pick up a Sparkfun converter at Microcenter and it works like a charm. So just some caution for anyone who used the Adafruit converter and ends up having the same problem.

paddy0174 · May 12, 2021, 11:03am

If your time permits, you could ask Adafruit for a statement? It would be interesting to know why this level shifter isn’t working as expected.

But it’s nice to see, how you figured it out (I followed your experiments on Telegram).

erdek · May 14, 2021, 10:00pm

The display is extremely bright and annoying, so we still need the remote on our nightstand to turn it off. Or we have to disable the display more permanently
Would it be possible to use the ESP to send the IR code to disable the display, by connecting an IR LED to it and point towards the IR receiver internally? Did anyone manage to decipher the IR data yet?

aceindy · May 15, 2021, 6:20am

So far it seems the display dimmer is IR only and not t controllable over uart.

Some people have started developing it, but not sure what the status is…

nvschilleman · May 15, 2021, 10:26pm

Yes that is possible. I made a dongle using a Wemos D1 with an IR Led.

On this photo the Wemos is not soldered in place yet:

This is my config:

esphome:
  name: esp_hvac_skr
  platform: ESP8266
  board: nodemcuv2

wifi:
  ssid: "xxxxxxxxxxxxxx"
  password: "xxxxxxxxxx"

  ap:
    ssid: "xxxxxxxxxxxxxx"
    password: "xxxxxxxxxxxxx"

captive_portal:

# Enable logging
logger:
  baud_rate: 0

api:

ota:

uart:
 tx_pin: TX
 rx_pin: RX
 baud_rate: 9600

midea_dongle:

climate:
 - platform: midea_ac
   name: "Slaapkamer"
   beeper: false

remote_transmitter:
  pin: D7
  carrier_duty_percent: 50%
  
switch:
  - platform: template
    name: "Display toggle"
    turn_on_action:
       - remote_transmitter.transmit_raw:
            carrier_frequency: 38kHz
            code: [  4390, -4371, 572, -1573, 548, -525, 570, -1575, 547, -1598, 547, -525, 573, -1570, 574, -500, 547, -1598, 551, -520, 549, -1597, 572, -498, 549, -524, 547, -1597, 572, -500, 550, -1596, 571, -500, 574, -1571, 572, -1574, 548, -1597, 546, 
                     -1598, 548, -523, 549, -1596, 572, -499, 573, -1571, 573, -500, 570, -501, 548, -524, 573, -500, 572, -1572, 548, -524, 549, -1597, 547, -523, 572, -1573, 572, -499, 548, -1596, 550, -522, 578, -495, 548, -1596, 571, -499, 549, -1598, 548, -523, 549, 
                     -1595, 571, -500, 549, -1596, 548, -1597, 548, -523, 574, -1571, 549, -523, 572, -5157, 4390, -4368, 548, -1596, 550, -521, 574, -1571, 572, -1573, 547, -525, 548, -1595, 549, -523, 550, -1594, 549, -524, 549, -1595, 548, -523, 550, -523, 548, -1596, 
                     548, -523, 550, -1595, 547, -524, 549, -1595, 549, -1595, 550, -1595, 549, -1598, 546, -524, 548, -1595, 549, -523, 548, -1598, 547, -522, 550, -523, 551, -520, 550, -522, 550, -1595, 549, -522, 551, -1596, 572, -499, 547, -1596, 548, -524, 549, -1596, 
                     548, -523, 550, -523, 571, -1574, 547, -523, 549, -1596, 548, -523, 549, -1597, 547, -523, 550, -1594, 574, -1572, 549, -522, 549, -1596, 549, -522, 550]

erdek · May 16, 2021, 7:20am

Cool Noël! Many thanks.
Been lurking other forums but did not find a proper solution yet. Time to order a IR LED and check this out

nvschilleman · May 16, 2021, 6:05pm

You’re welcome! You’ll also need a transistor and a resistor. I used the diagram from this page:

I did not add the IR Receiver to my dongle, but a receiver can be useful for sniffing IR commands from the remote.

erdek · May 16, 2021, 7:15pm

Hi, I assumed a transistor was necessary, so thanks for the schematics. Just dismantled an old IR blaster so I don’t need to order a LED. I must have some transistors lying around also, not the one mentioned in the linked GitHub page, but a simple BC547B should do the trick also. And otherwise I’ll just dismantle an old IR remote, there should be a suitable IR LED and transistor to salvage from that.

nvschilleman · May 16, 2021, 7:18pm

I used a BC549C, also works fine