We have been asked by an organist to modify his nightingale stop
(two pipes inverted in a glass of water) so that when the piston is
pressed the twittering would be intermittent rather than continuous.

Some kind of pinned barrel mechanism would seem appropriate here, as
the twitters could be randomly spaced out, lasting from a fraction
of a second to several seconds.  A total cycle of 15 seconds or so
should be adequate to get the random effect.

We have no experience with such automata, and would appreciate sugges-
tions from MMD readers for a suitable mechanism.  At the moment, a
simple electric valve on 12v DC is used to control organ wind to the
pipes.

Don Pole
http://www.pandk.com/