Searching for the proximity sensor on the Xiaomi Redmi 8 smartphone is often a necessity when the device starts to behave unpredictably during a conversation.The screen may not go out when you bring the phone to your ear, or, conversely, lock at the most inopportune moment, interrupting dialing. Understanding the physics of the location of this element is critical for proper diagnosis of problems.
Unlike older models where the sensor could be seen by the naked eye, modern gadgets hide it under the display. On Redmi 8, this component is integrated into the top of the front panel, but it depends on the software and the absence of physical obstacles, and we will discuss how to find this module, check its performance and what to do if standard methods stop working.
Sometimes the problem isn't a breakdown, but a simple calibration problem: software failures can knock down sensitivity settings, causing the phone to stop responding properly to objects approaching. Below are detailed instructions to help you return the device to normal functionality without going to a service center.
Physical location of the sensor on the body
On the Redmi 8, the manufacturer has abandoned the in-hole infrared sensor that was typical of earlier budget lines. Now the touch zone is hidden under the screen's protective glass. Visually, you can see a slight dimming or a specific area at the top of the screen, next to the speaker.
Technically, the proximity sensor is in the upper center, or slightly offset, depending on the board revision, but always in the immediate vicinity of the upper end. This is the area that needs to stay clean. If you use a low-quality protective glass or a dense case with high sides, they can block the beam, giving the illusion that the phone is constantly near the ear.
⚠️ Attention: Using cheap, black-framed perimeter safety glasses is a common cause of failures. The frame can block the invisible beam of the sensor, causing the screen to go out chaotically.
To determine the exact location, try running the engineering menu (which will be discussed below) and holding your finger to different points on the top of the screen, where the readings change from 0.0 to 5.0 (or similar values), and the active zone of the sensor is located.
It's important to consider that the Xiaomi Redmi 8 doesn't have a separate physical hole next to the camera for this feature, as it was in some Redmi Note models of past years.All the electronics are hidden under the display, making the device more sealed but more sensitive to accessory quality.
Checking the work through the engineering menu
The most reliable way to find and test a sensor is to use MIUI's built-in diagnostic tools. The engineering menu allows you to see raw data from the sensor in real time, eliminating the operating system's impact on signal processing. This is the first step in any professional diagnostics.
You don't need root rights to enter the test mode, just open the standard Phone app and enter a special combination of characters, and once you enter the last digit, the menu will open automatically, and you're interested in the section related to the Proximity Sensor.
In the window that opens, you'll see a numerical value. Usually, when there's nothing in the way of the sensor, it'll show "0.0" or "5.0" (depending on the firmware version and the type of calibration you've got), if you put your palm to the top of the screen, the numbers should change, and if you don't react, it'll indicate a software failure or a physical failure.
☑️ Sensor diagnostics
If you don't have to jump or you don't change your hand, you need to recalibrate. Often, it's the discrepancy between the actual position of objects and the values you've written in memory that causes problems. There's a button for automatic calibration that's often available in the same menu.
Software calibration of the sensor
When a physical check confirms that the sensor is responding but is acting strangely in real calls, it requires software calibration, a process where you train the phone to understand what is near and far. On Redmi 8, you can do this through the same engineering menu.
In the sensor testing section, find the Calibration or Calibrate button. The process is simple: you remove your hand from the screen, press the button, then close the top of the screen with your hand and press the confirmation button again, and the system will record new sensitivity thresholds.
After successful calibration, the phone may ask for a reboot. Don't ignore this request, as new settings must be written to the device's permanent memory. Without rebooting, MIUI can continue to use the old, downgraded settings.
| Symptoms. | Probable cause | Method of decision |
|---|---|---|
| The screen doesn't go out when you ring. | Pollution or calibration failure | Wipe the top of the screen, do the calibration. |
| The screen goes out in your hand | Finger's blocking the sensor | Change the grip, remove the cover. |
| Interlocutor hears an echo | Don't switch the speaker | Checking in the engineering menu |
| Sensor's not responding. | Physical breakdown of the plume | Replacement of module in the service |
It is worth noting that after updating the Android operating system or the MIUI shell, the sensor settings can be reset to factory ones, so if problems start immediately after the software update, recalibration almost always solves the problem.
What if calibration doesn’t help?
Influence of accessories and protective glasses
Often, owners of Xiaomi Redmi 8 do not even suspect that the cause of all the troubles is a recently pasted protective glass. Accessories manufacturers do not always take into account the exact location of the sensors under the display.
Check if your glass covers the area above the speaker, sometimes it helps to shift the glass slightly (if it is not already glued to the top) or replace it with a model with a cutout under the sensor. In extreme cases, some users carefully paint the black glass frame with a marker to change the optical properties, but this is a risky method.
Cases can also be the culprits. If the sides of the case are too high and hang over the screen, the phone may think it's in your pocket or in your ear. Take off the case and check the device's naked. If the problem is gone, the accessory is to blame.
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Try to wipe the top of the screen with an alcohol napkin, and fat spots from your fingers can distort the optical sensor, creating a constant approach.
Glass quality matters. Cheap glass can have uneven transparency or distortion in the upper end, which is critical for an infrared emitter. Original accessories or proven brands usually have the right cutouts and transparency.
System settings and sensor lock
There are software switches in the MIUI shell that can force the sensor to turn off or change its logic, such as the In-Pack mode, which is designed to block random taps, but it can also interfere with the normal operation of the proximity sensor during a call.
Go to the settings and find the section that's associated with the lock screen or special features, and there might be a "Mode in your pocket" option, if it's activated, try turning it off and see if the behavior of the phone changes, and sometimes third-party call management apps conflict.
Also worth checking is the theme settings. Some custom themes downloaded from MIUI Themes store may contain errors in the code controlling the screen during a call. Switch to the standard theme "Classic" or "No Limits" to rule this out.
Note that call-blocking apps take precedence over system functions and may not properly process hardware signals. If you use these applications, try temporarily removing them for testing.
Solving the iron problem
If neither calibration, removal of the glass, nor flashing helped, there is likely a physical malfunction. On the Redmi 8, the proximity sensor is often integrated into the display plume or into a separate module of the front camera, falls, moisture intrusions or just a factory defect can put it out of order.
Symptoms of hardware failure: a constant value in the engineering menu (does not change when you close your hand), cracks in the top of the screen, moisture entering the speaker area, in which case software methods are powerless.
Repairs usually involve replacing the plume or the entire display module, which is done quickly in service centers, and self-replacement requires skills and tools, because the screen is glued around the perimeter and requires careful heating to remove.
⚠️ Warning: If the phone falls and the sensor stops working, don’t try to “develop” it with multiple taps, which can lead to detachment of the matrix plume and the appearance of stripes on the screen.
In some cases, a temporary solution in the form of a call management app that ignores the sensor and uses the volume button to reset or turn on the screen helps, but it is only a crutch, not a solution.
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If the sensor shows constant values in the engineering menu and does not respond to the hand, it is in 90% of cases a physical failure of the module or plume that requires replacement.