/*
MQ-2 Temperature Sensor Test

Wiring :
MQ-2         Arduino
GND     ---->    GND
DOUT    ---->    2 
VCC/VDD ---->    5V
AOUT    ---->    A0

    *** O-Tech ***
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https://wa.me/201207738604
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*/
#define D_pin 2
#define Buzzer 3
#define LED 4
bool Dout = 0;

void setup(){
  Serial.begin(9600);
  Serial.println("MQ2 Sensor Test\nBy O-TECH");
  pinMode(D_pin, INPUT);
  pinMode(LED, OUTPUT);
  pinMode(Buzzer, OUTPUT);
}

void loop(){
  Dout = !digitalRead(2);
  if(Dout)
  {
    tone(Buzzer, 500, 250);
    digitalWrite(LED, HIGH);
    Serial.print(millis());
    Serial.println("\t GAS LEAK DETECTED");
  }
  else{
    noTone(Buzzer);
    digitalWrite(LED, LOW);
  }
  delay(500);
}