MIDI In for 3.3V Microcontrollers – Simple DIY Electronic Music Projects
serial - MIDI IN : many circuits - Electrical Engineering Stack Exchange
Amazon.com: Novation Circuit Tracks: Groovebox sequencer with synth tracks, MIDI tracks and drum tracks for electronic music making : Musical Instruments
Combination MIDI In and Out jack — Parallax Forums
Notes and Volts: Midi for the Arduino - Build a Midi Input Circuit