Here is its upscale cousin -- the Gloggomobil, made by Naef, a swiss company.
The wooden barrel is spun by means of a hand-crank on the side. Small pegs are inserted into pre-drilled holes in the barrel to determine what note plays and when. The music plays on a small-scale metallophone or Glockenspiel (like a xylophone but with metal tuned bars rather than wood).
Where you see more than one peg on a line, the instrument will play a chord. It looks like it comes with pair of mallets for composing or non-automated playing.
The Gloggomobil will set you back over $1000 USD, but I am told it is of excellent craftsmanship and that they are made in limited quantities. This design cries out for a DIY version.
Once again, my thanks goes out to Falk Keuten who tells me he has had one of these amazing musical, mechanical gizmos for 30 years.
Check out a few more details on the Gloggomobil.