#include <LiquidCrystal_I2C.h>

#define I2C_ADDR    0x27
#define LCD_COLUMNS 16
#define LCD_LINES   2

#define RUN_BTN 5

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

void setup() {
  // Init
  lcd.init();
  pinMode(RUN_BTN, INPUT_PULLUP);
  
}


void loop() {
  while (digitalRead(RUN_BTN)) {
    delay(1);
  }
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Hello, world!");
  delay(1000);
  lcd.noBacklight();
}