MIDI Harp: Schematics


Above, you can find the wiring diagram for our MIDI harp.  Surprisingly simple, considering how awesome the result is.  The infrared sensors are Sony GP2Y0A21YK0F which have a range up to 80cm.  For the foot pedals, we used two basic sustain pedals such as would be used with a digital piano/keyboard.  These function like your basic switch, with easy operation by foot.   The 2.5V Vref was created by using another USB cord for 5V power, then incorperating a voltage divider to get a 2.5V output.  Any Zener diode with a 3.3V cutoff will function.  These are used to prevent accidental over-voltage outputs from the IR sensors from damaging the A3BU boards inputs.

One notable mistake we made was ordering surface mount zeners. Below you can see our shoddy soldering involved with fixing this mistake. Always be aware of what you’re buying, folks!