Xiaomi Mijia Bluetooth Hygrothermograph: How to connect your phone in 5 minutes

Xiaomi has long been popular with smart appliances with a combination of affordable price and high quality. One of the most popular gadgets of the brand is the Mijia Bluetooth Hygrothermograph (model LYWSD03MMC or LYWSD02), which allows you to track the temperature and humidity of the air in the room with an accuracy of tenths. But many owners face difficulties when connecting the device for the first time. This article will help you understand how to synchronize the hygrometer with the phone, what applications are needed for this and what to do if the connection is not installed.

Controlling your home climate is not just a matter of comfort, it's also a matter of health. Too dry air can irritate your mucous membranes and high humidity can cause mold to develop. Mijia Hygrothermograph solves this problem by sending data directly to your smartphone. However, before you use it, the device requires the right setup. In this guide, we'll look at everything from unpacking to integrating with the smart home system, without unnecessary technical details, but with an emphasis on practical nuances.

If you have already tried to connect the hygrometer and encountered errors (for example, the device is not located or the data is not updated), do not rush to return it to the store. In 90% of cases, the problem is solved by simple actions, which we will discuss in the section "Typical errors and their elimination".

What is included and how to prepare the device for work

Before connecting, make sure you have everything you need. In the standard package Xiaomi Mijia Bluetooth Hygrothermograph you will find:

• 📦 The sensor itself (white or black plastic box with display)
• 🔋 Battery CR2032 (It is already installed, but protected by film)
• 📄 Brief instruction in Chinese/English (often without a Russian translation)
• 🧲 Magnetic stand (in some versions)

The first thing you need to do is activate the battery.

1. Turn the device over and find a small ledge on the back.
2. Tap the battery compartment cover (you can use a coin or plastic card).
3. Remove the protective film from the CR2032 battery.
4. Close the lid back - the sensor should squeak and turn on.

If after activation on the screen did not appear temperature and humidity readings, check:

• 🔋 Polarity of the battery (it should be placed "+" sideways).
• 🔄 Density of closure (sometimes contacts do not reach the battery).
• 🕒 Wait 1-2 minutes – the device needs time for the first calibration.

💡

If the sensor does not respond to activation, try to slightly press the battery through the lid - sometimes the contacts oxidize during storage.

Requirements for telephone and applications

To connect to Mijia Hygrothermograph, you will need:

• 📱 Smartphone on Android 5.0+ or iOS 10.0+.
• 📶 Bluetooth 4.0 enabled (or newer).
• 🌐 Sustainable Internet connection (for downloading applications and synchronizing data).
• 📱 Mi Home (official from Xiaomi) or Aqara Home (for some regions).

Important: the device only works with original Xiaomi applications. Third-party programs like Home Assistant or SmartThings may support the sensor, but they are not suitable for initial configuration.

You can download Mi Home at the following links:

• 🤖 Google Play for Android
• 🍎 App Store for iOS

After installation of the annex:

1. Sign up or sign in to your Xiaomi account (via Google/Facebook).
2. Choose Mainland China (if your sensor is purchased in China) or Russia (for official shipments to Russia), and the wrong choice of region can lead to the device not being available for connection!
3. Allow the app to access geodata and Bluetooth.

Step-by-step instructions for connecting

Now, to the most important thing, synchronize the sensor with the phone, follow the instructions carefully, because skipping even one step can cause a failure.

Step 1: Sensor preparation

• Make sure the hygrometer is on (the screen displays temperature and humidity).
• Bring the device to the phone at a distance of no more than 1 meter.

Step 2: Start adding the device

1. Open the Mi Home app.
2. Click on the + (add device) icon in the upper right corner.
3. Select the category "Sensors".
4. In the list, look for the Thermometer Hygrometer or the Mijia Bluetooth Temperature and Humidity Sensor.

Step 3: Synchronization

• Click "Connect" and wait for the app to find the device.
• If the sensor is not detected, click "Does the device blink?" and follow the prompts (usually you need to manually press the button on the sensor).
• Once you have successfully connected, assign a name to your device (such as “Bedroom” or “Children’s”) and select a room in the home.

If it's a success, the Mi Home menu will show you your current hygrometer card.

• 📊 View the history of temperature and humidity changes.
• 🔔 Set up notifications when going beyond the norm.
• 🌡️ Integrate the sensor into a smart home scenario (e.g., automatically turning on the humidifier).

Set up notifications and automatic scripts

Basic synchronization is just the beginning, and to make the hygrometer work as efficiently as possible, set up personal alerts and automation.

How to set up notifications:

1. Open the sensor card in Mi Home.
2. Press three points (⋮) in the upper right corner and select "Notification settings".
3. Activate the "Notice of Excess" option.
4. Set thresholds: 🌡️ Temperature: for example, from 18°C to 25°C. 💧 Humidity: for example, from 40% to 60%.

Save the settings.

Example of automatic scenario:

Let's say you want to use a humidifier when you drop humidity below 40 percent.

1. In Mi Home, go to Automation.
2. Click "Add Script."
3. Select the condition: "Humidity < 40%" (from the list of sensors).
4. Add the action: "Enable the humidifier" (if it is also connected to the Mi Home).
5. Save the script.

There is no native support for Google Home or HomeKit in the Mijia Hygrothermograph.