#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16, 2);
#define echoPin 3
#define trigPin 2
#define LEDPin 13
long duration, distance;
void setup() {
lcd.init();
lcd.backlight();
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(LEDPin, OUTPUT);
}
void loop(){
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distance = duration / 58.2;
lcd.clear();
lcd.setCursor(0,0);
lcd.print("distance");
lcd.setCursor(9,0);
lcd.print("    ");
lcd.setCursor(9,0);
lcd.print(distance);
lcd.setCursor(13,0);
lcd.print("cm.");
if(distance>300){
  digitalWrite(LEDPin, HIGH);
}
else{
  digitalWrite(LEDPin, LOW);
}
delay(1000);
}