R308 All-in-one Optical Fingerprint Reader Sensor Module for Arduino

SKU: FA2036
Supply Voltage

DC 4.2V – 6.0V
Operating Current

Typical: ≤50mA; Peak: 120mA
Fingerprint Capacity

500 Templates
Resolution

500 DPI
Verification Speed

< 0.3 seconds
Scanning Speed

< 0.3 seconds
False Acceptance Rate (FAR)

< 0.0001% (at Security Level 3)
False Rejection Rate (FRR)

< 0.1%
Interface

UART (TTL logical level)
Default Baud Rate

57600 bps
Operating Temperature

-20°C to +45°C
Window Dimension

15mm x 18mm
Product Description
The R308 is a comprehensive, standalone biometric solution designed for high-speed fingerprint identification and secure access management. This all-in-one module integrates a high-precision optical sensor, a high-speed specialized DSP (Digital Signal Processor), and an onboard Flash memory chip to manage the entire biometric process—from image acquisition and feature extraction to template storage and matching—without requiring an external computer or complex processing from the host microcontroller.

Its compact, integrated structure makes it an ideal “plug-and-play” component for both hobbyist projects using Arduino and professional industrial applications. The module supports two primary operation modes: 1:1 verification (matching a finger against a specific ID) and 1:N search (identifying a finger from the entire database), providing flexible security options for various scales of deployment.

Key Features
  • Integrated All-in-One Design: Combines the optical path, imaging array, and biometric algorithm chip into a single unit, simplifying secondary development.
  • Touch Sensing Output: Includes a dedicated finger detection signal that can wake up a host CPU, making it perfect for battery-powered, ultra-low-power standby devices.
  • High-Speed Processing: Rapidly captures and verifies fingerprints in under 0.3 seconds, ensuring a smooth user experience for busy access points.
  • Industrial-Grade Reliability: Features a 500 DPI high-resolution scanner with an abrasive resistance intensity of up to 1 million scans and 15KV anti-static capacity.
  • Flexible Communication: Uses standard UART (TTL) serial communication, allowing direct connection to Arduino, ESP32, STM32, and Raspberry Pi.
  • Adjustable Security: Users can customize the security level (1–5) to optimize the balance between the False Acceptance Rate (FAR) and False Rejection Rate (FRR).
Usage Scenarios
  • Personal & DIY Projects: Custom biometric PC login, smart home locks, secure storage for jewelry or gun boxes, and personalized vehicle ignition systems.
  • Business & Commercial: Employee time-attendance machines, office access control, industrial machinery authorization, and gym/club membership verification.
  • Security Infrastructure: High-security safes, banking terminal identity verification, and secure document lockers.
Q: Is this sensor compatible with 3.3V microcontrollers like the ESP32?

While the module typically requires 5V for power, its UART interface uses TTL logic levels. Some users report success with 3.3V power, but for the best stability, it is recommended to power it with 5V while ensuring the RX/TX pins are compatible with your controller’s logic.

Q: Can I use the Adafruit Fingerprint Library with this module?

Yes, the R308 is part of the R30X series and is compatible with standard Arduino libraries such as the Adafruit Fingerprint Sensor Library or the R30X Fingerprint Sensor Library.

Q: What happens to the fingerprints if the power is disconnected?

The R308 features non-volatile Flash memory. All enrolled fingerprint templates are saved permanently on the module and will not be lost when power is removed.

Q: How do I use the "Touch Trigger" feature to save power?

The module has a TOUCH signal output (often Pin 6). You can connect this to an interrupt pin on your Arduino. This allows you to keep the main system in deep sleep until a user places their finger on the sensor, triggering a wake-up

Q: Can I change the communication baud rate?

The default baud rate is 57600 bps. While some versions of the R308 have a fixed baud rate, others allow adjustment via specific software commands. It is best to use the default for maximum compatibility

Q: Does it work with wet or dirty fingers?

As an optical sensor, it performs best with clean, dry fingers. While it can handle slight moisture, extreme wetness or thick grease may interfere with the optical imaging and reduce recognition accuracy.

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