Xiaomi’s ultra-affordable Bluetooth temperature sensor can be easily flashed with the ATC custom firmware using your phone’s web browser to allow for customization.
Once flashed, just follow the ESPHome instructions to use an ESP32 board and bridge this data into your Home Assistant instance.
Uses one CR2032 coin cell battery (included)
Stephen O (verified owner) –
While it isn’t required, I actually flashed alternative firmware on these little guys found here:
https://github.com/pvvx/ATC_MiThermometer
I used ESPHome with an ESP32 in order to have 3 of these devices report back into home assistant.
They are smaller than I expected. I have about 8 days worth of data now. Extrapolating that out at current burn, the battery will last somewhere between 45-50 days
Jay –
I also use the newer firmware based on ATC. They have been running for nearly a year, and have had to replace only 2 batteries out of 15, so far.
T (verified owner) –
I bought 3 of these and flashed them to use with ESPhome. Its been about 3 months and they still work perfectly. My only complaint is that I wish they displayed in F, but that’s not a CloudFree issue. Keep up the good work!
Kenny Stier –
Connect to them using the TelinkMiFlasher page, there is an option to change the unit to Fahrenheit.
https://pvvx.github.io/ATC_MiThermometer/TelinkMiFlasher.html
Mike Reish (verified owner) –
These are much less expensive than the Tuya an AliexpressI was looking at. However, I was a little concerned about having to flash them. I just couldn’t resist the price so I bought a bunch of these along with an ESP32. Turning the ESP32 into a BT Proxy was super easy. Flashing these with the link provided in the description was almost as easy. I’m glad I bought these from a guy just a couple state away than Aliexpress.
A+. Will buy from again.
Steve Mendoza (verified owner) –
I purchased the Xiaomi Mijia Bluetooth Temperature and Humidity Sensor from cloudfree.shop back in 2021, and I must say that this little gadget has exceeded my expectations in terms of reliability. Although I haven’t conducted a formal accuracy test, I’ve found that the stability and battery life of these sensors is outstanding.