Have you ever noticed how your Xiaomi screen goes out during a phone call when you hold your device to your ear? This feature is the proximity sensor, a small but critical component of modern smartphones. Without it, calls would turn into a series of random taps: you would constantly touch the screen with your cheek, activating a speaker, keyboard or even completing a call. However, this sensor often becomes a source of problems: the screen does not turn off when you call, react with a delay or works unpredictably.
In this article, we will discuss how the proximity sensor in Xiaomi smartphones (including Redmi models) works, POCO And the flagship series, why it might fail, and what to do if it stops working properly, and you'll learn how to test it without special tools, what settings affect its behavior, and when it will need repairs. Particular attention will be paid to the typical errors of users who mistakenly mistake software failures for hardware breakdowns.
What is a proximity sensor and how does it work
The proximity sensor is an optoelectronic device that detects the presence of an object (like your head) near the screen of a smartphone. In Xiaomi smartphones, it is usually located at the top of the display, next to the front camera and other sensors, and its operation is based on infrared (IR) radiation:
- 🔦 The emitter sends an invisible IR signal.
- 🪞 If there is an object nearby (like your ear), the signal is reflected back.
- 📡 The receiver picks up the reflected signal and transmits the data to the processor.
- 📱 The processor turns off the screen to prevent accidental taps.
Unlike light sensors, which measure light levels, the proximity sensor responds exclusively to the proximity of an object, activating not only during calls, but also when watching videos (to turn off the screen if you are distracted), and in some Xiaomi models, even when reading books in the Mi Reader app.
Xiaomi smartphones use two types of sensors:
| Type of sensor | Principle of work | Xiaomi models | Advantages | Deficiencies |
|---|---|---|---|---|
| Infrared (IR) | The emitter + receiver | Redmi Note 10/11, POCO X3/X4, Mi 11/12 | High accuracy, low power consumption | Sensitive to pollution, can fail in bright sun |
| Capacitive | Responds to changing screen capacity | Redmi 9A, POCO M3 (budgetary models) | Cheaper in production, no moving parts | Less accurate, can trigger moisture or protective glass |
| Hybrid (IR) + capacitive) | Combination of two technologies | Xiaomi 13/14 Pro, Mix Fold | Maximum reliability, adaptability | More expensive, more difficult to repair. |
In smartphones Xiaomi with AMOLED-The proximity sensor is often integrated into the display, making it less visible but more vulnerable to software failures. 12T The Pro sensor is hidden under the top of the screen, and its operation depends on the correct calibration of the system.
Why you need a sensor approach in smartphones Xiaomi
At first glance, the proximity sensor may seem like a minor detail that is easy to do without, but in reality, it performs several critical functions:
- 📞 Preventing accidental taps during a call. Without the sensor, you would constantly activate the speakerphone, keyboard, or even complete a call with your cheek.
- 🎥 Battery savings: The screen consumes up to 30 percent of the smartphone's power, and turning it off during a conversation prolongs the life of the smartphone.
- 🔒 Privacy protection: In some Xiaomi models (such as the Black Shark), the sensor locks the screen when the face approaches so that outsiders do not see the notifications.
- 🎮 In games with Game Turbo support, the sensor can turn off touch buttons if you hold your phone too close to your face.
Interestingly, in some of the firmware MIUI The proximity sensor is used to automatically switch between the speaker and the tube, for example, if you listen to music through the speaker and then hold the phone to your ear, the sound automatically switches to the tube — and vice versa.
⚠️ Note: In Xiaomi models with Always-on Display (such as Xiaomi 13 Ultra), the proximity sensor may conflict with the display of persistent information. If the screen does not go out during a call, check the settings of the Screen → Always-on Display → Exceptions.
The proximity sensor also plays a role in the operation of the control gestures. MIUI 14 has a wake-up feature that activates the screen when you put your hand up to the phone. If the sensor is faulty, this feature may not work properly.
Signs of malfunction of the proximity sensor
How do you know if your Xiaomi approximation sensor is not working properly?
- 🚫 The screen doesn’t go off when you call, even when you hold your phone to your ear.
- ⏳ Reaction delay: the screen goes out through 2-3 seconds after the phone was lifted.
- 🔄 Spontaneously turning on/off the screen for no apparent reason.
- 🌞 Does not work in sunny weather (typical for IR sensors).
- 💧 It works in humid weather or in the shower (typical for capacitive sensors).
However, not all of these symptoms indicate a sensor failure, for example, if the screen does not go out during a call, the problem may be:
- 🔋 A protective film or glass covering the sensor.
- 📲 Firmware failure (especially after update) MIUI).
- 🔧 Incorrect settings (for example, the disabled screen function turns off during a call).
⚠️ Attention: If the sensor stops working after a phone drop or moisture hits, it is likely that not only the optical components are damaged, but also the plume connecting the sensor to the motherboard.
To pinpoint the cause, first check the sensor with built-in tools. MIUI or third-party applications.
