Calibration of autobrightness on Xiaomi: how to configure the light sensor and fix errors

Automatic screen brightness is one of the most useful features of modern Xiaomi, Redmi and POCO smartphones, which must adapt the display illumination to ambient light. However, many users are faced with the fact that the autobrightness works incorrectly: the screen is too dim in bright light, too bright in the dark or changes the backlight dramatically for no apparent reason, the reason most often lies in the wrong calibration of the light sensor or malfunction of the MIUI algorithms.

In this article, we will understand how to correctly calibrate autobrightness on Xiaomi devices, including models with a high-performance model. AMOLED- and IPS-And we'll also look at the solutions to the typical problems, and you'll learn where the light sensor is, how to reset it to the factory settings, and what to do if the calibration doesn't work. Special attention will be paid to hidden settings through the engineering menu and third-party applications for fine tuning.

Why does the autobrightness on Xiaomi work wrong?

Before you start calibrating, it's important to understand why autobrightness can behave inappropriately.

• 🔍 Illumination sensor contamination – dust, greasy traces or protective film can distort readings.
• ⚙️ Failure in settings MIUI — after updating the firmware or resetting, the autobrightness parameters can fly.
• 📱 Hardware restrictions – cheap models (e.g. Redmi) 9A or POCO C31) They are often equipped with low-quality sensors.
• 🔄 Conflict with third-party applications – some programs (such as Lux Auto Brightness or Tasker) may interfere with the standard algorithm.
• 🌡️ Extreme temperatures – in overheating or extreme cold, the sensor may give incorrect readings.

If the autobrightness started to glittle after a phone drop or moisture hit, the problem may be physical damage to the sensor, in which case calibration will not help - it will need repairs, and it is worth checking whether the settings include Reading or Vision Protection, which forcibly reduces brightness regardless of the ambient light.

Where is the light sensor on Xiaomi?

The ambient light sensor on most Xiaomi smartphones is located at the top of the screen, next to the front camera.

• 📱 Xiaomi 11/12/13 series, Redmi Note 10/11/12, POCO F3/F4/F5 — The sensor is hidden under the display (for AMOLED-screens) or in a small cutout to the right of the camera.
• 📱 Redmi 9/10, POCO X3/M3 — The sensor is seen as a tiny black dot next to the speaker.
• 📱 Xiaomi Civi, Mix 4 – sensor integrated into the chamber module (under glass).

To check whether the sensor is working, you can use the test mode:

1. Open the Phone app and type ##6484## (for some models, #4636##).
2. Select the Hardware Testing option → Sensors.
3. Cover the sensor with your finger – the Light sensor value should drop sharply to 0 or close to it.

If the readings don't change, the sensor is malfunctioning or is software-level disabled, and in this case, the calibration is meaningless, and you need to have a diagnosis at the service center.

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On some models (such as the Xiaomi 12 Pro), the light sensor is combined with the proximity sensor, and if you don't have autobrightness and lock the screen during the call, the problem may be in the general module.

Method 1: Calibration of autobrightness through standard MIUI settings

The easiest method is to use the built-in MIUI tools. It is suitable for most devices, including the Redmi Note 11 Pro, Xiaomi 12T and POCO X5.

1. Go to Settings → Display.
2. Activate the Auto Brightness slider (if it is turned off).
3. Slip on the inscription "Autobrightness" (not on the slider!) - the calibration menu will open.
4. Follow the instructions on the screen: the phone will suggest adjusting brightness in a dark and light environment.

During calibration:

• 🌑 In a dark room, set a comfortable brightness level for the eyes (usually). 20-30%).
• ☀️ In bright lighting (for example, under a lamp or on the street), select a value at which the text is well read, but the screen does not blind (60-80%).

Once you save the settings, the system will remember your preferences and adjust the brightness automatically. If the result does not suit, repeat the procedure.

