Ultrasonic security system

1//Security Alarm with Ultrasonic Sensor//
2
3#define trigPin 6  
4#define   echoPin 5
5#define buzzer 2
6float new_delay; 
7
8
9void setup() 
10{
11   Serial.begin (9600); 
12  pinMode(trigPin, OUTPUT); 
13  pinMode(echoPin, INPUT);
14   pinMode(buzzer,OUTPUT);
15  
16}
17
18
19void loop() 
20{
21  long duration,   distance;
22  digitalWrite(trigPin, LOW);        
23  delayMicroseconds(2);              
24   digitalWrite(trigPin, HIGH);
25  delayMicroseconds(10);           
26  digitalWrite(trigPin,   LOW);
27  duration = pulseIn(echoPin, HIGH);
28  distance = (duration/2) / 29.1;
29   new_delay= (distance *3) +30;
30  Serial.print(distance);
31  Serial.println("   cm");
32  if (distance < 50)
33  {
34   digitalWrite(buzzer,HIGH);
35   delay(new_delay);
36    digitalWrite(buzzer,LOW);
37 
38  }
39  else
40  {
41    digitalWrite(buzzer,LOW);
42
43   }
44  
45 delay(200);
46}
47

1//Security Alarm with Ultrasonic Sensor//
2
3#define trigPin 6  
4#define  echoPin 5
5#define buzzer 2
6float new_delay; 
7
8
9void setup() 
10{
11  Serial.begin (9600); 
12  pinMode(trigPin, OUTPUT); 
13  pinMode(echoPin, INPUT);
14  pinMode(buzzer,OUTPUT);
15  
16}
17
18
19void loop() 
20{
21  long duration,  distance;
22  digitalWrite(trigPin, LOW);        
23  delayMicroseconds(2);              
24  digitalWrite(trigPin, HIGH);
25  delayMicroseconds(10);           
26  digitalWrite(trigPin,  LOW);
27  duration = pulseIn(echoPin, HIGH);
28  distance = (duration/2) / 29.1;
29  new_delay= (distance *3) +30;
30  Serial.print(distance);
31  Serial.println("  cm");
32  if (distance < 50)
33  {
34   digitalWrite(buzzer,HIGH);
35   delay(new_delay);
36   digitalWrite(buzzer,LOW);
37 
38  }
39  else
40  {
41    digitalWrite(buzzer,LOW);
42
43  }
44  
45 delay(200);
46}
47