Hall Sensor in Xiaomi Phone: Assignment, Verification and Repair

Ever wondered why Xiaomi’s magnetic-mounted cases close so tightly and smartwatches automatically lock when worn on your hand? In today’s Xiaomi smartphones (especially flagship and mid-budget models), this element plays a key role not only in the work of accessories, but also in energy management, security and even some hidden features. MIUI.

If your Redmi Note 12 has stopped responding to the magnetic case closing, POCO F5 Does not recognize wireless charging with support Qi2, The problem may be in the Hall sensor:

• 🔍 What is a Hall sensor and how does it work in Xiaomi phones (from a physical perspective).
• 📱 In which models it is installed and what it is specifically responsible for (spoiler: not in all smartphones of the brand!).
• ⚡ Signs of malfunction - from banal (the cover does not work) to critical (the phone does not charge).
• 🛠️ How to check the sensor yourself without disassembling the device.
• 💰 Cost of repair and can you do without a service center.

Particular attention will be paid to the hidden functions of the Hall sensor in firmware MIUI 14+, For example, why some Xiaomi models can automatically go into “Do Not Disturb” mode when placed in a magnet case — and how to turn it off if the feature interferes with the device.

What is a Hall sensor and how does it work in a phone

Hall's sensor is an electronic component that responds to a change in the magnetic field, and his work is based on the Hall effect (discovered in 1879 by physicist Edwin Hall): when a current passes through a conductor placed in a magnetic field, a transverse potential difference occurs.

• 🧲 Magnet's coming. → sensor.
• 📶 The signal is generated → transmits to the phone processor.
• 🤖 MIUI performs an action (for example, locks the screen or turns off Wi-Fi).

In Xiaomi smartphones, the Hall sensor is usually a microchip the size of 2×2 It's located on the motherboard next to the charging connector or under the battery:

• 🔋 Wireless charging (detects the position of the phone at Qi stations).
• 📱 Magnetic covers (activates the screen lock when closed).
• 🔌 Charging docks (in some models includes fast charging only when in the correct position).

It's important to understand that the Hall sensor is a passive element, it doesn't consume power all the time, it only activates when the magnetic field changes. For example, in the Xiaomi 13 Ultra, it only consumes 0.01 mA in standby mode, but can fire up to 100 times per second when you use wireless charging intensively.

⚠️ Attention: Don't confuse the Hall sensor with the compass (magnetometer) in the phone! the compass measures the direction of the Earth's magnetic field for navigation, and the Hall sensor responds to local magnets (such as in cases or chargers). At Xiaomi, these components are often combined into a single chip but perform different tasks.

Which Xiaomi models have a Hall sensor (full list)

Not all Xiaomi smartphones are equipped with a Hall sensor, which is installed mainly in models with support for:

• 🔋 Wireless charging (Qi standard or proprietary solutions).
• 🧲 Magnetic accessories (cases, docking stations).
• 📱 Flagship features (e.g. automatic screen locking).

Note: In budget models (e.g. Redmi) 10A or POCO M5) Hall sensor is missing. We can check if it's available:

1. In the characteristics on the official website (see the mention of "wireless charging" or "magnetic case").
2. Through the engineering menu (enter ##4636## → Sensor Test → Check for Hall Sensor availability).
3. Physically: Hold the magnet to the top or bottom of the phone – if the screen reacts (like going out), the sensor is there.

⚠️ Note: In Xiaomi models with support Qi2 (For example, Xiaomi 14, the Hall sensor is calibrated automatically when you first wirelessly charge. If you interrupt the process (for example, remove the phone from the station), sensitivity may be lost - you need to reset through the service menu.

What is responsible for the Hall sensor in Xiaomi: 5 key features

The Hall sensor in Xiaomi smartphones performs not only obvious tasks (such as reaction to a case), but also hidden functions that users often do not know.

