John Kinkennon has retrofitted a classic Rodgers 32B organ using a Teensy 3.6 and custom hardware console.
John Kinkennon retrofits old organ consoles with new hardware, allowing them to be used with virtual pipe organ software such as Hauptwerk, Miditzer, or JOrgan. He used a Teensy 3.6 to retrofit a classic Rodgers 32B console, a process involving building custom hardware for the audio encoder, including input boards for pedals, stop tabs and pistons.
Kinkennon’s Rodgers 32B retrofit uses the Teensy 3.6 and plenty of chained 74HC165N shift registers. It has eight analog inputs plus eight GPIO open collector outputs which Kinkennon uses to control solid state relays that turn on audio power.
Kinkennon has helpfully provided code, schematics and other useful information for a number of his projects on his website. You can also find details about another one of his Teensy organ projects, a MIDI message receiver, on the PJRC forum.