Simple user-adjustable DIY Nixie Clock

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As first instructable of the year I managed to finally complete my age-long nixie clock project.
Nixies are neon valve tubes, where ten cathodes have shape of digits and are lighted up by plasma when high voltage flows through them. I love these old era displays, which have been employed in last century before I was born.
In last year I've been slowly collecting components and knowledge to build some nixie clocks as Max Pierson's beautiful creation, I like the old style, the roundness of glass tubes, the rough wood case, the simplicity of the design. That clock has definitely inspired my project. Even though I really love vertical digits arrangement I keep that original feature for my next clock.

Therefore this first born is a six digits horizontal wood desk clock, with six big round Russian IN-4 nixie tubes, no dots, no visible buttons, no LED illumination, only a big massive rosewood block and the power of plasma ;-)
I have to explain you what the title means:

simple because it can be entirely built with common tools and from common components, you only have to order six IN-4 nixies and one nixie driver

user-adjustable because it's predisposed for many external sensors and additional features (as neon dots between digits, alarm, etc.)

DIY since you neither have to buy external shields or to pay for pcb manufacturing, just follow my instructable ;-)

WARNING: this circuit raises the voltage to deadly 300V so you must avoid to touch contacts while working, I'm not kidding, please BE CAREFUL!

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salexandridis2 months ago


Yesterday I finished the project and I tested it. All nixies lit up apart from the first hour nixie. After some measurements, I found out that one MPSA42 transistor was burned out, so I will replace it soon.

Now, the problem is that when I powered the circuit again this morning I noticed that all nixies would display the digit 2 and the digit they are supposed to display (have a look at the attached photo). Keep in mind that I have already tried disconnecting the K155ID1 pin that controls digit 2 (which is pin 8). Digit 2 turned off on all tubes, but when it was time to display this digit, the nixie would go crazy and a fade "red-ish shadow" would appear around each digit. Do you have any idea about what might be wrong?

Thank you in advance,


andrea biffi (author)  salexandridis2 months ago

Ouch... that's very strange. I would say that there is an high voltage across all anodes when no signal goes to transistors. I found out that there is actually an interference between hv circuit and transistor, but the effects were not so evident in my clock. I designed a new pcb where voltage is constant on all anodes, I'll post it soon here.

ps: you forgot to attach the photo

Thank you very much! What's more peculiar is that yesterday it was working just fine (except for the nixie on the left), but today I got this problem... Anyway... I' m looking forward to new PCB.

Oops! It seems that I did forgot to upload the photo! Here it goes!

andrea biffi (author)  salexandridis2 months ago

new pcb design updated (attachments to step2)!

And here are some more photos!

andrea biffi (author)  salexandridis2 months ago

salexandridis, that toroidal choke in the picture is not good for this high voltage circuit, when I tested it the mosfet, the coil and other parts got very hot! Use a radial inductor as this.

andrea biffi (author)  andrea biffi2 months ago

I updated the guide with this info (step3)

SpectrHz2 months ago

What a gorgeous looking clock! I absolutely need to make a project like this eventually :) I really like the wood you used, the nice warm orange glow against that dark wood looks amazing.


imperio2 months ago

just say, it's nice .... not enough ... this item is rejuvenating!

Imperio from Florence

andrea biffi (author)  imperio2 months ago

Grazie Imperio!

TheFruktus3 months ago

Can i use IN-14 For this project?

andrea biffi (author)  TheFruktus3 months ago

Yes of course, I'm also improving the circuit to remove a magnetic interference between traces, and I'll design an IN-14 clock too.

To use IN-14 you have to change tubes' pins arrangement on the tubes shield.

yeah i figured this out, i was just curious if the voltage will work. Thanks :)

andrea biffi (author)  TheFruktus3 months ago

Yes, this circuit could supply a wide range of voltage, just set the pot to have the voltage needed.

artRiot3 months ago
Awesome, great job man. I love nixes, so cool. I found a good place to buy them back when I was doing a project in school. Check it out
andrea biffi (author)  artRiot3 months ago

cool, tube are also cheap there, but no IN-4 ;-)

no...but a very good friend of him...we talked about you today.... if you have Facebook you can look on my site Titus Timeless

andrea biffi (author)  Titus Timeless3 months ago

Titus your projects are awesome! Please post at least an instructable here :-)

zacnotes3 months ago
Andrea- Great build, the finished product looks fantastic. I have a nixie tube racquetball scorecard that turned out nicely, but it was my first project with any sort of meat to it at all, and i learned a lot that i intend on implementing in my next project, a nixie clock. I will be using the IN-4 tubes as well, but i am finding designing a pcb around them in Fritzing to be difficult. Would you mind making your Diptrace IN-4 part available?
andrea biffi (author)  zacnotes3 months ago

Hi zac, thanks. I'll pm you about the IN-4 part.

