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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!

 
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Step 1: The schematic and working principle

Picture of The schematic and working principle
nixieclock02.png

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
(maxwellrosspierson.comelbastl.sweb.cz,
mlknaweb.blogspot.itglowbug.nl,
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.

Step 2: The board design

Picture of The board design
nixieclock04.png

Diptrace lets you to autoroute the traces, but in my case I had to route them manually since I wanted to keep the board as small as possible.
The clock is composed by two different boards: the bottom part contains all the power source and logic sections, and the top board is to connect the tubes, each one with a proper resistor. Indeed since different tubes could need different resistor values, I decided to leave 10K resistors on the clock board and add a second resistor for each tube on the tube shield, so that you can easily transfer the same main board from a clock to another. To calculate the total value or resistors I referred to Threeneuron's great explanation.

To set the right voltage set the right position of the 9V / 12-35V switch depending on your PSU, then plug the jack and connect your multimeter to a GND pin and to the "+180(TEST)" pin. Calibrating the potentiometer you will see voltage varying from about 140 to 300V, set it to 190V.

Actually the pcb you see here is an new version of my clock board, since I improved the component arrangement and I still have to etch the new board, so maybe you will note some minor differences.
If you look the "top silk" pdf file you'll see that I marked on the board top surface all the info to place components, such as name and polarity, so you should be able to solder them easily with the help of the b.o.m. 
Furthermore in the other documents you find the traces ready to print and to transfer on the copper board, for both clock circuit and tubes shield. Top-silks are mirrored for this purpose.

Step 3: B.o.m.

Picture of b.o.m.

The bill of material is the longest I've ever needed for one of my electronic projects. I know it's far from to be professional and there should be many imperfections, but I tried to be more exhaustive I could.

You must add to the list: 66 sockets for tube pins, two male pin header strips for tube shield (1X10 and 1X6), the case, the IN-4 tubes and the PSU.
 
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.
 
I've used a buzzer taken from a Nokia phone since it's great to play multi-tone sounds for alarm, but you can change it with any 5V buzzer, or you can remove it, as some more components (resistors for neon dots, 9V voltage regulator, reset button, etc.).

L1 is a fixed radial inductor (avoid toroidal chokes) 100 uH 1A. On the board you can find space to place a stocky or slender inductor, just ignore the hole you don't need. R17 and R18 should be 1% accuracy metal film resistors, to achieve a better voltage stability. D1 has to be a ultra-fast 400V diode, as BAV21, UF4004, UF4007, MUR140, or MUR160.
bom.pdf64 KB

Step 4: The code

Picture of the code

The code I used in this clock version is taken from the open source material available on Arduinix website, and I really suggest you to go looking Brad Lewis "Sloth Furnace" impressive projects (he's an instructables member too).
 

I modified the code to use only one nixie driver instead of two, since I don't need to run more than 6 digits, and I prefer to save drivers. There is a parameter which you can change if you have problem with your displays, it's the delay, but 2 ms works fine for me. You can try 3 or 4 ms but more will flicker the digits, since software has to go through all digits before lighting a digit again.



To burn the code to the Atmega IC I used Arduino. Just remove the Arduino chip, insert your Atmega8 (or better), change board and serial port under "tools" menu, paste my code and upload it. Take out the IC and insert in the socket on the clock board. Please notice that your Atmega IC could need to be burn with bootloader before you upload the code, you can find instruction on this page. I used a USBtinyISP programmer, but you can buy IC already burned with the bootloader.

Step 5: Toner transfer

Picture of toner transfer
nixieclock11.jpg

Ok guys, you're certainly happy that theory section is ended and we can now see something concrete.
As I usually do I've etched two boards at the same time, so to reduce the chance to make a faulty pcb.

First thing to do is to polish the copper surface with a sponge (the one for dished on the scratching surface) and then clean it with a strong soap. After that step absolutely avoid to touch the surface or to dry it with a dirty towel, toner has to find a perfectly degreased surface to adhere at 100%.

Now join printed paper and copper board and keep them together with paper tape pieces, put them with paper up under a clean towel, set your iron at maximum temperature and pass over the paper to make the toner adhere on the copper surface. Now pour into water, wait some minutes and when paper is all wet remove it with the help of a soft brush (maybe a toothbrush).

This is a pretty damn process and the success mostly depends by the type of paper, in this case I've tried a cheap inkjet photographic paper. I definitely need to switch to photoresist method.

Step 6: Etching

Picture of etching
nixieclock12.jpg

When you're absolutely sure there is no remain of paper between tracks, and after retouching every interrupted track with permanent marker, you can pour the board into ferric chloride solution for about 40-50 minutes (it depends by many factors as the percentage of solution, the temperature, how much often you agitate the basin, etc.). You see in the picture that I always use the pcb holder I built. I suggest to shake gently the container every 10 minutes and check the traces every 5 minutes when 30 minutes or more has passed. When you see there is no more copper on areal clean from toner you can wipe the board with a paper towel and wash it in abundant water. Dispose of the exhaust acid in proper centre.

Step 7: Finishing the main pcb

Picture of finishing the main pcb
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To remove the toner from the copper traces use a metal sponge or sand paper. If you're not sure about the electrical conductivity of some traces you have to check them with the multimeter and fix any mistake soldering a bit of tin.
Then make holes where needed using 0.8 mm drill bit and a precise column drill (if you want to build one look here).

