(i) Code For  Mohit Project :

#include <Wire.h>

#include <LiquidCrystal_I2C.h>

// ================= LCD =================

LiquidCrystal_I2C lcd(0x27, 16, 2);

// ================= SENSOR PINS =================

const int soundPin = A0;

const int pirPin   = 2;

const int irPin    = 3;

// ================= OUTPUT PINS =================

const int greenLED  = 8;

const int yellowLED = 9;

const int redLED    = 10;

const int buzzer    = 11;

// ================= VARIABLES =================

int soundValue = 0;

int averageSound = 0;

bool pirState = false;

bool irState  = false;

int disturbanceScore = 0;

unsigned long disturbanceStart = 0;

bool disturbanceActive = false;

String currentMode = "";

// ===================================================

// SETUP

// ===================================================

void setup() {

  pinMode(pirPin, INPUT);

  pinMode(irPin, INPUT);

  pinMode(greenLED, OUTPUT);

  pinMode(yellowLED, OUTPUT);

  pinMode(redLED, OUTPUT);

  pinMode(buzzer, OUTPUT);

  lcd.init();

  lcd.backlight();

  Serial.begin(9600);

  // Startup Screen

  lcd.setCursor(0, 0);

  lcd.print("EduSense AI");

  lcd.setCursor(0, 1);

  lcd.print("Initializing");

  delay(3000);

  lcd.clear();

  // PIR Stabilization

  lcd.setCursor(0,0);

  lcd.print("Sensor Stable");

  lcd.setCursor(0,1);

  lcd.print("Wait 20 Sec");

  delay(20000);

  lcd.clear();

}

// ===================================================

// MAIN LOOP

// ===================================================

void loop() {

  // ================= SOUND AVERAGING =================

  // Multiple readings for stable detection

  long totalSound = 0;

  for(int i = 0; i < 15; i++) {

    totalSound += analogRead(soundPin);

    delay(2);

  }

  averageSound = totalSound / 15;

  // ================= SENSOR READ =================

  pirState = digitalRead(pirPin);

  irState  = digitalRead(irPin);

  disturbanceScore = 0;

  // ===================================================

  // SMART SOUND FILTERING

  // ===================================================

  // Teacher voice ignored as much as possible

  // Only high classroom disturbance counts

  if(averageSound > 520) {

    disturbanceScore += 3;

  }

  else if(averageSound > 420) {

    disturbanceScore += 2;

  }

  else if(averageSound > 350) {

    disturbanceScore += 1;

  }

  // ===================================================

  // MOVEMENT ANALYSIS

  // ===================================================

  // Small movements ignored

  if(pirState == HIGH) {

    disturbanceScore += 2;

  }

  if(irState == LOW) {

    disturbanceScore += 1;

  }

  // ===================================================

  // MODE SELECTION

  // ===================================================

  // ---------------- GREEN ----------------

  if(disturbanceScore <= 2) {

    disturbanceActive = false;

    greenMode();

  }

  // ---------------- YELLOW ----------------

  else if(disturbanceScore <= 4) {

    disturbanceActive = false;

    yellowMode();

  }

  // ---------------- POSSIBLE RED ----------------

  else {

    // Start timing disturbance

    if(!disturbanceActive) {

      disturbanceActive = true;

      disturbanceStart = millis();

    }

    // Disturbance must continue for 7 seconds

    if(millis() - disturbanceStart > 7000) {

      redMode();

    }

    else {

      yellowMode();

    }

  }

  // ===================================================

  // SERIAL MONITOR

  // ===================================================

  Serial.print("Sound: ");

  Serial.print(averageSound);

  Serial.print("  Score: ");

  Serial.println(disturbanceScore);

  delay(200);

}

// ===================================================

// GREEN MODE

// ===================================================

void greenMode() {

  if(currentMode != "GREEN") {

    currentMode = "GREEN";

    digitalWrite(greenLED, HIGH);

    digitalWrite(yellowLED, LOW);

    digitalWrite(redLED, LOW);

    noTone(buzzer);

    lcd.clear();

    lcd.setCursor(0,0);

    lcd.print("Class Focused");

    lcd.setCursor(0,1);

    lcd.print("Status: GOOD");

  }

}

// ===================================================

// YELLOW MODE

// ===================================================

void yellowMode() {

  if(currentMode != "YELLOW") {

    currentMode = "YELLOW";

    digitalWrite(greenLED, LOW);

    digitalWrite(yellowLED, HIGH);

    digitalWrite(redLED, LOW);

    noTone(buzzer);

    lcd.clear();

    lcd.setCursor(0,0);

    lcd.print("High Activity");

    lcd.setCursor(0,1);

    lcd.print("Monitoring...");

  }

}

// ===================================================

// RED MODE

// ===================================================

void redMode() {

  if(currentMode != "RED") {

    currentMode = "RED";

    digitalWrite(greenLED, LOW);

    digitalWrite(yellowLED, LOW);

    digitalWrite(redLED, HIGH);

    lcd.clear();

    lcd.setCursor(0,0);

    lcd.print("Discipline");

    lcd.setCursor(0,1);

    lcd.print("ALERT ACTIVE");

  }

  // Soft siren

  tone(buzzer, 1000);

  delay(150);

  noTone(buzzer);

  delay(150);

}