Picture of simple user-adjustable DIY Nixie Clock

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!

Remove these adsRemove these ads by Signing Up
1-40 of 107Next »
sinaarian20 days ago

Hello, in the schematic I can not figure out what the "neon dot" connection is and where it connects to. Can anyone help me and also I'm using IN14 tubes but don't know what resister to use? The equation did not help at all.

andrea biffi (author)  sinaarian20 days ago

neon dots are the two dots between hours minutes and seconds, but I didn't use them in my clock. Resistors are already in the schematic and b.o.m. if I remember right.

blkadder26 days ago

It would be interesting to see if you could add a PIR module so the clock only activates when there is movement in the room. I have built several Nixie clocks, but none of them have this feature. I have not built one with the IN-4 tubes as yet, so now I have a new project to work on.

Great looking clock and a very nice build description. I wish some of the others were as in depth as you are. Thanks again.

andrea biffi (author)  blkadder20 days ago

I already provided the pcb with "connections to external sensors", and you can use them to connect the PIR module. Of course you have to update the software. It's one of my next projects.

vodkapom5 months ago


I would like to get a Nixie clock, I saw some on websites that you can buy, but in addition to be quite expensive for a clock, I'd like to make mine, just like I want it.

Do you think it is possible to build the whole, complete circuit on a matrix board (since I don't have the possibility to make industrial PCB's) ?

Hey there. I'm not sure if you could do it on a matrix board. You would have to be carefull with trace spacing etc, because a nixie clock will deal with some rather high voltages.

I'd recommend designing a PCB in something like KiCAD and then get it made by It's a very cheap means of getting PCB's fabbed. It's a pooling service though, so it will take some time for the boards to be delievered to you, but for 5$/sqin (x3 because you order in multiples of 3 boards, so 5$ for 3 1sqin boards.)

andrea biffi (author)  vodkapom2 months ago

I don't know, but you can try, just be very careful with high-voltage!

Very cool clock.

Maybe some one could help. I have already made a PCB and everything works, till the clock stops and won't continue counting. I cant reset with the reset button, but i can change the hours and minutes with the buttons.

Can somebody point me in the right direction?

davidm2001 month ago

hello Im having troubles transferring the toner to the copper plating on the PCB... is it the paper or is my iron too cold? its not adhering completely so im having a bit of trouble... and as for the 74141N I have a PD74141P? I think.... will that be ok? plus I have the American Burroughs (I think B4032 the letters are erased and im reading off of marks etched in the glass) will that work in substitution for the IN-4's ???
all in all very nice build!! you have successfully converted me from a tube amp builder to a nixie tube clock builder...
Cheers from Korea!!! (eeuuuhhh South Korea If you were wondering :P)

btw the voltages are similar (170V for the Burroughs B5031?) with 1.5 ma peak cathode current and a series resistor (according to the data sheet) of 15K ohms for 170V, 91Kohms for 250V and 200Kohms for 300V

GordonCrisp2 months ago
Awesome! I really want to build one!

Where do you get the 16khz crystal though?
andrea biffi (author)  GordonCrisp2 months ago

try on eBay or in an electronic components shop

Ive looked in those places. I can find plenty pf 16mhz crystals, but no 16 khz
andrea biffi (author)  GordonCrisp2 months ago
yes M16.000 is 16mhz, not kHz, if i wrote 16khz i made a mistake!
Ok, that makes more sense. It is listed in your BOR as 16000 Hz.

Thanks again for taking the time to share your outstanding skill with us!
Do you have any part # or specific identifier to the ones you have purchased? M16000 is coming up with nothing.
andrea biffi (author)  GordonCrisp2 months ago
it's the crystal for Arduino, it's 16Mhz
Garagebrand5 months ago

Awesome Project, astounding skill! I would like to build one myself. I have a question though...would i be able to substitute the IN-4's with IN-14's without adjusting the construction. Sorry if this is a silly question, I make noob's look like rocket scientists... it seems that you have left huge margins in terms of customizing!

Once again, Brilliant!

andrea biffi (author)  Garagebrand2 months ago

you can connect tubes with wires, instead of making a new tube-shield, good luck!

sinaarian2 months ago

Would i have to change the circuitry to use IN-14 rather than IN-4? I
also looked at the dimensions of the PCBs and the length by width did
not match up at all.

andrea biffi (author)  sinaarian2 months ago

you have to change tube shield and probably some resistors..

emil.godjaev made it!2 months ago

thank you so much for this Instructable! I finally managed to complete this
project. It took me so long because I made a few changes in way of making this
circuit. First of all, I used photoresist method instead of toner transfer. I
would say, that method is the way easier, than method that suggested, even I
am, total newbie, succeed in it at first time. I included a few photos that you
could see the final product of this method. (By the way, I am really sorry that
you’ve seen my first attempt, I’ve learned a lot :) ) I consider about writing my first
instructable exactly about this method.

Next thing
that made me to slow down are pin holders. In my hometown I couldn’t find any
of them, so I had to make them by myself with copper wire. Well, they are not
as straight as these that you used, but it does its job just fine.

The last
thing is a code. I knew that I’m going to stuck with for too long. Firstly, I
tried to program it with LPT programmer, but I got no luck in it. I tried a lot
of times to program it, I tried tons of software, but only thing that worked is
Arduino, that I bought recently.

I would like to say “thank you” again, Andrea. Photos
of your clock have inspired me to make it. Every time that I was looking at clock
that you’ve made, I felt like I was so close and so far away from success at
the same time. Something was burning in my chest, after one little sight at
this masterpiece, something as neon in these indicators, so it made me keep
going, even after so many technical problems, that I got in process.

