Approximation sensor in the smartphone Xiaomi Redmi: the principle of operation, configuration and problem solving

Have you ever wondered why your Xiaomi Redmi screen goes out during a phone call as soon as you hold the device to your ear? Or why sometimes touch buttons don't respond when you call? All of this is due to a tiny but crucial component, the proximity sensor, without which using your smartphone would be not just uncomfortable, but sometimes impossible.

In this article, we will analyze in detail what is the proximity sensor in Xiaomi Redmi smartphones, how it is arranged, what functions it performs and why its malfunction can turn even the flagship device into a “brick”. You'll also learn how to test the sensor for yourself, calibrate it, and fix the typical problems without going to the service center. MIUI, Which most users don’t even know about!

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 ear or hand) close to the screen of a smartphone. In Xiaomi Redmi smartphones, it is usually located at the top of the display, next to the front camera and light sensor, and its operation is based on infrared radiation:

The sensor emits an IR beam that bounces off nearby objects and returns back, and depending on the time of delay and the intensity of the signal reflected, the smartphone "understands" how close the obstacle is. If the object is too close (for example, when you hold the phone to your ear), the system automatically turns off the screen and touch buttons to:

• 📵 Prevent accidental tapping during conversation (cheek, ear, or fingers).
• 🔋 Save battery power, as the backlight of the screen is one of the main "eaters" of energy.
• 👂 Improve sound quality, as the microphone better captures voice when the screen is off.
• 🛡️ Protect the display from scratches and prints that may remain with prolonged skin contact.

In smartphones Xiaomi proximity sensor is closely integrated with firmware MIUI. Algorithms for processing its signals are constantly being improved, for example, in the new models of Redmi Note 12 and Redmi. K60 Support for dynamic calibration is added, which automatically adjusts the sensor sensitivity to environmental conditions (bright sun, darkness, humidity).

Where is the proximity sensor in Xiaomi Redmi

The location of the sensor depends on the model of the smartphone and the design of its front panel.In most Xiaomi Redmi devices (for example, the Redmi Note). 10/11/12, Redmi 9/10/11) It's located to the right of the front camera, under the display glass. In models with a cut-out under the camera ("drop"), the sensor is usually hidden behind a black strip next to the speaker. K50) It can be found under the screen, just to the left of the lens hole.

To accurately determine the location of the sensor on your model, follow the following steps:

1. Enable Developer Mode (Go to Settings) → The phone. → Version. MIUI and press 7 times in a row).
2. Return to the main settings and open Additional settings → Developer settings.
3. Activate the Debugging option USB Visualization of the boundaries of elements.
4. Run any call (you can call another phone) and hold your hand to the top of the screen, the area where the screen goes out is the sensor's range.

In some models (e.g. Redmi). 8A Or Redmi 7, the proximity sensor can be combined with the light sensor in a single module, which saves space, but sometimes leads to conflicts in operation — for example, the screen can spontaneously go out when the lighting changes.

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If you have a smartphone with AMOLED-screen (e.g. Redmi) K40 Or the Redmi Note 11 Pro.+), The proximity sensor can be hidden under the display, and in this case, it's not visible visually, but the range remains the same -- upper right corner.

Why you need a proximity sensor: 5 key functions

Many users mistakenly believe that the proximity sensor is only used to turn off the screen during a call, but in fact, its tasks are much broader.

Interesting fact: in the firmware MIUI 14, a smart approximation feature that analyzes user habits, for example, if you often pull your phone away from your ear to look at the screen while you're talking, the system automatically reduces the sensor sensitivity so that the screen doesn't go out immediately.

⚠️ Note: If the proximity sensor fails, the smartphone will behave unpredictable – the screen can go out arbitrarily, do not respond to touches or, conversely, remain on during the call. Not only is this annoying, it also leads to quick battery discharge (up to 30% per hour of talk!) and the risk of accidental tapping.

How to check the proximity sensor on Xiaomi Redmi

If you notice that your Redmi screen is acting strangely (it doesn’t go out when you call, it turns off spontaneously or it reacts with a delay), the first thing you need to do is check the operability of the proximity sensor.

Method 1: Testing through the Engineering Menu

This is the most reliable method, because it shows the raw data from the sensor.

Open the phone app and dial ##6484##

Select Proximity Sensor (Proximity Sensor)

Put your hand to the top of the screen – the value should change from 5.0 cm to 0.0 cm

Remove your hand – the value should return to 5.0 cm

If the numbers do not change or show incorrect data, the sensor is defective.-->

In some models (e.g. Redmi). 9A or Redmi 8) the engineering menu code may differ:

• ##4636## → Testing of equipment → Sensors.
• #36446337## (for older versions of MIUI)

Method 2: Checking through applications

If the engineering menu is not available, use third-party utilities:

• 📱 CPU-Z (Sensors section – shows the status of all sensors.
• 🔍 Sensor Test – a specialized diagnostic application.
• 🛠️ MIUI Hidden Settings – reveals hidden firmware features.

