I'm no musician, but lately I've been experimenting with MIDI (Musical Instrument Digital Interface) in my projects. MIDI is a standard for controlling instruments that works by passing messages between pieces of connected equipment. The messages aren't actual music in the same way as, say, an MP3 is. Instead, they are commands for making music—"Play middle C on an electric piano," for example. Messages consist of a channel number (1 through 16) followed by a status byte, which indicates the type of message (such as Note On or Note Off) and, where needed, data (such as the note to be played). MIDI devices known as controllers create the messages, and MIDI synthesizers receive them, with the result usually being musical sounds (although I've also built projects that map notes to relays that control Christmas lights and fireballs).