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mitsubishi2MQTT ESP8266/ESP32 module to control Mitsubishi Electric HVAC unit. Support control with Home Assistant, buit-in web app and MQTT.

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Screenshots:

Main Control Config
Init Unit Status

Features:

  • Initial config: WIFI AP mode and web portal
  • Web interface for configuration, status and control, firmware upgrade
  • Homeassistant autodiscovery and control with MQTT
  • Control with MQTT
  • Web server can be disable/enable after MQTT connected
  • Multilanguages, user can change in SETUP->UNIT or choose in initial setup

Supported Mitsubishi Electrict Units

Basically, if the unit has a CN105 header on the main board, it should work. The HeatPump wiki has a long confirmed list.

The same CN105 connector is used by the Mitsubishi KumoCloud remotes, which have a compatibility list available.

The software and hardware has been tested by the author for 5 years on the following units:

  • MSZ-HL25VA
  • MSZ-GE25VA
  • MSY-GM24VA

Demo Circuit

This circuit using by the author (ESP8266), here is some boards before install. More pictures in hardware folder.

You can also use ESP32 (including ESP32-S2, ESP32-S3 and ESP32-C3) module for more processing power:

  • ESP32 by default app use UART0 (TX - GPIO 1, RX - GPIO 3)
  • ESP32-S2 by default app use UART0 (TX - GPIO 43, RX - GPIO 44)
  • ESP32-S3 by default app use UART0 (TX - GPIO 43, RX - GPIO 44)
  • ESP32-C3 by default app use UART0 (TX - GPIO 21, RX - GPIO 20)
  • You can assign any compatible pin in the SETUP->OTHERS to use custom pin, example TX: 26, RX: 27, check ESP32 manual for pin. When TX and RX set it will use UART1 port.
  • Better not using UART0, it is default for logs and flash the chip.

Attention:

⚠️ You have to open the indoor unit to have access to the CN105 port. You should disconnected the main power before install the module. Faulty handling may cause leakage of water, electric shock or fire! ⚠️

Parts

Parts required to make a CN105 female connector

Other part suggestions

How to use:

  • Step 1: Flash the sketch with flash size include SPIFFS option.
  • Step 2: Connect to device AP with name HVAC-XXXXXXXXXXXX (XXXX... 12 character MAC address)
  • Step 3: You should be automatically redirected to the web portal or go to 192.168.4.1 or 8.8.8.8 (version later than 2025.02.08)
  • Step 4: Set Wifi information, mqtt(optional), language and save & reboot. Fall back to AP mode if WiFi connection fails (AP password sets to default SSID name from step 2).
  • Step 5: Connect to the device I with local domain: HVAC-XXXXXXXXXXXX.local
  • Step 6: (optional): Set MQTT information for use with Home Assistant
  • Step 7: (optional): Set Login password to prevent unwanted access in SETUP->ADVANCE->Login Password
  • Step 8: (optional): Turn off heat mode or quiet mode in SETUP->UNIT

Nightly builds are available for select platforms via GitHub Actions. Go to the workflow, select the latest build, then check the Artifacts section.

How to build code from source:

  • ESP IDF (Recomended): clone the project with --recursive tag: git clone https://github.com/dzungpv/mitsubishi2MQTT.git --recursive, Install ESP IDF 4.4.6 , set the target idf.py set-target esp32|esp32s2|esp32s3|esp32c3, and run command to build: idf.py build, flash to the chip with command: idf.py flash
  • Arduino: Intall require libraries (name and path in platformio.ini), rename file main.cpp in main folder to main.ino, open it and build
  • Platformio: Install, open it and choose a variant to build

How to flash pre-build bin file:

ESP32, ESP32-S2, ESP32-S3 and ESP32-C3

  • Download latest release bin file mitsubishi2MQTT_ESP32_IDF.bin.zip for ESP32 and exact it.
  • Flash mitsubishi2MQTT_ESP32_IDF.bin with esptool.py with command: esptool.py -p PORT -b 460800 --before default_reset --after no_reset --chip esp32 write_flash --flash_mode dio --flash_size keep --flash_freq 40m 0x0 mitsubishi2MQTT_ESP32_IDF.bin
  • If you do not want to install EspTool, just use EspTool web with Chrome or Edge browser here: https://espressif.github.io/esptool-js/, after connected, choose file: mitsubishi2MQTT_ESP32_IDF.bin and then enter Flash Address 0x0 and press Program.
  • With ESP32-S2, ESP32-S3 and ESP32-C3, replace ESP32 with ESP32S2, ESP32S3, ESP32C3 in file name and command above to flash it.

ESP8266:

  • Download latest release bin file mitsubishi2MQTT_WEMOS_D1_Mini.bin.zip or mitsubishi2MQTT_ESP8266-ESP01.bin and exact it.
  • Flash mitsubishi2MQTT_WEMOS_D1_Mini.bin with esptool.py with command: esptool.py -b 460800 --before default_reset --after no_reset --chip esp8266 write_flash --flash_mode dio --flash_size keep 0x0 mitsubishi2MQTT_WEMOS_D1_Mini.bin
  • If you do not want to install EspTool, just use EspTool web with Chrome or Edge browser here: https://espressif.github.io/esptool-js/, after connected, choose file: mitsubishi2MQTT_WEMOS_D1_Mini.bin and then enter Flash Address 0x0 and press Program.

MQTT topic use cases

The topic is: "mqtt_topic/mqtt_friendly_name"

  • topic/power/set OFF
  • topic/mode/set AUTO HEAT COOL DRY FAN_ONLY OFF ON
  • topic/temp/set 16-31
  • topic/remote_temp/set also called "room_temp", the implementation defined in "HeatPump" seems not work in some models
  • topic/fan/set 1-4 AUTO QUIET
  • topic/vane/set 1-5 SWING AUTO
  • topic/wide-vane/set << < | > >>
  • topic/settings (replaced by topic/state)
  • topic/state
  • topic/debug/packets
  • topic/debug/packets/set on off
  • topic/debug/logs
  • topic/debug/logs/set on off
  • topic/custom/send as example "fc 42 01 30 10 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 7b " see https://github.com/SwiCago/HeatPump/blob/master/src/HeatPump.h
  • topic/system/set to control the device with commands: "restart": reboot the device, "factory": reset device to fatory state.
  • topic/system/opt/rqt with json data to change to Web Panel option. Payloads: {"options": {"webpanel": "Off" }} or {"options": {"webpanel": "On" } }

MQTT secure connection

MQTT secure connection via 8883 port only support ESP32, app inlude default CA-Root-Certificate for Letsencrypt base domain. You can set your Certificate in the Setup -> Unit

Special thanks

SwiCago for the great libraries: https://github.com/SwiCago/HeatPump

Hadley in New Zealand. His blog post, describing baud rate and details of cn105, Raspberry Pi Python code:

https://nicegear.co.nz/blog/hacking-a-mitsubishi-heat-pump-air-conditioner/

Wayback machine link as the site no longer exists: https://web.archive.org/web/20171007190023/https://nicegear.co.nz/blog/hacking-a-mitsubishi-heat-pump-air-conditioner/

License

Licensed under the GNU Lesser General Public License. https://www.gnu.org/licenses/lgpl-3.0.txt

If you like my work and use it, give a star.

About

Mitsubishi Electric CN105 to MQTT with ESP8266/ESP32 module

Topics

mqtt arduino esp32 esp-idf hvac hvac-control cn105 esp32s2 esp32s3 esp32c3 hvac-iot mitsubishi-electric

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2025.06.15 Latest
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