Important: Check reviews before installing apps – some utilities may contain ads or collect data. Official applications from Xiaomi (such as Mi Check) are safe, but their functionality is limited.

Method 3: Visual Testing

If you don’t have access to the engineering menu, try this method:

1. Call another phone (or use a voice assistant).
2. Hold the Redmi to your ear – the screen should go out through the ear. 1-2 seconds.
3. Remove the phone – the screen should turn on immediately or after pressing the power button.
4. Repeat the action. 3-5 If the screen is delayed (more than 3 seconds) or not switched back on - the sensor requires calibration.

⚠️ Note: On some models (e.g. Redmi Note 8 Pro), the proximity sensor may conflict with the film or glass on the screen. If you recently put on the protection, try removing it and repeating the test. Thick or poor quality films block the infrared signal!

Typical problems of the proximity sensor and their solutions

Even with the new Xiaomi Redmi smartphones, the proximity sensor can malfunction, and here are the most common problems and ways to fix them:

Problem 1: The screen does not go out during the call

Reasons:

• 🔧 Sensor contaminated (dust, sweat, cosmetics).
• 📱 Damaged plume or contacts after falling.
• 🤖 Firmware failure (especially after update) MIUI).
• 🛡️ Disabled function in settings.

Decisions:

1. Wipe the top of the screen with an alcohol napkin (without pressing!).
2. Check the settings: Settings → System applications → Phone. → Turn off the screen during a conversation (should be turned on).
3. Reset the sensor settings: ##6484## → Proximity Sensor → Calibrate.
4. If nothing helps, you need to replace the sensor (cost in the service: 800-1500 ruble).

Problem 2: The screen goes out too soon or too late

It's due to incorrect calibration.

Open the engineering menu (#6484##)

Choose Proximity Sensor

Press Calibrate (Calibrate)

Put your hand away from the screen. 3-5 once-in-the-system

Reboot your smartphone-->

If calibration doesn't help, try resetting the settings. MIUI (without deleting data: Settings → The phone. → Resetting settings.

Problem 3: The sensor is activated arbitrarily

This is most often due to:

• 📱 Magnet case (magnetic field interferes with sensor).
• 💧 Moisture under the screen (after rain or bathing).
• 🔋 Overheating of the processor (the sensor begins to "glutch" at a temperature above 50)°C).

Decisions:

• Remove the case and check the sensor.
• Put your phone in rice or silica gel on 12-24 hour (if moisture is involved).
• Use the Cool Tool app to cool the processor.

Hidden functions of the proximity sensor in MIUI

Few people know, but the proximity sensor in Xiaomi Redmi can be used not only to turn off the screen. MIUI hidden-in:

1. Quick flashlight activation

In some models (for example, Redmi Note 10 Pro) you can adjust the activation of the flashlight with a gesture:

1. Go to Settings → Additional settings → Gestures.
2. Turn on the flashlight option when approaching.
3. Now, to turn on the flashlight, it is enough to swipe your hand twice above the top of the screen (where the sensor is located).

2. Automatically answer the call

The "Rise to Answer" function uses the proximity sensor and accelerometer:

• 📞 Included in Settings → System applications → Phone. → Answer automatically.
• 🤳 It works like this: when you hold your phone to your ear during an incoming call, it will automatically pick up the phone.

3. hidden mode "Do not disturb" during a conversation

If you receive a notification during the call, the proximity sensor can automatically:

• 🔕 Turn off the notification sound.
• 📵 Block pop-ups.
• 📴 Dim the vibration.

To activate this function, go to Settings → Notifications → Don't disturb mode" → Automatic rules → During the call.

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The proximity sensor in Xiaomi Redmi is not only a tool for saving battery, but also the key to hidden capabilities. MIUI. Proper setting allows you to automate routine actions and make using a smartphone even more convenient.

How to turn off the proximity sensor (and whether it is worth it)

Some users want to turn off the proximity sensor because they think it's "interfering," but it's not recommended, because without the sensor, you'll have to:

• 📵 Accidental taps during a conversation (the cheek may activate a speakerphone or complete a call).
• 🔋 Accelerated battery discharge (the screen will burn in vain).
• 👂 Deterioration of communication quality (microphone will be worse to catch voice).

If you still want to turn off the sensor, do it through the engineering menu:

1. Dial ##6484##.
2. Select Proximity Sensor.
3. Press Disable (Disable).

Alternative way (for root users):

su


echo 0 > /sys/class/sensors/proximity/enable

⚠️ Warning: Disabling the proximity sensor may cause some functions to malfunction MIUI, For example: - Automatic answer to a call. - Gestures for a flashlight or camera. - Ear mode to improve sound. To return everything back, restart the phone or re-activate the sensor in the engineering menu.

FAQ: Frequent questions about the proximity sensor in Xiaomi Redmi