Update: Easier way that does not void warranty!: Click
After a couple of nights tinkering ,PCBA designing , software writing and a couple of PCBA revisions later success: (see GIF , above)
Why:
Using these air purifiers is a wasteful and expensive experience. There are no third party filters on the market , and no options to disable the NFC check.
I wanted to use these filter cloths around my filters:
These filter cloths will extend the life of the filter by 2-3 times and will be less wasteful for the environment. These cloths can be bought for 3-4 USD for 10 Pcs.
How does it work:
By probing around on the bus (I2C) that is used by the NFC chip and the main microcontroller we could identify how these filters work. I was able to Emulate the NFC IC within an STM32 microcontroller and fooling the system that a 100% new filter is installed.
And now:
Im planning of distributing these modchips trough friends & Tindie (click).
FAQ:
Does this void the XIAOMI warranty: YES
Is it undetectable by XIAMI: YES (for now, if they are smart , and update their software they might find a workaround)
Do i lose any of the functionally when i use this modchip: NO, everything will work fine.
Is it easy to install: YES (10 screws and you are done)
Where can i find an installation manual: https://www.flamingo-tech.nl/2021/06/30/how-to-install-xiaomi-air-purifier-mod-chip-to-your-3h-3c-or-pro-device/
It’s open source: https://www.flamingo-tech.nl/2021/07/10/xiaomi-modchip-open-source/
## Compatibility list:
| Xiaomi Air Purifier: | Compatible: | Tested | Tested By |
|---|---|---|---|
| 1 | ❌ | ❌ | ❌ |
| 2S | ✔️ | ✔️ | TheFlamingo |
| 2H | ❔ | ❌ | – |
| 2C | ❔ | ❌ | – |
| 3H | ✔️ | ✔️ | tuxuser & The Flamingo |
| 3C | ❌ | ✔️ | |
| PRO | ✔️ | ✔️ | The Flamingo |
| PRO H | ❔ | ❌ | – |
| MAX | ❔ | ❌ | – |
| F1 | ❔ | ❌ | – |
❔= Untested , If you are able to verify or test , Send me an email. ✔️= Works/tested ❌= Does not work or is untested
Special Thanks to DER_T, Tuxuser and Koelie
Hi,
I own a 3C and could test it.
I live in Germany though.
Best
Hans Peter
Hey Hans Peter,
Sorry! I forgot to edit the table. The 3C was tested, but it does not have a NFC chip inside. There is a manual way to reset the filters here: https://www.flamingo-tech.nl/2021/11/21/reset-procedure-filters-xiaomi-air-purifier-3c/
Thanks for the offer :D!
Hi!
What kind of filter cloth do you use?
Best regards
Matt
Hey Matt,
checkout this link : https://nl.aliexpress.com/item/32958097736.html?
Hope that helps 🙂
Just accidently found filter reset procedures,
1. Disconnect from power, and wait couple of second’s
2. Push led brightness push button in back (Air Purifier 3H)
3. While holding button, connect power cord, and wait for beep.
4. After a while, it will boot with chinses characters on it, don’t know reali what it means and is it possible to navigate, but pushing any button, fan will kick in, and dissaperes some text from screen.
5. While in that mode, remove filter and reinsert.
6. Plug out power cord (don’t know how to exit ether..)
and after waiting for couple seconds bring back power, after it boot’s shows 100% filter capacity.
I have tried on 2 old filter cartridges, and all them are reset.. just hit that accidently.
Thank you! Confirmed working. Device itself is also reset (wifi) but thats ok.
I think the the custom firmware the 3c most needs, is one which will allow you to adjust the thresholds, at which the fan speeds will increase when in Auto mode.
Would you be willing to share your nfc methodology?
I currently can’t afford replacement filters or stickers and my girlfriend has terrible allergies
You can download the ELF file, and flash it to an STM32F103 and connect it yourself! You can just use a bluepill! Will save you the trouble of talking trough the I2C protocol.