How about clocking the PIC from a simple RC, monitor the AC line
(through a transformer & diode & series resistor to a PIC input pin) to
give you a 60Hz timebase, and then monitor your other signal through
another PIC input pin, then run a counter off the 60Hz clock input?

  For measuring the input frequency, there's been a 16F84 Frequency
Counter around, but I don't see it just now where I remember it being
last (Anyone know the facts on that?)  Given a 60Hz time base, you could
count both the 60Hz and the unknown frequency for, say, 1 second, (i.e.
60 counts for the counter on the F84), to get a rough count.  (Yeah, you
could use a crystal, and at 4MHz you're at 1 MIPs, but he says
"relatively low frequency" here.)  Should help you get ideas here.

  Mark

Andrew wrote:
>
> Hey all,
>         I'm a new person to this PIC stuff and was wondering what the best way
 is
> to generate a low frequency < 1 Hz. I want to create a pulse that is low
> for 1 hr and hi for 10 min. Also a low for 24 hrs and high for 10 min.
> Ideally I would like to use a 1 16F84 but think that won't be possible. a
> code snippit would be really helpful if anybody has one.
>
> Another project I have in mind requires measuring a frequency and outputing
> a pulse that is delayed from the input. I have an equation worked out, but
> need to measure the input frequency, how do I go about doing this? Again
> this is a relatively low frequency and would like to use a 16F84.
>
> Thanks
> Andrew