The problem with the proximity sensor on the smartphones of the line of Redmi is one of the most discussed among users of the budget and mid-size segment. Owners of the Xiaomi Redmi Note 8 T model often face a situation when during a phone conversation the screen does not go out when the device is brought to the ear, which leads to accidental pressing of the cheek or ear. This not only causes discomfort, but can cause interruption of important communication or sending erroneous messages in messengers.
In most cases, the sensor is not software-enabled, but requires proper calibration or removal of a physical obstacle. The Android system installed on the device fully supports the infrared sensor located at the top of the housing above the display. However, failures in the MIUI shell or accumulated cache can disrupt the correct transfer of data from the sensor to the processor.
This article will help you understand the causes of the malfunction and take steps to restore normal operation of the gadget. We will look at both standard methods of setting through the engineering menu, and more complex methods, including cleaning the interface and checking protective films. In 90% of cases, the problem is solved by simple calibration through the hidden menu of the engineer, without the need to flash the device.
The reasons for the incorrect operation of the sensor on the Redmi Note 8 T
Before you start activating functions, you need to understand the nature of the failure. On the Redmi Note 8 T, the proximity sensor is designed as a separate module located in a narrow frame above the screen, rather than embedded in the display itself, as in more expensive flagships. This makes it sensitive to contamination, dust and improperly pasted protective accessories. Often users do not even suspect that the thick protective glass covers the infrared beam.
Software conflicts also play a role: After updating the operating system or installing third-party launchers, the calibration settings can get lost, the system starts getting incorrect data about the distance to the object, believing that the phone is near the ear when it is not, or vice versa, ignores the approximation, in some cases, the culprit is the malfunction of a particular application for calls.
⚠️ Note: If you have recently changed the screen or repaired the case, make sure that the sensor plume is tightly inserted into the motherboard connector. Mechanical damage to the plume during sloppy assembly is a common cause of complete failure of the function.
Also worth considering is the effect of magnetic fields and covers. Some Xiaomi accessories have magnetic fasteners or inserts that can interfere with the operation of electronic components. If you use a thick shockproof case, check if it does not overlap the upper edge of the device where the sensor is located.
Diagnostics and check of the sensor status
The first step before any manipulation is to make sure that the problem is software-based, not a physical defect, and for that, there is a built-in testing tool in the MIUI shell that allows you to check the response of all sensors without installing third-party software, and the tester is launched through a special engineering menu.
To enter Diagnostic mode, dial ##6484## on your phone keyboard. Once you enter the last digit, the CIT menu (Customer Information Test) will open. In the list that appears, find Proximity Sensor or Approximation Sensor. Click on it to enter the Check Mode. You will see two values: the current state (usually 0.0 or 5.0) and the threshold value.
In the test, hold your hand to the top of the screen at a distance of 2-3 cm. If the sensor is working, the value on the screen will change, and the phone may emit an audible signal or vibration. If there is no reaction, try to wipe the top frame with an alcohol wipe. In case of no reaction, even after cleaning, it is likely that hardware replacement of the module or deep calibration is required.
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Before testing, remove the protective case to rule out its effect on the sensor readings, which will help to obtain more accurate diagnostic results.
Calibration of the sensor through the engineering menu
If the diagnostics show that the sensor is responding but is not responding correctly (e.g., the screen goes out too soon or too late), you need to calibrate. This procedure "trains" the system to correctly determine the distance to the object. On the Xiaomi Redmi Note 8 T, this process can be performed directly in the CIT menu, which we opened earlier.
When you're in the Proximity Sensor, look at the instructions at the bottom of the screen. You'll usually need to close the sensor with your hand (simulated earlifting) and press the Pass or Calibrate button, then remove your hand and confirm the action again. Repeat the cycle several times until the system accepts the calibration. Successful completion of the procedure is usually accompanied by a green indicator or the words Success.
☑️ Calibration checklist
In some versions of MIUI firmware, the interface may be different. If the standard calibration in the CIT menu doesn't help, you can try resetting the calibration data through the developer menu, but this requires the inclusion of USB debugging. For most users, the standard procedure described above is enough. After successful calibration, be sure to restart the device for the changes.
