How to reset the sensor temperature and humidity Xiaomi: all the ways and nuances

Xiaomi’s temperature and humidity sensors are some of the most popular smart home devices due to their accuracy, compactness and integration with the Mi Home ecosystem. However, even such reliable gadgets sometimes start to lie: they show inflated humidity, “hung” temperature or stop synchronizing with the application. In 80% of cases, resetting the sensor to the factory settings solves the problem, but there are nuances here – not all models support “soft” reset, and some require complete flashing.

In this article, we will analyze all working methods of resetting for different models of Xiaomi sensors (LYWSD03MMC, LYWSD02, Mijia Bluetooth, etc.), including software methods through Mi Home and hardware methods using a button or contacts on the board, and also find out when a reset is really necessary, and when the problem lies in the settings of the phone or router. If your sensor “gluts” after updating the firmware or changing the battery – here you will find a solution.

When you need to reset the sensor Xiaomi: symptoms and causes

Before you drop the device, make sure that the problem is not due to external factors, for example, inflated humidity can be real - if the sensor is installed next to the aquarium, bathroom or houseplants, and "hang" temperature is often the result of poor contact of the battery or its discharge.

• 🔋 Battery charge: even if the indicator in the Mi Home is 100%, physical contact may have been disrupted.
• 📶 Bluetooth signal: sensor must be within a 10-15-meter radius of a gateway (Xiaomi Gateway) or smartphone.
• 📱 App version: Older versions of Mi Home (up to 6.0) had data display bugs. Update the app via Google Play or App Store.

If external factors are excluded and the sensor is still:

• 🌡️ Shows the same temperature for several days in a row (for example, +23°C regardless of the actual conditions).
• 💧 Displays humidity of 0% or 100% under normal indoor conditions.
• ⚠️ Mi Home: Error "Device disabled" or "No data".
• 🔄 Not synced with the gateway after changing Wi-Fi or moving.

— So, it needs to be reset. Exception: the series of sensors. LYWSD03MMC firmware ATC (Custom) can only be “discharged” through the terminal – more on this below.

Method 1: Software reset via Mi Home

The easiest method is to reset the settings directly in the official app, and it works for most models, except for sensors with custom firmware (ATC, PVVX). Instructions:

1. Open Mi Home and go to the Devices tab.
2. Find your sensor in the list and tap it.
3. In the upper right corner, press on ⋮ → Settings of the device.
4. Scroll down and select Remove Device (or Reset Settings if there is one).
5. Confirm the action – the sensor will “forget” all settings and disconnect from the account.

After that, the device will appear in the Add Device as New list. Importantly, if the sensor doesn't appear in the Add-on list, try:

• 🔄 Reboot your smartphone – sometimes the app doesn’t see the device because of the cache.
• 📱 Change the region in Mi Home to China (Mainland China) – some models require this to work properly.
• 🛠️ Update the gateway firmware (Xiaomi Gateway) if the sensor is connected through it.

⚠️ Note: If the sensor is connected via Apple HomeKit or Google Home, resetting to Mi Home may disrupt integration, in which case remove the device from third-party ecosystems first, and then reset it.

Method 2: Hardware button reset (for models with a physical button)

Some Xiaomi sensors (e.g. Mijia Bluetooth Temperature & Humidity Sensor) LYWSD02) They have a hidden reset button on the body:

• 🔘 Tactile – a small button under a rubber plug (pressed by a paper clip).
• 🔄 Touch – the area on the back panel that you need to hold your finger for 5-10 seconds.

Reset algorithm:

1. Remove the battery from the sensor.
2. Find the reset button (usually signed) RESET or dotted).
3. Insert the battery back and hold the button for 10-15 seconds until the indicator (if any) blinks 3 times.
4. Release the button – the sensor will reboot and be ready for a new setup.

If there is no button, try an alternative method:

1. Remove the battery for 30 seconds.
2. Insert it back and immediately start holding the touch area (usually next to the Mi logo).
3. Hold it until the indicator flashes red (reset signal).

⚠️ Attention: On sensors with custom firmware (for example, ATC or PVVX) hardware reset can lead to "bricking" - the device will stop turning on. USB-TTL adapter.

Method 3: Reset sensors with custom firmware (ATC, PVVX)

Sensors. LYWSD03MMC firmware ATC (They don't support standard reset, they have two options:

1. Mild reset via commands (if the sensor responds):

Connect to the sensor via Bluetooth (for example, via Termite or nRF Connect)

Send a team:



{"reset":1}



The sensor will reset and reset settings (except calibration).

