Review Xiaomi Reminder Mijia Smart Door & Window Sensor 2

Review of the door and window sensor for Xiaomi smart home bluetooth 5.1 2022. Today we will talk about the door and window opening sensor for a smart home from Xiaomi. The sensor works over Bluetooth and has many useful features in domestic use, while consuming a minimum amount of energy. It can be used in security scenarios (controlling the opening of a window or front door), as well as in indoor climate control scenarios (controlling whether a window is open when the air conditioner is running or when the air humidifier is on). We will consider how this sensor works in the review.

Buy Xiaomi Reminder Mijia Smart Door on Aliexpress


Type of: Door and window opening sensor
Connection type: Bluetooth
Interaction with the mobile app: Mi Home
Dimensions: 34 x 32.7 x 14.5 mm
Operating temperature: -10 ° to + 50 ° С

Packaging and equipment

The sensor is delivered in a package made of white thick cardboard with printing in gray tones. The packaging contains fairly detailed information about the device. On the front surface there is an image of the sensor, as well as the Xiaomi logo. On the back you can find brief technical data and a barcode. The packaging is of good quality and compact enough. Protects the contents well during transport.

Opening the package, we will see that everything is folded very neatly. The package includes: the sensor itself, instructions with illustrations in Chinese and a spare set of double-sided tape for fixing the sensor to the surface. One set is already glued to the sensors. The battery is a CR2032 battery, which is included in the kit and is already installed.

Device appearance

The sensor consists of two rectangles. One is larger (the sensor itself), the second is smaller (magnet). The body is made of white matte shock-resistant plastic, which not only looks good, but also pleasant to the touch. Thanks to its compact size, the sensor is almost invisible and many use cases can be found.

On the front side of the sensor there is an indicator peephole, which is also a light sensor. When two parts of a rectangular shape are connected, an LED is triggered, which, when closed or opened, lights up in a pleasant blue color.

On the side of the case is the only button that is required for pairing. Easy to press. On the back of the case there is double-sided tape for attaching the sensor to the surface.

The CR2032 battery is located under the back cover of the device. It is insulated with a plastic tab. To turn on the sensor, you must remove this tab. As soon as the energy from the battery goes, the sensor will work immediately. One battery is enough for 2 years of autonomous work.

Principle of operation

The principle of operation of the sensor is quite simple and does not differ from sensors from other manufacturers. A reed switch and a battery are located in the largest part of the sensor, and a magnet is installed in a small part. When two rectangular parts of the sensor are connected, the magnetic field acts on the contacts and a short circuit occurs. This is what is the status indicator for a window or door. It should be noted that the maximum distance at which the sensor is triggered is no more than 18 mm. The operating temperature of the statement to manufacturers is from -10 to + 50 ° C.

To open the sensor, it is unnecessary to exert significant efforts; for this you need a flat screwdriver, with which you need to gently pry a small notch on the case and remove the cover. Just a few seconds and the sensor is open, now you can look inside.


To detect the sensor on the phone, you need to activate Bluetooth and launch the proprietary application from Xiaomi Mi Home. In the application, select “Add device”, and in the proposed list of devices, find our sensor.

Then hold down the pairing button on the body of the sensor itself and follow a simple instruction, after a few seconds it is synchronized with the application. The application is quite simple and straightforward. The interface is in English, which is very convenient.

The sensor is connected via a smartphone, so the application contains an inscription about the absence of a Bluetooth gateway. In the center of the blue circle, information about the state of the sensor itself is displayed – open or closed. In addition, information is provided on the illumination – bright or dark. In the device log, you can view the sensor opening and closing history, which is displayed with date and time.


Information about the opening and closing of the sensor is displayed in the application at lightning speed, which cannot be said about the light sensor. For example, if you cover the eye of the light sensor, then this information will be displayed in the application with a slight delay. If necessary, you can disable the light sensor in the application settings.

To set up smart scenarios, you need to go to the corresponding menu item “Smart scenarios”, in which 5 conditions are available: dim ambient light, bright ambient light, enable, disable and close timeout. There will definitely not be any problems with configuring scripts, all the information provided in the application is quite simple and straightforward. Therefore, you can easily customize the sensor for yourself.


For testing, the sensor was attached to a window frame using double-sided tape, which was applied to the back of the case. When opening and closing the edge, the sensor works correctly. When triggered, the blue LED lights up, and the information is displayed in the proprietary application.


The door and window opening sensor from Xiaomi left a positive impression. It has compact dimensions and low weight, if desired, a lot of use scenarios can be found for the sensor. In addition, the device is equipped with a built-in light sensor. It works in the smart home system, has the ability to synchronize with other devices of the system, which is very convenient and will help make your life more technological and safe. It has good autonomy (2 years of continuous operation from one battery), easy installation and simple settings. No significant drawbacks were found when using. In general, a useful, inexpensive and multifunctional sensor that can be recommended for purchase.

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