How to set up a screen lock when talking on Xiaomi Redmi

Xiaomi Redmi smartphones are famous for their functionality, but sometimes users face an annoying problem: the screen does not go out during a conversation, which leads to accidental cheek pressing, resetting calls or turning on the hands-free at the most inopportune moment, the reason for this behavior is often the incorrect operation of the proximity sensor, which should respond to the device’s lift to the ear.

In modern versions of the MIUI and HyperOS shell, sensor algorithms have become more complex, sometimes causing conflicts with protective films or covers. You don't need to be an engineer to fix this, since most of the settings are hidden in the standard menu or engineering mode. Understanding how this mechanism works will help quickly restore comfort when communicating.

In this article, we will discuss in detail how to calibrate the sensor, where to find hidden settings and what to do if the software methods do not help. It is important to know that on Redmi Note models with AMOLED displays, the sensor is often built directly into the screen matrix, which requires a special approach to calibration. Follow the instructions Step-by-step to fix the malfunction.

The principle of the proximity sensor on Xiaomi smartphones

The main thing that's going to do the screen blackout is the infrared sensor, which emits invisible light and reads the reflection from nearby objects. When you hold the phone to your head, the reflected signal comes back, and the MIUI system gets a command to turn off the display, and if the screen is still active, then the sensor is either contaminated or software disabled.

The implementation of this module is different on different Redmi models: budget segments use a separate window at the top of the case, which is easily covered with low-quality protective glass. Flagship and mid-budget models often feature ultrasonic or optical sensors built under the screen, making them less susceptible to external contamination, but more sensitive to software failures.

⚠️ Note: Using non-original protective glasses with a black bezel over the top of the display is the most common cause of false positives or complete disregard of the sensor.

Understanding the physics of the process helps diagnose the problem: If the sensor is closed, it "thinks" that the phone is always in the ear, and the screen may not light up at all. If it does not see obstacles, the screen will burn even while talking, and the correct operation depends on the synchronization of the hardware and drivers by the operating system.

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Before settings start, wipe the top of the screen with a soft cloth without pile to exclude the effect of fat and dust on the sensor.

Basic settings through the phone menu

The first step should always be to check the standard system settings. In some cases, the lock function may be accidentally disabled by the user or reset after updating the firmware. To access the basic parameters, you need to go to the Settings application and select the Lock screen section.

Here, you should pay attention to Mode in your pocket. This feature uses the same proximity sensor to prevent accidental taps when the phone is in your bag. If this mode is not working correctly, it may conflict with the logic of the call. Try switching the switch and check the result in test mode.

Also, check the settings of the Phone app itself. Click on the three dots in the top right corner of the contact list and select Settings. In Incoming calls, make sure you don't tick the boxes on features that might block the sensor, such as "Move Response" or "Response to Answer" if they're unstable.

• 📱 Open the Settings. → Lock the screen and check the active options.
• 📞 Go to the settings of the Phone application and reset the parameters of incoming calls.
• 🔄 Restart the device after making changes to apply the settings.

If simple manipulations of the menu fail, a deeper calibration is required. Often the system simply forgets the zero values of the sensor, and it needs to be reminded of what is "nothing near" and what is "object close."

Calibration of the sensor through the engineering menu

The most effective way to solve the problem is to use the CIT (Customer Integration Test) Menu, which is designed to test hardware components and allow you to perform accurate calibration. To enter the menu, type the combination ##6484## or ##4636## in the Phone application.

When you enter the menu, look for Proximity Sensor or Approximation Sensor, and you will see a window with two digital values, usually one showing the current state and the other showing the threshold. The task is to normalize the values. Cover the top of the screen with your finger, the values should change.

Calibration procedure:




1. Press the Calibrate button ).




2. Remove your hand from the screen (green indicator should light up or the inscription Success should appear).




3. Close the sensor with your hand (reaction should appear).




4. Press OK to save.

If the automatic calibration fails, try to do it manually by following the instructions on the screen. In some versions of MIUI, you need to close the sensor first, press the button, and then open it, and the system will prompt the desired action with a text message at the bottom of the display.

⚠️ Warning: Do not leave the engineering menu until you have made sure that the test is successful. Interrupting the calibration process may cause the sensor to malfunction in the future.

Use of calibration applications

When the built-in engineering menu is unavailable or malfunctioning (as is the case on global firmware versions), third-party utilities come to the rescue. There are many applications on the Google Play store, such as Proximity Sensor Reset & Test or Sensor Test, that allow you to access raw sensor data.

These programs often have a software calibration function that forcibly resets the sensor values in the Android driver. After installing the application, run a test. If the graph jumps or values do not change when you close the top of the screen, the problem may be hardware. If there are values, but the screen does not go out, the Calibrate button inside the application will help.

It's worth noting that some applications require enhanced access rights, and data security depends on the developer's reputation, and choose high-rated and high-review utilities to avoid installing junk.

• 📥 Download the Proven Sensor Testing App from Play Market.
• 🔍 Run the test and observe for changes in numerical values.
• ⚙️ Use the reset or calibration function within the program.

After working with third-party software, be sure to restart your smartphone, which will allow the system to reread the new calibration data and apply it to the standard behavior of the system during calls.

Solving problems with protective films and covers

One of the most common but common causes is a physical obstacle: Even a microscopic crack on the protective glass in the sensor area can scatter the infrared beam, preventing it from coming back or, conversely, creating a false echo. Xiaomi Redmi owners often swap the glass for cheap counterparts that have an opaque black bezel.

If you have a protective glass, carefully examine the area above the speaker. If the glass frame covers even the edge of the sensor (which can be shifted to the left or right), the screen will behave unpredictable, in such cases, it helps to carefully cut the hole in the film or completely replace it with a model marked "Full Coverage compatible" or specifically for your model.

Cases can also play a cruel joke, especially those with thick sides. When you talk, your finger may accidentally overlap the sensor through the neck of the case. Try removing the case and checking the phone's operation in the "naked" form. If the problem disappears, the cause is found.

Don't ignore physical factors. No amount of software tweaking can compensate for the lack of infrared signal because of a dense layer of glue or thick plastic.

Additional methods and resetting settings

If none of the above methods worked, there may be a deep system failure, in which case you can try resetting all applications. Go to Settings → Apps → All applications, find the Phone app and click Clear → All data. This will return the call settings to factory.

A radical but effective method is a full Hard Reset, and make sure to back up your important data before doing so, because all the information will be deleted, and once reset, the phone will return to the "out of the box" state, and all sensor drivers will be reinstalled clean.

⚠️ WARNING: A full reset will delete all your photos, contacts and apps. make sure you have an up-to-date copy of the data in the Mi Cloud or on your computer.

In the rare cases where even the reset doesn't work, it can be a malfunction of the sensor module itself or the plume, and if the phone falls or falls into the water, the probability of hardware damage is high, and in this situation, only contacting a service center to replace the component will help.

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If the software calibration and resetting of the settings did not help, and the protective glass is a whole - a hardware breakdown of the sensor is likely, requiring repair.

Frequently Asked Questions (FAQ)