It may seem like a minor detail, but when the The mobile phone's proximity sensor is starting to malfunction The experience becomes a real ordeal: you hang up calls with your face, accidentally activate the speakerphone, open menus you didn't even know existed… all just by holding the phone to your ear. The good news is that, in most cases, you can try recalibrating, restarting, or adjusting its operation before having to go to a repair shop.
In recent years, many manufacturers have also replaced the classic optical sensor with virtual proximity systems based on ultrasound and softwareThese are cheaper and allow for smaller bezels, but they are more unreliable and require very fine-tuning. If your smartphone's screen turns off unexpectedly or does the exact opposite, here's a comprehensive guide to understanding what's happening and how to calibrate and repair the proximity sensor on Android phones, with special attention to Xiaomi, Redmi, and POCO models where the problem is more common.
What is a proximity sensor and how does it actually work?
Essentially, the proximity sensor is a small component that detects very close objects to the front of the phone. Its main function on a smartphone is to turn off the screen and disable touch detection when you bring the phone to your ear during a call or when playing voice notes in apps like WhatsApp or Telegram, preventing unintentional touches.
On most current Android phones, this sensor is located in the upper front area of the device, usually next to the earpiece or integrated under the panel itselfIn many models with very narrow bezels (such as some recent Galaxy or Xiaomi models), the sensor is "hidden" within the screen, which complicates its calibration somewhat and makes it more sensitive to cases, screen protectors, and dirt.
Traditionally, the classic proximity sensor has been an infrared optical sensor that integrates a light emitter and receiver: the emitter launches a infrared beam outwards The receiver measures the light reflected off your face or another object, calculating whether it's close enough to turn off the screen. However, it's not the only system used.
Types of proximity sensors and related technologies
Different things are used in electronics and mobile telephony types of proximity sensors with varied technologiesSome of them are used mainly in robotics or industry, and others are common in modern smartphones, either as the main sensor or as part of a "virtual" system.
Photoelectric (infrared) proximity sensor
The most classic one in mobile phones is the sensor infrared photoelectricIt consists of an emitter (IR LED) and a receiver (photodiode or phototransistor) that collects the light reflected by whatever is in front of it: your face, your hand, a case, etc. The output circuit processes this signal and converts it into a value that the system understands as "object near" or "object far."
In other areas, these sensors can use coded signals to distinguish its own infrared beam from the environment or to work with multiple emitters and a single receiver, as in robotics. In mobile phones, the system is simplified, but the logic is the same: if the reflected light reaches a certain threshold, it is considered that something is touching the phone and the screen turns off.
Ultrasonic sensors
Ultrasonic sensors are proximity detectors that operate using high-frequency soundInaudible to humans, it emits pulses of ultrasound. These pulses bounce off an object and return to the microphone. By measuring the time and intensity of the echo, the device calculates the approximate distance.
In robots or industrial machines, these sensors can detect objects at distances of several meters and with very different materials. In mobile phones, ultrasound-based systems usually work at short distances and rely on other sensors (accelerometer, gyroscope, microphones) and software algorithms to decide when to turn off the screen, which opens the door to more calibration errors.
Magnetic sensors and other nearby sensors
There are also industries magnetic proximity sensorsThese sensors are capable of detecting magnetic objects at relatively large distances, even through certain non-magnetic materials. They are designed for automation, limit switches, open door detection, etc. In mobile devices, the magnetic sensor appears primarily as a digital compass (magnetometer) and not as a proximity sensor, but it's important not to confuse the two.
In addition to the typical proximity sensor, a modern smartphone integrates a much wider range of sensors: accelerometer, gyroscope, barometer, light sensor, battery and temperature sensors, fingerprint reader, biometric sensors…They all work together to offer advanced features such as automatic screen rotation, augmented reality, energy saving, and biometric unlocking.
Physical sensors versus virtual proximity sensors
In many Android phones, especially some Xiaomi, Redmi and POCO models, the manufacturer has replaced the physical optical proximity sensor by a virtual system based on ultrasound and other existing sensors. The best-known example is the technology from Elliptic Labs (INNER BEAUTY), which was used extensively between 2020 and 2022.
On these devices, the phone It emits an ultrasonic signal from the upper area of the screen. towards the user's ear. The secondary microphone picks up the echo of that signal: if it bounces back sooner than expected or with greater intensity, it's interpreted as something being very close (your cheek or ear) and the system turns off the screen. The gyroscope, meanwhile, helps detect the gesture of bringing the phone closer to the head and reinforces the decision to turn the screen on or off.
