Barrel organ

A barrel organ (also called roller organ or crank organ) is a French mechanical musical instrument consisting of bellows and one or more ranks of pipes housed in a case, usually of wood, and often highly decorated. The basic principle is the same as a traditional pipe organ, but rather than being played by an organist, the barrel organ is powered by either a person turning a crank, or by clockwork driven by weights or springs. The music is encoded onto wooden barrels (cylinders) using pins. The pins strike levers which are analogous to the keyboard of the traditional pipe organ. A person (or in some cases, a trained animal) who plays a barrel organ is known as an organ grinder.