Radio RF Wifi Circuit Diagrams

RFID Based Attendance System – Circuit, Working, Source Code

We’ve used an 8051 microcontroller and an AVR (ATmega 8) Mirocontroller to construct two separate RFID-based Attendance system projects in this post.

College attendance is usually done on paper, which might lead to mistakes. Manually taking attendance takes longer. As a result, the suggested attendance system takes attendance using technology.

Each pupil is given an tag in this method. The institute has a control unit. The card will take attendance whenever it is placed near the reader. The same is explained in this article.

However, before reading this post, you should have a basic understanding of how to connect an LCD to an AVR microcontroller, as it is also included in this circuit.


  • Construction and Output Video
  • Based Attendance System Circuit Principle
  • Circuit 1 Based Attendance System Circuit Diagram using AVR
    • Circuit Components
    • Circuit Design of Based Attendance System
    • RFID based Attendance System Circuit Simulation Video
    • How to Operate RFID Based Attendance System Circuit?
    • Output Video (RFID Attendance System using AVR)
  • Circuit 2 RFID based Attendance System using 8051
    • Circuit Diagram
    • Components Required
    • Circuit Design
    • Working
  • Applications of RFID Based Attendance System
  • Limitations of RFID Based Attendance System

Construction and Output Video

RFID Based Attendance System Circuit Principle

RFID readers, RFID tags, LCD displays, and microcontroller units make up an RFID-based attendance system. Through USART, RFID can be connected to a microcontroller. RFID cards send data to a reader, which then sends it to a microcontroller.

Many applications make use of radio frequency technology. RFID tags are divided into two categories: passive tags and active tags. Passive tags have a 13-digit number tag built in, whereas active tags have read/write tags, meaning they can be read from and written to. This project makes use of the passive tag.

Active tags can be issued to students in real time, with their roll numbers as tags. A copper winding is included in the RFID reader.

When the tag is placed near the reader, due to the induced mutual inductance energy, data is transferred to reader. Reader then transfers data to the microntroller. Microcontroller checks for the data continuously, if any data is received, microcontroller compares the data in data base.

If the tag is authenticated, microcontroller takes the attendance. Also you can check out the rfid based attendance system output video.

Circuit 1 RFID Based Attendance System Circuit Diagram using AVR

Circuit Components

  • ATMEGA8 Microcontroller.
  • RFID Reader
  • RFID Tags.
  • LCD display

Circuit Design of RFID Based Attendance System

The circuit architecture of an RFID-based attendance system is fairly straightforward. There are transmit and receive pins on the RFID Reader. These pins are connected to the microcontroller’s transmit and receive pins, which are the PD0 and PD1 pins. GND is connected to ground while VCC is connected to 5v.

If the module’s pins aren’t available, use a DB9 connection to connect it. The receiver pin is PD0, while the transmitter pin is PD1.

USART is a communication protocol that the RFID module uses to communicate with the controller. Universal Synchronous and Asynchronous Receive and Transmit (USART) is an acronym for Universal Synchronous and Asynchronous Receive and Transmit.

UART can be used to send serial data from the RFID module to the microcontroller. Internally, the ATmega8 microprocessor has USART registers. In order to send or receive data serially, these registers must be declared.

The microcontroller’s Port B is connected to the LCD display. The LCD is connected to the microcontroller in 4 bit mode, as indicated in the circuit diagram. The data ports D4–D7 are connected to the microcontroller’s PB0–PB3 pins.

RS pin is connected to PB4, RW pin is connected to PB5 and enable pin is connected to PB6 of microcontroller. To display data on LCD, initially set the LCD in 4bit mode. Then make Rw pin low, RS pin high, enable pin high. Send the data on data pins and make enable pin low. 

RFID based Attendance System Circuit Simulation Video

How to Operate RFID Based Attendance System Circuit?

