How does a smartphone read my fingerprint accurately

Fingerprint scanners have become pivotal in modern samrtphones. Budget friendly sometimes comes along side with biometric unlocking options like facial recognition. Phones use three differnt technologies to read your fingerprint: optical, capacitive, and ultrasonic.

Optical is the oldest of the three, it uses specialized miniature camera to take picture of your finger and transforming it into digital data. Unfortunately, these sensors are easy to fool, a good photo can trick them.

A capacitive fingerprint uses a grid of tiny capacitors that stores electricity, which is discharged only at the points where your fingerprint ridges touch. An array of thousands of capacitors can be used to map the pattern of your fingerprint.

The third and the most advanced is the ultrasonic which uses ultrasonic sound pulse transmitted to your finger and the reflected pulse is measured. Animals like Bats, Whales, and dolphins use ultrasonic to understand the shape of their surroundings, the sensors on a smartphone use it to understand the 3D shape of the ridges of your fingerprint.