You made me wonder just how often Touhou is even mentioned on HN, so I did a quick search and... less than 15 results! (not counting dupes).

Niche indeed...

That seems weird. Bad Apple is up there with doom in terms of "make it run", and a few high profile-ish hackers seem to enjoy touhou stuff (drew devault off the top of my head)

Someone on reddit did it: https://www.reddit.com/r/arduino/comments/1rcs8dc/flipdot_di...

You're in luck: https://m.youtube.com/watch?v=5NXSMdUH_Cg

Not niche enough :) https://www.youtube.com/watch?v=5NXSMdUH_Cg

I wonder if you could have it play the music as well by the right timing of flipping, just like how the Floppotron works.

The first thing I dig in the article was a search for "bad". Glad I'm not the only one.