  1. Switch on the circuit after making all of the above connections.
  2. “PLEASE SWIPE THE CARD” is displayed on the LCD.
  3. Place the RFID tag in close proximity to the reader.
  4. The data in the tag is then read by the reader and transmitted to the controller.
  5. The tag is compared to the database by the microcontroller. If the tags match, the LCD will display “authenticated” and your attendance will be taken.
  6. Now insert a card that isn’t in the database and verify that it is authenticated.
  7. The LCD now reads “Unauthorized,” and the attendance will never be taken.
  8. In this way, we can use implement this circuit.

Output Video (RFID Attendance System using AVR)

Circuit 2 RFID based Attendance System using 8051

The above circuit shows RFID based attendance system using AVR. Here is the same project but using 8051 microcontrollers. Let us see the circuit and working of this circuit.Circuit working principle is same as the above circuit.

Circuit Diagram

Components Required

  • AT89C51 Microcontroller
  • AT89C51 Programming Board
  • 11.0592 MHz Quartz Crystal
  • 2 x 33pF Ceramic Capacitors
  • 2 x 10KΩ Resistor
  • 10µF Electrolytic Capacitor
  • 2 x Push Button
  • 16 x 2 LCD Display
  • 3 x 1KΩ Resistor
  • 10KΩ POT
  • EM-18 RFID Reader Module
  • RFID Tags or Cards
  • Connecting Wires

Circuit Design

The project’s major components are an 8051-based microcontroller, a 162 LCD, and an RFID reader module.
We’ll start by looking at the microcontroller’s fundamental connections. A crystal, a reset circuit, and external access will all be required here.

An 11.0592 MHz quartz crystal is attached to pins 18 (XTAL2) and 19 (XTAL1) of the microcontroller to use the on-chip oscillator. From the crystal to ground, two 33pF ceramic capacitors are connected.

The reset on the 8051 microcontroller is active high, which means it will reset when a high pulse is applied to the RST pin. From the microcontroller’s RST (Pin 9) to ground, a 10K resistor is connected.

Between the positive supply and the RST pin is a 10F electrolytic capacitor. The capacitor is attached to a push button.

A 10K resistor is used to link the External Access pin (Pin 31) to positive supply. The basic connections to the microcontroller are now complete.

The LCD will now be connected to the microcontroller. A pot is attached to the LCD’s contrast adjust pin, Pin 3, to modify the display’s contrast.

To begin, connect the LCD’s three control pins, RS, RW, and E, to P3.6, GND, and P3.7, respectively. Then connect the LCD display’s 8 data pins to the microcontroller’s PORT1 pins.

After connecting the display, now we are going to connect the RFID reader module. Connect the TX pin of RFID Reader to RXD pin i.e. P3.0 of the microcontroller. Similarly, connect the RX pin of RFID Reader to TXD pin i.e. P3.1 of the microcontroller.

Finally, a button is connected to P3.3 (IN) to view the attendance details. 

RFID Based Attendance System


The goal of this project is to create an RFID-based Attendance System utilising an 8051 microcontroller, in which students or employees’ attendance is automatically recorded with the swipe of a card. This page explains how the project works.

When this circuit is turned on, the microcontroller displays the message Swipe the card on the LCD display at first. When the RFID reader finds an ID card, it sends the card’s unique number to the microcontroller via serial port.

We must check the obtained card number with the numbers previously recorded in the microcontroller or any database using appropriate code.

Once, if any of these numbers are match with the received card no., then the corresponding name stored in that no. is displayed on the LCD display and also the attendance for the name stored in the corresponding number is marked.

By pressing the button, the attendance recording will be closed and the details are displayed on the LCD repeatedly until the microcontroller has been reset. 

Applications of RFID Based Attendance System

  • RFID based attendance system can be used in educational institutions, industries, anywhere.
  • RFID is emerging technology and is used in applications where authentication is needed.

Limitations of RFID Based Attendance System

  • RFID attendance system is secured, but there is a chance of misusing the cards. One person can give another person’s attendance if he/she had RFID card.
  • If the card was swiped for more than once, there is a chance of giving attendance for next days also if code is not written properly.


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