// Ultrasonic semsor(HC-SR04) test

#include <LiquidCrystal_I2C.h>
#define TRIGGER 6
#define ECHO 7

LiquidCrystal_I2C lcd(0x27,16,2);

void setup() {
  lcd.init(); 
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("COSMOLIGHT");
  lcd.setCursor(0, 1);
  lcd.print("Project Arduino");

  pinMode(TRIGGER, OUTPUT);
  pinMode(ECHO, INPUT);

  delay(3000);
}

void loop() {
  digitalWrite(TRIGGER, LOW);
  delayMicroseconds(5);
  digitalWrite(TRIGGER, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER, LOW);
  float duration = pulseIn(ECHO, HIGH);
  float cm = (duration / 2) * 340 * 100 / 1000000;
  
  // data ---> LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Distance (cm):");
  lcd.setCursor(0, 1);
  lcd.print(cm);  
  delay(1000);
}