const int trigPin = 12;
const int echoPin = 13;
int flame_sensor_pin = 10 ;// initializing pin 12 as the sensor output pin
int flame_pin = HIGH ; // state of sensor
#define RELAY_PIN 8
#define SPRINKLER_START_DELAY 5000  //5 seconds 
#define SPRINKLER_ON_TIME 3000      //3 seconds Sprinkler on time
const int buzz1 = 2;
const int buzz2 = 3;
const int buzz3 = 4;
const int LED1 = A0;
const int LED2 = A1;
const int LED3 = A2;

int duration = 0;
int distance = 0;

unsigned long previousTime = millis();

void setup() 
{
  pinMode(trigPin , OUTPUT);
  pinMode(echoPin , INPUT);

  pinMode ( LED3 , OUTPUT ); // declaring led pin as output pin
  pinMode ( flame_sensor_pin , INPUT ); // declaring sensor pin as input pin for Arduino
  pinMode(RELAY_PIN, OUTPUT);

  pinMode(LED1 , OUTPUT);
  pinMode(LED2 , OUTPUT);

  pinMode(buzz1, OUTPUT);
  pinMode(buzz2, OUTPUT);
  pinMode(buzz3, OUTPUT);
  Serial.begin(9600);

}

void loop()
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);  
  duration = pulseIn(echoPin, HIGH);
  distance = duration/58.2;

  flame_pin = digitalRead ( flame_sensor_pin ) ; // reading from the sensor
  if (flame_pin == LOW ) // applying condition
  {
  Serial.println ( " FLAME , FLAME , FLAME " ) ;
  digitalWrite ( LED3 , HIGH ) ;// if state is high, then turn high the led
  digitalWrite(buzz3, HIGH);
  if (millis() - previousTime > SPRINKLER_START_DELAY)  //We will wait for few seconds before sprinkler can be started once fire is detected.
    {
      digitalWrite(RELAY_PIN, LOW);                       //Relay is low level triggered relay so we need to write LOW to switch on the light 
      delay(SPRINKLER_ON_TIME);                           //Keep sprinkler on for sometime.
    }
  }
 
  else
  {
  Serial.println ( " no flame " ) ;
  digitalWrite ( LED3 , LOW ) ; // otherwise turn it low
  digitalWrite(buzz3, LOW);
  digitalWrite(RELAY_PIN, HIGH); 
  previousTime = millis();  

  delay(50); 
  }


  if ( distance < 20 )
  {
    digitalWrite(LED1, HIGH);
    delay(1000);
    digitalWrite(LED1,LOW);
    digitalWrite(buzz1, HIGH);
  }
  else
  {
    digitalWrite(LED1, LOW);
    digitalWrite(buzz1, LOW);
  }
  if ( distance <= 50 )
  {
    digitalWrite(LED2, HIGH);
    digitalWrite(buzz2, HIGH);
  }
  else
  {
    digitalWrite(LED2, LOW);
    digitalWrite(buzz2, LOW);
    
  delay(100);
  }

  
}