When you bring the smartphone to your ear during a call, the touch screen of an Android device should instantly go dark, but a failure of the proximity sensor leads to the fact that the display remains active and reacts to touches on the cheek, causing accidental activation of the speakerphone, ending a call or unintentional dialing of numbers.
In this article we will analyze in detail the reasons for the incorrect operation of the proximity sensor and methods of forced or automatic display locking. You will learn how to configure the system so that the screen goes dark exactly when necessary and remains active in other use scenarios.
The principle of operation of the proximity sensor and its role
The main tool responsible for turning off the display during a call is proximity sensor. This small sensor, usually located at the top of the screen next to the earpiece, uses infrared radiation to determine the distance to an object. When you bring the phone to your face, the sensor detects the reflected signal and sends a command to the system to block the touch layer.
However, the operation of this component is not always ideal. The accuracy of the readings can be affected by a variety of factors, from the quality of the calibration to physical obstructions. If the sensor does not work, the screen continues to light up and the system does not go into lock mode, which creates the inconvenience described above.
In some cases, the problem lies not in a breakdown, but in a software glitch or interface features of a particular shell. Understanding exactly how Android processes signals from the sensor helps you find the right solution for your device model.
If the proximity sensor is covered with a thick protective glass with a wide frame, it may not correctly determine the distance. Try removing the case or glass to check.
Standard lock settings in the Phone application
The first step in solving the problem should be to study the settings of the calling application itself. Most standard dialers (Phone applications) have built-in options for controlling screen behavior. These options may be hidden in additional menus, access to which is not always obvious.
You need to open the application Phone and go to the settings menu, which is often indicated by three dots or a gear. Here you should look for sections related to incoming calls or answering a call. It is in these subsections that the switch responsible for blocking when brought to the ear is usually hidden.
- 📞 Find the item "Proximity sensor" and make sure it is activated.
- 🔒 Check the option "Block during a call"if it is provided separately.
- ⚙️ In some versions MIUI or EMUI this function is located in the section "Advanced settings" inside the call menu.
If you use a third-party application for calls, for example Truecaller or Google Phone in its pure version, the logic of the settings may differ. In such cases, it is worth updating the application to the latest version, since developers often correct errors in working with hardware sensors in new releases.
Manually locking the screen with the power button
In situations where the automatic system fails, manual control remains the most reliable way. Pressing the button power (or the side lock button) instantly turns off the display and locks the sensor, regardless of the proximity sensor readings.
This method is universal and works on all devices running Android. However, it has a significant drawback: in order to turn on the screen again and see information about the duration of the call or switch the call, the button will have to be pressed again. This is not always convenient if your hands are full.
However, if the proximity sensor is completely out of order, using the power button becomes the only way to prevent accidental presses. Some users even develop the habit of locking the screen immediately after starting a conversation, without waiting for the automation to work.
☑️ Manual locking algorithm
Third-party applications for controlling the screen
If the built-in system tools do not cope with the task, specialized utilities from the store come to the rescue. Google Play. There are applications that intercept the call start event and forcefully turn off the display, ignoring the standard sensor.
One of the popular solutions is to use applications like "Screen Off" or specialized call managers. They work in the background and are only activated when there is an incoming or outgoing call. It is important to provide such apps with the necessary permissions, especially access to the phone and device status.
When choosing third-party software, you should pay attention to reviews and the number of installations. Low-quality applications can, on the contrary, drain the battery or conflict with the security system Android. Before permanent use, test the app for several days.
⚠️ Attention: When installing third-party screen control applications, carefully study the requested permissions. Avoid apps that require access to contacts or SMS without a clear need for their functionality.
Examples of popular utilities
Black Screen (Proximity Sensor Fix), Screen Off and Lock, Call Screen Off. These applications often have their own sensor calibration algorithms.
Diagnostics and calibration of the proximity sensor
Often the problem is solved by simply calibrating the sensor. The engineering menu of most processor-based smartphones MediaTek or Qualcomm has tools for testing hardware components. They are usually accessed through a special code in the dialer.
To enter the engineering menu, you can try entering the combination ##6484## (for Xiaomi) or #0# (for Samsung). In the menu that opens, you need to find the section Proximity Sensor. There you can see the current sensor readings in real time.
| Action | Expected value | Status |
|---|---|---|
| The sensor is not covered by anything | 5.0 or "Far" | Normal |
| Sensor closed with finger | 0.0 or "Near" | Normal |
| Values jump for no reason | Chaotic numbers | Failure |
| Always shows "Near" | 0.0 constantly | Contamination/Failure |
If in test mode the sensor responds correctly (shows "Far" in the air and "Near" when closing), which means the problem is software. If the values do not change or behave chaotically, hardware cleaning or replacement of the component may be required.
Correct operation of the sensor in the engineering menu ensures that the screen locking problem lies in the software settings and not the hardware.
The influence of protective accessories and contamination
Do not underestimate the influence of external factors on operation sensors. Protective glass, especially non-original or incorrectly applied glass, may block the proximity sensor area. Even a thin film of dust or grease on the top of the screen can distort the infrared signal.
Carefully wipe the top frame of the device with a soft cloth moistened with an alcohol solution. Make sure there is no accumulation of dirt in the speaker area. If you recently changed the protective glass, try removing it and checking the operation of the phone in its “bare” form.
Also pay attention to the cases. Some models with high sides or a tight fit may put mechanical pressure on the sensor area or create a shadow that the system perceives as an approaching object. In such cases, the screen may go dark immediately after dialing a number, preventing you from pressing the call button.
⚠️ Attention: Using magnetic cases with the "Smart Cover" function may conflict with the sensors if the magnet is poorly positioned. Try removing the case for diagnostics.
Why does the screen go blank when I just hold the phone in my hand?
This is a sign of excessive sensitivity of the sensor or its incorrect calibration. The system mistakenly believes that the phone is brought to the ear. Try resetting the sensor settings through the engineering menu or calibration application.
Is it possible to disable the proximity sensor completely?
Yes, this can be done through the engineering menu or special applications, but this is not recommended. Without a sensor, you risk constantly pressing buttons with your ear during a call.
Does rebooting the phone help with this problem?
Often yes. A reboot clears the temporary cache of system services responsible for processing sensor signals and can restore the correct operation of the screen lock.
Does the Android version affect the operation of the lock?
Yes, in new versions Android (12, 13, 14) the algorithms for working with sensors have been redesigned to improve security and energy efficiency. On older versions, problems occur more often due to less advanced drivers.