//NAME: MARK JASSON F. SIMANGCA
//COURSE: BSIS EXT
//LABORATORY FINAL EXAM


#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

#define trigerPin 12
#define echoPin 13
#define ledPin 2
#define speakerPin 10
#define pitch 262

double duration, distance;

void setup() {
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("System Ready"); // Initial message

  // SENSOR
  Serial.begin(9600);
  pinMode(trigerPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // LED
  pinMode(ledPin, OUTPUT);

  // SPEAKER
  pinMode(speakerPin, OUTPUT);
}

void loop() {
  // LOOPING SENSOR
  digitalWrite(trigerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigerPin, LOW);

  // DURATION
  duration = pulseIn(echoPin, HIGH);

  // DISTANCE
  distance = (duration / 2) * 0.0343;

  if (distance < 200) {
    // Trigger alert
    digitalWrite(ledPin, HIGH);
    tone(speakerPin, pitch);
    
    // Display "INTRUDER ALERT" on the LCD
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("INTRUDER ALERT");
    lcd.setCursor(0, 1);
    lcd.print("Distance: ");
    lcd.print(distance, 1);
    lcd.print(" cm");
    
    delay(300); 
  } else {
    // Reset alert
    digitalWrite(ledPin, LOW);
    noTone(speakerPin);
    
    
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("System Ready");
    lcd.setCursor(0, 1);
    lcd.print("ARMED MODE");
  }

  delay(200); 
}