Recently I've got this air purifier for a really cheap price on iBOOD. Since the devices are no longer produced they do not receive any software updates and the app also is quite outdated with many broken features. The device communicates only through the cloud, so if the server stops working in the future, the device can no longer be controlled wirelessly.
Because the air purifing hardware is really great for this price, I wan't to check how the device works internally and how hackable it is.
The device consists of three main parts:
- The main body which includes power supply, the fan and the air quality sensor
- The filter
- The top panel which is attached magnetically to the main body. It includes the screen and buttons to control the device
The brains of the device are located in top panel, so this is the part that I would like to look at.
On the bottom of this part we have a bunch of screws, a pogo connector that is used to get the power for this panel, control the fan and read the air quality sensor. Also there is an exposed micro USB connector which probably can be used to flash new firmware for this device.
By removing the screws we can get to the main board of the device. Easy!
The device is controlled by USI WM-N-BM-09/A microcontroller. It consists of STM32F205 MCU and a Broadcom BCM43362 for WI-Fi connectiion. Near the module is an RGB LED (LED59), antenna connector (X2), two buttons labelled RESET and SETUP. We can see another power LED in the center of the board (LED58). We will get back to it later.
This can be the touch detection chip for the four capacitive buttons at the top of the device. By searching the text from the chip I found this datasheet.
It is a 8-bit shift register. It is probably used to control the many LED's on this board.
To see the back of the main board first we need to unmount the screen. The screen according to alibaba listing that I found is a 2.4" TFT LCD with the resolution of 240x320. It can probably support RGB color, but the purifier uses only white color.
On this side we can see a LED ring, The four springs used for the capacitive touch buttons and two connectors. One of the connector is used to connect with the rest of the device using pogo pins. The second connector is unused. It can probably be used for JTAG interface.
This is a 3.3V voltage regulator. There is datasheet that I found.
It is an LED Driver. Probably used for the LED ring. And this it a datasheet for it.
When connected to USB the device identifies itself as "Photon with WiFi".
It looks like the device is created using a particle.io platform. The hardware is build on top of the Photon board. It even has the same SETUP and RESET buttons and RGB LED as the purifier's main board.
So it looks like the purifiers motherboard works, can be programmed and flashed the same as the Photon board. The purifier board also has easly accessible connector that can be used as JTAG inteface. It looks like it is entirely possible to flash your own firmware to the device and control it locally without the cloud.
So have you found a way to connect it to home assistant? I have bought this model and am looking for a work around.