We’ve all been there: you pick some random anachronistic object up from the thrift store, with vague intentions of sticking a microcontroller in it and giving it a new life, but usually its an old telephone or phonograph; not an entire church organ!?
That is, unless you’re Sam Battle, better known as Look Mum No Computer, who drove halfway across the UK to extract an organ he bought on eBay that had been fairly comprehensively plumbed into a small house.
Sam then designed a custom organ/MIDI interface board, based around the Teensy 2.0 ++ plus a handful of ULN2803A Darlington transistor arrays to control the many, many, many solenoids used by the organ. See it in action in the video below, or grab the Gerbers and source code from the LMNC site, should you find yourself in a similarly absurd situation!