Sonnerie Half-Hour and Hour Repeater Watch project

This is a nicely sized movement for wearing on the wrist, with a particularly unusual repeater function. Due to the complexity and originality of the module design, at first it wasn’t entirely clear what kind of function it was, although eventually it turned out to be an hour and half hour automatic repeater (self-striking, sonnerie).

The back of the watch is very simple, with regular plates from the 1910’s, such as Alpina or Unitas. The whole fascinating mechanism is hidden under the dial.

At the same time, there are no buttons or sliders apart from the crown. With only two hands and a crown, this is a seemingly simple watch. But every hour it chimes the time all by itself – just like a large wall clock! Additionally, every half hour the hammer strikes a single blow on a gong, resulting in just a single chime.

The dial and hands appear to come from the earlier designs from the pocket watches of the 1860’s and 1870’s.

In the video below, you can listen to the sound of the repeater chiming 7 and 8 o’clock, as well as a single chime signalling the half-hour. In person the sound is even better, especially with a front bezel with a resonating glass cover.

The watch that bears the closest similarities to this one is the Ulysse Nardin ‘Hourstriker’ which also chimes the hour and half-hour, but the sound is much weaker and less impressive.