Fingerprint Detection Using Microcontroller

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Detecting Human Fingerprint Using AVR  Microcontroller

INTRODUCTION:

  • In the modernized world that we are living in, security plays a crucial role in identifying each individual.

Biometric fingerprint scanning is one of the most reliable security techniques and widely popular in companies.

  • Here we place any of our desired finger for a period of one second so that the image is recorded on the sensor.
  • This created finger impression is compared with the stored fingerprint collection within the security database.
  • Hence a match is initiated and  produced if existing in database.
  • After the corresponding match is detected precisely then the details of the individual with that fingerprint emerges onto screen.

Necessary Components:

  1. Fingerprint scanner module device.
  2. 16×2 alphanumeric LCD display.
  3. ATMega16 microcontroller board
STEPS INVOLVED IN FINGER SCANNING:

These are the following steps involved in fingerprint scanning:-

  1. Recording image of finger impression.
  2. Producing a character file from the recorded image
  3. Creating corresponding template for the character file.
  4. Storage of this template in database(flash memory)
  5. Searching finger library.

WORKING OF SCANNING MODULE:

  1. Initially when the device is powered on that is for about half a second, It is in an inactive state, it cannot accept any commands.
  2. A memory size of 512 bytes is allocated to the user when the data for power-protection can be stored.
  3. There exists two separate buffers for storing character and template files.
  4. The communication employed here is half duplex asynchronous serial communication
  5. The Baud rate is initially set to 57600 kbps which can be alternated from 9600 to 115200 bps.

ENROLLING:

  • The use has to enroll the fingerprint twice.
  • The device record both the instance of finger impressions.
  • Flash templates can extend upto N numbers.
  • Usually around 1000 flash templates are used.
  • The Liquid Crystal Display is connected to PORTB of the microcontroller.(Works under 4 bit mode).
  • The light emitting diodes are connected to PORTC of the microcontroller.
  • For a ratio of 1:1 matching the input fingerprint impression is compared with a specific module in template.
  • Otherwise if the ratio needed is 1:N the input is matched with the entire flash templates.

COMMUNICATION PROTOCOL USED:

  • This module uses UART protocol to transmit and receive data with the aid of Tx and Rx pins of microcontroller ATMega16.

1.) ADDER:

  • The primary default value is 0xFFFFFFFF which can be altered later on.

2.) HEADER:

  • Here a constant hexadecimal value 0xEF01 is used.

3.) PACKAGE LENGTH:-

  • This denotes the maximum size of package.The size of checksum is 2 bytes and maximum length is 256 bytes.

4.) PACKAGE CONTENTS

  • Can comprise of the following:-
  1. Data
  2. Commands
  3. Acknowledge signal
  4. Parameters for command signals

5.) CHECKSUM:

  • It is the sum total of package contents, package identifier and package length.
  • The bits that overflow are ignored.

6.) PACKAGE IDENTIFIER:

  • The size it occupies is 1 byte.
  • The memory address for command data packet  is 01H
  • For acknowledge data packet memory address is 07H.

Fig 2. Command Package

APPLICATIONS:

  1. Used for  biometric attendance.
  2. In security gates for high level personnels(VIP).