Modern Xiaomi smartphones running MIUI or HyperOS have a wide range of functionality that sometimes requires fine-tuning to the user’s individual habits. One of the common problems that device owners face is accidentally pressing buttons during a phone conversation when the screen is held up to the ear or placed on the table. The approach sensor is designed to solve this problem, but its work can be incorrect or disabled by default in some use scenarios.
In this article, we will discuss in detail the mechanisms responsible for cancelling the display during incoming or outgoing calls, you will learn where the hidden settings of the system are, how to calibrate the touch layer and what to do if the software methods do not help. Properly configuring these parameters will not only improve communication comfort, but also save battery power, preventing excessive backlighting.
It is worth noting that the menu interface may vary slightly depending on the firmware version and model of your Xiaomi, Redmi or POCO. However, the logic of the system components remains the same throughout the brand ecosystem.
The principle of the proximity sensor on Xiaomi smartphones
The main element that locks the screen is the proximity sensor, which is a small infrared sensor that is usually located at the top of the display, next to the speaker. And its job is to determine the distance between the surface of the screen and a foreign object, in this case your ear or cheek, when the object is closer than the object is. 2-3 centimeter, the system receives a signal and turns off the touchscreen and backlight.
Xiaomi devices use two types of sensors: physical and virtual. The physical sensor is a separate window on the front panel that reads the reflection of the IR beam. The virtual sensor, embedded in many new models, uses ultrasonic technology or software analysis of data from the front camera and accelerometer. The data processing algorithms in MIUI are constantly being improved to minimize false positives.
⚠️ Warning: Black-framed protective glass or an incorrect sticker may block the physical sensor, causing the screen to go out immediately after the call starts, not giving a response, or, conversely, will not respond to the approach.
Understanding the type of sensor you have installed in your device helps you diagnose the problem more quickly, and if you have a model with a subscreen or virtual sensor, the problems may be due to software calibration failures, not surface contamination.
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If you use a case with thick sidebars, make sure it doesn’t overlap the top edge of the smartphone where the sensors are located.
Configure the lock function through the standard call menu
The first and easiest way to make sure that the lock function is active is to check the settings of the Phone application itself. MIUI This is the responsibility of the system application from Google or Xiaomi's own call, depending on the region and firmware version, access to these options through the contact menu or call history.
You have to open the call app and find the menu icon, which usually looks like three dots or a gear in the corner of the screen. After you go to Settings, you have to scroll down to Incoming Calls. That's where the switch that controls how the screen responds to the approach is located. If it's off, the screen will burn constantly, which often leads to accidental call resets or hands-free switches.
☑️ Checking the call settings
In some firmware versions, this item may be called "Proximation Sensor" or "Accumulation Lock." Make sure the slider is blue or green, which means active. Once activated, the settings do not require the device to restart and take effect instantly.
- 📞 Open the Phone app and go to settings.
- 🔍 Find the section “Incoming calls” or “Call settings».
- ⚙️ Activate the "approximation sensor" switch».
- 📱 Check the screen by holding your hand to the top of the smartphone during a call.
If the problem persists after this option is enabled, a deeper system calibration or hardware check may be required, and standard settings are just the first level of functionality management.
Using an engineering menu to calibrate the sensor
When standard methods fail, an engineering menu comes to the rescue, accessible through a special code, and this hidden section allows you to test and calibrate hardware components, including the same proximity sensor, and you don't need a superuser license to enter this mode, you just need to enter the character combination in the dialer.
Enter the code ##6484## or ##4636## in the call app. Once you enter the last digit, the CIT menu will open. In the test list, you will find the item "Proximity Sensor" or "Proximity Sensor" in this section, you will see the current readings of the sensor and the possibility of calibrating it.
Codes for entering the engineering menu:
1. ##6484## (Main test menu)
2. ##4636## (Information Testing Menu)
3. ##377## (Special for some POCO models)The calibration process is usually like this: you close the sensor with your finger, press the calibration button, then remove your finger and press the button again. If after the procedure, the value in the Max or Current column changes from 0 to 5 (or another number depending on the model), then the sensor is healthy and calibrated. If the values do not change, it may be contaminated or has a hardware defect.
What if the code doesn't work?
Comparison of screen locking methods
It is important for users to understand the difference between software locking and sensor hardware response. Below is a table that will help to systematize knowledge about different screen management techniques during a conversation on Xiaomi devices.
| Management method | Level of access | Efficiency | Risks. |
|---|---|---|---|
| Call settings | Customized | High (staff) | Minimum |
| Engineering Menu (CIT) | Systemic | Maximum (calibration) | Medium (calibration error) |
| Third-party annexes | Applied | Medium | High (PO conflicts) |
| In the pocket mode | Systemic | Tall (for bags) | False positives |
As you can see from the table, the most reliable way is to set up the system in conjunction with the correct calibration through the engineering menu. Third-party applications often require unnecessary permissions and can conflict with MIUI system processes, causing delays in screen response.
Separately, the Mode in Your Pocket feature, which also uses a proximity sensor but with more aggressive algorithms, is designed to prevent dialing when the phone is in your bag or pocket, and can be useful as an addition to the main lock when calling.
Solving proximity sensor problems
Even when the lock is enabled, the screen can behave unpredictably. A common cause is a software failure in which the system forgets the sensor state. In such cases, it helps to simply reboot the device or clean the cache of the Phone application and system services. Go to Settings → Applications → All applications, find Phone and select Clear Cache.
Another common problem is the use of poor-quality protective glasses. If the glass is opaque or shifted relative to the body, it physically overlaps the sensor. In the case of virtual sensors, the problem can be solved by updating the firmware, since Xiaomi regularly releases patches that improve the algorithms of the sensors.
⚠️ Note: If the calibration in the engineering menu shows a value of 0.0 when the sensor is closed and 0.0 when the sensor is open, this is likely to indicate a hardware malfunction or unstuck sensor plume inside the housing with 99% probability.
In some cases, resetting all settings to factory settings helps, but this is an extreme measure that requires prior data storage. Before contacting the service center, try gently wipe the top of the screen with an alcohol wipe to remove fatty contamination that can distort the sensor readings.
- 🧹 Wipe the top of the screen from pollution and fat.
- 🔄 Reboot your smartphone to reset temporary errors.
- 🗑️ Clear the cache of the Phone and System Services app».
- 🛠️ Check if the protective glass covers the sensor area.
If none of the software methods worked, and in the engineering menu, the sensor does not respond to hand closing, it is likely that replacement of components will be required. In modern smartphones, the sensor is often integrated into the plume of the display or front camera.
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Hardware malfunction of the proximity sensor is rare, most often the problem is solved by correct calibration or removal of the protective glass.