The R308 Fingerprint Module is an all-in-one optical biometric processing system designed for embedded applications. It integrates a high-precision optical sensor, a high-speed DSP processor, a specialized fingerprint matching algorithm, and onboard Flash memory. The module handles image capture, feature extraction, template storage, and 1:N fingerprint matching directly on-chip, making it easy to integrate secure biometric identification into custom microcontrollers and security hardware.

Specifications

• Sensor Type: Optical fingerprint scanner
• Interface: UART (TTL logic level)
• Baud Rate: Fixed at 57,600 bps
• Operating Voltage: 4.2V to 6.0V DC
• Working Current: Typical 50mA, Peak 120mA
• Image Capture Resolution: 500 DPI
• Storage Capacity: Up to 500 fingerprint templates
• Verification / Scanning Speed: 0.3seconds
• Matching Mode: 1:N Identification & 1:1 Verification
• False Acceptance Rate (FAR): 0.0001%
• False Rejection Rate (FRR): 0.1%
• File / Template Sizes: 256 bytes (character file) / 512 bytes (template size)
• Operating Temperature: -20°C to +45°C

Interface and Pinout Guide

The module connects via a standard 6-pin JST connector interface:

• Pin 1: Finger detection power (4.2V to 6.0V DC)
• Pin 2: VCC: 4.2V to 6.0V DC Power Supply Input
• Pin 3: TX (TXD): Serial Data Output (TTL level, connects to MCU RX)
• Pin 4: RX (RXD): Serial Data Input (TTL level, connects to MCU TX)
• Pin 5: GND: Common Ground Reference
• Pin 6: Finger detection signal (max output current: 50mA)

NOTE: The wire colour code may change with each revision, but the pin layout remains the same.

Key Features

• All-in-One Processing: Houses image collection, template processing, and database matching on an internal DSP chip, offloading heavy computations from your main host processor.
• Simplified Command Set: Utilizes a streamlined set of 8 primary hex instruction packets for straightforward software control and development.
• Hardware Finger Sensing Output: Includes a dedicated finger detection signal line to wake the host microcontroller from sleep mode only when a touch is detected.
• High Image Precision: Features professional optical imaging with a 500 DPI resolution window for accurate feature identification across dry, moist, or aged skin textures.
• Low Power & Compact Layout: Designed with a small physical footprint and optimized current draw, suitable for battery-operated locks and enclosures.

Common Applications

• Biometric Access Control: Electronic door locks, turnstiles, and secure keypad bypasses.
• Time & Attendance Terminals: Employee check-in/check-out tracking nodes in office environments.
• Safe Boxes & Lockers: Biometric cabinet locks, gun safes, and smart storage units.
• Automotive & Asset Security: Vehicle engine ignition permission controls and tool storage authorization.

Usage Tips

• Baud Rate Matching: The default UART communication speed is locked at 57,600 bps. Ensure your host microcontroller's serial port or SoftwareSerial instance is initialized to match this rate.
• Logic Level Caution: When interfacing with 3.3V microcontrollers (e.g., ESP32, STM32, or Raspberry Pi), ensure signal line compatibility. While VCC requires 4.2V–6.0V (typically powered from a 5V rail), the UART logic lines generally operate cleanly at 3.3V/5V TTL levels.
• Power Supply Decoupling: Because the internal optical LEDs and DSP chip draw a peak current of 120mA during a scan, provide a stable 5V rail to prevent voltage drops that could disrupt serial communication.
• Optical Glass Maintenance: Keep the triangular glass prism surface clean and free of oil or dust buildup by gently wiping it with a microfiber cloth to maintain low False Rejection Rates (FRR).

Tutorial: ElectroPeak

NOTE: Tutorials in this page are for reference only. You have to do your own R&D to make your product.