Electrical Issue: PIC input false triggering, Signal Noise suspected.

[Amoque]

I'm not a professional; I'm a hobbyist. My only qualification is a lack of expertise that has lead to many similar issues - odd, inconsistent behavior that seemingly comes from nowhere. For me, it seems always to be a power issue - sagging voltage, poor connection somewhere, two wires touching... I'm careful, I worked twenty years soldering under a microscope, but somehow...

So, I'd first say, "I feel your pain!" For me, better it doesn't work at all - those kinds of problems I can isolate.

I'd first try isolating your power - run it from batteries or a second supply to be sure your power is good. Be sure you have a healthy smattering of filter caps around your inputs. Henrik's idea is good, good solid power at decisive levels!

Presuming you're "light" on equipment as I am, maybe you could hook up your inputs (reed switch lines) to ADC and take a look at voltage that way... see what kind of jitter you've got...

The other thing is, perhaps you've got some debounce issues - comes to mind as you say, "The PIC jumps to the next event."

It's hard to say anything for sure as I cannot see the program, track, or wiring. Just some ideas and moral support...

Let us know how it works out (and I think it would be ok to post a picture of the layout - I know I'd like to see it).

[abecker]

Amoque,

Thanks for your thoughts and empathy from a fellow "enthusiast."

I have read some related posts that the forum software provided presumably due to the tags I defined. There were also some good insights though most of the users there had sensors which were much more sophisticated devices than my lowly reed switches. One person recommended double sampling and rejecting the highs to short to be legitimate by delaying some micro seconds between the samples. I had thought that perhaps using the "Button" command in PBP3 would help de-bounce the input.

I will try running with battery power. Presently I have a 5vDC wall type supply with no ground. I am also going to heavily shield the wires from the reed switches and attempt to use best practices in grounding the shields. I also read elsewhere on the net that I might have to reference my main control board ground plane to the same "earth" ground if I am going to shield/ground all devices.

I have the project fully drawn and documented but I thought due to its size, I would submit that as a last resort.