#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

#define TRIG 7
#define ECHO 6

#define red 2
#define yel 3
#define gre 4

//HCsr Code
long baca(int pinTrig, int pinEcho) {
  pinMode(pinTrig, OUTPUT);
  digitalWrite(pinTrig, LOW);
  digitalWrite(pinTrig, HIGH);

  delayMicroseconds(10);
  digitalWrite(pinTrig, LOW);
  pinMode(pinTrig, INPUT);

  return pulseIn(pinEcho, HIGH);
}
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  //lcd init
  lcd.init();
  lcd.backlight();

  //lcd static print
  lcd.setCursor(3, 0);
  lcd.println("HC-SR Monitor");

  lcd.setCursor(0, 2);
  lcd.print("Jarak(cm): ");

  pinMode(red, OUTPUT);
  pinMode(yel, OUTPUT);
  pinMode(gre, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
  int cm = 0;
  cm = (0.03446 * baca(TRIG, ECHO)) / 2;

  Serial.print(cm);
  Serial.println(" cm");

  //lcd Print
  lcd.setCursor(11, 2);
  lcd.print(cm);

  /* Menggunakan "   " untuk mengatasi flickering, daripada menggunakan lcd.clear() */
  lcd.print("    ");

  //bar led

  if (cm > 16 ) { //green nyala
    digitalWrite(red, LOW);
    digitalWrite(yel, LOW);
    digitalWrite(gre, HIGH);

  } else if (cm >= 5 && cm <= 15) { //yellow nyala
    digitalWrite(red, LOW);
    digitalWrite(yel, HIGH);
    digitalWrite(gre, LOW);
  } else if (cm < 5) { //red nyala
    digitalWrite(red, HIGH);
    digitalWrite(yel, LOW);
    digitalWrite(gre, LOW);
  }

  delay(500);

}