Arduino Projects

Fingerprint Door Lock System

Biometric Security System with Arduino and Fingerprint Sensor


In today’s world, security plays a crucial role in our everyday lives. One innovative solution is a fingerprint door lock system that offers enhanced security and convenience. In this article, we will explore how to build a fingerprint door lock system using Arduino, a versatile microcontroller platform. By following the steps outlined below, you can create your own biometric security system.

If you are interested in more Project Related to the Fingerprint Sensor

Bill of Materials




Link To Buy


Arduino nano



R-307 Fngerprint Sensor



5V 1 Channel Moduule



16x2 LCD Display



Solenoid lock



Red Led



Green Led






Zero PCB



12v Dc Supply



R-307 Fingerprint Sensor

  • We Used the R-307 Fingerprint Sensor And They connected To the Pin Numbers D2 And D3 
  • Fingerprint Sensor Connected to the UART Through Is Only 2 Pin Communication System

Fingerprint sensors are electronic devices that capture and analyze the unique patterns of ridges and valleys on an individual’s fingertip. They are commonly used for biometric authentication, as fingerprints are unique to each person and can be used as a reliable means of identification.

Components3 1

  • Image Capture: When a finger is placed on the sensor, it uses various technologies (such as optical, capacitive, or ultrasonic) to capture an image of the fingerprint. The sensor detects the ridges and valleys on the fingertip’s surface and converts them into a digital representation.
  • Image Enhancement: The captured image may undergo enhancement techniques to improve its quality and clarity. This can involve removing noise, adjusting contrast, and enhancing details to ensure accurate fingerprint recognition.


  • Feature Extraction: The fingerprint sensor analyzes the captured image and extracts specific features or minutiae points. These features may include ridge endings, bifurcations, and other unique characteristics of the fingerprint.
  • Template Creation: Based on the extracted features, a mathematical representation of the fingerprint called a template is created. This template is a compact representation of the fingerprint that can be stored and compared for future authentication purposes.


  • Matching and Authentication: When a user attempts to authenticate using their fingerprint, the sensor captures a new image and creates a template from it. This template is then compared to the stored templates in a database or memory. If there is a match within an acceptable threshold, the authentication is successful.


5V 1 Channel Relay Module

  • We Connected To the relay module To Pin Number D4 

The main component of the module is a relay, which is an electrically operated switch. The relay consists of an electromagnet and a set of contacts. When the electromagnet is energized, it mechanically activates the contacts, either connecting or disconnecting the circuit.

Components1 1

  • The relay module also features relay contacts that can handle higher voltage and current. In the case of a 1-channel relay module, there is typically one set of contacts. These contacts are usually labelled as “NO” (normally open), “COM” (common), and “NC” (normally closed).
  • When the relay is not activated, the NO and COM pins are disconnected, while the NC and COM pins are connected. When the relay is activated, the NO and COM pins are connected, while the NC and COM pins are disconnected.

16×2 LCD Display

  • We Connected To the LCD Display with I2C protocol Through Only Four Wire Required 
  • VCC, GND, SDA And SCL.

A 16×2 LCD display with I2C interface refers to a liquid crystal display (LCD) module that has 16 columns and 2 rows of characters and uses the I2C (Inter-Integrated Circuit) communication protocol for interfacing with other devices.

Components0 1

The module is equipped with an integrated I2C interface, which is a widely used serial communication protocol. The I2C interface allows for easy communication between the LCD module and other devices, such as microcontrollers or Arduino boards, using only two wires: SDA (data line) and SCL (clock line).

Solenoid lock

A solenoid lock is an electromechanical device used for securing doors or other access points. It consists of a solenoid, which is an electromagnetic coil, and a locking mechanism. When activated, the solenoid generates a magnetic field that moves the locking mechanism, either engaging or disengaging it to lock or unlock the door.

Finger print Sensor

Block Diagram


Circuit Diagram 

Circuit Diagram 1

Arduino Nano With fingerprint sensor

Circuit Diagram 2

  • Now We Connected To The Solenoid lock, We Connected To The Relay module Pin Number D4
  • If You Flow The Circuit Diagram then You Upload the Code2 Source Code

Circuit Diagrams 1

Circuit Diagram 3

In This Circuit Diagram, We connected to the 16×2 LCD Display With I2C Through.

They Connected to the Pin Number 

  • VCC – 5V
  • GND – GND
  • SDA – A4
  • SCL – A5

And We Connected To the 2 LEDs red And green When We put the finger on the Fingerprint Sensor if the finger is valid then Green LED will Be On If is not Valid Then Red Led Will Be ON.

  • Green Led – 11
  • Red Led – 12

If you flow the circuit diagram 3 then just upload the code 3 

Fingerprint sensor with fingerprint sensor1 1

Source Code

Library Adafruit Fingerprint Sensor

  • Step 1 First we Download The Library

adafruit 2

  • Step 2 Just Go To the Example, Adafruit fingerprint Sensor Library and click Enroll Code

adafruit 1

  • Step 3 Just Check The Code And Connected To The Rx, Tx Pin To Arduino pin Numbers D2 And D3.

adafruit 0

Code 1

Code 2

Code 3

GitHub e1697076839430

Video Tutorial


Building a fingerprint door lock system with Arduino provides an exciting opportunity to enhance security and convenience in your home or office. By integrating an Arduino board, fingerprint sensor module, and lock mechanism, you can create a reliable biometric security system. Following the outlined steps, you’ll be on your way to implementing your own personalized fingerprint door lock system.


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