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!

Step 1: The schematic and working principle

Lately, after some research and a fast designing, I attained this functional high voltage power source circuit. Since there is a full step to step guide about the hv power source section of my clock, I will pass over that explanation. There is only something to say about the input voltage for the clock: to increase the universality of the project I decided to give the possibility to power the clock with a voltage from 9 to 35V. The best solution (in terms of efficiency and thermal dissipation) is to connect a 9V DC PSU (500 mA or more), but if you want to power the device with a voltage from 12 to 35V you only have to shift the voltage switch in direction of the ON-OFF switch (which has a center ON position between two OFF ones).
With the pot you have to set the voltage (read next step for high voltage pins) to the about 190V needed to power the IN-4 nixies (in multiplexing displays is better to use a bit more than the 180V needed to light a single nixie tube). You can of course set up the proper voltage for any other nixie tube.

The other section is the logic circuit, where a cheap Atmega8 IC (but you can also use an Atmega168 or Atmega 328), through a nixie driver and some high voltage transistors, controls the digits.
The nixie driver is a K155ID1 which is the Russian equivalent of the 74141N, and it spares you to use 20 more high voltage transistors. This driver is not very expensive, but it's not longer manufactured, so with time it will be more difficult to find, for this reason I wanted to use only one in my project (while there are many nixie clock projects which uses one driver for each digit).
This has been possible thanks to some references I found in the web
neon1.net, threeneurons.wordpress.com)
but mainly thanks to Jeremy Howa and Brad Lewis for their Arduinix project, which enlightened me about multiplexing power and from where I took the original code.

My schematic is drawn in Diptrace, a simple pcb design software, I divided it into two pats so to show it better, read notes on the image to understand circuit parts.

