Save data into program memory

Before you get too far you should be aware that the EEPROM has a finite life and will eventually wear out if you keep writing to it. Normally that wouldn't be a problem, but if you make a mistake in your sketch and end up writing to EEPROM very frequently then you could wear it out within minutes. So before you start testing, think carefully about the design of your sketch to make sure it won't do repeated writes by mistake.