#include <Wire.h> 
#define echoPin 2 //Defined and the pin no.s are according to the connection
#define trigPin 3
long distance , duration; //declared distance and duration 

int buzzerPin =25;

#include <DHT.h>  //Header file for DHT sensor 
#define DHTPIN 15
#define DTYPE DHT22 //DHT 22 
//Initialize DHT sensor
DHT dht(DHTPIN , DTYPE);

#include <LiquidCrystal_I2C.h>
//Initialize the LCD with I2C address
LiquidCrystal_I2C lcd(0x27, 15,2); 

void setup() {

  Serial.begin(9600);
  pinMode (echoPin , INPUT); //as echopin of ultrasonic sensor is used as input mode 
  pinMode (trigPin , OUTPUT); // and trigpin of ultrasonic sensor as output mode
  pinMode (buzzerPin , OUTPUT); //buzzerPin as output mode 
  
  dht.begin();

  lcd.init();       //initialize LCD
  lcd.backlight(); //Turn on the LCD backlight
  lcd.setCursor(0,0); //Set cursor to the 1st row , 1st column
  lcd.print("FLOOD MONITORING SYSTEM~~~!");

  Wire.begin(); //initialize I2C
  Serial.begin(115200);
  Serial.println("I2C Scanner");

}

void loop() {

//Ultrasonic sensor's code:
  digitalWrite(trigPin , LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin , HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin , LOW);

  duration = pulseIn(echoPin , HIGH);
  distance=duration/5820;             // we can divide by 58.2 to get the distance in meters
  String disp=String (distance);

  Serial.print("Distance: ");
  Serial.print(disp);
  Serial.println("m");
  delay(1000);

  //Buzzer's code:
  digitalWrite(buzzerPin , HIGH);
  delay(1000);                   //wait for a second after buzzer gets ON
  digitalWrite(buzzerPin , LOW);
  delay(1000);                  //again wait folr a second when buzzer turns OFF

  //DHT22's code
  float tc= dht.readTemperature(); //In Celsius
  float tf= dht.readTemperature(true);
  float hu= dht.readHumidity(); //In %
  Serial.print("Temp:");
  Serial.print(tc);
  Serial.println("°C");
  Serial.print(tf);
  Serial.print("F,Hum:");
  Serial.print(hu);
  Serial.println("%");

  //I2C's code 
  byte error , address;
  int nDevice = 0;

  Serial.println("Scanning...");

  for(address =1; address<127; address++)
  {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if(error==0)
    {
      Serial.print("I2C device found at address 0x");
      if(address < 16) Serial.print("0");
      Serial.print(address , HEX);
      Serial.println("  !");
      nDevice++;
    }
    else if(error==4)
    {
      Serial.print("Unknown error at address 0x");
      if(address < 16) Serial.print("0");
      Serial.println(address , HEX);
    }
  }
  if(nDevice ==0){
    Serial.println("No I2C device found\n");
  }
  else{
    Serial.println("done\n");
  }

    delay(3000); //wait for 3 seconds for next scan
}