OK andrea, I will start buying the necessary components ..is there a chance in the meanwhile to upload the improved PCD design? Mostly for phycological reasons :))
yup, go reading my last nixie clock instructable ;) and use that design
thank you andrea! take care my friend.<br>
<p>Hi guys! Great project Andrea! I would like to try it myself but cannot locate the BOTTOM side of the PCBs...? Do I need new glasses? :)))) I found the TOP side silk prints but not the bottom.. Any directions are greatly welcome!</p>
forget what I answered before l, it's the top view PDF ;)
:) its ok!, I think I found the bottom design on your other Nixie projects? Or is that not the correct one?<br><br>Basically I need the bottom side for the tube PCB and the main circuit... <br><br>Keep up the good work!<br><br>Salute from Greece :)
it should work, last version only has minor improvements, good luck!
step 2 - main pcb top silk pdf ;)
Really like this project and really well documented. Did you progress any of the improvements, in particular the rtc?
<p>Last week I managed to finish mine! :) I was trying to achieve something similar to your design because I loved it so much... Unfortunately I couldnt get a box that is even close to your beautiful rosewood box, so I needed to create it myself from an old solid wood block. This of course resulted a much less attractive outcome, but I still like the results. :) I also needed to add this dark brown color and apply an oil finish on the box. Instead of the screws at first I created the stands from small wood pieces, but finally I found it would look better to replace them to screws.</p><p>I used my existing controller board design for the electronics, but applied your panel design for the tubes' board and the same IN-4 tubes.</p><p>This is made for a birthday present and will be handed over tomorrow so keep your fingers crossed... :)</p><p>Thank you again for inspiring me to create this, I'm so happy that I could finally make it! :)</p>
woow that's awesome!<br>beautiful pictures too.<br>I'm happy you made it!
Thank you!!! :)
<p>This is the most beautiful nixie design I have ever seen, congratulations!<br>Awesome project description too, thank you very much for sharing! :)<br>I built a nixie clock successfully back in 2008, but your work actually inspired me to build a new one, as close to your design as possible. (I hope it's not copyrighted. :D)<br>I'm already done with the electronix, so I need to create a nice case from old/wheathered/reclaimed wood, which is going to be a challenge for me... :)<br>Keep up the good work!<br>Moire</p>
Awesome! I'm really happy you like it, I've been inspired by a nice project too.
<p>Very nice project.<br>Could you please share an estimate cost for the parts for this project?</p><p>Thanks</p>
<p>Hello, in the schematic I can not figure out what the &quot;neon dot&quot; 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.</p>
<p>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.</p>
<p>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. </p><p>Great looking clock and a very nice build description. I wish some of the others were as in depth as you are. Thanks again.</p>
<p>I already provided the pcb with &quot;connections to external sensors&quot;, 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.</p>
<p>Hi,</p><p>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.</p><p>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) ?</p>
<p>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.</p><p>I'd recommend designing a PCB in something like KiCAD and then get it made by <a href="http://oshpark.com" rel="nofollow"> http://oshpark.com</a> 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.) </p>
<p>I don't know, but you can try, just be very careful with high-voltage!</p>
<p>Very cool clock.</p><p>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.</p><p>Can somebody point me in the right direction? </p>
<p>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 ??? <br>all in all very nice build!! you have successfully converted me from a tube amp builder to a nixie tube clock builder... <br>Cheers from Korea!!! (eeuuuhhh South Korea If you were wondering :P)</p>
<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</p>
Awesome! I really want to build one!<br><br>Where do you get the 16khz crystal though?
<p>try on eBay or in an electronic components shop</p>
Ive looked in those places. I can find plenty pf 16mhz crystals, but no 16 khz
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. <br><br>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.
it's the crystal for Arduino, it's 16Mhz
<p>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! </p><p>Once again, Brilliant!</p>
<p>you can connect tubes with wires, instead of making a new tube-shield, good luck!</p>
<p>Would i have to change the circuitry to use IN-14 rather than IN-4? I <br>also looked at the dimensions of the PCBs and the length by width did <br>not match up at all.</p>
<p>you have to change tube shield and probably some resistors..</p>
<p>Andrea, <br>thank you so much for this Instructable! I finally managed to complete this <br>project. It took me so long because I made a few changes in way of making this <br>circuit. First of all, I used photoresist method instead of toner transfer. I <br>would say, that method is the way easier, than method that suggested, even I <br>am, total newbie, succeed in it at first time. I included a few photos that you <br>could see the final product of this method. (By the way, I am really sorry that <br>you&rsquo;ve seen my first attempt, I&rsquo;ve learned a lot :) ) I consider about writing my first <br>instructable exactly about this method.</p><p>Next thing <br>that made me to slow down are pin holders. In my hometown I couldn&rsquo;t find any <br>of them, so I had to make them by myself with copper wire. Well, they are not <br>as straight as these that you used, but it does its job just fine.</p><p>The last <br>thing is a code. I knew that I&rsquo;m going to stuck with for too long. Firstly, I <br>tried to program it with LPT programmer, but I got no luck in it. I tried a lot <br>of times to program it, I tried tons of software, but only thing that worked is <br>Arduino, that I bought recently.</p><p>I would like to say &ldquo;thank you&rdquo; again, Andrea. Photos <br>of your clock have inspired me to make it. Every time that I was looking at clock <br>that you&rsquo;ve made, I felt like I was so close and so far away from success at <br>the same time. Something was burning in my chest, after one little sight at <br>this masterpiece, something as neon in these indicators, so it made me keep <br>going, even after so many technical problems, that I got in process.</p><p>P.S. I am terribly for the mess on my desk.</p>
<p>Hi Emil,</p><p>great work! I know how you can feel, I had the same feeling when I saw Max Pierson's <a href="http://www.maxwellrosspierson.com/2010/10/13/my-nixie-clock-build/" rel="nofollow" style="">beautiful creation</a> some years ago, and I begun studying electronics and buying nixies! :^)</p><p>This is great satisfaction!</p>
<p>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 &quot;Please note that where you read 15K resistors you have to interpret 10K <br>on the main circuit plus 4.7K (or 3.3K) on the shield pcb.&quot; .Could someone explain?</p>
<p>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 <a href="http://threeneurons.wordpress.com/nixie-power-supply/" rel="nofollow" style="">Threeneuron's great explanation</a>.</p><p>Read also my explanation on step 2. I hope everything is clear now... </p>
<p>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!</p>
<p>photoresist would probably work, but this is a very difficult pcb as first try..</p><p>you can read dimensions in step2 images. Good luck!</p>
<p>good instructable, Thanks. . . .Im planning on working on it If i got my money now. . . .</p>
<p>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!</p>
<p>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. </p><p>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. </p><p>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. </p><p>I was wondering whether you ran into these issues, or if you might have an idea on what was going on?</p>
<p>looks great!</p><p>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.</p><p>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.</p><p>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!</p>
<p>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? </p>
<p>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 &quot;at home&quot;.</p><p>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.</p>
<p>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. </p><p>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! </p><p>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. </p>
<p>It seems that changing Atmega will solve the issue.</p><p>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.</p>

About This Instructable


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Bio: I'm an Italian freelance structural engineer, graphic designer and photographer. I'm also investigating electronics, robotics and science in general. I enjoy hacking and ... More »
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