Once the HIDUINO is loaded your Arduino can show up as any HID compliant device you wish, no extra drivers necessary.

It interfaces as a PS2 device which makes it pretty simple to use in conjunction with the Arduino. But that’s not the only touch-enabled input device.

TheMIDInator MIDI controller has been created by Switch & Lever using an Arduino Mega with its 54 digital IO and 16 analog pins to provide a wealth of ...

DIY musical instruments are their own thing entirely, but if you're looking for a place to start, Adafruit has a guide to building your own MIDI controller using an Arduino. The OONTZ uses a 3D ...

And, through the Arduino PluggableUSB interface, you can easily make one of these doohickeys into a MIDI endpoint! It's a common enough use that there's an example for it.

YouTuber Alex Coover, aka Glacial Geyser, has build an awesome Arduino-powered MIDI controller to help with his budding music career. Here's a demo.