Why you need a proximity sensor and how it works on the Poco X3 Pro
The proximity sensor in the Xiaomi Poco X3 Pro is a small but critical component that is responsible for automatically turning off the screen during phone conversations. When you hold your smartphone to your ear, the sensor captures the obstacle and extinguishes the display, preventing accidental brushing with your cheek or ear. The Poco X3 Pro uses an infrared sensor that works in tandem with MIUI software algorithms to accurately determine distance.
But many users face problems: the screen doesn't go out when you call, the sensor is too late or reacts to any hand movement, most often due to incorrect calibration, sensor contamination or software failures. In this article, we'll discuss how to properly configure the proximity sensor, check its performance and fix typical problems without going to the service center.
The Poco X3 Pro features two sensors: the main one (for calls) and the secondary one (for gestures, such as “lift to wake up”). Their settings overlap, so it’s important to understand which setting you’re changing. If you’ve never calibrated the sensor after buying or updating your firmware, chances are it’s not working optimally.
Where is the proximity sensor on the Poco X3 Pro
On the Xiaomi Poco X3 Pro, the proximity sensor is located at the top of the screen, to the right of the speaker, and you can't see it visually -- it's hidden under the display glass, but you can tell its position from a small hole for the infrared emitter, to find the exact location:
- Turn on the flashlight and light on the top frame of the screen at an angle - the sensor will reflect light slightly.
- Or run the test mode (we will talk about it below) - the diagram with the location of the sensors will be displayed on the screen.
Important: don't confuse the proximity sensor with the light sensor, which is next to you and is responsible for automatic brightness control. They often work together, but they are tuned differently. On the Poco X3 Pro, both sensors are combined in one module, but software controlled separately.
How to check the operation of the proximity sensor
Before you set up the sensor, make sure it's functioning at all. There are several ways to do this:
Method 1: Test mode MIUI
The most reliable method is to use the built-in diagnostic menu:
- Open the Phone app.
- Dial the combination: ##6484## (or #4636## → "Equipment Testing").
- Select Proximity Sensor (Proximity Sensor).
- Raise your hand to the top of the screen – the value should change from 5 (no obstacle) to 0 (object detected).
Method 2: Manual check during the call
If the test mode is not available, check the sensor as follows:
- 📞 Call another phone (or use a voice assistant).
- 👋 Hold your hand to the top of the screen – the display should go out.
- 🖐️ Remove your hand, the screen should light up again.
If the screen is unresponsive or unpredictably dimmed (e.g., with a delay of 2-3 seconds), the sensor needs calibration or cleaning, and check if the protective film or cover is interfering with the work, which can block the infrared signal.
What to do if the test code doesn’t work?
Step-by-step instruction for calibration of the proximity sensor
The Poco X3 Pro calibrates the sensor through an engineering menu, which resets the sensor's current settings and sets new boundaries for the response. Importantly, once calibrated, the sensor can run unstable for the first 10 to 15 minutes, which is normal because the system is learning to match your movements.
Remove the protective film from the top of the screen
Make sure there is no dust or dirt on the sensor
Close all background applications
Connecting your smartphone to charging (recommended)-->
Step 1: Entering the Engineering Menu
Open the phone application and enter:
##36446337##After that, the Engineering Mode menu will open (if the code doesn't work, try ##4636## → "Hardware Testing").
Step 2: Calibration of the sensor
On the engineering menu:
- Go to the Hardware Testing → Sensor section.
- Select Proximity Sensor.
- Press Calibration.
- Place your phone on a flat surface and wait until the process is complete (usually 10-20 seconds).
- The message Calibration Success will appear – restart the device.
If the sensor is worse after calibration (for example, the screen goes out too early), repeat the procedure or reset the sensor settings to factory (reset option in the same menu).
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After calibration, check the sensor in real-world conditions: call a friend and simulate a conversation by changing the angle of the phone. If the screen goes out at the slightest approach of the hand, reduce sensitivity in the settings (more on this below).
Adjustment of the proximity sensor sensitivity
On the Poco X3 Pro, the sensor sensitivity can be adjusted manually, which is useful if the sensor is too sharp after calibration or ignores the approximation.
- Open the Settings. → The phone.
- Press 5-7 times on the MIUI version until the message “You are a developer” appears.
- Return to the main Settings menu → Additionally. → For developers.
- Find the option of Debugging the proximity sensor (or Proximity Sensor Offset).
- Change the value from 0 (maximum sensitivity) to 10 (minimum sensitivity) and the recommended value for most users is 3-5.
A critical feature of the Poco X3 Pro is that when the sensor is above 7, it can completely ignore obstacles, which will lead to random taps during calls. If the screen stops dimming after changing the parameters, return the value to 5 and recalibrate.
| Significance of sensitivity | Sensor behavior | When to use |
|---|---|---|
| 0–2 | It works with the slightest movement of the hand. | For users with thick glasses or covers |
| 3–5 | Optimal balance | Recommended for the majority |
| 6–8 | It only reacts to a direct approach. | If the sensor is triggered too often |
| 9–10 | Almost unresponsive. | Only for testing |
Solving common sensor problems
If after all the manipulations, the proximity sensor on the Poco X3 Pro is not working correctly, check the following points:
Problem 1: The screen does not go out during the call
- 🔄 Reset the sensor settings via the engineering menu (Reset option).
- 📱 Check if the sensor is turned off in the settings: Settings → Annexes → Phone. → Permits → Sensors.
- 🔧 Update the firmware - in older versions MIUI There were bugs with the processing of sensor signals.
Problem 2: The sensor is going off too late.
- 🧹 Clean the top of the screen of dust and grease (use a lilac-free wipe).
- 🔍 Reduce sensitivity to 3-4 in developer mode.
- 🛠️ If the problem persists, it is possible that the sensor is physically damaged (replacement is required).
Problem 3: False positives (screen goes out for no reason)
- 📵 Check whether the sensor interferes with a metal cover or magnet.
- 🔄 Increase sensitivity to 6-7.
- 🔄 Turn off the “Raise to Wake Up” gestures – they may conflict with the sensor.
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If the sensor stopped working after a phone fell or moisture hit, calibration won't help - it requires diagnostics at a service center. The spontaneous "fell off" of the sensor is often associated with the oxidation of contacts on the plume.
Additional tips for optimizing the sensor
To ensure that the proximity sensor on the Poco X3 Pro works stably, follow these recommendations:
- 📲 Clean the top of the screen from contamination regularly (dust and fat reduce the accuracy of the response).
- 🔄 After updating MIUI Always recalibrate the sensor.
- 🛡️ Avoid using thick cases with high sides – they can block the signal.
- 🔋 If the sensor started to glittle after replacing the battery, check if the sensor plume was damaged.
It's also useful to turn off unnecessary gestures that might conflict with the sensor, such as the "Double tap to wake up" feature, which sometimes leads to false positives, to turn it off:
- Go to Settings → Screen → Lock and Protection.
- Turn off the double touch option to wake up.
If you are actively using wireless headphones, the proximity sensor can be turned off altogether (but it is not safe - the risk of accidental pressing will increase). To do this, in the phone settings, find the option to turn off the screen when approaching and deactivate it.
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To test the sensor in the field, install the Sensor Test app from the Play Market, which shows the real-time graph of the response and helps you fine-tune the sensitivity.