The AS608 is a popular optical fingerprint sensor module that’s widely used in DIY electronics projects, security systems, and Arduino/Raspberry Pi applications. It captures and processes fingerprint images, stores them in its internal memory, and matches them for authentication.

Here’s a breakdown:

Key Features:

Type: Optical fingerprint reader

Operating Voltage: 3.6V – 6V (typically 5V with Arduino)

Communication: UART (TTL serial) and sometimes USB (depending on the breakout board)

Baud Rate: Default 57600 bps (can be changed)

Fingerprint Capacity: Usually up to 120–200 templates (varies with firmware version)

Image Resolution: 500 dpi approx.

Built-in DSP: Handles image rendering, feature extraction, and storage

Storage: Flash memory inside the module to save templates even after power off

How it Works:

Place a finger on the optical sensor surface.

Module captures an image of the fingerprint using optical imaging.

Internal algorithm extracts unique features (minutiae points).

Features can be stored in memory or compared with existing templates.

Returns results via serial commands (success, fail, match ID, etc.).

Pinout (common AS608 breakout):

VCC → 3.6–6V

GND → Ground

TX → Data output (to RX of microcontroller)

RX → Data input (to TX of microcontroller)

Touch/IRQ (optional) → Finger detect (not always present)

Typical Uses:

Door locks / access control

Attendance systems

Safe boxes

Arduino / ESP32 / Raspberry Pi biometric projects