⚠️ Warning: Do not interrupt the calibration process. If you remove your hand early or press the wrong button, the data may be recorded incorrectly, which will exacerbate the screen problem during calls.
Configure through the Engineering Mode application
For a more subtle setup that is not available in the standard test menu, many users resort to using the Engineering Mode app.This is a third-party utility available in the Play Market that provides access to hidden modem and sensor settings. Download the application and give it the necessary access rights when you first start.
In the application interface, go to the Common section and select Proximity Sensor. Here you can see more detailed graphs and values. If you see values "jump" without touching the screen, the sensor may be faulty. If the values are stable but the screen is not going out, try changing the threshold (Threshold).
An alternative way is to use ADB-commands to reset the sensor settings if a software failure has blocked the possibility of calibration. USB And put in a command:
adb shell settings put system proximity_sensor_state 0This command forcibly resets the sensor state, and then you have to restart the smartphone, and this is effective when the software bug prevents the system from re-initiating the module in a normal reboot.
What if the Engineering Mode does not see the sensor?
Physical factors and elimination of interference
There's no need to ignore the physical reasons, as on the Redmi Note 8 T, the sensor is very close to the speaker and notification LED. Dust, pocket villi or greasy fingerprints are able to block infrared radiation. Use a soft microfiber and a small amount of isopropyl alcohol to clean the top of the front panel.
Pay special attention to protective glass. Cheap films often have opaque edges or simply do not have a technological cutout for the sensor. If you recently pasted a new glass and immediately after that the sensor stopped working, the problem is almost certainly in it. Take off the glass and check the sensor. If it works, replace the accessory with a better one, marked "Compatible with proximity sensor".
| Type of interference | Symptoms. | Decision |
|---|---|---|
| Protective glass | The screen doesn't go out at all. | Replacement of glass with a model with a cutout |
| Pollution | The screen goes out chaotically | Drying with an alcohol napkin |
| Cover | It works in your pocket. | Removal of cover or trimming |
| Moisture | False positives | Drying device (without hair dryer) |
Moisture can also cause false positives. If the phone is caught in the rain or in a room with high humidity, the condensate can create a conductive bridge on the contacts of the sensor. In this case, do not use a dryer to dry, as hot air can damage the adhesive bases of the display.
Solving problems through developer settings
Sometimes the standard system settings conflict with energy saving, turning off the sensor to save charge. To eliminate this factor, activate the developer menu. To do this, go to Settings → About the phone and quickly press 7 times on the MIUI version.
Then go to Advanced Settings → For developers. Find a section related to network or multimedia and check if there are options that force sensors to turn off. Some versions of Android have an option called Adaptive Brightness, which can affect the operation of light and proximity sensors. Try turning it off and turn it back on.
⚠️ Attention: The developer menu contains critical system settings. Do not change the settings that you do not know, so as not to disrupt the stable operation of the Xiaomi operating system.
Also on the developer menu, you can find the option to reset all settings to factory without deleting user data, a softer option than a full reset, which can help if the problem lies in deep system configuration errors.
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Activating the developer menu allows you to access hidden sensor management settings that are not visible in the normal interface.
Resetting and software update
If none of these methods worked, there are two radical but effective ways: One is to update your firmware to the latest available version. Go to Settings → Phone → System Update. Even if the system says you have the latest version, try clicking on three dots in the corner and select "Check for updates." Sometimes hidden patches come out that fix sensor errors.
The second method is a full Hard Reset. Before you do that, make sure to back up all the important data as it will be deleted. Go to Settings → Phone → Settings → Reset → Erase all the data. Once reset, the phone will return to factory status and all the software conflicts will be fixed. This often helps if the problem occurs after a failed update or installation of "severe" themes.
In conclusion, the Redmi Note 8 T has a robust hardware base and sensor problems are often solved software-based, and regular cleaning of the top of the screen and the use of quality accessories will help avoid a recurrence of malfunction in the future.