A small windmill is used to rotate a drum or cylinder with a series of pins in it, similar to a music box. The pins travel over an escapement mechanism that both limits the rotation of the drum and applies tension to the output chimes.
The chimes form a chromatic set and swing freely from one another. Each chime has its own clapper to which the tension is altered in the mechanism. If a pin is pressing against the escapement, the clapper is free to swing and sound the chime. The sounding impact frees the escapement and allows the drum to rotate to the next pin.
The result is a wind-driven, somewhat random performance, but the notes are always played in exactly the same order.-- mitxela, Aug 13 2019 Musical Whirligigs https://www.google....lAUwQ4dUDCAo&uact=5These are already a thing. [neutrinos_shadow, Aug 13 2019] Musical whirligigs are already extant, and there's no need for it to be "somewhat random"; the drum can be quite precise.-- neutrinos_shadow, Aug 13 2019 ^nice.
A perfect wind today, to chime timely. Though, no storage generally means no consistency.-- wjt, Aug 14 2019 "somewhat random" is a feature.
To be clear, the tension mechanism simply un-mutes the chime in question, it still has to wait for an appropriate gust of wind to activate it.-- mitxela, Aug 14 2019 random, halfbakery