Welcome to the family Xiaomi Air Purifier H3!
If something enters my house I open it as quickly as possible and start probing around.
The following information is for educational Purposes only!
Note, I absolutely love Xiaomi stuff since it is cheap, of decent build quality, and it’s fun to probe around in!
How to disassemble the device:
The device itself is quite easy to disassemble. One of the first things that is noticeable is that a bare minimum of screws that are used. The bottom side has four, and underneath the bottom plate has another four screwed in. Almost the complete assembly is made to click-clack-badabing-badaboom and your done (my way of putting things together). Seldom I see products this well constructed with mass production in mind. The engineers at Xioami absolutely did a great job! For every product engineer on this planet: buy this device, take it apart, and learn from it!
When opening the device we find the following main board:
AC-M6-B01
REV3-BDR
Connector _pins: |
Function |
J1 |
ESP_PROG_HEADER |
-1 |
3V3 |
-2 |
GND |
-3 |
ESP-32-UART0-TX |
-4 |
ESP-32-UART0-RX |
J2 |
STM_SERIAL_DEBUG |
-1 |
STM32-RX |
-2 |
STM32-TX |
-3 |
GND |
-4 |
3V3 |
J3 |
ESP_GPIO_0_HEADER |
-1 |
ESP-32-GPIO-0 |
-2 |
GND |
J4 |
MOTOR_CONNECTOR |
-1 |
24V |
-2 |
GND |
-3 |
5V |
-4 |
PWM |
-5 |
BRK? |
-6 |
? |
-7 |
FG? |
J7 |
PLANT_POWER_CONNECTOR |
-1 |
? |
-2 |
? |
-3 |
? |
-4 |
RX |
-5 |
TX |
-6 |
SET |
-7 |
GND |
-8 |
5V |
J8 |
POWER_CONNECTOR |
-1 |
24V |
-2 |
GND |
J9 |
STM_PROGRAMMING_HEADER |
-1 |
3V3 |
-2 |
GND |
-3 |
SWDIO |
-4 |
CLK |
-5 |
SWO |
-6 |
NC? |
J10 |
NFC_HEADER |
-1 |
SDA |
-2 |
3V3 |
-3 |
STATE |
-4 |
GND |
-5 |
SCL |
J11 |
SHT_20+BUTTON_HEADER |
-1 |
SCL |
-2 |
GND |
-3 |
LED_ON |
-4 |
3V3 |
-5 |
SDA |
-6 |
? (button?) |
J12 |
DOOR_SWITCH |
-1 |
BOT_DOOR |
-2 |
GND |
J6 is the header that is used for the OLED display. I could not be bothered to probe it as I’m not trying to hack the display.
IC’s used:
| Designator | IC |
| U3 | Fremont FT24C64A |
| U4 | Espressif ESP-WROOM-32D |
| U5 | ST STM32F412RET6 |
U3 = an 64K EEPROM datasheet: Click
U4 = an Espressif wifi adapter. This IC/ Package handles all the WIFI/BLE Traffic.
U5= The main Microcontroller.
This is a good start for reverse engineering. No mysterious Chinese crap IC’s. In the following parts of this series of blog posts we will look into the contents of these chips 😀
More info on this project will be added on the project’s Github page.