Modern smartphones store huge amounts of personal information, so screen protection is no longer just a formality. Owners of the popular budget Xiaomi Redmi 9 often look for ways to improve the security of the device, and biometrics here is the best solution. Unlike the pattern lock or PIN-Scanning your finger takes a fraction of a second and does not require remembering complex combinations.
The MIUI activation process is intuitive, but newcomers may have questions about the sensor calibration. This article will detail each step of the setup so you can be sure that your data is protected. We will not only look at the standard procedure, but also at the nuances of the fingerprint scanner in different conditions.
Customizing biometrics allows you not only to unlock your device instantly, but also to confirm payments in stores or log in to bank apps, and it turns your smartphone into a personal secure safe that only you have access to. Let's figure out how to activate this feature on your device.
Scanner location and preparation for setting up
Before you start, you need to know exactly where the sensor is on your particular device. In the Redmi 9, the manufacturer placed the fingerprint scanner on the back of the case, directly under the main camera module, which is considered a classic location for smartphones in this price segment, and provides convenient access with the thumb of the right hand when holding the phone.
It is important to understand that the sensor surface must be clean for proper operation. Fatty traces, dust or moisture can significantly reduce the recognition speed or lead to scan errors.
⚠️ Warning: If a protective film or a neckline cover is installed on the back cover, make sure they do not overlap the scanner's active area. Thick or improperly fitted covers may block the signal.
It is also worth checking the condition of the screen and the finger itself. Too dry skin or, conversely, sweaty hands can make it difficult to read the picture initially, in which case the system may suggest a repeat attempt or use an alternative method of input.
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Rub the scanner area with a soft cloth before each adjustment attempt if you have dry hand skin – this will improve grip and readability.
Step-by-step instructions for activating biometrics
To start the setup process, you need to go to the corresponding system menu, you can do this through the main settings menu, where all the security settings are collected, and the algorithm is the same for all versions of MIUI firmware installed on Redmi 9, so there should be no complications.
Follow the algorithm to successfully add your biometric key:
- 📱 Open the Settings app on your desktop or in the notification curtain.
- 🔒 Go to the Passwords and Security section, which is usually at the top of the list.
- 👆 Select “Unlock by fingerprint” to start registration.
- 🆔 Enter your current password, PIN-code or pattern lock to confirm the identity of the owner.
Once you enter the security code, the system will go into training mode, and you'll see a palm image showing you where to put your finger, and you'll take your time, and you'll do it slowly and consistently, so that the sensor can read all the faces of your fingerprint.
☑️ Checklist before registration
In the process of registration, the system will vibrate when the next section of the finger is read successfully, and this tactile confirmation helps you understand the progress of the task. 10-15 Touches to form a full digital image.
Scanning process and sensor calibration
The most important step is to scan directly, and the system will ask you to put your finger on the sensor in different parts: center, edges, upper and lower phalanges, so you don't have to press your finger too hard, light enough, but tight.
If you wear a security glass on a screen, it doesn't affect the rear scanner, but if you plan to use face unlock in the future, the cleanliness of the camera is also important. For now, focus on the fingerprint scanner. Try to change the angle of your finger with each touch, mimicking real-world unlock conditions.
What if the progress is 90% stuck?
Once the process is complete, the system will suggest adding another fingerprint, which is a very useful option, because in life we hold the phone with different hands, and adding a second finger (like the thumb of the left hand) will greatly improve the comfort of use.
Reading quality depends on many factors, including the individual characteristics of the skin, and the table below shows the main parameters that affect the speed of work:
| Influence factor | Impact on work | Recommendation |
|---|---|---|
| Moisture on the finger | Reduces accuracy by 60% | Wash your hands with a towel |
| Sensor contamination | Complete scan failure | Wash with a dry napkin. |
| Body temperature | Cold fingers are worse read | Warm your hands before using |
| Skin damage | Pattern recognition error | Use a reserve finger |
Note that Redmi 9 uses a capacitive type of scanner that reads the electrical charge of the skin, which means that conventional protective films on the sensor itself can not be glued — they completely block the module.
Configure additional security functions
After successful registration, the system will offer you to configure additional options for using biometrics. In the “Additional Features” menu, you can activate the device unlock with one touch, this option allows you not to press the on button separately, but immediately go to the desktop when you apply your finger.
Also worth considering is app authorization. Many banking clients and password managers support fingerprint login, and to activate this feature, you need to go to your application settings and select the biometric or fingerprint login method.
⚠️ Note: When you install system updates or reset to factory settings, all saved prints will be deleted for security reasons.
Some versions of MIUI have an Advanced Unlock feature that uses artificial intelligence algorithms to improve recognition over time, and analyzes successful and unsuccessful login attempts, gradually adapting to changes on the surface of the finger.
Resolving Recognition Problems and Errors
Despite the reliability of the technology, users may face situations where the smartphone no longer recognizes the owner, most often due to software failure or severe pollution, the first thing to do is always to wipe the sensor and hands.
If the problem persists, try removing the old fingerprint from memory and registering it again, paying special attention to those areas that are read worse. Sometimes it is useful to add the same finger twice under different names, for example, "Finger 1" and "Finger 1 copy", which will increase the database for comparison.
In rare cases, static electricity or a plume malfunction may be the cause, and if the phone falls or is exposed to moisture, a hardware breakdown is more likely, and software won't help.
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If the scanner stopped working after falling or getting water, do not try to dry it with a hair dryer - this can damage the adhesive elements of the case, it is better to contact the service.
Also check if the Gloves mode is included in the screen settings, although it has a greater impact on the touchscreen, indirectly this can affect the overall responsiveness of the security interface. Make sure the device has the latest firmware version installed, as Xiaomi regularly releases patches that improve the performance of security modules.