Owners of Xiaomi and Redmi smartphones often face a situation when during a phone conversation the screen does not go out when the device is brought to the ear. This causes accidental cheek pressing, resetting calls or turning on the hands-free. In system logs and engineering menus, Proximity Sensor, the proximity sensor that is an integral part of the interface of any modern Android device, is responsible for this function.
Many users mistakenly believe that a breakdown of this component requires immediate access to the service center, but in most cases, the problem lies in software failure, contamination or the need for simple software calibration. Understanding the way this sensor works will help you diagnose the malfunction and restore the correct operation of the phone.
In this article, we will take a closer look at what Proximity Sensor is in the Xiaomi ecosystem, what types of sensors are used in different models, and how to properly configure the system to make the screen go off exactly when it is needed.
Principle of operation and types of proximity sensors
The Proximity Sensor is an infrared emitter and receiver located on the front of the device. Its task is simple: emit invisible light and analyze the reflected signal. If an object (like your ear) is less than 2-3 centimeters away, the sensor sends a signal to the system to lock the screen. Xiaomi smartphones use two main types of such sensors, and the method of their maintenance depends on it.
The first type is a classic hardware sensor that has a physical window on the front, usually next to a conversational speaker, which works regardless of the state of the display. The second type is a virtual sensor that appeared in models with frameless screens and cutouts (for example, Xiaomi Mi 8, Redmi Note 8 Pro), in which case the sensor is played by part of the screen itself or ultrasonic technology, which often causes software conflicts.
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If you have a model with a virtual sensor, approximation problems can only be solved by updating the firmware or a patch from developers, since there is nothing physically to change there.
Hardware sensors are more reliable, but they're susceptible to contamination, and virtual sensors depend on the quality of the software calibration. Understanding what type of sensor you have on your device is critical to your repair method. In some cases, the system can use a gyroscope to emulate the sensor if the main module is not responding.
- 📡 Infrared sensor – a classic solution with a separate window, requiring line of sight.
- 🖥️ Virtual sensor – software emulation through the display, often causes false positives.
- 🔊 Ultrasonic module – used in flagship models to work through glass.
- 🧭 Gyroscopic emulation – an auxiliary method for determining the position of the phone in the ear.
It is worth noting that in the low-end models of the Redmi series, manufacturers sometimes save on the quality of components, which leads to the need for manual sensitivity adjustment.
Diagnostics of malfunctions: testing in the engineering menu
Before you start complex manipulations, you need to make sure that the sensor is really faulty or requires calibration. There is a built-in engineering menu in the MIUI shell to test all components. To get there, open the Phone app and type in the combination ##6484#. If the code is not working, check the access rights or the firmware version.
In the CIT (Customer Integration Test) menu that opens, look for the Proximity Sensor. Click on it. You'll see a screen with numerical values. Normally, when nothing is closing the top of your smartphone, it should be 5.0 or close to maximum. If you close the top with your palm, the value should change to 0.0.
☑️ Sensor diagnostics
If the values don't change or change randomly, it indicates a software failure or a physical malfunction, and you should also pay attention to the presence of a protective film. Often users glue thick glasses that block the IR radiation, and the system simply "does not see" the obstacle.
⚠️ Warning: Don't try to disassemble your phone to clean the sensor until you check it through the engineering menu. 80% of the time, the problem is solved by software.
After the initial test, you can go to calibration. In the same CIT menu, there's often a button called "Calibration," press it, remove your hand from the screen, and wait for the success message, which resets the base sensitivity values to factory ones.
Software calibration through hidden settings
If the standard engineering menu fails, you can use the deeper Android settings. You will need to activate the developer mode to access them. Go to Settings → About the phone and quickly click 7 times on the MIUI version. After that, a new section will appear in the menu “Additional” or “Extended settings”.
Inside the developer menu, find the sensor-related item. In some versions of MIUI, it's hidden and requires you to enter special code through the Engineering Mode app, which you can download from the Play Market Store. In the window that opens, select the Single Test tab and then the Proximity Sensor.
