Location of the proximity sensor on Xiaomi Redmi 8: search and configuration

Owners of the budget but reliable Redmi series often face a situation where the screen does not go out during a conversation or, conversely, interrupts the call immediately after putting the tube to the ear. On the Xiaomi Redmi 8, this problem is solved by understanding the physical design of the device, since it uses an industry-unconventional sensor layout. Many users mistakenly look for a separate hole in the upper part of the case, unaware that the company’s engineers have hidden a key element under the display.

Understanding where the proximity sensor is on the Xiaomi Redmi 8 is critical to properly diagnosing faults. If you search it from the outside, you will be wasting your time because there is no visible window. In this article, we will take a closer look at the front panel architecture, explain the technology’s operation, and provide step-by-step instructions for software calibration that eliminates malfunctions 90% of the time.

⚠️ Warning: Don't try to disassemble your smartphone or remove the protective glass in search of a sensor.The internal components of the Redmi 8 are tightly located, and careless interference can damage the display plumes or the light sensor itself.

Features of the design of the front panel Redmi 8

The Redmi 8, launched in 2019, was one of the first low-end models to move away from the cut-out or mechanical lift of the camera in favor of a classic framed design, and it was the presence of a wide bezels at the top and bottom that enabled the introduction of Proximity Sensor under Display, which means that the optical sensor is hidden directly under the screen matrix, at the top of the screen, above the brand logo.

This solution has its advantages and disadvantages. On the one hand, the design looks holistic, without black islets or holes. On the other hand, the sensor works less accurately than its physical counterparts, because the light must pass through several layers: the protective glass, the display matrix itself and the glue layer. The optical sensor responds to a change in reflected light, and any interference, such as a thick protective film or dirt, can distort its readings.

And it's important to note that in this model, the proximity sensor is integrated into one module with a light sensor, and they're in the same spot, but they're different, and if you're having problems with the automatic brightness of the screen, it could also indicate that the area above the Redmi logo is contaminated, and the cleanliness of this area is the key to the correct operation of all front-facing sensors.

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Use a microfiber to wipe the top of the screen. Fat fingerprints create a thin film that scatters the light of the infrared emitter and knocks the sensor calibration.

Exact location of the sensor under the screen

If we could look inside a smartphone, we would see that the physical module is located right in the center of the top of the case, directly under the speaker, and visually on the screen, this zone is impossible to determine, but when the display is turned off, under bright light, you can sometimes notice a subtle dimming in the area above the logo, and this is where the infrared emitter emits beams that reflect off the object and return to the receiver.

The distance between the sensor and the screen surface is minimal, which creates specific requirements for accessories. Users often complain that after gluing a new protective glass, the phone stops responding correctly to the approach, this is because cheap glasses can have an opaque edge or insufficiently high-quality glue in the central upper part, blocking the IR ray.

To determine the sensitivity zone accurately, you can use the engineering menu below, but the physical coverage area is about 1-1.5 centimeters in diameter around the central axis above the logo, and anything that falls within that radius during a call is considered by the system as "object nearby," and the screen must go out.

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Physically, the sensor is located under the screen in the upper central part, but the software area of its sensitivity can be wider and cover the area around the Redmi logo.

Diagnostics of work through the engineering menu

Before you bring your device to the service or reset your settings, you need to make an accurate diagnosis. The MIUI shell on which Redmi 8 is based has a powerful hardware testing tool built in. To get into it, open the Phone app and enter the universal code ##6484##. If the code is entered correctly, the CIT menu will open.

You'll need to find a test item that might be called "Proximity sensor," "Proximation sensor," or a number that depends on the firmware version (often one of the first items), click on it. You'll see a screen with two values: "Near" and "Far" (far), and a digital value of the distance in centimeters. Hold your palm to the top of the screen, the value should change, and the status switch.

If the values don't change or change randomly without touching, it indicates a software failure or physical damage to the plume. Also, the Calibrate button is often available on this menu, which allows you to reset the current sensor readings and set new reference values.

By ania.

The process of program calibration of the sensor

Calibration is the process of "training" a smartphone to understand what counts as proximity and what deleting an object. On Xiaomi Redmi 8, this procedure can be done in two ways: through that same CIT engineering menu or through the hidden verification menu. If there is no calibration button in CIT, use the second method: enter the code ##64663# (or similar to your version of MIUI, sometimes works #3646623##), find the "Hardware Testing" section -> "Sensor" -> "Proximity Sensor".

The algorithm is simple, but it requires precision. Put your phone on a flat horizontal surface, making sure there are no objects above the screen (not even your hand). Press the Calibrate button. The system will ask you to remove your hand, then bring it up. Follow the instructions on the screen. During the calibration process, the base values are reset, and the phone remembers the current light level as "normal."

After the procedure is successfully completed (it will appear the words "Pass" or "Success"), be sure to restart the device. The usual screen switching off is not enough, it requires a full restart cycle of the Reboot system to write the new parameters into permanent memory and take effect for all applications, including the standard "caller".

⚠️ Attention: During calibration, ensure stable indoor lighting. Bright sunlight or total darkness can knock down reference values, and the sensor will not work properly in normal conditions.

Influence of accessories and protective glasses

As mentioned earlier, the Redmi 8's subscreen sensor design is extremely sensitive to the quality of protective glass. Cheap films and glass often have a black perimeter frame that can overlap the sensor's active zone, even if the speaker hole appears to match. If the problems started immediately after the glass was replaced, the accessory is the cause.

Some models of book covers or bumpers with high sides can physically cover the top of the screen or create a shadow that the optical sensor perceives as an approximation, in which case only the replacement of the accessory or its slight modification (cutting the hole), although the latter spoils the appearance, helps.

If you're using a hydraulic or hydrogel coating, make sure it fits tightly to the screen without the air bubbles at the top. The air bubble acts like a lens that refracts the IR beam to the side, causing the sensor to "blind" or, conversely, see an object where there is none.

Comparison with other Redmi models

To understand the uniqueness of the Redmi 8, it is useful to compare it with other models in the lineup. While the more expensive models (Redmi Note 8 Pro, Redmi Note 9) have moved to the embedded cameras or point cutouts with the removed sensor, the Redmi 8 has remained true to the classic, but with modern implementation.

The table below shows a comparison of the location of sensors on popular models of the period:

As you can see from the table, Redmi 8 is at risk for accessory sensitivity, along with Redmi Note 7. However, the lack of bangs makes the sensor area less visible to the user, which often leads to confusion. Understanding these differences helps to find a solution to the problem faster, without applying methods suitable for other devices.

Frequent problems and ways to fix them

One of the most common problems is when the screen doesn't light up when you remove the phone from your ear. This often involves sticking the "Near" value, which is solved by forced calibration or, in rare cases, cleaning the cache of the Phone app. Go to Settings → Apps → All Apps → Phone → Memory → Clear cache.

The reverse is that the screen goes out in your pocket or when you watch video, if you hold your phone with both hands, it's a sign of too high sensitivity or the presence of background apps using the sensor. Check which apps have access to the proximity sensor in the permission settings. Often the culprits are garbage cleaners or third-party launchers.

If the software methods don't work, and the sensor shows zero values or a constant error in the engineering menu, there's a physical breakdown. On the Redmi 8, the sensor is soldered into the display plume or glued to the inner frame. Replacing it requires the skill of a master and the presence of a thermophen to carefully peel off the matrix.