How to turn on screen lock while talking on Xiaomi: the complete guide

Modern Xiaomi smartphones, which are based on the MIUI shell or the new HyperOS, offer users a wide range of options for personalizing the interface. One of the basic but critical features is automatic locking of the screen during a phone conversation, which prevents accidental pressing of buttons with the cheek or ear, which could interrupt the call, turn on speakerphone or start a voice recorder without the owner’s knowledge.

However, many users are faced with a situation where the display continues to burn or go out too early, not responding to the device being held to the ear. The proximity sensor is a hardware component that, in conjunction with the software, is responsible for darkening the screen. In this article, we will discuss in detail how to activate this feature, where to look for hidden settings and what to do if standard methods do not work.

Understanding the sensor will help you avoid having to go to the service center, and often the problem is not a breakdown, but a software failure or miscalibration, and we'll look at everything from standard system settings to deep diagnostics through the engineering menu.

The principle of the proximity sensor on Xiaomi smartphones

The main element responsible for darkening the screen is the infrared proximity sensor, which is located, as a rule, at the top of the front panel of the device, often next to or embedded in the speaker, and its operation is based on the emission of invisible infrared light and analysis of its reflection from nearby objects.

When you hold the phone to your ear, the infrared beam bounces off the skin and returns to the sensor, and the system reads that signal and sends the command to the display to go out. Once you remove the phone, the flow is interrupted, and the screen lights up again. On Xiaomi devices, this process is controlled by the Phone system service and hardware drivers.

It's important to understand that there are two types of sensors: hardware and virtual. Older or budget models of Redmi and Poco could use a virtual sensor that analyzes data from the accelerometer and gyroscope, determining the position of the phone near the ear at the angle of tilt. However, modern models rely solely on hardware accuracy.

Where to find lock settings in the MIUI and HyperOS interface

In most current firmware versions from Xiaomi, there is no separate button "Enable Screen Lock" because this feature is activated by default, but if it stopped working or was deactivated by third-party software, you can check its status through the standard call menu.

To do this, open the Phone app (green handset) and click on the three dots in the upper right corner or the settings button (cogs). In the menu that opens, select Settings. Next, scroll through the list to Incoming Calls, which is where the settings that control the screen behavior during the call are hidden.

Inside this section, you need to find an option that might be called "Approach Sensor" or "Block Buttons." Make sure the switch opposite it is in the active position. If you use a third-party "caller" from Google, the path may be slightly different: Settings → Incoming Calls → Approach Sensor.

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If you can't find the switch, try resetting the Phone app through the app menu, which will return all settings to factory values, including hidden lock flags.

Note that in some firmware regions (e.g. Global or China) item names may differ. In Chinese versions of HyperOS, this item is often deeper in the call security menu. Always check for system updates, as Xiaomi regularly changes the menu structure in new versions of Android.

Calibration of the sensor: step-by-step instructions

If the settings are on but the screen is not going out, you probably need to calibrate the sensor, which is a procedure that trains the system to understand where the boundary between "far" and "close" is. There is a special engineering menu for the MIUI diagnostics.

Open the Phone app and dial the secret code ##6484##. The device will automatically go to CIT (Customer Interface Test) mode. If the code does not work, go to Settings → About Phone → MIUI version and quickly press 7-10 times the version number to unlock access to the advanced settings, then find the "Testing" item in the main settings.

In the test list, look for the Proximity Sensor. You'll see a numerical window. Ideally, when there's nothing in front of the screen, it should be 5.0. When you close the top of the screen with your palm (to simulate a conversation), the value should change to 0.0. If there's no change or the values "jump," press the Calibrate button and follow the instructions on the screen.

After successful calibration, be sure to restart the device. Only after a full cycle of on and off, the new parameters will be applied by the system and begin to correctly affect the operation of the locking screen.

Influence of protective glasses and accessories

One of the most common reasons for the screen locking to work is poor quality protective glass or film. Many users, wanting to protect the display Xiaomi, buy cheap accessories that overlap the area of the IR sensor.

The proximity sensor requires direct contact with the outside environment or a transparent window in the speaker area. If the glass is black or just covers the top, it distorts the IR beam, and the phone thinks it's in the ear all the time, locks the screen immediately after dialing, or vice versa, does not extinguish it at all.

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The quality of the protective glass directly affects the operation of the proximity sensor, and cheap glasses with a thick adhesive base or a black frame often cause malfunction.

If you notice that the problem started after sticking a new glass, try to remove it carefully and check the sensor's performance. In some cases, cutting a small hole in the speaker area helps, but this is aesthetically unacceptable for many users.

Also worth mentioning are the cases: Some massive bookcases or bumpers with high sides can physically overlap the sensor, especially if they don't have a special cutout, in which case the locking won't work until the accessory is removed.

Third-party applications and software conflicts

Sometimes embedded MIUI features come into conflict with user-installed applications, especially with third-party callers like Truecaller, GetContact, or various number detectors that can intercept the sensor.

If you use a third-party app to make calls, check its internal settings. It often has its own "Block Screen" or "Use Approximation Sensor" switch. Make sure that the app's access rights to the hardware sensors are not limited to the power saving system.

• 📱 Conflict of rights: Android system can limit the background operation of applications, considering them to consume battery, which blocks access to the sensor.
• 🔋 Energy savings: Super-saving mode can turn off secondary sensors to extend battery life.
• 📞 Standard Call: Try to temporarily return to the standard Google Phone app or MIUI Dialer to check.

In addition, some design themes (MIUI Themes) may contain code errors that disrupt system interfaces, including the call screen. If the problem occurs after the theme changes, return the standard design.

⚠️ Warning: Installing modified versions of apps ("calls") from unverified sources can cause not only screen failures, but also leak your personal data and conversation records.

Solving problems with phantom touches

There are times when the screen goes out, but the buttons don't lock, and you accidentally reset the bell with your cheek, and that could be a sign of a problem with the capacitive layer of the display, so even with the lights off, the touchscreen continues to respond to pressure.

In the developer settings (which you need to activate multiple clicks on the build number in the About section), you can find a setting that improves the touchscreen. However, the average user should use the built-in test. In the same CIT engineering menu, there is a Touchpanel test. Swipe around the screen to make sure all zones respond correctly.

If the test shows a failure in the top of the screen (where the cheek is usually located), this may indicate a physical malfunction of the digitizer, in which case software methods, including resetting, will not help.

It's also worth checking if you're not using "Gloves" mode, which increases the sensitivity of the screen, which can lead to false positives when you press the phone tightly against your head. → Additional settings → Working in gloves.

FAQ: Frequently Asked Questions

⚠️ Warning: Do not attempt to disassemble the phone to clean the sensor yourself if the device is warranty-free.Falling seals and autopsy marks will result in denial of warranty service.