Awesome, thanks
valveman3 months ago

Andrea this is so retro I love it! I'm kicking myself for giving away older nixie tube HP equipment.

andrea biffi (author)  valveman3 months ago



Great Job...greetings from Aeon Junophor

andrea biffi (author)  Titus Timeless3 months ago

Are you incognito, Aeon? ;-)

vroom3503 months ago

Good idea make put small PIR module with Nixie Clock if no-one walk around for 5mins cause turn off the Nixie automatic, save life tubes and energy bill, someone walk into area cause Nixie turn on itself.

andrea biffi (author)  vroom3503 months ago

yes, life of IN-4 tubes is only 10.000 hrs (about one year) so I really suggest to add some cathode poisoning prevention routine and also some code it turns them on only if needed.

shizumadrive3 months ago
how much did the nixies cost? And the project as a whole? Ive want to build one of these since I first saw one in '92
andrea biffi (author)  shizumadrive3 months ago

Nixies are becoming more and more difficult to find, and IN-4 are pretty rare, anyway you can buy some of them from ebay for about 4-5 $ each, maybe less if you buy a full set. The entire project could be expensive if you buy retail components, the same as pcb manifacturing. All part should be available at

agis683 months ago


vroom3503 months ago

Great idea! Love it, but Nixie is run more current than Led, rare made nixie tube, hardly order, no idea how long life that nixie tube like valve tube heat up.

nice job
andrea biffi (author)  mbristophiles13 months ago
salexandridis3 months ago
What an amazing Instructable! The instructions are so detailed and the final project looks absolutely beautiful!

I intend to make one as well and I would like to know if there other kinds of nixies that could be used instead of the IN-4 ones. I did a little research and I found out that nixies of the IN (ИН) series have similar characteristics (not identical though...).
I am looking forward to your response,

Thank you in advance,
andrea biffi (author)  salexandridis3 months ago
Hi Sotos, I really love any type of Nixie tubes, but I prefer the end-view models.
Anyway you can find a detailed list here: The Vintage Technology Association
Thank you for your quick response! I am also a huge fan of nixies! So, you say that I could use any kind of numerical nixies in place of the IN-4 ones without making any changes in the schematic you provide in your Instructable? Could I just buy any nixies that have the similar firing voltages, keep-up voltages and cathode currents and wire them up directly to your PCB (making any necessary changes to the pinout, of course)?
Also, I would like to share something that I found out about the nixie pins-sockets. If anyone considers purchasing some, they will probably find themselves searching through the endless eBay results without actually finding the appropriate pins for the IN-4 nixie tubes. Nevertheless, they might find some, but those are inexplicably expensive in comparison with the more common pins for IN-8, IN-12 and IN-18 nixies. I searched the web for the diameter of these pins and I found that it is exactly 1mm (~0.04"), which luckily matches the pin diameter of the IN-4 nixies. So, feel free to buy pins for these nixie tubes; they will definitely fit to the IN-4 tubes!
andrea biffi (author)  salexandridis3 months ago
Yes, you're right about female pins, the only with huge pins are IN-1 tubes.
search the values for the tubes you want to use, my circuit has a potentiometer with which you can vary voltage ~ from 140 to 300 volt, so you can make it matching your tubes. If you don't find values for IN-1, IN-2, IN-4, IN-12, IN-14, ask me that I should have them, but I'm sure I found them in google.
You have of course to change the tubes shield with pins layout, and maybe also the resistor on the shield, look the link I provided in the ible.
OK! Thank you very much. I have found datasheets for lots of different kinds of nixies (including the ones you mention on your last post). I will go through all of them and I will decide which one I like more. IN-18 tubes are magnificent, but they are extremely pricy.
IN-4 are beautiful, too, because they are end-view type. IN-14 and IN-8 are quite similar and affordable, as well, but I find IN-8 nicer, because IN-14 has a plastic base, which makes it less pleasant to the eye.
I let you know for my progress on the project!
andrea biffi (author)  salexandridis3 months ago
On that site I see there is no information about firing voltage, keep-up voltage and current. You should google it...
patchie3 months ago
Wow, cool..where can i see price's and where to buy components you have used?

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