As mentioned when I made my MIDI In-Out Half-Shield, there are some neat opportunities for MIDI related effects, so this is my MIDI delay implementation.
This is marked “beginner” from the point of view of “just download the code and use it”, but if you want to dig into the code it is really in the “advanced” category for the contents. But you don’t need to worry about the internals to start playing with it.
Warning! I strongly recommend using an old or second hand keyboard for your MIDI experiments. I am not responsible for any damage to expensive instruments!
As you can see, I also used my Mini USB-MIDI to MIDI converter (powered from the Arduino 5V and GND pins) so I could play it with my Korg miniKeys.
This implements a MIDI delay function by recording which notes are being played and replaying the back after a fixed delay. It can store up to 16 notes, but that is configurable (I’ve only tested it with 16). In order for it to work, the code will disable the automatic MIDI THRU functionality of the Arduino MIDI library.