I am working on a project where I need 50 Digital Input/Outputs. Each one of the 25 of the Digital Inputs will be connected to a small piece of metal, triggered by Capacitive Touch with a finger and thus a different audio sound (note) to play, the other 25 digital inputs will be triggered by Resistive (two pieces of metal touching that when a key is pressed the metal connection is broken).
This project is for an electronic Irish bagpipe I am designing, so I need quick reaction time on the fingers that capacitive touch provides. I was looking at the Raspberry Pi, which has 26 GPIOs available, falling short of my digital input needs. Is there any expansion GPIOs boards for the Raspberry Pi that will give me the ability to control each of the 50 Digital inputs in need individually?
I also need a customizable small LCD GUI screen which the Raspberry seems to offer (to control different "patch settings" that I need i.e. play all notes in the "Key of D", then setting for playing in "Key of C", etc. I would estimate I would need at least 20 patches or more).
I initially looked into the Arduino, but that does not have an onboard processor, so I would be limited to a single "patch" setting which is not acceptable. While I am at it, I might as well ask if I need to connect to a MIDI software, as I need to record actual sound samples of the notes I need played, or can I get around this somehow?
Reason I want to get around using MIDI software is I want the entire unit easily portable as to not have to drag a computer around to operate it. I know this a lot of questions, but any advice or help would be greatly appreciated as I am just getting starting this "labor of love" project.