Marcelo

 

//Security Alarm with Ultrasonic Sensor//

#define trigPin 6  

#define echoPin 5

#define buzzer 2

float new_delay; 

void setup() 

{

  Serial.begin (9600); 

  pinMode(trigPin, OUTPUT); 

  pinMode(echoPin, INPUT);

  pinMode(buzzer,OUTPUT);

  

}

void loop() 

{

  long duration, distance;

  digitalWrite(trigPin, LOW);        

  delayMicroseconds(2);              

  digitalWrite(trigPin, HIGH);

  delayMicroseconds(10);           

  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);

  distance = (duration/2) / 29.1;

  new_delay= (distance *3) +30;

  Serial.print(distance);

  Serial.println(" cm");

  if (distance < 50)

  {

   digitalWrite(buzzer,HIGH);

   delay(new_delay);

   digitalWrite(buzzer,LOW);

 

  }

  else

  {

    digitalWrite(buzzer,LOW);

  }

  

 delay(200);

}