How to Open the Xiaomi Temperature Sensor: Instructions with Photos and Videos

Xiaomi’s temperature sensors are some of the most popular smart home devices due to their accuracy, compactness and integration with the Mi Home ecosystem. However, sometimes users need to disassemble them to replace the battery, repair after a fall or modification of the firmware. In this article, we will detail how to safely open the sensor case without damage, what tools you will need and what to look for when working with different models from the classic Mijia Bluetooth Temperature and Humidity Sensor to the Aqara TVOC Air Quality Monitor.

It's important to understand that disassembling the sensor removes warranty (if it's still valid) and can lead to failure if you're not doing it properly. We've collected proven methods from power users and service centers, and we've added unique tips for adhesives and fragile boards that aren't in the standard instructions. If you've never taken electronics apart, start by watching the video guides at the end of this article.

What Xiaomi sensor models can be disassembled independently

Not all Xiaomi temperature sensors are disassemblable at home, and here is a list of models that can be opened without specialized equipment:

• 📱 Xiaomi Mijia Bluetooth Temperature and Humidity Sensor (LYWSD03MMC) — The most common version with a round body and battery CR2032.
• 🌡️ Xiaomi Mijia Bluetooth Temperature and Humidity Sensor 2 (LYWSD02) — rectangular body, is more difficult to understand due to glue latches.
• 🏠 Aqara Temperature and Humidity Sensor (WSDCGQ11LM) — compatible with Apple HomeKit, the case is mounted on 4 latches.
• ☁️ Xiaomi ClearGrass Temperature and Humidity Sensor (CGDK2) — budget model with minimalistic design, disassembled by a screwdriver.

These models are not recommended to be disassembled by yourself:

• ⚠️ Aqara TVOC Air Quality Monitor - sealed case with gas sensors, disassembly can disrupt calibration.
• ⚠️ Xiaomi Mi Temperature and Humidity Sensor Pro – uses ultrasonic welding of the body.

If your model is not on the list, check it for compatibility on the official Mi Home website or in the Aqara catalog. Rare devices may require a soldering iron or a special tool to open iFixit Opening Picks.

Preparation for disassembly: tools and security measures

Before you start opening the case, prepare the workspace and tools.

• 🔧 Plastic mediators or blades (e.g. iFixit Opening Tools) – to disconnect latches without scratches.
• 🔥 Dryer or thermo-air station - if the body is glued (temperature 60-80)°C will soften the glue).
• ⚡ Multimeter – to check the battery voltage before replacing.
• 📸 Smartphone with macro lens – to photograph the location of parts before disassembly.
• 🧲 Magnetic mat or container – for storing small screws and parts.

Security measures:

• 🔌 Disconnect the sensor from the Mi app Home/Aqara before disassembly to avoid false positives.
• 🧤 Work in antistatic gloves – static electricity can damage the board.
• 🚫 Do not use metal screwdrivers for opening – they leave scratches and can close contacts.

⚠️ Warning: If the sensor has fallen into water or been exposed to high humidity, dry it in rice or silica gel for at least 24 hours before disassembly. Otherwise, the risk of short circuit at opening increases by 3 times.

Take a picture of the body from all sides |

Disable the sensor from the Mi Home/Aqara| app

Prepare an antistatic surface |

Check the battery charge with a multimeter (if possible)|

Wear protective glasses (when working with a hair dryer)-->

Step-by-step: how to open the sensor Xiaomi Mijia LYWSD03MMC

This is the most popular model among users, so let's start with this one: the sensor body consists of two parts, held together by latches and glue.

1. Heat the case. Turn on the dryer at minimum power (60-70 °C) and evenly warm the body around the perimeter for 1-2 minutes. This will soften the glue. Don't overheat - temperatures above 80 °C can damage the board.
2. Latches disconnect. Insert a plastic mediator into the gap between the top and bottom of the case (start on the side where there is no reset button). Carefully guide the mediator around until you hear the flicks of the latches.
3. Remove the top cover. Once all the latches are snapped, lift the top of the body. If it doesn't respond, dryer the problem area again.
4. Removing the board. Carefully pull out the board with the sensors, holding it by the edges. Don't touch the contacts with your fingers, it can disrupt calibration.

Inside you'll see:

• 🔋 Battery CR2032 (substitute CR2032 3V brand).
• 📡 Bluetooth antenna (don't rot it!).
• 🌡️ Temperature and humidity sensor SHT30 or SHT31.

