Diatonic button accordion (or melodeon as we call it here in the UK) player here. I wasn't expecting to see my, rather niche, instrument on the front page of HN!

Neat app for experimentation. The bellows control is always the sticking point on electronic DBAs but this works well enough to play a simple tune. I don't think I could do tune, bellows and bass at once on this though!

Nice write-up too.