#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
    lcd.begin(16, 2);
    lcd.backlight();
    lcd.print("On!");
    delay(2000);

    lcd.noBacklight(); 
    lcd.clear();
    lcd.print("Off");
    delay(2000);

    lcd.backlight();
    lcd.clear();
    lcd.print("Hello!");
}

void loop() {
 
}