#include <LiquidCrystal_I2C.h>

#define PIN_TRIG 2
#define PIN_ECHO 15
#define PIN_LED 5
#define SDA_PIN 12
#define SCL_PIN 13

#define SOUND_SPEED 0.034

long duration;
float distance;
float distanceCm;

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  Serial.begin(115200);
  pinMode(PIN_TRIG, OUTPUT);
   pinMode(PIN_LED, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  // inisialisasi komunikasi I2C
  Wire.begin(SDA_PIN, SCL_PIN);
   // inisialisasi LCD
  lcd.init();
  lcd.backlight();
}

void loop() {
  // Start a new measurement:
  digitalWrite(PIN_TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);

  // Read the result:
  int duration = pulseIn(PIN_ECHO, HIGH); 
  if (distance < 10) {
    digitalWrite(PIN_LED, HIGH);
  } else {
    digitalWrite(PIN_LED, LOW);
  }
  // calculate the distance
  distanceCm = duration * SOUND_SPEED/2;
  // melakukan cetak hasil di serial monitor
  Serial.print("Jarak dalam CM: ");
  Serial.println(distanceCm);
  // menampilkan pesan pada LCD
  lcd.setCursor(0, 0);
  lcd.print("Jarak : ");
  lcd.println(distanceCm);
  delay(1000);
}