Check for a protective film over the sensor|
Run the sensor test in ##6484 mode##|
Make sure the screen turns off during a call is enabled|
Try calling in a dark room (for IR sensors)|
Update the firmware to the latest version-->
How to check the proximity sensor on Xiaomi
Before you carry the phone for repair, you should check the performance of the sensor yourself.
1. Built-in sensor test (Engineer Mode)
On most Xiaomi smartphones, you can run an engineering menu by typing the combination in the Phone application:
##6484##After that:
- Select Proximity Sensor (Proximity Sensor).
- Raise your hand to the top of the screen – the value should change from 5.0 cm (or similar) to 0.0 cm.
- Remove your hand, the value should return to the original.
If the values do not change or an error is displayed, the sensor is faulty.
Applications for diagnostics
Google Play has several tools to check the sensors:
- 📱 CPU-Z (It shows the status of all sensors).
- 🔍 Sensor Test (specialized application for testing).
- 🛠️ Phone Doctor Plus (checks all hardware components).
Download one of these and run a proximity sensor test, and if the app shows that the sensor is not responding, it's a hardware problem.
3. Verification through MIUI settings
In some versions MIUI There is a hidden function of checking sensors:
- Go to Settings. → The phone.
- Click 5 times on the MIUI version to activate the developer mode.
- Back to Settings → Additionally. → For developers.
- Find the Debugging by USB and turn it on.
- Connect your phone to your PC and use the command: adb shell dumpsys sensorservice In the output, find the line with proximity - there will be the status of the sensor.
If the sensor shows a constant value of "0" or "1" regardless of the approach of the hand, this indicates hardware failure or damage to the plume.
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If the engineering menu doesn't open, try the combination ##4636## → "Phone information" → "Sensor test".
Why the proximity sensor may not work
The reasons for the malfunction of the proximity sensor in Xiaomi smartphones fall into two categories: software (which can be fixed independently) and hardware (require repairs).
Programmatic reasons
- 📱 Firmware failure after update MIUI (Especially important for beta versions).
- 🔧 Incorrect settings (disabled screen switching off during a call).
- 🦠 Viruses or conflicting applications (e.g., screen locking programs).
- 🔄 Resetting settings to factory without further sensor settings.
Hardware causes
- 💥 Falling phone, causing damage to sensor or plume.
- 💧 Moisture ingestion (even if the phone hasn't sunk, condensation can cause corrosion).
- 🛡️ Factory marriage (found in budget models, for example, Redmi) 9A).
- 🔋 Wear over time (IR sensors lose sensitivity through the 3-4 year-end).
Most often, users experience software failures, for example, after updating to the MIUI 14 Many Xiaomi Owners 11T Pros complained that the screen stopped going out during calls, whether it was a reset or a rollback to a previous firmware version.
| Symptoms. | Probable cause | Decision |
|---|---|---|
| The screen does not go out during the call. | Disabled function in settings | Enable Settings → System applications → Phone. → The screen turns off during the call. |
| The sensor only works in a dark room. | IR sensor contamination or bright light | Clean the sensor, use the phone in a less lit place |
| Spontaneous switching on/off of the screen | Conflict with protective glass or film | Replace the protective glass with a cutout for the sensor |
| The sensor is not responding at all. | Hardware failure or damage to the plume | Diagnostics at the service center |
⚠️ Note: If the sensor stopped working after the screen was replaced, it is likely that the master damaged the plume or improperly connected the new display.
How to fix problems with the proximity sensor
If the proximity sensor is not working properly, try the following solutions (from simple to complex):
1. Check the settings MIUI
Sometimes the problem lies in the disabled function:
- Open Settings → System applications → Phone.
- Make sure the screen is turned off during the call.
- If it is not, check the settings. → Screen. → Sleeping mode. → Turn off the screen when approaching.
2. Clean the sensor.
IR sensors are sensitive to contamination.
- 🧴 Cotton swab soaked in alcohol.
- 🕯️ A flashlight to see the location of the sensor (usually next to the front camera).
- 🧹 Soft brush (for example, to clean the camera lenses).
Carefully clean the sensor area. Don't use sharp objects!
3. Remove the protective film or glass
Many of the security glasses and film block the IR signal.
- Remove the protective glass and check the sensor.
- If the sensor is working, buy glass with a notch for sensors.
4. Update or reinstall the firmware
Failures after update MIUI — It's a common cause of problems:
- Update to the latest stable version of the firmware.
- If the problem appears after the update, roll back to the previous version via Settings. → The phone. → Updating the system → Three points. → Select a Service Package.
- In extreme cases, perform a reset to factory settings (don’t forget to make a backup!).
Calibration of the sensor
In some Xiaomi models, the sensor can be calibrated manually:
- Please dial the phone application ##6484##.
- Select Proximity Sensor.
- Press Calibrate and follow the instructions.
If nothing worked, it's probably a hardware problem.
- Contact the Xiaomi service center (if the phone is warranty).
- Check the cost of replacing the sensor - in budget models (Redmi 9, POCO M3) It will cost 500-1500 rubles, in flagships (Xiaomi 13) - 2000-3500 rubles.
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Before visiting the service center, be sure to back up the data - a complete phone reset may be required during hardware repairs.