#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,20,4);  // set the LCD address to 0x27 for a 16 chars and 2 line display
int ss = 12;

void setup() {
  lcd.init();
  lcd.backlight();
  pinMode(ss, INPUT_PULLUP);
}


void loop() {
  static int ssstate = 0;
  int ssnew = digitalRead(ss);
  if (ssnew != ssstate) {
    if (ssnew)
      lcd.print(F("On"));
    else
      lcd.clear();
  }
  ssstate = ssnew;
}