#include <SPI.h> #include <MFRC522.h> #include <WiFi.h> #include <WebServer.h> #include <time.h> #include <Wire.h> #include <Adafruit_GFX.h> #include <Adafruit_SSD1306.h>

// WiFi credentials const char* ssid = "Exam Server"; const char* password = "Exam_Admin";

// RFID pins #define SS_PIN 27 #define RST_PIN 5

// OLED display settings #define SCREEN_WIDTH 128 #define SCREEN_HEIGHT 64 #define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin) #define OLED_I2C_ADDRESS 0x3C // I2C address for the OLED display

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

MFRC522 rfid(SS_PIN, RST_PIN); // Create MFRC522 instance

// Structure to hold user details struct User { String id; String name; String serialNumber; String gender; String dateTimeIn; String uid; };

// Array to hold users User users[] = { {"1", "Prudence Mwelwe", "20211351001", "Female", "", "257B07AD"}, {"2", "Hassan Chilumba", "20211351074", "Male", "", "041A0F63A85280"} };

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

// Array to store logged entries User loggedEntries[10]; int loggedCount = 0;

WebServer server(80);

void setup() { Serial.begin(115200); SPI.begin(); rfid.PCD_Init(); Serial.println("RFID reader initialized");

// Initialize OLED if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_I2C_ADDRESS)) { Serial.println(F("SSD1306 allocation failed")); for (;;); } display.display(); delay(2000); display.clearDisplay();

// Initialize WiFi WiFi.softAP(ssid, password); Serial.println("ESP32 Hotspot started"); Serial.print("IP Address: "); Serial.println(WiFi.softAPIP()); serial.println("internet connection web")

// Initialize time configTime(0, 0, "pool.ntp.org");

// Start web server server.on("/", handleRoot); server.on("/data", handleData); // Endpoint for JSON data server.begin(); Serial.println("Web server started"); }

void loop() { server.handleClient();

if (rfid.PICC_IsNewCardPresent() && rfid.PICC_ReadCardSerial()) { String uid = ""; for (byte i = 0; i < rfid.uid.size; i++) { uid += String(rfid.uid.uidByte[i] < 0x10 ? "0" : ""); uid += String(rfid.uid.uidByte[i], HEX); } uid.toUpperCase();

String scannedUIDMessage = "Scanned UID: " + uid;
Serial.println(scannedUIDMessage);
printToOLED(scannedUIDMessage);

int userIndex = matchUID(uid);
if (userIndex != -1) {
  addLoggedEntry(userIndex);
  String successMessage = users[userIndex].name + " has successfully signed in.";
  Serial.println(successMessage);
  printToOLED(successMessage);
} else {
  String unknownCardMessage = "Unknown card scanned.";
  Serial.println(unknownCardMessage);
  printToOLED(unknownCardMessage);
}
rfid.PICC_HaltA();
rfid.PCD_StopCrypto1();

} }

void handleRoot() { String html = "

// Table for logged entries html += "

// Add JavaScript for AJAX html += "<script>"; html += "function updateData() {"; html += " var xhr = new XMLHttpRequest();"; html += " xhr.open('GET', '/data', true);"; html += " xhr.onreadystatechange = function () {"; html += " if (xhr.readyState == 4 && xhr.status == 200) {"; html += " var data = JSON.parse(xhr.responseText);"; html += " var entriesTable = document.getElementById('entriesTable');"; html += " entriesTable.innerHTML = 'IDNameSerial NumberGenderDate and Time In';"; html += " for (var i = 0; i < data.loggedEntries.length; i++) {"; html += " var entry = data.loggedEntries[i];"; html += " entriesTable.innerHTML += '' + entry.id + '' + entry.name + '' + entry.serialNumber + '' + entry.gender + '' + entry.dateTimeIn + '';"; html += " }"; html += " }"; html += " };"; html += " xhr.send();"; html += "}"; html += "setInterval(updateData, 5000);"; // Update data every 5 seconds html += "updateData();"; // Initial load html += "</script>"; html += "";

server.send(200, "text/html", html); }

void handleData() { String json = "{";

// Add logged entries data json += ""loggedEntries":["; for (int i = 0; i < loggedCount; i++) { if (i > 0) json += ","; json += "{"; json += ""id":"" + loggedEntries[i].id + "","; json += ""name":"" + loggedEntries[i].name + "","; json += ""serialNumber":"" + loggedEntries[i].serialNumber + "","; json += ""gender":"" + loggedEntries[i].gender + "","; json += ""dateTimeIn":"" + loggedEntries[i].dateTimeIn + """; json += "}"; } json += "]";

json += "}";

server.send(200, "application/json", json); }

String getTimeStamp() { time_t now = time(nullptr); struct tm* timeinfo = localtime(&now); char buffer[80]; strftime(buffer, 80, "%Y-%m-%d %H:%M:%S", timeinfo); return String(buffer); }

void addLoggedEntry(int userIndex) { if (loggedCount < 10) { loggedEntries[loggedCount] = users[userIndex]; loggedEntries[loggedCount].dateTimeIn = getTimeStamp(); loggedCount++; } }

int matchUID(String uid) { uid.toUpperCase(); // Ensure UID is in uppercase for (int i = 0; i < userCount; i++) { if (users[i].uid == uid) { Serial.print("Match found for UID: "); Serial.println(uid); return i; } } Serial.print("No match found for UID: "); Serial.println(uid); return -1; }

void printToOLED(String message) { display.clearDisplay(); display.setTextSize(1); // Normal 1:1 pixel scale display.setTextColor(SSD1306_WHITE); // Draw white text display.setCursor(0, 0); // Start at top-left corner display.println(message); display.display(); }