Ah, that parsitic glow. The Zirrfa boards don't do something important that they should: The drivers on my board are clamped with a Zener, which stops them from breaking down when there is no load on undriven digits. The unclamped voltage can range between 90 and 120V and that's just plain too much for the ULN drivers, so I added a clamp.
I use a DS3231 RTC chip (original Maxim - the Atmel is original as well - this was very important to me and cost a few pennies extra) and that is usually good for 1 second a month. However, if you go for the WiFi version, you get NTP synchronisation, as well as a nice GUI to configure the clock with. My firmware is not at all locked down. It's FOSS and is there for all to see / modify / and hopefully contribute to. ;) On Saturday, 6 February 2021 at 14:48:09 UTC+1 Robert G. Schaffrath wrote: > On Friday, February 5, 2021 at 6:26:36 AM UTC-5 Ian Sparkes wrote: > >> So, it started like this: I liked the Zirffa style Chinese boards - I >> thought the hardware was pretty good, but the firmware was really >> primitive. I was going to set about re-writing the firmware for these >> boards, but them came up with the idea of simply taking the hardware >> approach and using my existing firmware on it. >> > > I have two Zirffa style boards. One for IN-12's and the other for IN-14's. > I agree that while the hardware is pretty good (more details follow) the > firmware is really primitive. > > The IN-12 hardware is wonky in that if a digit is blanked, or the whole > clock is off in night mode, there is a parasitic glow from various > elements. As such, I have to leave all digits powered at all times. Also, I > find it will drift a second or two over a week. > > Meanwhile I have an IN-14 board that I use with Rodan Gr-111Pa tubes. I > replaced the anode resistors with 18K to give the tubes the needed 2mA to > drive them properly. That board firmware is also primitive but I am stunned > at the accuracy of the clock chip. It runs for weeks and stays on the > second. No idea why that board should be so accurate. When the clock turns > itself off at 10 PM, there is no parasitic glow. > > It is a shame the firmware on those boards is locked down. The hardware > had such potential. > > -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/68eb1eda-4453-412c-a8f9-051fd1006bb9n%40googlegroups.com.
