ESPHome for various Xiaomi Air Purification Devices

For a step-by-step guide with pictures visit this thread on the official home assistant forum.

There are two separate microcontrollers inside the device: one STM32F4 which actually controls the device, and one ESP32 which only acts as a gateway to the internet/local network. This config replaces the firmware running on the ESP32 and implements the MIoT protocol used to communicate with the STM32.

Features:

• turning the purifier on/off
• exposing PM2.5, humidity, temperature, and remaining filter life as sensor values
• switching modes
• controlling speed in manual mode
• changing various settings (display brightness, beeper, lock)
• sending custom commands using the esphome.mipurifier_send_command service (e.g. sending down set_properties 5 1 false disables beeping)

FAQ

Does this remove the Filter remaining 0% warning?

Flashing this firmware does NOT change anything about how the remaining filter life is read/managed. However you can easily reset your filter to continue using it by following this video for example.

Is my air purifier supported?

The following devices are known to work with this library (this list is not exhaustive)

• Air Purifier 3 (2019) (zhimi.airpurifier.ma4)
• Air Purifier 3H (2019) (zhimi.airpurifier.mb3)
• Air Purifier Pro H (AC-M13-SC)

Please don't hesitate to expand this list by opening a pull request if your device also works with this library! Make sure to backup the original firmware on your device's ESP32 before flashing ESPHome.

Flashing

For a step-by-step guide with pictures visit this thread on the official home assistant forum.

Connect any USB-to-serial adapter and power on the ESP32 while GPIO0 and GPIO2 are pulled low.

The following steps have been tested with the AC-M6-B01 Board (REV3-BDR) by using the ESPHome Add-on within Home Assistant:

• Prepare an usb-to-serial adapter (a CP2102 chip has been used here) by installing the required drivers on the computer you will flash the board
• Pull GPIO0 low by bridging soldering spot 1 (GPIO0) and 2 (GND)
  • No need to solder here if you have a wire that fits more or less tight into the soldering spot
• Pull GPIO2 low by connecting Pin 24 (GPIO2) to GND (e.g., Pin 15, spot 1, or spot 2)
• Open Home Assistant on any client machine via Web Browser using https
  • A Windows 10 client was used here while Home Assistant was running on a different machine
  • Your browser must support WebSerial to flash from a different client than the ESPHome Server. Chrome do support WebSerial.
• Open the ESPHome Web Interface
  • If not done before, enter your Wi-Fi settings in secrets.yaml
• Select "NEW DEVICE"
• Name your device, e.g. with "Air Purifier Livingroom"
• Select the device type, ESP32 in this case
• Do not install the device in the next step, instead, press Skip
• Use "EDIT" on the device tile to overwrite the device settings with the content of mipurifier.yaml
• Copy the mipurifier.h file into the same directory where the .yaml (Air-Purifier-Livingroom.yaml if you have named the device as written above) file is located
  • Default path is /Config/esphome/.
• Connect the usb-to-serial adapter with the board as shown on the image below
• Plug in the usb-to-serial adapter on the client machine
  • The board will beep two times on powering up
  • If it does not - you may need to power it externally as the USB/TTL adapter may not be powerful enough (IMPORTANT: first disconnect VCC from the USB/TTL adapter)
• Use "Install" on the device tile within the 3 dots and select "Plug into this computer" and follow the further instructions
• After the install process has been finished, detach the usb-to-serial adapter from the client
• Remove the bridges both for GPIO0 and GPIO2
• Reassemble your Purifier
• Power on the device
• Wait for the device to connect to your WiFi
• Test the device by using the control panel in Home Assistant

Typical problems:

• ESPHome is unable to find the usb-to-serial adapter
  • Make sure that you have installed the latest drivers for the adapter matching your client OS
• ESPHome is unable to connect to the AC-M6-B01 board
  • Check all connections between the adapter and the board
  • Exchange RX and TX if the problem remains
• Compiling/Installing takes a very long time
  • Compiling on an Raspi 4 might take more than 10 minutes
  • If this step takes more time, you can try to restart the ESPHome AddOn and restart the install process
• The device will not join your WiFi
  • Make sure that your router allows new unknown devices to join
  • Power off the device and power on the device again