1. Work with magnetic covers

The most prominent feature is the automatic lock/unlock screen when opening/closing the case. MIUI 14+ Hall sensor also:

• 🔇 Disables notifications when the case is closed (Do not disturb mode").
• 📵 Blocks sensory gestures (e.g., double touching to wake up).
• 🔋 Optimizes energy consumption (disables background processes).

2. Wireless charging

In phones with Qi-charging, the Hall sensor:

• 🎯 Determines the exact position of the phone to the station (prevents overheating).
• ⚡ Activates fast charging (for example, 50W Xiaomi 13 Pro only when aligned correctly.
• ⚠️ Disables charging when offset (damage protection).

3. Accessories work

In some models (such as the Black Shark 5 Pro), the Hall sensor is used to:

• 🎮 Connecting gamepads with magnetic fastening.
• 🔊 Activation of the "Game Turbo" mode when installing the phone in the docking station.

4. Hidden functions MIUI

In the firmware MIUI 13/14 Hall sensor could:

• 📱 Turn on reading mode when placing the phone in a magnet case (configured in Settings) → Display. → Reading mode).
• 🔕 Automatically turn off the microphone when closing the case (protection against wiretapping).

5. Security

In Xiaomi 13 Ultra and Mix Fold 3, the Hall sensor is involved in:

• 🔒 Locking the phone when you try to open it (activates on magnetic instruments).
• 🛡️ Protection against unauthorized disassembly (sends notice to the owner).

💡

If your Xiaomi doesn’t respond to a magnetic case, try recalibrating the Hall sensor: go to Settings → The phone. → All specifications, tap 5 times on Kernel, then select Sensor Test → Hall Sensor and follow the instructions.

Signs of a Hall sensor malfunction: when to sound the alarm

The Hall sensor breakdown manifests itself differently depending on the Xiaomi model.-7 symptoms that should alert:

1. The phone does not respond to the magnetic case (the screen is not locked/unlocked).
2. Wireless charging works unstable (it turns on, then turns off).
3. The error “Incorrect position on the charging station” appears (even if the phone is lying correctly).
4. Unintentional locking of the screen without a cover.
5. The phone does not detect the docking station (e.g., Xiaomi Smart Dock).
6. In the engineering menu, the Hall sensor shows "N/A" or zero.
7. Fast battery discharge (the sensor is constantly trying to calibrate).

Xiaomi. 12T Pro and newer faulty Hall sensor may also lead to:

• ❌ Failure of Face Unlock (the sensor is involved in checking the position of the phone relative to the face).
• 🔄 Spontaneous reboot when connected to wireless charging.

To distinguish sensor malfunction from firmware problems, perform the test:

Hold the magnet to the top of the phone (where the camera is)|Try wireless charging at another station|Check the reaction to the magnet case|Run the sensor test using #4636##

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If at least one of the points does not work, the Hall sensor is faulty or requires calibration.

⚠️ Note: In Xiaomi models with LPDDR5 In memory (e.g. Xiaomi 13), a faulty Hall sensor can cause artifacts on the screen when wirelessly charging.This is because the sensor chip is located next to the GPU, and interference from the magnetic field affects rendering.

How to check the Hall sensor on Xiaomi indiscriminately

Before you bring your phone to the service, try 4 diagnostic methods at home. They do not require special tools and are suitable for most Xiaomi models:

Method 1: Testing through the Engineering Menu

1. Open the Phone app and type ##4636##.
2. Select Sensor Test (or Sensor Test).
3. Find the Hall Sensor or Magnetic Field line.
4. Put the magnet to the phone – the values should change from 0 to 1 (or from False to True).

Method 2: Checking with a magnetic case

• 📱 Close the cover – the screen should go out through 1-2 seconds.
• 📱 Open the case – the screen should turn on (if the function is activated in the settings).
• ❌ If there is no reaction, the sensor is faulty or disabled in the firmware.

Method 3: Diagnostics of wireless charging

Put your phone on the charging station and observe:

• ✅ Normal: charging starts immediately, the indicator burns stably.
• ❌ Problem: Charging is interrupted, the phone is warming, there is an error "Check position".

