>Does anybody know how to produce a reasonably loud "click" from a
>3V battery powered circuit?  I tried sending a square pulse to a
>teensy weensy miniature speaker, but it's very quiet.
>

Try using a piezo speaker, and hitting it with a train of pulses, say 10
milli-seconds of a 4 KHz (250 uS period) square wave. If its too short to
sound like a tone, it will sound like a click. Drive the speaker with two
port lines (complemented, 180 phase) with an appropriate inductor in
parallel with the piezo, around 100mH, to get a louder signal, or use an
audio step-up transformer. Common piezo's are around .001uF.

>Programmer Software for Free
>============================
...
>I'd be happy to release my source code (although it still has some
>very rough edges!) if there is demand.

I'd like to see it. Thanks.