Close the curtains or turn off the lights for dark environments|Make sure that the sensor does not receive direct sunlight.|Remove the protective film or cover covering the top of the screen|The battery should be at least 30%-->

Method 2: Reset autobrightness settings to factory

If the calibration doesn't work, try resetting the brightness settings, which will help if you've previously experimented with manual settings or installed third-party applications to control backlighting.

1. Open the settings → Display → Autobrightness.
2. At the bottom of the screen, find Reset brightness settings (on some firmware - Restore default values).
3. Confirm the action.

After discharge:

• 🔄 Autobrightness will work according to the standard algorithm MIUI.
• 📱 Recalibration may be required (see Method 1).
• ⚠️ Manual brightness settings (such as in Google Books or Chrome apps) will also reset.

If there is no brightness reset, try an alternative method:

1. Turn off Auto Brightness in the settings.
2. Manually set the brightness to 50%.
3. Reboot the phone.
4. Turn on the autobrightness again and perform the calibration.

Method 3: Fine tuning through the engineering menu (for advanced)

If standard methods don't work, you can try calibrating the light sensor through an engineering menu (Engineer Mode), which is suitable for advanced users and requires caution!

Instructions:

1. Open the Phone app and enter the code: ##3644633## Some models (e.g. POCO F1) may require a code: #4636###
2. Go to Hardware Testing → Sensors → Light Sensor.
3. Remember the current Min and Max values (usually 10-50000 lux).
4. Go back to the main menu of the engineering mode and select Light Sensor Calibration.
5. Follow the instructions on the screen (usually cover the sensor and then illuminate it with bright light).

Warning: Incorrect values in the engineering menu can lead to sensor malfunction or even overheating of the screen. If you are not sure, do not change the settings!

Method 4: Using third-party calibration applications

If the built-in MIUI tools don't work, you can use third-party tools.

• 📱 Lux Auto Brightness - allows you to create your own brightness profiles for different lighting conditions. ADB-permissions for full control.
• 🌓 Velocity: Auto Brightness uses machine learning algorithms to adapt. AMOLED-screen.
• 🔧 Screen Filter – does not replace autobrightness, but allows you to additionally darken the screen if necessary.

Example of Lux Auto Brightness setup:

1. Install the app from Google Play.
2. Permission to change system settings (required) ADB-Command: adb shell pm grant com.vito.lux android.permission.WRITE_SECURE_SETTINGS
3. In the app, select Auto (Manual) and adjust the brightness curve by moving the dots on the chart.
4. Save the profile and activate it.

Advantages of third-party applications:

• ✅ More flexible setting than in MIUI.
• ✅ The ability to create separate profiles for day/night time.
• ✅ Support AMOLED-Adaptive color temperature screens.

Disadvantages:

• ⚠️ Increased battery consumption (the application works in the background).
• ⚠️ Possible conflicts with system autobrightness (you need to turn off the standard function).

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The side of the application for autobrightness requires permission WRITE_SECURE_SETTINGS, which can be provided only through ADB. Without it, they will be working in a limited mode.

What do you do if nothing helps?

If all methods have been tried, but the autobrightness still works incorrectly, check the following points:

⚠️ Note: Some Xiaomi models (e.g. Redmi) 9T or POCO M4 Pro) the problem may be due to a hardware defect in the sensor. If after calibration the brightness jumps or does not change at all, contact the service center.

• 🔄 Update the firmware - in new versions MIUI They often fix sensor bugs. Check the updates in Settings. → The phone. → Updating the system.
• 🧹 Clear the cache: Turn off the phone. Press the power button. + Volume up to log in to Recovery. Select Wipe Cache (not Wipe Data!).Reboot the device.

Check the developer's settings

USB debugging

Keep the screen down.

Settings → The phone. → Version. MIUI

Developer settings

If the problem occurs after installing custom firmware (such as LineageOS or Pixel Experience), the reason may be the lack of drivers for the sensor.

1. Check if your firmware supports light sensor (information is available on the XDA Developers forum).
2. Install the Magisk module to fix sensors (e.g. Sensor Disabler).

FAQ: Frequent questions about autobrightness on Xiaomi