#include <LiquidCrystal_I2C.h>

#define ECHO_PIN 2
#define TRIG_PIN 3

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);

  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 / 2;
  float y = (1E-06*distance*distance) + (1.0055*distance) + 0.0012;

  lcd.setCursor(1, 0); 
  lcd.print("Jarak: ");
  lcd.print(y);
  if (y < 200){
    lcd.setCursor(0, 1);
    lcd.print("Hati-hati!");
    //lcd.scrollDisplayleft();
    digitalWrite(13, HIGH);
    delay(10);
    digitalWrite(13, LOW);
    delay(10);
  }
  else if (y > 200){
    lcd.setCursor(0, 1);
    lcd.print("Aman Aman cuy!");
    //lcd.scrollDisplayleft();
    digitalWrite(12, HIGH);
    delay(1000);
    digitalWrite(12, LOW);
    delay(1000);
  }
  else {
    lcd.setCursor(0, 1);
    lcd.print("           ");
  }
  delay(100);
}