I will be releasing a full tutorial on this shortly. I only put up 12 strands of Christmas lights this year, which matched perfectly with the 12 notes that make up an octave. I matched each light to a different midi note: for instance all 'F' notes control the lights on the top of the right tree. I imported the midi file from here:

https://www.midiworld.com/files/1130/

Credit to Mannheim Steamroller for writing this version of the song and to the unknown person who created this midi file.