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jaromeyer / mipurifier-esphome

ESPHome for the Xiaomi Mi Air Purifier 3H (and similar devices using the same protocol)
The Unlicense
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Airpurifier 2S #16

Open deify opened 10 months ago

deify commented 10 months ago

Hey, did some1 by any chance try to get this running on the 2S? Just wanted to check before I disassembled it if some1 already knows that it’s not working

BetterToAutomateTheWorld commented 9 months ago

Same question here :)

bai-yi-bai commented 6 months ago

Doesn't look promising.

I also have one of the ac-m2-aa Air Purifier 2S products which I purchased in 2016. The ESP8266 was on the market by then; I think the first commercial product I found with this device was a smart IR blaster, but the ESP32 didn't come out until years later.

I did some investigating, first by finding a disassembly video on YouTube, then I searched Aliexpress for replacement parts and came up with the PCBA ACM2-AA-B01. I found a link on a Polish language forum where a poster posted about their unit failing. The poster included very high resolution photos of the device.

Unfortunately, the design is very different from the Air Purifier 3. I should mention I took my Air Purifier 3 apart last weekend and successfully flashed it, although I always have trouble getting solder to stick to Xiaomi's black PCBs.

Back to the disassembly, there is a large RF shield covering what's underneath. The shield is stamped with "MI". I do see two sets of UART headers. The label reads: PN: TPK4023CN MODEL: MHCW01P CMIT ID: 2014DP5056

It seems the TPK4023CN was also used in a Phillips lamp which has an external STM32F030 microcontroller.

Searching for the model number, MHCW01P, took me to this page in Chinese which disassembles a Xiaomi SmartHome Hub (with Zigbee?). The poster took the shield off of a different module with part number TPK4000CN. It has a Marvell 88MC200 and 88W8801 Wi-Fi chip. According to the 88W8801's data sheet, it seems to have a USB 2.0 interface as well as an SDIO interface for transferring data. I think it's reasonable to assume that Xiaomi also likely partnered with Marvell for the 2S given the similarity of the design. I do not recall seeing a lot of hobbyist/open source enthusiasm for Marvell microcontrollers compared to Atmel's Arduino, Espressif's ESP, or the Raspberry Pi foundation.

While I'm tempted to take apart my Airpurifier 2S to de-solder the shield, I'm skeptical that there will be a hackable Wi-Fi IC underneath. I suppose someone could figure out how to de-solder the Wi-Fi IC and connect a replacement ESP32 to the "main" microcontroller, but this assumes the communication protocol which jaromeyer deciphered is the same. The particulate matter sensor is different, there's no NFC tag reader, and no display.

Alternatively, it might be possible to purchase an AC-M6-B01 replacement PCB (if I have the part number correct), replace the firmware on the ESP32 on that, and attach it inside the Airpurifier 2S... but I cannot find it on aliexpress nor on any other Chinese-language shopping site I tried.

I might sell this unit and replace it with a more hackable 3/3h.

szymucha94 commented 4 months ago

2S uses marvell mw300 which is not esphome compatible, so I guess this answers your question :P