Ultrasonic sensor with Arduino - Complete Guide

1const int buzzer = 8;
2const int trig_pin = 9;
3const int echo_pin = 10;
4float timing = 0.0;
5float distance = 0.0;
6
7void setup()
8{
9  pinMode(echo_pin, INPUT);
10  pinMode(trig_pin, OUTPUT);
11  pinMode(buzzer, OUTPUT);
12  
13  digitalWrite(trig_pin, LOW);
14  digitalWrite(buzzer, LOW);
15    
16  Serial.begin(9600);
17}
18
19void loop()
20{
21  digitalWrite(trig_pin, LOW);
22  delay(2);
23  
24  digitalWrite(trig_pin, HIGH);
25  delay(10);
26  digitalWrite(trig_pin, LOW);
27  
28  timing = pulseIn(echo_pin, HIGH);
29  distance = (timing * 0.034) / 2;
30  
31  Serial.print("Distance: ");
32  Serial.print(distance);
33  Serial.print("cm | ");
34  Serial.print(distance / 2.54);
35  Serial.println("in");
36  
37    
38  if (distance <= 50) {
39  	tone(buzzer, 500);
40  } else {
41  	noTone(buzzer);
42  }
43  
44  delay(100);
45}