Don't forget Arduino - twice in two consecutive sentences! Someone really wanted to hit all the buzzwords and the result was definitely not pleasant to read.
After reading all that, I'm still confused whether this is a physical analog pipe organ, or a software pipe organ simulator.
In these times, I find myself asking "Is this LLM output?"
Virtual, so pipe organ simulator, but this is the hardware side of it.
If you want to do something like this on the cheap: buy an old electronic organ and refurbish it, then run GrandOrgue (free) or the PianoTeq organ pack ($) once you have midi. Sounds great and it isn't nearly as much work as building a whole console from scratch.
I did this with an old Heyligers that I bought from a school here for a song, it came with two fantastic Laukhuff (unfortunately, out of business since June 2021) wooden keyboards. The whole conversion took about a week, it has a touchscreen for the stops. If I would do it again I would search a bit longer to find slightly wider keyboards, these are 61 keys, there is also a 66 version (much more rare), so the highest notes are a full octave rather than that it ends on 'g'.
It's a simulator. Download here.[1] Runs on a Raspberry Pi. Playable from a MIDI keyboard, or keyboards. Additional button boxes and controls can be hooked on. Nothing wrong with that, but it's not earth-shaking.
The article also mentions someone who built a mini pipe organ from plastic pipe and laser-cut wood, but that's not what the project is about.
You need a great speaker system to really make it sound good. Organs can put out a large range. Your typical sub and midrange speaker system can't produce good bass in that area too high for the subs and too low for the midrange. Note that subs is plural, you probably want more than one unless the room is tiny.
I had the privilege of playing on one of the largest mechanical pipe organs in the world and no sound system comes close to the kind of raw power that thing put out in the low register. Just unbelievable, to the point that you start wondering if it can damage the building itself.
'backstage' it is even more impressive, the size of those pipes is just amazing.
The organ is all mechanical so the force on the keys is many times larger than on a piano. The regular organist said she loses significant weight when practicing a new piece (and that's with the 'pneumatic assist' the organ has, which is kind of like powersteering for Organs...).
It is a physical console and virtual sounds. The best of both worlds as it plays like a real organ (unlike most keyboards with an organ sound or 3), but doesn't need a massive room for pipes.
The 'organ' section for most keyboards is unusable for anything except for short effects. Usually the samples (if they use samples...) are extremely short and the presets are boring. On some models you can even hear the sample loop points. I have the same irritation with most wind instruments in keyboards, they sound terrible and aren't even close to what an actual instrument sounds like.
Turn the hype generator down from 11, please.