Crime Detecting Robot

1/*
2
3*/
4const int trigpin = 9;
5const int echopin = 10;
6const  int buzz = 5;
7const int led = 7;
8
9long duration;
10int distance;
11
12void  setup() {
13  pinMode(trigpin, OUTPUT);
14  pinMode(echopin, INPUT);
15  pinMode(buzz,  OUTPUT);
16  pinMode(led, OUTPUT);
17  Serial.begin(9600); 
18}
19
20void loop()  {
21   digitalWrite(trigpin, LOW);
22  delayMicroseconds(2);
23  
24  digitalWrite(trigpin,  HIGH);
25  delayMicroseconds(10);
26  digitalWrite(trigpin, LOW);
27  
28   duration  = pulseIn(echopin, HIGH);
29   distance = duration*0.034/2;
30   
31   Serial.print("Distance:  ");
32   Serial.println(distance);
33    
34    if(distance <= 25){
35  tone(buzz,  900);
36  delay(200);
37  noTone(buzz);
38  delay(0);
39} 
40
41 if(distance  <= 25){
42  digitalWrite(led, HIGH);
43  delay(50);
44  digitalWrite(led, LOW);
45  delay(50);
46}
47}