1. Hard reset via contacts (if sensor does not respond):

It will require:

• 🔧 Screwdriver to open the body.
• 🔌 Connection-closing wires (or tweezers).
• 💻 USB-TTL adapter (e.g, CP2102) for re-flashing, if the reset does not help.

Instructions:

1. Remove the back cover of the sensor (carefully so as not to damage the seal!).
2. Find contacts on the board RST (or RES) and GND (usually signed).
3. Close them for 3-5 seconds with tweezers or wire.
4. The sensor needs to reset (the indicator will blink), if not, repeat the procedure.

Important: After a hard reset, the sensor will lose all calibration data. If you did not save it in advance (via the command {"calibrate":?}), you will have to calibrate again using a reference (for example, a Xiaomi Mijia hygrometer or a professional device).

Method 4: Reset via Xiaomi Gateway (for Zigbee sensors)

If your sensor is connected to your smart home via the Xiaomi Gateway, you can reset it without directly accessing the device, a technique that works for Zigbee sensors (like the Aqara Temperature Sensor), but sometimes helps for Bluetooth models if they are tied to the gateway.

Instructions:

1. Open Mi Home and go to the Xiaomi Gateway settings.
2. Select Connected Device Management.
3. Find your sensor in the list and tap it.
4. Click Remove the device (or Reset if there is such a item).
5. Confirm the action - the gateway will send the team to reset.

If the sensor does not appear in the list for re-addition:

• 🔄 Reboot the gateway (turn off power for 30 seconds).
• 📡 Check the distance – the sensor should be within a radius of 10 meters from the gateway.
• 🛠️ Update the gateway firmware through Settings → Update of the PO.

💡

If the sensor does not connect to the gateway after reset, try adding it in "Other Zigbee Sensor" mode (manual). To do this, select Add the device in Mi Home → Zigbee → Manually and specify the model.

Frequent Resetting Mistakes and How to Avoid Them

Even following the instructions, users often encounter problems.-5 mistakes and their solutions:

1. Sensor not reset via Mi Home Reason: The device is tied to another account (e.g. if you bought a used one). Solution: Try resetting with a hardware button or through the gateway. If it doesn't work, contact the previous owner to remove the sensor from your account.
2. After resetting the sensor does not turn on the Reason: Flowed firmware (relevant for custom firmware) ATC/PVVX). Solution: Flip the sensor again via esphome or Tasmota (instructions are available on GitHub).
3. The sensor is reset but again shows incorrect data Reason: Calibration is broken (for example, after changing the battery or falling). Solution: Calibrate the sensor using a reference (see section below).

Another common problem is that the sensor resets, but it doesn't connect to the Mi Home.

• 📱 Check that Bluetooth and geolocation are enabled in the phone settings (needed to search for devices).
• 🌐 Make sure the phone and sensor are on the same Wi-Fi network (for Wi-Fi models).
• 🔄 Restart your router – sometimes it blocks new devices from connecting.

💡

If the sensor is unstable after reset (for example, periodically shuts down), check the firmware version through the command {"version":1}. Outdated versions may conflict with new versions of the Mi Home.

Calibration of the sensor after reset: how to return accuracy

Resetting settings resets all calibration data, so after the procedure, the sensor can show temperature and humidity with an error. ±2–5°. To return accuracy, perform calibration:

Method 1: Through commands (for firmware) ATC/PVVX)

Example of temperature calibration command (indicate the difference in degrees)


{"temp_calib":-1.5}




For humidity (specify the difference in %)



{"hum_calib":+5}

Method 2: Manual calibration with reference

1. Place the sensor next to the reference instrument (e.g. Xiaomi Mijia Hygrometer or Netatmo weather station).
2. Wait 30 minutes, the readings should stabilize.
3. Compare the data. If the difference is greater ±1°, Calibrate the sensor through commands (see above).

For models without command support (e.g, LYWSD02) Calibration is possible only programmatically - through adjustment in Mi Home:

1. Open the sensor settings in the application.
2. Select Calibration (if there is such a point).
3. Specify the correction for temperature and humidity.

⚠️ Warning: If the sensor after calibration shows humidity above 100% or temperature below -40°C, so there's a bug in the teams. Reset the settings and recalibrate with lower correction values.

FAQ: Answers to Frequent Questions