Ultrasonic sensor interfacing with Arduino

1#include <LiquidCrystal_I2C.h>
2
3LiquidCrystal_I2C lcd(0x27, 20,  4); // I2C address 0x27, 20 column and 4 rows
4
5int trigPin = 9;    // TRIG  pin
6int echoPin = 8;    // ECHO pin
7
8float duration_us, distance_cm;
9
10void  setup() {
11  lcd.init();               // initialize the lcd
12  lcd.backlight();
13  pinMode(trigPin, OUTPUT); // config trigger pin to output mode
14  pinMode(echoPin,  INPUT); 
15  lcd.clear();              // config echo pin to input mode
16}
17
18void  loop() {
19  // generate 10-microsecond pulse to TRIG pin
20  digitalWrite(trigPin,  HIGH);
21  delayMicroseconds(10);
22  digitalWrite(trigPin, LOW);
23  
24  //  measure duration of pulse from ECHO pin
25  duration_us = pulseIn(echoPin, HIGH);
26
27  // calculate the distance
28  distance_cm = 0.017 * duration_us;
29  
30
31  lcd.setCursor(0, 0);
32  lcd.print("DISTANCE IN CM-");
33  lcd.setCursor(0,  1);
34  lcd.print(distance_cm);
35
36  delay(10);
37
38}
39