Xiaomi Mijia LYWSD03MMC

I use three Xiaomi LYWSD03MMC - combined thermo and humidity meter via Bluetooth. Setup is a tiny bit cumbersome but at $4 a pop, it was a no brainer. The integration is in HACS: https://github.com/custom-components/sensor.mitemp_bt I had the Sonoff th10 but the sensor is a wired addon and it stopped working for me.

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

Xiaomi Mi sensors. LYWSD03MMC They are like $5 each and with the BLE Module it’s super easy to set up https://hackaday.com/2020/11/17/custom-firmware-for-cheap-bluetooth-thermometers/ https://blog.quindorian.org/2020/10/4-xiaomi-temperature-sensor-for-home-assistant.html/ https://github.com/custom-components/ble_monitor

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

I am currently using both BLE and zigbee thermo/hygrometers at home, so here are my experiences. For BLE I am using about 6 Xiaomi Mi thermometers (LYWSD03MMC) with custom firmware and single esp32 for getting the data to esphome/homeassistant. More info: ESPHome Xiaomi BLE. You can get one of those way under 10$. Big advantage i see in these sensors is the display to have the info visible without looking into HA. As for update times, those are rather random, but always below 5 minutes. Single battery should last for about 1 year and so far it seems that way. For places where I dont need to …

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

The problem Just updated from 2023.3.2 to 2023.3.3 and all of my BT Home based temperature sensors are now unavailable. They are Xiomi LYWSD03MMC flashed with the ATC firmware and were previously working without any issues. I've tried restarting but they're all still unavailable. There's also nothing in the logs about them. ### What version of Home Assistant Core has the issue? 2023.3.3 ### What was the last working version of Home Assistant Core? 2023.3.2 ### What type of installation are you running? Home Assistant Container ### Integration causing the issue BT Home ### Link to integration …

Excerpt saved from GitHub on 2026-10-23.

Als het een lywsd03mmc is, dan zou je die kunnen flashen met ATC flasher naar standaard BThome of Zigbee. Ook voor ZTH05 is dit mogelijk.

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

I switched over to a BLE setup from aqara zigbee. https://esphome.io/components/sensor/xiaomi\_ble.html I use Xiaomi Mijia Sensors ### LYWSD03MMC¶ Absolutely reliable. I get 1 value per minute and i can read the temperature from the lcd display. The custom FW (not even mandatory) can be flashed with your browser and then i have just two ESP32 with ESPHome well placed to collect the BLE data.

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

Zigbee: * Third Reality * Xiaomi Mijia LYWSD03MMC flashed with custom firmware * BLE: * Xiaomi Mijia LYWSD03MMC * Switchbot Meter Plus Govee H5075 * rtl\_433: * Acurite 06044M

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

LYWSD03MMCs have a \~2yr battery life with pvvx firmware (including native HA support via BTHome), yes it's BLE but it's solid as a rock.

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

Tbh I have a ton of the xiaomi Bluetooth thermometers. They're about four to $5 a piece, and you can easily reflash them with zigbee support if you want. You get a little LCD screen with them, and you can switch them to use double A's instead if you want. But just reflashing the firmware increases their battery life If you look for the choice shipping on AliExpress it's significantly faster.

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

Xiaomi Mijia LYWSD03MMC BLE Temperature/Humidity sensors running the ATC\_MiThermometer firmware with BTHome. They have increased a bit in price over the last year or so, but can still be had for about $6 a piece when purchased in 5 packs

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.

DHTs aren't very accurate BUT if all you care about is trends they work just fine. I have Xiaomi LYWSD03MMC distributed around the house running BLE. They work fine and have a display so anyone can see the temp.

Excerpt saved from the Arctic Shift Reddit archive on 2026-10-23.