#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);
lcd.init();
lcd.backlight();
//lcd.scrollDisplayleft();
}
 
void loop() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2); //dilai untuk low
  digitalWrite(TRIG_PIN, HIGH); //menembak gelombang
  delayMicroseconds(10); //selama 10 ms
  digitalWrite(TRIG_PIN, LOW);
int duration = pulseIn(ECHO_PIN, HIGH); //membaca gelombang
float distance = (duration * 0,034) / 2;
float jarak = (1E-06*distance*distance) + (1.0055*distance) + 0.0012;
 
lcd.setCursor(1, 0); //2 itu adalah jumlah 0 adalah barisanya
lcd.print("Jarak: ");
lcd.print(jarak);
if (jarak < 200){
  lcd.setCursor(0, 1);
  lcd.print("Hati-hati)!");
  //lcd.scrollDisplayleft();
  digitalWrite(13, HIGH);
delay(100);
digitalWrite(13, LOW);
delay(100);
digitalWrite(12, LOW);
}
else {
  lcd.setCursor(0, 1);
  lcd.print("  ");       
  }
  delay(100);
  }