Modern smartphones like the Poco X3 Pro come with a variety of sensors that make it more comfortable to use. One of these useful features is automatically locking the screen when placing the phone in a case or pocket. This option not only saves battery power by preventing accidental switching on, but also protects the screen from scratches if the case has a rigid internal structure. Many users do not even suspect that their phone can recognize the closure of the lid without having to buy special accessories with a magnet.
However, by default, this feature may be inactive or not work properly due to software failures in the shell of MIUI or HyperOS. Owners of Xiaomi Poco X3 Pro often wonder how to make the device respond to the closure of the cover of the case, especially if they use third-party accessories. In this material, we will detail the settings, hidden functions and methods of calibrating the proximity sensor to make your smartphone behave “smart”.
To start with, the smart case relies on a proximity sensor at the top of the front panel, which captures the change in light and distance to the object. It's important to understand that the standard Smart Case feature on the Poco X3 Pro menu only works with original magnetic tagged accessories, but there are workarounds for any case. We'll look at all the activation options available.
The principle of operation of sensors and types of covers
To properly adjust the automatic locking, you need to distinguish between the mechanisms of the accessories. There are two main types of cases: with a magnetic fastener (or built-in magnet) and conventional silicone or plastic linings. In the first case, a special Hall sensor is installed in the case of a smartphone that responds to the magnetic field. When the cover is closed, the magnet goes to the sensor, and the screen goes out.
In the second case, when there is no magnet, the system relies solely on the proximity sensor. The operating system algorithms analyze the sharp change in light and the distance to the obstacle. If you close the cover of a conventional case, the sensor "sees" the object close to the screen and should initiate the display shutdown. However, on the Poco X3 Pro, this process sometimes requires manual activation in the security settings.
Some users mistakenly believe that the function requires an original accessory. This is not quite true. Although the original Xiaomi cases guarantee 100% compatibility and the presence of the right magnets, the software settings allow you to emulate this process, the main thing is that the proximity sensor works correctly and is not blocked by a thick layer of glass or metal.
- 🧲 Magnetic cases: React to a physical magnetic field, require a Hall sensor in the phone.
- 👁️ Optical sensors: Use a light and proximity sensor to determine the closure of the cover.
- 📱 Software emulation: Using third-party applications to force locking when closing.
It's worth noting that the sensors in the Poco X3 Pro are located under the screen or in the top bezel, depending on the revision of the display, which makes them sensitive to the quality of the protective glass. If the glass is glued curved or has a thick black bezel that covers the sensor area, the smart functions will not work, regardless of the settings.
Activation of pocket mode in system settings
The first and most obvious step is to check the standard security settings. In the MIUI shell installed on the Poco X3 Pro, this feature is called "Mode in your pocket," which is designed to prevent accidental calls, but also affects the behavior of the screen when in a confined space, including a case-book.
To activate, go to the Settings menu, then select Lock and Protect (or Passwords and Security). Find the Mode section in your pocket and make sure the switch is active. If the slider is blue, the system will lock the screen when it detects the object's proximity to the top of the case.
⚠️ Warning: Turning on the mode in your pocket can lead to false positives if you wear your phone in tight jeans or use thick gloves.The screen may go out at the wrong time.
Additionally, check your screen lock settings. Go to Settings → Always on screen and lock. Here, make sure that the “Raise to Activate” function does not conflict with the proximity sensor. Sometimes, the simultaneous operation of these functions causes delays in the screen response to the opening of the case.
Some of the firmware versions for Xiaomi Poco X3 Pro have a separate menu for accessories. Try searching for settings with the word "Cover" or "Accessor." If your phone supports the definition of magnetic cases, there will be a corresponding item here. If there is no item, then your version of the software does not have native support for magnetic tags, and you will have to rely on the proximity sensor.
Use of third-party emulation applications
If MIUI is not available, Google Play apps come to the rescue. Since the Poco X3 Pro has a powerful processor, it can easily handle the background tasks of such programs. The most popular solution is the Proximity Sensor or Screen Off and Lock application.
The principle is simple: the app constantly monitors the proximity sensor readings, and once the value changes to "occupied" (the object is close), the program forcefully turns off the screen or locks the device, which creates the effect of a smart case even with a conventional cover.
To set up this method, perform the following actions:
- Download a sensor management app (e.g. Proximity Service).
- Give the application the necessary permissions in the Settings menu → Apps → Permissions.
- Enable auto-start for the application so that the system does not close it to save energy.
Risks of using third-party software
It is important to adjust the sensitivity in these applications correctly. Too high sensitivity will cause the screen to go out even if you simply hold the phone to your ear while talking, but have not yet completed the call. The optimal setting is selected empirically within 1-2 days of use.
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To save battery power when using third-party blocking apps, add them to the “No Limits” list in the battery settings, but turn off vibration and audible notifications from the app itself.
