# Would it be possible to use an Arduino Uno to interface with my Ender 3 pro so I can program it to beep when done?

I had an idea to make a program for my Arduino Uno that beeps whenever a print is done, but I can't find anything about interfacing it with the printer as all Google gives me is stuff about making a 3D printer from an Arduino.

Yes you could. But, as an alternative to the Arduino Uno, it might be far easier to send a beep by G-code M300 (or here for Marlin firmware), this will bypass the need for an Arduino Uno entirely. You can even play the soundtrack/theme of Beverly Hills cop from this previous answer.