Approximation Sensor on Poco X3: tuning, calibration and problem solving

Xiaomi Poco X3 is a popular smartphone with a powerful filling, but even it can have problems with the proximity sensor. This small but important sensor is responsible for turning off the screen during a call when you hold the phone to your ear, as well as for automatic functions in some applications. If the sensor does not work correctly, this leads to accidental pressing, a screen that does not turn off or, conversely, to prematurely shutting down the display.

In this article, we will discuss how to check the proximity sensor on the Poco X3, calibrate it through the engineering menu, adjust sensitivity and fix typical malfunctions. You will also learn which applications will help diagnose the problem and when to contact the service center. Instructions will be suitable for all modifications of the Poco X3 (including the Poco X3 NFC and Poco X3 Pro), since they use the same hardware platform.

What is a proximity sensor and how it works on the Poco X3

The proximity sensor is an infrared sensor that detects the distance between a phone and an object (like your ear).

• 🔦 Infrared LED (IR LED) — light that is invisible to man.
• 👁️ Photodiode – captures the reflected signal and transmits data to the processor.

On the Poco X3, the sensor is located at the top of the screen, next to the front camera. When you hold the phone to your ear during a call, the sensor picks up the obstacle and turns off the display to avoid accidental touches. Once you pull the device away, the screen turns on again, which saves battery power and improves the user experience.

However, over time, the sensor may start to fail due to contamination, software errors or mechanical damage, for example, if the sensor gets dust or moisture, it may falsely fire or, conversely, ignore the approach of the object, and problems may occur after updating the firmware or installing custom ROMs.

How to check the operation of the proximity sensor on the Poco X3

Before you set up the sensor, make sure it is really faulty, and you can use both built-in MIUI tools and third-party applications to do this.

The easiest way is to test through the code of the engineering menu. Open the Phone app and type in the combination:

##6484##

Then you open the Manual Test menu, where you select Proximity Sensor, and you'll see a graph or a numerical value on the screen (usually 0 is no obstacle, 1 is an obstacle), and you'll close the sensor with your hand, and the value will change. If there's no reaction, the sensor won't work.

You can also use apps from Google Play, for example:

• 📱 Phone Doctor Plus – Checks all sensors, including the approximation.
• 🔍 Sensor Box for Android – Shows Detailed Sensor Information.
• 🛠️ CPU-Z — in the Sensors section displays data from the proximity sensor.

⚠️ Warning: If the sensor is not responsive in either the engineering menu or third-party applications, the problem may be hardware (a cable is damaged, contacts are oxidized or the sensor itself is out of order.

Calibration of the proximity sensor through the engineering menu

If the sensor is working but is not working correctly (for example, the screen goes off too early or does not turn off at all), calibration will help.

1. Open the Phone app and enter the code: ##36446337## This will open the Engineering Mode.
2. Go to Hardware Testing → Sensor → Proximity Sensor.
3. Press Calibration and follow the instructions on the screen. You usually need to put your phone on a flat surface and wait 10-15 seconds.
4. After calibration, restart the device.

If the engineering menu is not available (for example, it is blocked on some MIUI firmware), you can use the MTK Engineering Mode app (for phones with a MediaTek processor, like the Poco X3). Download it from Google Play, open and select Hardware Testing → Sensor → Proximity Sensor Calibration.

Make sure the screen is clean (wipe the sensor with a napkin)

Close all background applications

Connect your phone to charge (in case of a long procedure)

Do not interrupt the calibration process.

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Important: After calibration, the sensor may temporarily be unstable, which is normal. Give the phone 5-10 minutes to "get used to" the new settings.

Adjustment of the proximity sensor sensitivity

On Poco. X3 There is no built-in option to adjust the sensor sensitivity, but it can be changed using the ADB-For example, the Proximity Sensor Reset app allows you to manually set the trigger threshold.

If you prefer to use ADB, follow the following steps:

1. Enable USB debugging in the developer settings (Settings → About Phone → MIUI version – press 7 times, then go back to Settings → Additional → For Developers).
2. Connect your phone to your PC and type in the command: adb shell settings put system proximity_delay 1000 Here. 1000 — millisecond delay (1 You can experiment with the values of 500 before 2000.
3. To reset to standard settings, use: adb shell settings delete system proximity_delay

You can also change the parameter. proximity_offset, The one that controls the dead zone of the sensor, for example, the team:

adb shell settings put system proximity_offset 2.0

This will increase the distance at which the sensor starts to respond, and the optimal values are selected by experiment.

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If the sensor becomes worse after changing the settings, return the standard settings with the command adb shell settings delete system. proximity_offset and reboot the phone.

Typical proximity sensor problems and their solutions

Even after calibration, the sensor can behave incorrectly, and let's look at some of the most common problems and how to fix them.

If the problem occurred after the MIUI update, try to roll back to the previous firmware version or wait for a patch from Xiaomi. Sometimes sensor failures are associated with conflicts in the new version of the software.

⚠️ Warning: Some cases with magnets or metal inserts may interfere with the proximity sensor. If problems start after buying a new accessory, try removing it and testing the sensor again.

What to do if the proximity sensor is broken

If all the software methods have been tried, but the sensor still doesn't work, it's probably a hardware problem.

• 🔧 Check the plume - often contacts oxidize or go away. This will require disassembling the phone (it is better to trust this specialist).
• 🔄 Replace the sensor – the cost of a new part for Poco X3 is about 300-500 rubles, and the replacement in the service will cost 800-1500 rubles.
• 📱 Use alternative methods – if the sensor is not repairable, you can turn it off completely and control the screen manually (for example, the power button). screen_off_while_call 0 However, this is inconvenient, as the screen will remain on during calls.

Before visiting the service center, make a backup copy of the data, as you may need to reset your settings or replace the motherboard.

Prevention of malfunctions of the proximity sensor

To make the proximity sensor on the Poco X3 last longer, follow the simple recommendations:

• 🧼 Clean the screen regularly - dust and greasy traces can block the infrared signal. Use a soft wipe and alcohol wipes (no more than 70% alcohol).
• 🚫 Avoid bumps and falls – even minor mechanical impacts can displace the sensor or damage the plume.
• 🔋 Do not use your phone in extreme temperatures – overheating or hypothermia can cause sensor malfunctions.
• 🛡️ Install only official firmware - custom ROM Sometimes conflict with sensor drivers.

It is also worth periodically checking the sensor through an engineering menu or applications like the Sensor Box, which will help to detect a malfunction in time and prevent more serious problems.

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The proximity sensor is a consumable that wears out over time, with an average lifespan of 3-5 years, after which it may need to be replaced.

FAQ: Frequent questions about the proximity sensor on the Poco X3