I have the circuit built and tested but need a little time to calibrate (the software constants) the cycle time to 60 seconds ticks (120 second clock).
A older PCB version of this with the PWM analog filter replaced with a coupling capacitor.
https://github.com/nsaspook/ihc_mon/blob/re20a/ihc_monb.pdf
https://github.com/nsaspook/ihc_mon/blob/re20a/ihc_mons.pdf

View attachment 209749View attachment 209750View attachment 209752

https://github.com/nsaspook/ihc_mon/blob/tick60/dale_10mhx_osc.pdf

Rewritten existing software code for the PIC18F1320
https://raw.githubusercontent.com/nsaspook/ihc_mon/tick60/ibsmon.h

ISR routines. I just reused old code so the names don't related to timing generation.
https://raw.githubusercontent.com/nsaspook/ihc_mon/tick60/ihc_vector.c

Setup, main code.
https://raw.githubusercontent.com/nsaspook/ihc_mon/tick60/ibsmon.c

I'm really blown away that you are doing this... Thank so much

 

It's done.


The jumper selects 250 ms or 1 second pulse width every 60 seconds.
https://github.com/nsaspook/ihc_mon/blob/tick60/ibsmon.X/ibsmon.zip