This approach has design advantages (fewer frames, fewer dedicated components, reduced costs), but it is noticeably more complex and delicate than a dedicated optical sensor. Small calibration errors, changes in the phone's position, ambient noise, or certain cases can cause the system to not detect your face properly, resulting in the screen staying on during calls or turning off unexpectedly.
Xiaomi, Redmi and POCO models with more proximity problems
The problems with the proximity sensor have been particularly concentrated in several Xiaomi models released around 2020This occurred when the brand heavily invested in Elliptic Labs' virtual sensors instead of traditional optical sensors. As a result, many users began reporting that the phone's screen wouldn't turn off during calls or that it would turn on by itself with the slightest movement.
Among the most affected models, both in the Xiaomi and Redmi series and POCO, the following stand out: the following devices, some of them bestsellers:
- Xiaomi Mi 10T
- Xiaomi Mi 10T Pro
- Xiaomi Mi 10T Lite
- Xiaomi MiNote 10 Lite
- Redmi Note 10
- Notes redmi 10 Pro
- Redmi Note 9
- Redmi Note 11
- LITTLE M4
In many of these phones, the sensor is integrated under the screen and depends largely due to the MIUI or HyperOS softwareIn fact, in 2021 Xiaomi launched a public investigation, surveying users to find out how often the sensor failed, in which apps (phone, WhatsApp, etc.) and under what circumstances, with the idea of adjusting the system through updates.
Main symptoms and failures of the proximity sensor
When a proximity sensor (physical or virtual) malfunctions, the symptoms are usually very similar, regardless of the model or brand. Most commonly, the following occurs: The screen doesn't turn off when you hold the phone to your ear. or that he does it at times when he shouldn't.
One of the most common mistakes is that, when making or receiving a call, the screen It remains on and activates upon touch.By gently touching the panel with your cheek, it's easy to accidentally hang up, put a call on hold, activate the speakerphone, delete numbers, or even access advanced settings. Many people don't realize the sensor is the problem until they deliberately test it.
In other cases, the problem stems from a poor factory setting of the proximity sensorOn some Xiaomi devices, the default settings aren't properly calibrated, and the system is slow or incorrect in interpreting the distance to the face. This results in screens that turn off more than they should or don't turn on at all when you move the phone away.
There are also many playback errors voice notes on WhatsApp or TelegramThe phone should switch from the external speaker to the earpiece when you hold it to your face and return to the speaker when you move it away. If the calibration is poor, the audio may cut out abruptly, switch speakers for no reason, or detect nonexistent movements.
Finally, there are messages that confuse many users, such as the classic warning of “Do not cover the earpiece area”This message does not refer to the proximity sensor itself, but to the earpiece speaker, warning that you should not cover it with your hand, a case, or any other object, as this affects sound quality but does not necessarily imply a sensor failure.
External factors that impair detection
Before getting into calibration or tinkering with hidden menus, it's worth checking if the problem lies in something as simple as dirt, improperly placed covers or protectors that interfere with the sensor. In many cases, the problem is more related to "maintenance" than to hardware or software.
The proximity sensor is usually located in an area that is very prone to dirt: the top part of the front panel, right where you rest your ear.Skin oils, dust, makeup, sweat, and even traces of gels or sprays can adhere to the surface. Over time, these form a layer that partially or completely blocks infrared light or distorts ultrasonic signals.
It is recommended to regularly clean that part of the phone using a microfiber cloth and, if necessary, a little isopropyl alcoholThis type of alcohol evaporates quickly and leaves no residue. If the dirt is heavily ingrained, you'll need to work carefully, avoiding pressing too hard on the screen or getting liquid in any crevices.
Another classic accessory is phone cases and screen protectors. When they don't fit the model perfectly, they can end up costing you money. obstruct the exact area where the sensor is locatedSometimes the screen protector's cutout partially covers the area; other times the case adds a thick edge that alters the path of light or sound. If you suspect this, temporarily remove the case and screen protector, make several test calls, and see if the behavior improves.
Is it necessary to calibrate the sensors on Android?
The Play Store is full of them diagnostic apps They promise to "calibrate all your phone's sensors" with a single tap, but in practice, things aren't that simple. Most sensors come pre-calibrated from the factory, and it's rare for them to lose their calibration without physical damage or a software bug.
Furthermore, the actual calibration parameters are usually stored in the own operating system or on protected partitionsTo truly modify them, root access or system privileges would be required. Regular apps that don't request superuser permissions have very limited scope for altering these values, so many are limited to taking measurements, resetting caches, or applying internal fixes only within the app itself.
