#include <Wire.h> // alamat i2c lcd
#include <LiquidCrystal_I2C.h> // library lcd i2c

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int trigPin = 9;
const int echoPin = 8;
int LED = 4;

long waktu;
int jarak;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
  lcd.begin(16,2); // deklarasi baris dan kolom
  lcd.init (); //inisialisasi dari lcd i2c
  lcd.backlight();
  
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  waktu = pulseIn(echoPin, HIGH);
  jarak = waktu / 58.8;
  delay(100);

Serial.print("jarak=");
Serial.print(jarak);
Serial.print("CM");
Serial.println();

lcd.print("jarak :");
lcd.print(jarak);
lcd.print("CM");

if (jarak < 10)
{
  digitalWrite(LED, HIGH);
  lcd.setCursor(0,0);
  lcd.print(" jarak : ");
  lcd.print(jarak);
  lcd.print(" CM");
}
else
{
  digitalWrite(LED, LOW);
}
}