Build: Set the board back by matching the battery contacts with springs. Close the case by pressing it until the snap of the latch. If the case wobbles, use the B-7000 glue to seal (ply it with a thin layer!).

Features of disassembling sensors Aqara and ClearGrass

Aqara and ClearGrass have other types of mounts, and let's take a closer look at them.

For Aqara WSDCGQ11LM:

1. Warm up the body with a hairdryer (as in the instructions for Mijia).
2. Insert the mediator in the slot next to the Aqara logo and gently separate the halves.
3. Pay attention to the spring contact of the battery - it often falls out during disassembly.

For ClearGrass CGDK2:

1. Turn the sensor over and unscrew the 2 screws on the back cover (they are hidden under the sticker).
2. Remove the lid – inside you will see a CR2450 battery and a board with a SHT31 sensor.
3. When assembly, do not pull the screws - this can deform the body.

⚠️ Attention: Aqara sensors often use double-sided tape to fix the board. When disassembling, don't pull the board upwards, first tuck it in the side with a mediator so you don't tear the contacts off.

Frequent Mistakes and How to Avoid Them

Even experienced users sometimes make mistakes when disassembling sensors, and here are the most common ones and ways to prevent them:

• 🔥 Overheating of the body with a hairdryer, if the temperature exceeds 90°C, the plastic will warp and the glue will harden. Use a thermometer or hold a hair dryer 10 cm away.
• 🔧 It's a Bluetooth antenna that's located along the body -- don't rot when you remove the board. If the antenna's gone, you can solder it back in a thin solder.
• 🔋 Install the battery with a dead battery. Check the voltage with a multimeter: if it is lower 2.7V, The sensor will show incorrect data.
• 📱 Non-polarity of the battery. The board usually has a marking. + And, if you don't have one, take a picture of the old battery.

If the sensor is not synchronized with the application after assembly, try:

1. Remove it from Mi Home/Aqara and add it again.
2. Update the application firmware to the latest version.
3. Reset the sensor to factory settings (if there is a Reset button).

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If the sensor shows the wrong temperature after disassembly, place it for 12 hours in a stable environment (for example, next to the thermometer in the room), this will help recalibrate the sensor.

Modifications and upgrades: what can be done after disassembly

And by disassembling the sensor, you can not only replace the battery, but also improve its functionality. Here are some popular modifications:

• 🔋 Install the battery instead of the battery, for this you need to solder the holder for the battery 18650 or 10440 and add a charging circuit (for example, TP4056). This will eliminate the need to change the battery once every 1-2 years.
• 📡 Increase Bluetooth range. You can replace the regular antenna with a more powerful one (for example, from an old router) or solder the signal amplifier.
• 🌡️ Replace the humidity sensor if the original sensor SHT30 It is out of order and can be replaced by SHT31 or BME280 (I'll need a reflash).
• 🖥️ Custom software firmware. With ESPHome or Tasmota, you can make the sensor compatible with Home Assistant or Google Home.

The firmware will require:

1. Connect the board to the programmer (for example, USB-to-TTL) according to the scheme:
2. Download firmware from GitHub (for example, ATC_MiThermometer for LYWSD03MMC).
3. Fill firmware through esptool or PlatformIO.

⚠️ Attention: Firmware unofficial software can lead to loss of compatibility with Mi Home and disruption of sensors. Before firmware make backup of the original firmware command: esptool.py -p /dev/ttyUSB0 read_flash 0x00000 0x100000 backup.bin

Alternatives: When the Disassembly is Not Needed

Sometimes the purpose of disassembly can be achieved without opening the hull.

• 🔋 Replace the battery without disassembling. In some models (e.g. ClearGrass) CGDK2) The battery compartment cover opens without full disassembly - it is enough to poke it with a nail or mediator.
• 📱 Reset your settings through the app. If the sensor is buggy, try removing it from Mi Home and adding it again. To do this, click on the app: Profile → Devices → [Select a sensor] → Delete.
• 🔄 Update of firmware over the air (OTA). Go to the sensor settings → Update (if the option is available).
• 🧲 Calibration without disassembly. Place the sensor next to the reference thermometer for 24 hours, many models will automatically adjust to the surrounding conditions.

If your goal is to verify the accuracy of readings, compare the sensor data with a professional thermohygrometer (for example, Xiaomi Mijia). THS01). The difference ±1°C and ±5% of humidity is considered normal.

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Always check before disassembling if you can solve the problem software, and in 30% of cases, resetting or updating the firmware fixes the problem without risking damage to the device.

FAQ: Answers to Frequent Questions