To start off, I'm a total newbie when it comes to this. but I wanted to make a clock for a friend. A 4 digit in-12 tube nixie clock with an OG-4 dekatron cycling for the seconds. Plus auto dimming and a way to switch between a photoresistor to a manual dimming. There's so many schematics, codes, and ways to do it that I'm overwhelmed. Plus the only way I've seen it fully done is with 2 microcontrollers. The 2nd goes where the nixie drivers go for the seconds and then goes to the dekatron. Can someone sort this all out for me a way to use just one microcontroller?
A very interesting project, with a couple of difficulties:
- Russian documentation
- Voltage up to 450V
- No driver circuit diagram found
Attempt to translate the pins:
1 zero cathode
3 anode
4 pod cathode 1 (combined?)
6 pod cathode 2 (?)
8 cathode
2, 5, 7 no connection
Most probably the zero cathode has to be pulled low to zero the display. Then overlapping pulses (positive or negative?) on the two "pod cathodes" force up or down counting, depending on their sequence.
One or two current limiting resistors connect the power + to anode, - to cathode.
If you are free in the choice of the nixie tubes, choose ones that can be driven by the common SN74141 HV driver chips (decimal decoders). You'll find modules that include a tube, HV generator and decoder at affordable price.
Well there are ready made ones that do exactly that, give or take some features. But I don't think they're going to give out their secrets. This one guy though took a 6 digit nixie clock kit and added the dekatron to it by using another microcontroller in place of the drivers for the nixie tubes. It's in russian in the description link but can be translated.
So it is possible.. But he adapted the dekatron to the kit instead of being on all in one microcontroller.
I did find a schematic that would act like the original 6 digit, but I wonder how I could mod this schematic to gave the dekatron to it rather than needing to use a second microcontroller.
Hope this gives an idea of what I'm trying to do.
Edit:
This seems more like my idea than the one before:
But where the seconds go. I want to drive a dekatron somehow like in the youtube video. But what he did was use a second arudino just for the dekatron and hooked the outputs from the 74ls595n to it and controlled the dekatron that way. Is there a way to drive it like the video without having the use a second one?
That circuit diagram uses ordinary nixie tubes and SN74141, not decatrons.
DrDiettrich:
That circuit diagram uses ordinary nixie tubes and SN74141, not decatrons.
Yes, I know but I'm trying to figure out HOW to use dekatron with it for the seconds instead like in the video.
Actually, a TPIC6B595 will drive either Nixies or Dekatrons quite well!
OK, you obviously need more than one for Nixies.
A TPIC6B595 does not support the required voltages. Nixies operate with voltages above 150V, up to 450V for the Decatron.
A circuit link from Usenet: Dekatron
DrDiettrich:
A TPIC6B595 does not support the required voltages.
If you assert that, neither does the 74141. Note it has Zeners on the outputs rated at 60 V. The TPIC6B595 has amplified Zeners rated at 50 V, hardly any different and perfectly adequate for the purpose of switching cold cathode tubes.
DrDiettrich:
Nixies operate with voltages above 150V, up to 450V for the Decatron.
On the anode, but this is entirely irrelevant to the mechanism of switching the cathodes. Whether 50 V is sufficient to switch Dekatrons is not entirely obvious from the specification above, clearly it is for Nixie tubes.
You may not have noticed my avatar! 
Okay, I remembered wrong values for the TPIC voltage - my bad 
But can you show the circuit diagram for the Decatron, using transistors?
I believe one such circuit was in the page above or home page to the one you quoted.
I only found a circuit using a CV858 tube controlling a 39k load on 300V. Suitable MOSFETs are available, but 300V is far away from 50V. Also shift registers are not very handy in producing the required pulses.
It was this one:
from this page on the same site.
Shift registers are just fine - we are not talking of high-speed (in Dekatron terms) pulse counting here, just displays. 
I interpret "clock" as a time display, not a randomly spinning display. The Dekatron should count seconds, eventually a second one for 2 digit seconds? Then at least the second (higher) one must be reset every minute, or 4 extra pulses can bring the Dekatron to zero again.
Thanks for the modernized circuit. When C5 is omitted, digital counting pulses can be sent to the gate. Eventually a level shifter is required to drive the HV FET, unless a logic level FET for 500V can be found.
Dimming is somewhat complicated with Nixie displays. A HV circuit is required to lower the anode voltage or current. Eventually the anode resistors can be replaced or "enhanced" by LDR?
Ah! found a video of what exactly I'm trying to do.
If anyone knows how to make something like this with just one Arduino. That would be perfect. Would just be missing the dimming feature.
So, I had anotherfriend look at the code for the dekatron for me. Says they can probably edit it for me. Not sure how to use a TPIC though for it... But I can still use what they used on the schematic. But... of course there's real life.. gotta love financial set backs... I'll see later if I can cobble up some schematics and code for an UNO if anyone's interested to try for themselves. Also wanted to say that y'all are awesome for trying to help. 
This thread has got me interested in looking at dekatron tubes. I have only to find one at a reasonable price including delivery.
I found this article which is quite useful: Dekatron Stuff | Threeneuron's Pile o'Poo
6v6gt:
This thread has got me interested in looking at dekatron tubes.
Not surprising.
I have an old PCB with about four tubes I designed and hand etched some 40-odd years ago. I used transistor switches - not sure whether they were silicon or germanium though! And I forget what voltage I was presuming to use on them, but pretty sure it was less than 50 V and I had the datasheet(!) for the "compactron"-style tubes. Never got to try it out. Maybe one of these years I will actually try and operate it, or else use the tubes with a new board.
Of course I will have to find the board first, too!
G-M tubes are so expensive these days!
Since this all completely relevant to the OP's thread, I don't think we can be accused of hijacking it, but I've now realised that the dekatron tube is not merely a display device, it is a cascadable counting device. I found a video from someone who built a 6 digit nixie clock which used no logic elements at all. He simply used what looks like 8 dekatron tubes to drive the whole thing from 50Hz mains frequency. Часы на декатронах А-101. - YouTube .
I've also just been looking at some neon filled dekatrons (orange glow, not light violet) with an octal base in the OGn series which are cheap enough and which could easily form the basis of a future project to add to my clock collection which already includes a nixie, a vfd and many others with more modern displays.
6v6gt:
I've now realised that the dekatron tube is not merely a display device, it is a cascadable counting device.
Indeed, that is precisely its purpose and no other.
6v6gt:
I found a video from someone who built a 6 digit nixie clock which used no logic elements at all. He simply used what looks like 8 dekatron tubes to drive the whole thing from 50Hz mains frequency. https://www.youtube.com/watch?v=4bl5kSr8C3Q .
You think that's something? Try the other video!