This TTL GT-511C3 Biometric Sensor Module is awesome. Why use a key when you have one right at the tip of your finger? Unfortunately, they’re usually unreliable or difficult to implement. Well not anymore! We’ve found this great fingerprint module from ADH-Tech that communicates over TTL Serial so you can easily embed it into your next project.

The module itself does all of the heavy liftings behind reading and identifying the fingerprints with an onboard optical sensor and 32-bit CPU. All you need to do is send it simple commands. To get started, just register each fingerprint that you want to store by sending the corresponding command and pressing your finger against the reader three times.

This fingerprint scanner can store different fingerprints and the database of prints can even be downloaded from the unit and distributed to other modules. As well as the fingerprint “template,” the analyzed version of the print, you can also retrieve the image of a fingerprint and even pull raw images from the optical sensor!

This is the updated version of the GT-511C3 which has an increased memory capacity. The module can store up to 200 different fingerprints (that’s 10x more than the old version!) and is now capable of 360° recognition.

The module is small and easy to mount using two mounting tabs on the side of the sensor. The on-board JST-SH connector has four signals: Vcc, GND, Tx, Rx. A compatible JST-SH pigtail is in the related items below. Demo software for PC is available in the documents below, simply connect the module to your computer using an FTDI Breakout and start the software to read fingerprints!


Pin 1 is the transmit pin of the UART on the FPS (UART Tx) and transmits a logic high of up to a maximum of 3.3V.
Pin 2 is the receive pin of the UART on the FPS (UART Rx) and can receive a logic high level of up to 3.3V. The voltage level sent to this pin from a microcontroller needs to be reduced when working with 5V microcontrollers.
Pin 3 is the common GND or 0V pin of the FPS module.
Pin 4 is the 5V input to the FPS module use to power it. This value can be between 4.5V and 6V.

What Is It?

The GT-511C3 FPS (fingerprint scanner) is a small embedded module that consists of an optical sensor mounted on a small circuit board. The optical sensor scans a fingerprint and the microcontroller and software provide the functionality of the module which automatically processes the scanned fingerprint.

The interface of the FPS is very basic consisting of only four pins – power, ground, serial transmit and serial receive.


The module may use in projects for identifying users, for example allowing access through a door by scanning a finger instead of using a key.

Package Includes:

1 x TTL GT-511C3 Biometric Sensor Module

1 x Connecting Cable

Specifications and Features:

  1. Model: GT-511C3
  2. Operating Voltage: DC 3.3. to 6V
  3. CPU: ARM Cortex M3 Core(Holtek HT 32F2755)
  4. Sensor: Optical Sensor
  5. Image Size: 202 x 258
  6. Resolution: 450 dpi
  7. Module Dimensions: 37 x 17 x 9.5 mm(LxWxH)
  8. Effective Scanning Area: 20 x 16 mm
  9. Communication Interface: UART, default baud rate= 9600bps
  10. High-Speed, High-Accuracy Fingerprint Identification using the SmackFinger 3.0 Algorithm
  11. Download Fingerprint Images from the Device
  12. Read and Write Fingerprint Templates and Databases
  13. Simple UART protocol (Default 9600 baud)
  14. Capable of 1:1 Verification and 1: N Identification

Attachments and Links:


Demo Software:

Download zip file

 Video Tutorial:

TTL GT-511C3 Biometric Sensor Module

TTL GT-511C3 Biometric Sensor Module

TTL GT-511C3 Biometric Sensor Module


Additional information

Weight 0.1 kg


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