So here you're going to be asked to calibrate, put your phone on a flat surface, make sure there's nothing above the sensor, press Calibration or Do Calibration, and the system will read the current numbers and set them as reference, and after successful calibration, the phone may suggest a reboot.
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Calibration through Engineering Mode is often more effective than through standard calibration. CIT-Menu, as it affects system drivers.
It's important to do this in bright, but not direct sunlight. IR sensors are sensitive to outside light, and bright sun can knock down sensitivity settings. If after calibration the problem persists, you may need to reset to factory settings.
Physical causes of signal blocking
The design of modern Xiaomi smartphones involves placing the sensor in a very narrow frame above the screen. Any pollution in this area can block the IR ray.
- 🧴 Fat spots from fingers or cosmetics, creating an opaque film.
- 🛡️ Incorrectly pasted protective film or glass with a black frame.
- 🧹 Dust and pile stuffed into the speaker grid or micro-hole of the sensor.
- 💧 Moisture or condensate trapped inside the housing after use in the bathroom.
Special attention should be paid to protective glass. Cheap accessories often have a black edge that can partially or completely overlap the sensor. Even millimeter shifting when you stick it can disrupt the Proximity Sensor. Remove the security glass and check the phone without it - this is the fastest way to diagnose.
Use microfiber and a special screening tool to clean the stains. Do not use alcohol in its pure form, as it can damage the oleophobic coating. If the problem is the dust inside the mesh, you can carefully use a soft brush or a can of compressed air, but without fanaticism, so as not to damage the membrane of the speaker.
Solving problems with the virtual sensor
Owners of models with notch or hole-punch screens often find that the proximity sensor is not working properly due to software errors MIUI. The virtual sensor relies on algorithms that can fail after a system update. If calibration does not help, try disabling the function "Pocket mode".
This feature is designed to lock the phone in your pocket, but it uses the same algorithms as the proximity sensor. Sometimes the conflict between these features causes the screen to stay on the phone when you call. You can turn off the option from the Settings menu → Lock and Protection → Pocket mode.
⚠️ Warning: Turning off pocket mode will increase the risk of accidental tapping while the phone is in the bag.Be careful.
Another solution for advanced users is to use third-party apps that intercept sensor control. For example, the Proximity Sensor Reset & Fix app can force the sensor services to restart without restarting the entire device. This is a temporary solution, but it helps to wait for the official patch from Xiaomi.
It's also worth checking if the "High Sensitivity" mode is on in the screen settings, which is designed to work with gloves, but it can change the thresholds of sensors' response, making them too sensitive or, conversely, inert.
Comparative table of methods of solving problems
To make it easier to choose a method of solving the problem, we have compiled a table that will help determine the most effective way depending on the symptoms. Not all methods are universal, and what helped on the Redmi Note 9 may not work on the Xiaomi Mi 11.
| Symptoms. | Probable cause | Method of decision | Difficulty |
|---|---|---|---|
| The screen doesn't go out when you ring. | Pollution or film | Cleaning/Taping film | Low. |
| The screen goes out in your hand | Wrong calibration | Engineering Menu (CIT) | Medium |
| Accidental cheekstrokes | Software failure / Virtual sensor | Disabling pocket mode | Low. |
| Permanent locking of the screen | Physical breakdown | Replacement of plume/module | Tall. |
| Problems after update | MIUI firmware bug | Resetting settings / Waiting for a patch | Medium |
As you can see from the table, most problems are solved by low- and medium-sophistication methods. Rarely when physical intervention is required in hardware. If none of the software methods worked, and in the CIT test the sensor shows zero values or an error, the module itself or the plume most likely failed.
In this case, there are two ways: not to use hands-free communication (which is inconvenient) or to carry the phone to the service. Self-replacement of the sensor on modern monoblock designs Xiaomi is extremely difficult and requires heating the screen and the use of special tools.