P.S. I am terribly for the mess on my desk.

andrea biffi (author)  emil.godjaev2 months ago

Hi Emil,

great work! I know how you can feel, I had the same feeling when I saw Max Pierson's beautiful creation some years ago, and I begun studying electronics and buying nixies! :^)

This is great satisfaction!

sinaarian2 months ago

Do i have to put a 10K resister anywhere there is a 15K or 4.7K (or 3.3K)? I am not sure what this means "Please note that where you read 15K resistors you have to interpret 10K
on the main circuit plus 4.7K (or 3.3K) on the shield pcb." .Could someone explain?

andrea biffi (author)  sinaarian2 months ago

Since schematic is actually splitted in two different pcbs, I decided you can use a fixed value resistor (10K) on the main PCB, and a second resistor on the tube shield, wich can vary related to the type of tubes you use. The sum of both values has to respect formulas you find in Threeneuron's great explanation.

Read also my explanation on step 2. I hope everything is clear now...

jgluch7 months ago

Great writeup! I'm looking into making a clock and trying to start sourcing components. I was just wondering what the dimensions are on your PCBs. I think I'd like to try the photoresist method as this is my first time etching a PCB. Any other advice you have would be great. Thanks!

andrea biffi (author)  jgluch7 months ago

photoresist would probably work, but this is a very difficult pcb as first try..

you can read dimensions in step2 images. Good luck!

good instructable, Thanks. . . .Im planning on working on it If i got my money now. . . .

jgluch6 months ago

If it's possible could you send me your Diptrace files? I would like to use the same components but I need to make the board slightly smaller. That would be great. Thanks!

lawrence.loblevyt made it!7 months ago

Hey! Been meaning to have a go at one of these for a while, and have been doing my homework with a bit of help from your Instructables page. Honestly, its a fantastic design, simple yet functional, I like the way you have done away with the multiple drivers, even if it sacrifices a small amount of brightness.

Managed to get your schematic working as a base, and plan to add in either some diodes to combat the slight ghosting issues or some extra transistors to completely shut the signal off between the multiplexing signals. That and I will add in a modifiable relay circuit to attach a motion sensor to, or a simple button to display the time for a pre-determined time.

One issue i'm running into before i do that however is that the time every now and again resets itself to default with no interruption in the display. I've been puzzling over this all week and have narrowed it down to what i can think are the two issues, either the crystal oscillator has the wrong load capacitance (i'm using 16pF for the moment until the 22pF ones come through) although this doesn't seem to be likely. The other might be the N channel mosfet, as when i touch the rearmost plate, it naturally conducts but interferes with the atmega, making the display flicker and then freezing it.

I was wondering whether you ran into these issues, or if you might have an idea on what was going on?

andrea biffi (author)  lawrence.loblevyt7 months ago

looks great!

nope, I never had your issues, but it would probably fix when you put everything on a pcb and solder the components. The Atmega circuit part is a good old verified schematic, it should work well.

If you wish to add an external sensor or a pushbutton, my pcb design already provide connections for it, just on the edge near the atmega.

In my pcb I already managed to solve any ghosting problem, with no interruptions in the signal between multiplexing since there is no time to insert that with only one single driver, and now it works perfect! My next nixie clock is on the way!


I took your advice and stuck it all to the PCB. However have run into some problems again. The clock cycles fine, but only displays the digits 0 and 4 with all other blank, I've checked and there is a voltage across the 10 pins so i don't know what would be the cause of this. I suspect a burnt transistor from the soldering maybe?

andrea biffi (author)  lawrence.loblevyt7 months ago

ouch that's probably discouraging. I know that my pcb design is very compact and has very thin traces, so it's very difficult to make "at home".

usually a transistor doesn't burn for the soldering...I suggest you to look for short-circuits between adjacent traces, and also check for interrupted ones.

I went through and checked all of the traces for continuity, and to see if there where any branches. Also got the oscilloscope up and running and was able to see that the signal through the transistors was working perfectly, this leaves two options, the driver is faulty (i replaced it with another so i'm certain its not that) or the at mega has been fried. I've gone with the latter, so ordered a new one.

Running the oscilloscope was really cool and made possible to see the multiplexing signals clearly! I'll try and get a picture tomorrow to show you if your interested? Wish me luck with the new atmega!

And thanks for all the feedback, it's really refreshing to see someone with so much enthusiasm for his projects. I look forwards to seeing what new tricks you can cook up! Makes me wish i had chosen electrical engineering over mechanical.

andrea biffi (author)  lawrence.loblevyt7 months ago

It seems that changing Atmega will solve the issue.

When I saw nixie clocks I wished so much make one of those that it took two years of documenting (I'm a civil engineer, never studied electronics or IT before) to assimilate the necessary skills and design my own circuit. I also made more than 12 different versions of the pcb to reach that final one.

I'll also try replacing the atmega with a fresh one, there is a chance I've shorted it meaning the digital pin outs are not firing. I tried replacing it with another atmega which had this problem and it displays digits 0,1,4 and 5 instead of just 0 and 4. I'll report back if this solves it. I'l try to get it on an oscilloscope as well, just to be sure.

richb777 months ago

What a great looking clock! I just wish i could program enough (anything!) to add an alarm function and night dimmer/power save.

BRILLIANT work here. Love it!

andrea biffi (author)  richb777 months ago

I would like too... maybe I will be able soon to update the code with those features.

longpcb7 months ago


I want to diy for me one nixie clock the same this project, but i don't know how to convert code file you posted to file .hex! So, can you help me, convert the code fife of this project to file .hex and send to me please? Thank you very much!

My email:

andrea biffi (author)  longpcb7 months ago

I'm sorry I'm not very skilled in programming, not yet ;-)

I'm used to upload the code with arduino, then place the IC on my pcb. Good luck, please post the method when you'll find it, that will be useful!

1-40 of 107Next »