#include <LiquidCrystal_I2C.h>
#define ECHO_PIN 2
#define TRIG_PIN 3
float X=1.006;
const float GAMMA = 0.7;
const float RL10 = 50;

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  Serial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  lcd.init();
  lcd.backlight();
}

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

  int duration = pulseIn(ECHO_PIN, HIGH );
  float distance = duration * 0.034 * X / 2;
  Serial.print("Jarak:");
  Serial.print(distance);
  Serial.println("CM ");
  delay(100);
}