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

---

Screenshots:

---

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
• 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, here is some boards before install.

You can also use ESP-32 module for more processing power. If using ESP-32 by default app use UART0 (TX - GPIO 1, RX - GPIO 3) You can assign any compatible pin in the SETUP->OTHERS to use custom pin, example TX: 26, RX: 27, check ESP-32 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. You can see more pictures in hardware folder.

---

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

• PAP-05V-S CONN HOUSING PA 5POS 2MM WHITE
  • Digi-Key Part Number 455-1489-ND
  • https://www.digikey.com/product-detail/en/jst-sales-america-inc/PAP-05V-S/455-1489-ND/759977
• SPHD-002T-P0.5 CONN TERM PHD CRIMP 24-28AWG TIN
  • Digi-Key Part Number 455-1313-1-ND
  • https://www.digikey.com/product-detail/en/jst-sales-america-inc/SPHD-002T-P0.5/455-1313-1-ND/608809
• JUMPER SPHD-001T-P0.5 X2 12" (pre-crimped alternative to 455-1313-1-ND connectors)
  • Digi-Key Part Number 455-3086-ND
  • https://www.digikey.co.uk/product-detail/en/jst-sales-america-inc/APAPA22K305/455-3086-ND/6009462

Other part suggestions

• Premade pigtails
  • https://m.aliexpress.com/item/1005002904897793.html select 5P option
• ESP-8266 Wemos D1 Mini
  • https://m.aliexpress.com/item/1005005121150737.htm

---

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
• 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 and run command: idf.py build
• 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

---

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
• 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.

---

---

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.