In addition to being the most important smartphone in the Xiaomi catalog, the Mi5 represents the first smartphone of the Chinese giant to equip a fingerprint sensor under the central physical button. This particular position makes it very easy to use the feature. But how does a fingerprint sensor work specifically? How do you recognize that it is our finger that is trying to unlock the smartphone and not a "foreign finger"?
Before analyzing in detail, it's good to remember that every person has different fingerprints than everyone else. By exploiting this peculiarity of our body, it is possible to record and then recognize the traits of a particular impression (the so-called circles).
The fingerprint sensors work differently depending on the type used. At the moment, 3 has different types of sensors: the optical scanner, the capacitive scanner, and the ultrasound scanner. In the Xiaomi Mi5 there is the capacitive sensor, which is also the most common in the smartphone industry.
Its operation is neither simple to explain nor, as you can imagine, simple to implement. Each fingerprint, as we have said, has different grooves from any other. By making an electric current pass through the fingerprint sensor, it is possible to recognize which grooves make contact with the surface (through hundreds of arrays) and then, thanks to the calculations of the CPU which transforms the data into "0" and "1" and compares the fingerprint with that in the archive, provides the authorization or not to unlock, pay or whatever else identification by fingerprint is required. It is as if the imprint were in bas-relief and only certain points could interrupt the electrical grid formed in the sensor.
via | Xiaomi Fans Italia
