Well, i guess it’s my own fault starting to describe the “driving”.board when having this problem that i put myself into.
What you see on these two pictures is what i am experiencing. No microcontroller, Arduino or shield is used here. Only my homemade board with 4 tubes. https://www.dropbox.com/s/ua0835x6r19xssw/Nixie5.JPG?dl=0 <https://www.dropbox.com/s/ua0835x6r19xssw/Nixie5.JPG?dl=0> https://www.dropbox.com/s/vwt2b48hzrapknn/Nixie6.JPG?dl=0 What is off camera is a regulated lab power supply set at 180 Volts. For the sake of eliminating capacitively coupling from one anode to the others i even removed the anode pins from the PCB. I have soldered a 15K resistor direcly on the anode-pin (Pin4) which is in turn connected to the power supply. As you see, one of the other tubes is lit, too! So somehow the anode voltage is capacitively coupling inside the tubes to a nearby cathode and trough that, powering another tube. I /do/ know about blanking in software, but that’s not the problem here. I don’t know what i could do about that. // Per. > On 07 Jun 2015, at 19:08, David Forbes <[email protected]> wrote: > > Per, > > Hi. I built many copies of several types of Nixie clocks about 10-12 years > ago, using multiplexing. They worked very well, with no ghosting at all. > > Things to look for: > > 1. Ensure that you have a "dead time" after the anode is turned off, with the > same cathode selected, for about a millisecond. The reason is that if you > immediately change the cathode after turning off the anode, the residual > charge on the anode will cause the newly selected cathode to light in the > tube that was just turned on. > > 2. Any cables connecting the tubes to the drivers will extend this storage > time due to cross-coupling between the wires, so experiment with longer "off" > time with the previous cathode still selected. > > > > On 6/6/15 5:47 PM, Per Jensen wrote: >> Hi. >> >> Being a Nixie-hoarder for many years, i’m actually guilty of not having a >> working clock at home. The only clock i have working is sitting in the local >> hackerspace. It’s an direct driven design and have been working perfectly >> for about 6 years now. >> >> As i have a million “real” projects that i am working on, ii’m pretty sure >> that getting the time to design a clock “properly” isn’t just around the >> corner. >> >> On one of those late-night shopping-sprees i came across this board: >> http://switchmodedesign.com/collections/arduino-shields/products/open-source-nixie-tube-shield-cut-jump-pcb >> >> <http://switchmodedesign.com/collections/arduino-shields/products/open-source-nixie-tube-shield-cut-jump-pcb> >> and ordered 2 pcs. >> >> I “trusted” the website-name (switchmode designs) as the board being >> designed by one that knew what he was doing, so i didn’t check schematic or >> board layout before i had the boards in hand …. Maybe i should have done >> that, because that switcher is the worst design i have /EVER/ seen. >> >> Anyway, apart from that, it works ok-ish. >> >> I wanted to use this board as a “backend” for my own board with tubes. I >> quickly whipped up a board for 4 IN-4’s: >> https://www.dropbox.com/s/dsk1hv2xly7e9v2/Nixie.png?dl=0 >> <https://www.dropbox.com/s/dsk1hv2xly7e9v2/Nixie.png?dl=0> >> https://www.dropbox.com/s/yn42qtdki3vr7bo/Nixie2.jpeg?dl=0 >> <https://www.dropbox.com/s/yn42qtdki3vr7bo/Nixie2.jpeg?dl=0> >> >> It’s a milled PCB so that’s why the copper is left around the tracks. >> >> Now i am having this stupid problem - ghosting! >> >> No, it’s not software ghosting, because if i only connect a single tube with >> two wires (the wide cable isn’t connected) , sometimes the neighboring tube >> lights up, too. >> >> So somehow the tubes being connected only by the cathodes and the anodes >> floating, powering one can excite the others. >> >> I even removed the pins for the tubes so the anode pins of the unused tubes >> is not even touching the fibreglass-material. Only cathodes is thouching. >> >> (anode-pin connected by flying wire to anode resistor and driver) >> https://www.dropbox.com/s/y0xhc9gazrxa120/nixie3.jpeg?dl=0 >> >> Is there anything to do here, or should i scrap the boards and design my own >> direct-driven circuit? >> >> >> // Per. >> > > > -- > David Forbes, Tucson AZ > > -- > 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/55747A7B.3000108%40dakotacom.net. > For more options, visit https://groups.google.com/d/optout. -- 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/AF82D905-FA4B-4191-B99D-694A948BE020%40gmail.com. For more options, visit https://groups.google.com/d/optout.