Therefore, when calibrating the proximity sensor, it is more reliable to use official system tools, manufacturer's test menus (like Xiaomi's CIT menu) or developer settings, instead of blindly relying on any miracle app. Specialized apps can help measure and diagnose, but very few achieve deep and permanent sensor adjustment without advanced access.
How to see what sensors your mobile phone has and check if they work?
If you want to know exactly What sensors does your smartphone have? (including proximity sensors) and check if they respond; the most practical thing to do is use diagnostic applications such as “Multi-tool Sensors” and similar apps. These apps read the data provided by the sensors and display it in real time, without promising magical calibrations.
With tools like these sensor-boxYou can check if your device has gyroscope, barometer, magnetometer, ambient light sensor, proximity and others. They also let you see if the proximity sensor changes state when you cover the top of the phone with your hand, which is a good quick way to detect if there is at least a basic response from the hardware.
Activating and deactivating the proximity sensor on Xiaomi phones (MIUI)
On many Xiaomi devices with MIUI, there is a specific option within the system call settings to activate or deactivate the proximity sensor. This option has changed location and even disappeared in recent versions like MIUI 12.5 and later, but it is still present on many models with MIUI 11, 12.0.4 and some HyperOS branches.
If your phone doesn't turn off the screen during calls, the first thing to check is whether the sensor is actually working. activated in the calls menuIn MIUI settings, within the system application settings and the incoming calls section, there is usually a switch to enable or disable the use of the proximity sensor during calls.
A very useful trick when errors occur is Temporarily turn off the switch, restart your phone, and turn it back on.This cycle may "wake up" the function and cause MIUI to reapply the default settings. If the problem persists, you'll need to resort to more advanced solutions such as the CIT menu or recalibration.
Calibrate the proximity sensor on Xiaomi using the CIT menu
Xiaomi, Redmi, and POCO phones feature a ITCFrom there, you can test and, in some cases, calibrate internal sensors and components, including the proximity sensor. Access is granted using a code entered via the phone app.
On most recent Xiaomi devices, simply open the phone app and enter the code. * # * # * # * # 6484As soon as you complete the last character, without needing to press the call button, the CIT menu will automatically open where you will see a long list of numbered tests.
Within this menu, look for the option called “Proximity Sensor Test” or “Proximity sensor”Depending on your MIUI model and version, it may appear with a different number (in many cases, around 22 or 27). Once inside, follow these basic steps to test the sensor:
- Cover the top of the front of the phone with your hand, right where the proximity sensor is located.
- Observe the value displayed on the screen: if it exceeds 5 to 0 when covered and returns to 5 when uncoveredThe sensor correctly detects the changes.
- Some models have a dedicated button for "Calibrate" within this screen. Tap it and follow the instructions.
If the value does not change in the test (remains fixed at 5 or 0), or no calibration option appears on that screen, check if there is a subsection in the CIT menu for “Additional tools” or “Additional Tools”There you can find another "Proximity sensor" menu with more settings, where you can increase the sensitivity until, when you cover the top of the phone, the value responds.
Recalibrate the proximity sensor step by step in MIUI
On those Xiaomi devices where the CIT menu includes a specific function called “Proximity sensor calibration”It is possible to perform a near-automatic calibration. The usual process involves thoroughly cleaning the sensor area, accessing CIT with the code *#*#6484#*#*, and first entering the proximity test.
Once inside the test, many versions of MIUI display an icon of three dots in the upper right cornerIf you tap there, the sensor calibration option usually appears. Selecting it will prompt you to place your phone in a specific position (usually on a flat surface, with nothing in front of the sensor) and will complete the adjustment in a few seconds.
After calibration, it is recommended Restart your phone and make several test calls. to check if the behavior has improved. It is important that, during the process, there are no cases or screen protectors obstructing the sensor area, and no dirt in it, because that could skew the new readings.
Reset all sensors from Android developer options
Android doesn't offer a direct switch to "reset only the proximity sensor," but it does have a setting to Temporarily disconnect all device sensors (movement, proximity, temperature, battery, etc.) and reconnect them, which in practice acts as a small "reset".
To use this tool, you must first activate the developer options on the device. The process is similar in almost all brands and versions of Android: go into settings, go to the About phone section and tap several times on the “Build number” until the system indicates that developer options have been activated.
Next, from the main settings menu, go to “System” (or the equivalent in your Android skin) and open the new “Developer options” section. Inside, use the search bar at the top to locate the function called “Sensors deactivated”When activated, a new icon will appear in the quick settings panel that allows you to disconnect all the phone's sensors with one tap.