Calibration of the proximity sensor
A common reason why a smart case doesn't work on the Poco X3 Pro is because the sensor is not calibrated correctly. If the phone doesn't "understand" that the lid is closed, or thinks it's always closed, calibration is needed, especially after the display is replaced or moisture is injected.
To enter the engineering menu, dial ##6484## in your phone. The CIT (Customer Integration Test) menu will open. Find the Proximity sensor in the list. A window will open in front of you with two values: Near (close) and Far (far).
The calibration process is as follows:
- 📏 Remove your hand from the top of the screen – the value should change to 5.0 or close to the maximum.
- 🖐️ Close the sensor with your palm – the value should drop to 0.0.
- 🔄 If the values do not change, click the “Calibrate” button at the bottom of the screen and repeat the procedure.
After successful calibration, be sure to press "Pass" or "Save" to save the results. Reboot your smartphone to make the changes take effect. Now the proximity sensor must correctly respond to the closure of the case.
| Status of the sensor | Value (Far) | Meaning (Near) | Action. |
|---|---|---|---|
| Norma. | 5.0 | 0.0 | No calibration required |
| Overestimated values | 20.0+ | 10.0+ | We need calibration. |
| Zero values | 0.0 | 0.0 | Failure or pollution |
| Value jumps | Chaotically | Chaotically | Problem with the software or the plume |
Resolving problems with protective glass
One of the most common problems for Poco X3 Pro owners is that the sensor is in conflict with the protective glass. Many accessories manufacturers make the black bezels around the glass too wide or biased, resulting in the area of the sensor that is under the screen or in a narrow frame, overlapping.
You can diagnose the problem visually. You can flash a flashlight to the top of the screen (right of the speaker) when the display is off. You should see a small black dot or area where the sensor is located. If your security glass has a solid black frame that covers this point, the sensor will think that the case is always closed.
⚠️ Warning: Don't try to tear the black frame off the glass yourself or cut the hole with a blade. This will cause chips and can damage the display matrix. A temporary solution may be to use blue light software filters that darken the top of the screen, masking a broken sensor, but this will not solve the lock problem.The only reliable way is to replace the protective glass with a compatible Xiaomi Poco. X3 Pro, having a special cutout or transparent area above the sensor. ☑️ Is there a cutout over the speaker?: YesNet Can not be seen: Check in the engineering menu the work of the sensor: Does not work: Decision: Replace glass or use software: 0 / 4 Specific settings for window cases If you use a window case, the situation becomes more complicated. MIUI It may not support the output of information to the window of third-party manufacturers. For such cases, there are specialized applications, for example, "SecondScreen" or «AOD These apps allow you to configure the display of time, date and notifications in a specific area of the screen, simulating the work of Always On Display, even if you are not a user. AMOLED-poco X3 Pro does not support constant operation in this mode at the system level.The application will include a bright bar or square in the desired area when notified. Setting up these applications requires precision: Measure the position of the window on your case relative to the edges of the phone with a ruler. Enter the coordinates (X, Y) and dimensions (width, height) into the application settings. Install the application in autoboot and allow the display to be displayed on top of other windows. Keep in mind that even a small part of the fire is constantly burning. OLED-The screen carries the risk of pixel burnout. therefore, in the settings of such programs, be sure to set the timer of the shutdown (for example, 10 seconds after notification) and reduce the brightness to a minimum. 💡Using third-party applications for window cases is the only way to get the functionality of Always On Display on Poco X3 Pro with unoriginal accessories, but requires careful coordinate adjustment (FAQ) Why does the screen go out when I just hold the phone to my ear but the case is open? This is normal for a proximity sensor to respond to any obstacle. If this happens too often, try calibrating the sensor through an engineering menu or reducing sensitivity in the screen settings. Does the smart case feature affect the speed of unlocking from the print? No, the fingerprint scanner at Poco. X3 The Pro is built into the side button and works independently of the proximity sensor, but if the screen goes out too quickly when you close, you may not have time to put your finger on, so increase the timeout of the screen in the settings. Can you use a magnetic case from another Xiaomi model on Poco? X3 Physically, the case may fit in size, but the magnetic tag may not match the location of the Hall sensor in Poco X3 As a result, the automatic lock function will not work, although the case protection will provide. What if the MIUI stopped working after the MIUI update? Try resetting the sensors through the engineering menu again. If that didn't work, there may be a bug in the new update. Then you should wait for a patch from the developers or temporarily use a third-party application to lock the screen. Does the constant survey of the sensor drain the battery? The proximity sensor itself consumes negligible little power. However, if the system or application wakes the processor every millisecond to check the status of the sensor due to an error, the battery consumption can increase. With proper calibration, the effect on autonomy is imperceptible.