RFID-Powered Attendance Management System with Real-Time Display and Monitoring

If you want to buy the entire already coded combo click here
Link to download Arduino IDE App :-
Name of the library to be installed :- MFRC522

CODE

#include <SPI.h>
#include <MFRC522.h>

#define RESET_PIN 9
#define SELECT_PIN 10

MFRC522 rfidReader(SELECT_PIN, RESET_PIN);

int serialCounter = 1;
unsigned long startMillis;
int startHours = 12, startMinutes = 55, startSeconds = 50; // Manually set initial time

struct UserData {
String cardUID;
String rollNumber;
String name;
String lastTimeIn;
bool isInside;
};

// Array to store registered users
UserData userList[] = {
{“46e10a2957980”, “HST-01”, “Harsh Vardhan”, “”, false},
{“6a9df0”, “HST-02”, “Viraj”, “”, false},
{“5f93979”, “HST-03”, “Vaayu”, “”, false},
};

const int userCount = sizeof(userList) / sizeof(userList[0]);

// Function to get the current time using millis()
String getCurrentTime() {
unsigned long elapsedSeconds = (millis() – startMillis) / 1000;

int currentHours = startHours + (elapsedSeconds / 3600);
int currentMinutes = startMinutes + ((elapsedSeconds % 3600) / 60);
int currentSeconds = startSeconds + (elapsedSeconds % 60);

if (currentSeconds >= 60) { currentMinutes += currentSeconds / 60; currentSeconds %= 60; }
if (currentMinutes >= 60) { currentHours += currentMinutes / 60; currentMinutes %= 60; }
if (currentHours >= 24) { currentHours %= 24; } // Reset if over 24 hours

char formattedTime[9];
sprintf(formattedTime, “%02d:%02d:%02d”, currentHours, currentMinutes, currentSeconds);
return String(formattedTime);
}

// Function to find user index in the array
int findUserIndex(String cardNumber) {
for (int i = 0; i < userCount; i++) {
if (userList[i].cardUID == cardNumber) {
return i;
}
}
return -1; // Not found
}

void setup() {
Serial.begin(9600);
SPI.begin();
rfidReader.PCD_Init();

Serial.println(“Serial Number,RFID Card Number,Roll Number,Name,Time In,Time Out,Status”);
}

void loop() {
if (!rfidReader.PICC_IsNewCardPresent() || !rfidReader.PICC_ReadCardSerial()) {
return;
}

String cardNumber = “”;
for (byte i = 0; i < rfidReader.uid.size; i++) {
cardNumber += String(rfidReader.uid.uidByte[i], HEX);
}

String currentTime = getCurrentTime();
String timeIn = “-“, timeOut = “-“, status = “Unknown”;

int userIndex = findUserIndex(cardNumber);

if (userIndex != -1) { // Known RFID
UserData &user = userList[userIndex];

if (!user.isInside) { // Student entering
user.lastTimeIn = currentTime;
user.isInside = true;
timeIn = user.lastTimeIn;
status = “STUDENT ENTERED”;
} else { // Student exiting
timeIn = user.lastTimeIn;
timeOut = currentTime;
user.isInside = false;
status = “STUDENT EXITED”;
}

Serial.print(serialCounter++);
Serial.print(“,”);
Serial.print(cardNumber);
Serial.print(“,”);
Serial.print(user.rollNumber);
Serial.print(“,”);
Serial.print(user.name);
Serial.print(“,”);
Serial.print(timeIn);
Serial.print(“,”);
Serial.print(timeOut);
Serial.print(“,”);
Serial.println(status);
} else { // Unknown RFID
Serial.print(serialCounter++);
Serial.print(“,”);
Serial.print(cardNumber);
Serial.print(“,”);
Serial.print(“Unknown”);
Serial.print(“,”);
Serial.print(“Unknown”);
Serial.print(“,”);
Serial.print(currentTime);
Serial.print(“,”);
Serial.print(“-“);
Serial.print(“,”);
Serial.println(“STUDENT ENTERED”);

// Optional: Add new users dynamically if needed
}

delay(1000);
rfidReader.PICC_HaltA();
rfidReader.PCD_StopCrypto1();
}

if you are getting a stray error download the code from here :- click here

CIRCUIT DIAGRAM

Pin -> RFID -> UNO
1      -> 3.3V   ->  3.3V
2      -> RST   ->  9
3      -> GND  ->  GND
4      -> IRQ    ->  EMPTY
5      -> MISO  -> 12
6      -> MOSI  -> 11
7      -> SCK    -> 13
8      -> SDA    -> 10