Despite its age, the Xiaomi Redmi 3S remains a popular device due to its combination of price and performance. One of the key security features in this device is the built-in fingerprint scanner located on the back. Properly configured biometric data allows you not only to instantly unlock the screen, but also use your finger to log into applications or hide personal files.
The process of activating this feature in the MIUI shell is implemented as intuitively as possible, but users often have questions about calibration and read accuracy. Biometric protection on this device works quite quickly, but requires correct initial registration of the pattern of papillary lines. In this material, we will discuss all the stages of setting, as well as nuances that will help to avoid errors in reading.
Owners of the device should know that the scanner on the Redmi 3S is physically a button, but it does not have a mechanical press function. This is an important point, since some users try to push the sensor by inertia, which can lead to its failure.
Preparation of the device and familiarity with the sensor
Before you start directly recording your fingerprint, make sure your smartphone screen is clean and your hands are dry.The fingerprint scanner on the back is very sensitive to contamination, grease or water, which can significantly reduce the percentage of successful unlocks. Wipe the sensor area with soft cloth and wash your hands if they are sweaty or stained.
The location of the sensor on the Xiaomi Redmi 3S is ergonomically chosen: it is just below the main camera block. This positioning allows the right index finger to be naturally brought to the reader when you grab the phone. However, it also means that the sensor can get dirty from contact with surfaces if you put the phone down with the screen, so regular cleaning becomes a mandatory procedure.
⚠️ Warning: Never attempt to clean the sensor hole with sharp objects or alcohol in large quantities.Aggressive chemistry can damage the protective coating or the sensitive element itself, making it inoperable.
To get started, make sure the battery is at least 20-30%. Although the setup process does not require much power, suddenly turning off the phone while recording biometric data can cause the safety module to malfunction. Also check if there is a thick protective film in the scanner area that can interfere with reading on the back panel.
Step-by-step activation of the scanner in the settings menu
Starting the registration process starts with the main menu of operating system settings, you need to find the partition responsible for security and access to the device. In different versions of MIUI firmware, the path may differ slightly, but the logic remains the same for all versions of Redmi 3S.
☑️ Preparation for setup
Open the Settings app and scroll through the list to Password and Security, which is where all the privacy tools are concentrated. In some builds, this section may be simply called Lock and Protect, or have a lock icon, and inside you are interested in the Fingerprint Management option, which is responsible for adding new biometric keys.
When you first log in to this section, the system will ask you to set or confirm the primary password for unlocking the screen, which is a mandatory security requirement: a digital code or a pattern lock is a backup method of access if the scanner cannot recognize the finger for some reason. Without setting the primary password, biometric activation is impossible.
Once you enter your password, click the Add fingerprint button. The screen changes, and animations will appear, instructing you to put your finger on the sensor. The system will gradually read different parts of the papillary pattern, so it's important to change the angle of the finger by following the hints on the display. The process takes no more 30-40 second.
Technology of correct finger scanning
The quality of the unlocking in the future depends on how carefully you go through the initial scan. Don't just put your finger flat and hold it still. The MIUI algorithm requires you to read the edge, center and various areas of the finger pad.
When you record, the system will show a progress bar or a numerical value as a percentage. When one area is read, the phone vibrates, and you will need to slightly shift your finger to capture new areas. It is recommended that you scan your finger in the positions in which you usually take your phone in your hands: lying on a desk, in your pocket or when you wear it in a case.
Why can't the scanner see the finger?
To maximize efficiency, you can register the same finger twice under different names, such as Finger Right 1 and Finger Right 2, which will increase the fingerprint database and increase the likelihood of successful unlocking in difficult conditions, such as dim lights or when the phone is lying on a flat surface.
Setup of functions and use of fingerprint
After successful registration, Xiaomi Redmi 3S offers to expand the functionality of the scanner beyond simple unlocking of the screen. In the fingerprint management menu, you will find switches for various use cases.
First of all, you should activate the option “Unlock the screen” – a basic feature that replaces the password when you turn on the device, and the “Close in Second Space” feature is available, which allows you to hide certain applications or files that are only accessible when you scan a specific “master fingerprint”.
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Use your thumb to unlock with one hand – this is the most natural position for the Redmi 3S with its screen diagonal.
You can also configure the use of a fingerprint to stop an alarm clock, answer an incoming call, or flip through photos in a gallery, which makes navigation faster and more convenient, but it's worth remembering that activating too many actions can sometimes lead to false positives if you accidentally hit the sensor.
Table of main parameters and capabilities
To organize information about the capabilities of biometrics on Redmi 3S, it is convenient to use a summary table, which will help you quickly assess which features are available out of the box and which require additional customization or a version of MIUI.
| Function | Description | Requirements |
|---|---|---|
| Screen unlocking | Instant access to the desktop | Screen password set |
| Second Space | Hiding applications and files | Configured second space |
| Launching applications | Quick launch of programs on short tapu | Setup in the gesture menu |
| Authorization in Mi Pay | Payment for services and purchases | Linked card (depending on region) |
As you can see from the table, the range of applications is quite wide, but it is worth noting that some banking applications may not support the scanner on older Xiaomi models due to the security requirements of the banks themselves, in which case biometric authorization within the application will not be available, and you will have to use a password.
Troubleshooting and troubleshooting
Sometimes users are faced with a situation where the previously working print stops reading, this can be due to a software failure or a change in the condition of the skin. The first thing you try to reboot the device - this often solves the problem of the frozen scanner driver.
If the reboot didn't work, remove the old print from your memory and wash it back down, paying special attention to the edges of the finger pad. Also make sure that the sensor surface doesn't have the static electricity that can occur when you wear synthetic clothing. During the cold season, dry skin also reduces conductivity and impairs reading.
⚠️ Attention: If the scanner has stopped responding fully (no vibration or screen reaction), and the reboot does not help, the sensor plume inside the housing may have moved away.
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Re-recording a fingerprint with a change in the angle of the finger often solves 90% of problems with poor recognition.
In rare cases, the problem may be a system update that contains bugs. Check forums or official MIUI channels for other users' complaints about a particular version of the firmware. If the problem is massive, it's better to wait for the fix from the developers than try to reflash the device yourself.