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

const int trigpin = 3;
const int echopin = 4;
const int ntcpin = A0;
int pirsense;
int pirpin = 2;
int alert = 0;
int flashyiter = 5;
int templed = 9;
int buzzer = 8;
int systemled = 5;
int pirled = 6;
int ultrasonicled = 7;

LiquidCrystal_I2C lcd(0x27, 16, 2);

#define SOUND_SPEED 0.034
#define hightempthres 40.00
#define lowtempthres 8.00
#define thresdistance 20.00
const float BETA = 3950;
String alertmsg[4] = {"HIGH Temp", "LOW Temp", "Motion","Obstacle"};

void setup() {
  Wire.begin();
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
  pinMode(pirpin, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(templed, OUTPUT);
  pinMode(pirled, OUTPUT);
  pinMode(ultrasonicled, OUTPUT);
  pinMode(systemled, OUTPUT);

  digitalWrite(systemled, HIGH);
  delay(1000);
  digitalWrite(systemled, LOW);
  
  lcd.init();
  lcd.backlight();
}

void loop() {
  int analogValue = analogRead(ntcpin);
  float celsius = 1 / (log(1 / (1023.0 / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;

  digitalWrite(trigpin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin, LOW);
  long duration = pulseIn(echopin, HIGH);
  float distanceCm = duration * SOUND_SPEED / 2;

  pirsense = digitalRead(pirpin);

  lcd.setCursor(0, 0);
  lcd.print("T:");
  lcd.print(celsius);
  lcd.print("C  ");

  lcd.setCursor(9, 0);
  lcd.print("D:");
  lcd.print(distanceCm);
  //lcd.print("cm");

  lcd.setCursor(0, 1);
  lcd.print("M:");
  lcd.print(pirsense);

  alert = 0;  

  if (celsius >= hightempthres) {
    alert++;
  }
  if (celsius <= lowtempthres) {
    alert++;
  }
  if (pirsense == 1) {
    alert++;
  }
  if (distanceCm<=thresdistance) {
    alert++;
  }

  if (alert > 0) {
    for (int i = 0; i < flashyiter; i++) {
      lcd.setCursor(4, 1);
      
      if (celsius >= hightempthres) {
        Lcdprojection(0,templed);
      } else if (celsius <= lowtempthres) {
        Lcdprojection(1,templed);
      } else if (pirsense == 1) {
        Lcdprojection(2,pirled);
      } else if(distanceCm<=thresdistance){
        Lcdprojection(3,ultrasonicled);
      }

      if (alert > 1) {
        lcd.setCursor(4, 1);
        lcd.print("Other Alert");
        delay(500);
        lcd.setCursor(4, 1);
        lcd.print("            ");
      }
    }
  }

  delay(1000); 
}

void beep(int pin) {
  digitalWrite(buzzer, HIGH);
  digitalWrite(pin, HIGH);
  delay(500);
  digitalWrite(buzzer, LOW);
  digitalWrite(pin, LOW);
}

void Lcdprojection(int j,int pin){
  lcd.print(alertmsg[j]);
  beep(pin);
  delay(500);
  lcd.setCursor(4, 1);
  lcd.print("                    ");
}