Many thanks to all those readers who were kind enough to provide, both
directly and in the pages of MMD, solutions for my problem of finding a
suitable noise-making device for my machine.  The solutions proposed
ranged from purely mechanical to electronic.

A nice compromise electro-mechanical-acoustic device, very kindly
provided by Dr. Walter Tenten, very neatly fitted the bill.  (Oh,
dear, we nearly slipped back to the duck again.)

Best Wishes for 1998 to all,

Bob Klepner

 [ This thread was fun; it began in Digest 971215, and many
 [ onomatopoeic devices were proposed.  I hope the vending machine now
 [ says 'cluck cluck', not 'quack quack' or 'oink' or 'me-ow'!  Walter
 [ said that the sound of the device he found was indescribable, but
 [ "every listener starts laughing immediately!"  How do you describe
 [ the sound, Bob?   -- Robbie