Method 4: Applications for testing

Install one of the applications:

• CPU-Z (Sensors section).
• Sensor Test (from Smart Projects)
• Physics Toolbox Sensor Suite.

Note: Some applications may not show a Hall sensor if it is integrated into a magnetometer chip.

💡

If the Hall sensor doesn't respond to any of the tests, but the phone doesn't fall or get wet, the problem may be the firmware. Try resetting to factory settings (Settings) → Additionally. → Reset) or update MIUI.

Repair of the Hall sensor: the cost and can you repair yourself

If the diagnosis confirmed a malfunction of the Hall sensor, you have 3 options:

1. Program reset (free of charge)

Sometimes the sensor stops working because of a firmware failure.

• 🔄 Reset the settings to factory (Settings) → The phone. → Reset).
• 📲 Update MIUI last-minute.
• 🛠️ Fastboot phone (instructions for the 4PDA).

This helps in 30% of cases, if the problem is not hardware.

2. Replacement of the sensor in the service center

The cost of repair depends on the model:

Prices are indicated for official Xiaomi service centers in Russia (2026), in informal workshops repairs may cost less, but the risk of using non-original parts is higher.

3. Self-substitution (for experienced only)

If you're confident in your skills, you can replace the Hall sensor yourself.

• 🔧 Set of screwdrivers (star) T3, flat-footed 1.5 mm).
• 🔥 A hair dryer or soldering station (sensor soldered to board).
• 🛒 New Hall sensor (e.g, AH3512 or DRV5032 Xiaomi).

Step-by-step:

1. Remove the back cover (use a mediator and hair dryer at 80).°C).
2. Turn off the battery (required!).
3. Find the Hall sensor on the board (usually next to the charging connector, marked as HALL or MAG).
4. Carefully unseal the old sensor and install a new one.
5. Get your phone together and test it.

⚠️ Note: In Xiaomi models with IP53/IP68 (for example, Xiaomi 13) After replacing the Hall sensor on its own, the water shield can fly off. To restore the tightness, you will need to replace the adhesive layer and gaskets (cost - from the cost of a gasket). 1 000 ₽).

Hidden settings of the Hall sensor in MIUI: How to turn on or off functions

In the firmware MIUI 13/14 The Hall sensor is controlled not only at the hardware level, but also through hidden settings:

1. Disabling automatic locking with a case

If you are prevented from automatically locking the screen when closing the case:

1. Go to Settings → Display → Screen lock.
2. Find the option "Cover Lock" (or "Smart Cover").
3. Turn off the slider.

2. Adjust the reaction to magnetic accessories

In Xiaomi 13 Ultra and Mix Fold 3, you can configure:

• 📵 Disabling notifications when the cover is closed.
• 🔇 Going silent.
• 📡 Shutdown Wi-Fi/Bluetooth (battery-saving).

For this:

1. Activate Developer Mode (Tap 7 times on Build Number in Settings) → The phone).
2. Go to Settings → Additional → For developers.
3. Find the Hall Sensor Settings section.

Calibration of the sensor

If the Hall sensor is unstable (e.g., false positives), calibrate:

1. Enter the phone application ##36446337##.
2. Choose Hall Sensor Calibration.
3. Follow the instructions on the screen (usually you need to rotate the phone in different planes).

4. Hidden commands for diagnosis

Useful engineering codes for Xiaomi:

• ##4636## → Sensor test.
• ##36446337## → Hall sensor calibration.
• ##232338## → Verification MAC-Wi-Fi addresses (indirectly checks the sensor if it is connected to antennas).

💡

Xiaomi 14 has a new Hall sensor feature, which is to determine the position of the phone in your pocket. If the phone is lying with the screen to the body, the sensor blocks touch taps, preventing random actions. → Display. → Pocket regime.

FAQ: Frequent questions about the Hall sensor in Xiaomi