Fire_sensor_sprinkler_water_pump

 #define SENSOR_PIN 2

#define BUZZER_PIN 3

#define RELAY_PIN 4

#define SPRINKLER_START_DELAY 1000  //5 seconds

#define SPRINKLER_ON_TIME 1000      //3 seconds Sprinkler on time

unsigned long previousTime = millis();

void setup()

{

  pinMode(RELAY_PIN, OUTPUT);

  pinMode(SENSOR_PIN, INPUT);  

}

void loop()

{

  //If there is fire then the sensor value will be LOW else the value will be HIGH

  int sensorValue = digitalRead(SENSOR_PIN);

  //There is fire

  if (sensorValue == LOW)

  {

    analogWrite(BUZZER_PIN, 50);                          //Turn on buzzer

    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

  {

    analogWrite(BUZZER_PIN, 0);    

    digitalWrite(RELAY_PIN, HIGH);

    previousTime = millis();  

  }

}