J
Jack B. Pollack
- Jan 1, 1970
- 0
I have a digital thermostat that I have modified & interfaced with a
PIC16F88 for some custom automation. The thermostat run on 24VAC and I have
picked off one of the chips a 5VDC source to power the PIC.
All was working well for 6 months without a problem. Lately, when I push a
momentary switch (Switch is NO, pulled down with 10K when open ,+5V to PIC
input when closed) that is connected to one of the PIC inputs the PIC
executes its programming correctly, but the thermostat goes crazy (the
back-light comes on and stays on and the display goes blank and stays
blank). This does not happen all the time, but will usually show itself
within 24hrs. Power cycling everything fixes the problem.
Why has everything worked for months without a problem, and now started
doing this?
What would be the recommended way of isolating the PIC from the thermostat
(I would like to try to avoid adding my own rectifier & Vreg if possible)?
Thanks
PIC16F88 for some custom automation. The thermostat run on 24VAC and I have
picked off one of the chips a 5VDC source to power the PIC.
All was working well for 6 months without a problem. Lately, when I push a
momentary switch (Switch is NO, pulled down with 10K when open ,+5V to PIC
input when closed) that is connected to one of the PIC inputs the PIC
executes its programming correctly, but the thermostat goes crazy (the
back-light comes on and stays on and the display goes blank and stays
blank). This does not happen all the time, but will usually show itself
within 24hrs. Power cycling everything fixes the problem.
Why has everything worked for months without a problem, and now started
doing this?
What would be the recommended way of isolating the PIC from the thermostat
(I would like to try to avoid adding my own rectifier & Vreg if possible)?
Thanks