Well, might be me source code here, PDF description here.
Or Gary Limings. Journeyman’s website comprehensively describes his build of one.

Or World of Ward (PIC rather than Arduino), available as a finished product, or kit. Note posh keypad.

May be others.
Gary Limings uses a nested menu, which John Stephenson didn’t like, so I wrote a keypad controller

Where my ordinary £2 keypad is set-up as:

Dave