Button Encoder?

[bjhille]

I’m looking at putting a Rasberry Pi in an old Wurlitzer 3700 jukebox.  I want to gut everything in the 3700 and use a Rasberry Pi along with a new amp/speakers.  Obviously, I need some way to convert the buttons used for the record selection to a signal the Rasberry Pi can work with (there aren’t enough GPIO pins on the Rasberry Pi to attach directly – I need about 31-32 buttons).  The way the Wurlitzer model that I have works is you select a letter (that key is then held down) and then select a number.  Is there a way to tell the ipac to only send the keystroke once?  In other words, while a letter is being held down I don’t want the iPac to continue to send the letter to the Rasberry Pi (ie. “aaaaaaaaaaa”), I only want to send the keystroke once (ie. “a”).  Is that possible?  My other option was to use an Ardunio card, which I know nothing about.  Do you think an iPac would work or should I look into an Ardunio card?  If I need an Ardunio card, does it just connect via USB to the Rasberry Pi? 

Sorry for the dumb questions, I'm new to the Rasberry Pi / Ardunio thing so still not sure exactly how all this works yet. 

Thanks for the help!