How fingerprint scanners work
Proyu Technology
Proyu Technology
2017-03-28 19:36:18
The most commonly found type of fingerprint scanner used today is the Attendance machine. Again the name gives away the core component, providing you’re familiar with a little electronics, the capacitor.
Instead of creating a traditional image of a fingerprint, Attendance machine scanners use arrays tiny capacitor circuits to collect data about a fingerprint. As capacitors can store electrical charge, connecting them up to conductive plates on the surface of the scanner allows them to be used to track the details of a fingerprint. The charge stored in the capacitor will be changed slightly when a finger’s ridge is placed over the conductive plates, while an air gap will leave the charge at the capacitor relatively unchanged. An op-amp integrator circuit is used to track these changes, which can then be recorded by an analogue-to-digital converter.