When you press that icon, the phone completely turns off sensor readingsincluding proximity and motion sensors. After a few seconds, touch it again to reactivate them. This power cycle is usually enough to correct unusual behavior, provided the problem isn't physical damage or a serious software bug.
Other practical solutions before restoring your mobile phone
If the problem persists after cleaning, checking cases, activating the sensor in call settings, calibrating with the CIT menu, and restarting the sensors, there are still some possibilities. intermediate measures you can try before taking the leap to a complete factory reset.
One of the first is something as simple as restart the smartphoneSometimes, an internal failure or a "frozen" process can cause the system responsible for managing the sensor to freeze. Turning your phone off, waiting a few seconds, and turning it back on can resolve the issue without further complications.
Another option is to update the phone to latest available version of MIUI, HyperOS or whatever skin you useMany sensor issues are fixed via software, especially in newly released models. On Xiaomi devices, you can go to Settings > About phone and tap on the MIUI/HyperOS version to manually check for pending updates.
It is also useful to test the android safe modeWhen you start your phone in safe mode, all third-party apps are temporarily disabled. If the proximity sensor works fine in this mode but fails during normal startup, it's most likely that an installed app is interfering. In that case, it's best to uninstall the most recent or suspicious apps until you find the culprit.
In some Xiaomi models, there is also the possibility of Reset only app settings and data without deleting photos or personal files. This option is usually found in Settings > Additional settings > Factory data reset, where you can choose to reset only apps and settings. If a configuration conflict was affecting the sensor, this reset may help.
Completely reset the device and go to a technical service center.
When, despite all previous attempts, the proximity sensor still does not respond or does so erratically, there are only two options left: perform a full factory reset or contact an authorized technical service.
If you choose to restore your phone, the first thing to do is make a backup of all your data (photos, videos, chats, documents, etc.). Then go to Settings > Backup and reset (or equivalent) and select the option to erase all phone content. This procedure will return the system to its initial state, with the firmware versions and parameters it had when it left the factory.
After completing the reset and setting up the device again from scratch, it's a good idea to test the proximity sensor. before installing applications and to restore large backups. If the sensor continues to fail in this clean state, it's a pretty clear indicator that there may be a physical problem with the component or a structural defect in the model.
At that point, the best course of action is to go to official technical service of the brand or a trusted authorized service centerIf the device is still within the legal warranty period (in the EU, at least three years for defects in recent purchases), and the fault is not related to impacts, drops, or liquid damage, the manufacturer should cover the repair free of charge. Otherwise, the technician will provide you with a quote, and you can decide whether it's worth repairing or if you should consider getting a new phone.
Why do some users prefer to disable the proximity sensor?
It may sound strange, but some people prefer completely disable the proximity sensor on your mobile phone. The reasons range from privacy to simple convenience when using voice notes. On certain Xiaomi devices, this switch exists and can be found in the MIUI call settings menu.
A common reason is the fear that certain applications will take advantage of the sensor to record usage patterns, screen exposure times, or gesturesand use that data for analytics or advertising purposes. Although the actual risk is limited and restricted by Android permissions, some privacy-conscious users prefer to take drastic measures.
Another motivation comes from problems reproducing audio files from WhatsApp, Telegram, and other appsSome users complain that when they move their phone or switch hands while listening to audio, the sensor interprets this as the phone being brought closer to the ear and switches to the earpiece, cutting off the sound or lowering the volume unintentionally. In these situations, disabling the proximity sensor for incoming calls can be a relief, provided the user is willing to accept the risk of accidental touches during conversations.
If you decide to disable the sensor on a compatible Xiaomi device, go to Settings > Apps > System app settings > Call settings > Incoming call settings and use the corresponding switch. Later, if you start noticing that you're hanging up calls with your face or accidentally activating features, you can always... Reactivate the sensor and check the other solutions explained throughout this guide.
The key to preventing the proximity sensor from ruining the experience lies in combining Three fronts: good physical maintenance of the mobile phone, use of the testing and calibration tools offered by the manufacturer, and regular software updatesIn many cases, simply cleaning and adjusting will suffice; in others, you'll need to use hidden menus like the CIT or the "Sensors disabled" switch in the developer options.
Only when all else fails does it make sense to consider a complete reset or professional repair, knowing that, if the model has a problematic virtual proximity sensor, the definitive solution may lie with the manufacturer. Share this guide so more users can learn how to calibrate the proximity sensor on their mobile phone..
