This is the secret speaker that many mobiles have but can never hear

Advances in mobile technology have been giving in recent years at an impressive speed. In Spain we have passed in less than two decades of having phones that could barely do more than make calls and send messages to become computers that are able to do the same, sometimes, than desktop systems. There are more and more people than They do not use computers and perform all their computer tasks from the mobilealthough that may miss those who already have a certain age.

This has done that their safety has become a priority elementwhich is why brands have improved biometric identification systems, such as facial unlock or footprint sensors, which are currently in almost all smartphones, except for Apple. The latter have gone from being tactile elements to much more complex systems.

Currently the most advanced sensors are those under the screenbut do not use optical systems, but ultrasonic, which makes the speed of unlocking and safety much stronger than in other models. And they use sounds for this, as their name indicates.

Unlike optical sensors, which capture a 2D image of the footprint, the ultrasonic They emit high frequency sound waves towards the finger of the user when supporting the screen, in the right area, normally indicated by the icon of a fingerprint. These waves bounce on the surface of the footprint and are captured by the speaker included in the sensor, creating a detailed 3D map Of the ridges and valleys of the fingerprint itself.

The ability to map the 3D footprint allows you to capture finer details and Detect falsification attempts more efficiently, Not being possible to fool the sensor with a 2D photo or an element that tries to replicate the footprint. This makes these sensors safer.

In addition, ultrasonic sensors They are less susceptible to environmental conditions, such as dirt or moisturebecause they don’t use images, but sounds. However, both this method and others are also objectives of attacks that seek the theft of credentials, in this case of fingerprints. Through the sound that makes the finger on the screen, which is minimal but it exists, it is possible to steal information.