What could make one of the Mike Harrison Nixie clocks run erratically? It's basically running fast, but it also does this erratically- sometimes it looks like the seconds are counting at the proper speed, but then they will speed up...?
I build clocks using an 8051, synchronized to the power line. (I use a similar circuit - a resistance and voltage clamp diodes, but I pull the AC off the power transformer, and use external clamp diodes - still, there's no reason that Mike's circuit isn't OK. Microchip recommends just this type of circuit for direct off-the-line embedded products.) Regardless, I had the same problem with my clocks (running several minutes, sometimes as much as an hour) erratically fast each day. It turned out that the problem was false triggering from line noise. I solved it in firmware by ignoring the power-line pulse for 16.6 mSec after each previous pulse. Statistically, there could still be a noise event in that last 67 uSec, but in practice this seems to have completely solved the problem. After running for months, my bedroom clock is still within 1 minute of my (presumably always correct) cell phone. ~~ Mark Moulding -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a1af667c-d473-4fc9-b864-4597b68d6658%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
