Sean Breheny wrote:

> At 07:55 PM 5/9/98 -0400, you wrote:
> >Mark Devin Newland wrote:
> >
> >> ...hook the buzzer up to it's own oscillator and just have PORTA
> >> turn on (or off) the osc...
> >>
> >
> >And even your local Radio Shack has just the ticket -- a piezo elelment and
> >oscillator in a plastic can unit -- just apply 5V and you're in business. A
> >quick 40 mS pulse should be audible.
> >
> >Ken Pergola
> >
>
> I think that Jonathon IS already using a buzzer with an internal osc., and
> he is just making it beep at 400ms intervals instead of just a continuous
> tone. After all, a 1Hz signal would not excite a piezo element very well
> and it also wouldn't be very audible :)

I'm at fault for not being more detailed on my meaning.  I usually have two
oscillators hooked up to my piezo's.  One at about 2kHz, and the other
at about 1Hz.  The 1Hz osc. is used to turn on and off the 2kHz osc. so as
to give a pulsed buzzer.  I then simply use the MCU to turn the 1Hz osc
off which in turn silences the piezo.