However if you want the arduino to actually look like a MIDI input to ableton live then this is a bot more complicated. You have to have either an intermediate application on the computer that takes in the arduino serial and then creates an internal MIDI bus for ableton live to pick up on.
Mike, Do you have any suggestions for an application for mac osx that can convert the serial data from a usb port to MIDI?
I am attempting to do the same thing. Only with one input instead of a ton. I am using a Ping distance sensor which sends back a length of time to the arduino in milliseconds. I will have to figure out how to convert that time to what I will be sending over serial to the computer, which is where the intermediate application will convert it to MIDI.
So my second question is, what kind of data would an application like this accept?