Timing input pulses and re-outputting them

[skimask]

I was looking at PWM, but dont beleive it will go as low as 16hz?

Well, if you use a PIC that has a programmable clock source (a lot of the newer ones do), you could change that clock 'on-the-fly' to get it down to 16hz, or do it thru TMR interrupts until the freq gets up to a point where you can use the PWM. For one thing, I don't know which PIC you're going to use ! Also, 16hz is the minimum freq, what's the max?