Is it really possible to build a rotary encoder out of a flattened tin can and a couple of photodetectors? Sure it’s possible, but what kind of resolution are you going to get from such a contraption?

Cheap nostalgia, that’s the name of the game. If you can somehow build and ship ‘cheap nostalgia’, you’re going to be raking in the bucks. For the ‘musicians’ in the crowd, the king of cheap nostalgia ...