Step 8: Etching the tubes shield

Picture of etching the tubes shield
nixieclock16.jpg
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To build the tubes shield the process is the same as the main circuit. Also in this case I made two boards at the same time. Both came out well, except near the edges where I had to fix some toner lack with the permanent marker.
As before, remove toner after etching and drill holes for components.

Step 9: Top silk

Picture of top silk
nixieclock08.jpg

If you wish you can transfer the top silk on the board with the toner transfer method. This helps you placing the components and also adds useful information to connect external sensors and to act on the switches.
Then you can begin to solder the main components on the board. 

Step 10: Solder

Picture of solder
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Solder also the pins sockets on the tubes shield, together with resistors and jumpers. To solder the connection pins headers between main circuit and shield follow the suggestions in the next step.

Step 11: Pin rows

Picture of pin rows
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Since the pin male headers are on the same side of the copper, the process to solder them in place is a bit more complexed compared to all the components on the opposite side.
I suggest you to push the pin heads hard into the holes (0.8 mm is the better size in my opinion) and solder them on the pads. As in first picture you have now the rows upside down. Remove the plastic holder with little pliers, flip it and insert again with the groove toward the copper, then with your nails or the pliers push the plastic against the tin, that will cover pads and any soldering sign.

Step 12: Find the right case

Picture of find the right case
nixieclock25.jpg

I've been lucky and I found a case almost perfect to fit my circuit. Obviously it's much better to design the pcb referring to the exact measures of an existing case, so go looking for it at once ;-)
The same instant I've seen this box I loved it. I bought it a the Christmas Fair in my city and it was last piece, made in India from a single rosewood block. I chose the rougher side to become the front of the clock, since I like the irregular edge on the front top edge.

Step 13: Drill holes

Picture of drill holes
nixieclock27.jpg
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I had to drill the 3 cm diameter holes for the six digits, with the right drill bit and a medium column drill the process was long but not difficult. Try to not warm too much the bit.
You can mark the center of the holes with a ruler or to attanch a print of the circuit top side on the wood, then mark the dots with an awl.

Step 14: Perfect the case

Picture of perfect the case
nixieclock31.jpg
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To drill the holes avoiding wood cracks formation, push a wood block on the inside surface of the board, and try keeping it pressed with shims or clamps, then drill the holes until you reach it. Also try to leave at least a pair of millimeters of space between holes. My first shield was too short, and I had to make a little longer shield to match the holes.

Step 15: Fix the lacks

Picture of fix the lacks
nixieclock33.jpg
Since new shield was longer than the inside space I had to enlarge it on a corner. To do that I drilled some thin holes and I removed the wood pieces with the aid of a chisel. As you see now holes and pin sockets are perfectly aligned.

Step 16: Straighten the sockets

Picture of straighten the sockets
nixieclock35.jpg
to straighten the pin sockets so to simplify the insertion of the tubes, I suggest to insert all the tubes one time and remove them. That will help you a lot, since you can handy straighten up them with small pliers.

Step 17: Test the circuit

Picture of test the circuit
This will have also a second advantage, i.e. testing the circuit before assembling the clock.
... suspence...
If everything works you can continue with the assembling.

Step 18: Assembling nixies

Picture of assembling nixies
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Place the shield inside the case and insert back the tubes into it. Pay attention to not let any pin going out from his socket, you can look from the inside to check them.
You see that you can connect the main circuit to the tube shield with no trouble. This is very useful since you are now able to build a new clock and test it with the original clock circuit.

Step 19: Find cool case stands

Picture of find cool case stands

I had four rubber tips, to arrange four nice old style stands I decided to use them upside down glued to screws' heads.
With some gimlets drill the four holes, paying attention to not crack the wood. To be sure begin with a small gimlet and then pass to a bigger one, until you reach the desired hole diameter.

Step 20: Adjust them

Picture of adjust them
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These stands are very handy because you can screw them until they're perfectly aligned with a planar surface, and the wood box will have a very precise support, although it's very rough.
Glue the rubber tips with cyanoacrylate glue in the exact centre of the screw heads. Now you'll note that there is enough space to keep the power plug inserted under the clock and let the wire coming out from the rear.

Step 21: Build a bottom

Picture of build a bottom
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We need to add a cover to the bottom of the clock to prevent children touching the circuit, since it's very dangerous and could be lethal. To cut it from a thin wood board I marked the edges of the hole with a paper sheet and a pencil, then with a screwdriver I transferred the shape onto the wood surface. Then I cut the perimeter with a jig saw.
I also drilled holes for on-off switch, power plug, and time buttons. At the end I polished the cover with dark wax to give it a better color. Now the led is no more visible, but since the cover is snap-fit I can remove it or add another hole under the light.

Step 22: Extend buttons

Picture of extend buttons
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I know that some push-buttons have a long cylinder, to protrude out of the case. I also have many of them, and they are a good choice. Anyway in this case I forgot to solder that button type, so instead of desoldering and changing them with two long ones, I added a different style of extension.
I found some plastic supports for shelves with a brown cylindrical part, so I cut it and glued to the buttons. I also had to glue a washer so that some space remained between bottom cover and buttons body.

Step 23: Connect the clock

Picture of connect the clock
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Assembling is finally completed, you can connect your clock and admire your work!
There is enough space behind the pcb inside the case to keep a 9V power source, maybe 6 AA alkaline batteries or a Li-ion rechargeable battery-pack. I have to design a circuit to charge it via the power plug. I will add to the improvements list ;-)

Step 24: Place it

The top viewed nixie displays as these beautiful IN-4 have usually a narrow angle of view. It means that if you place your clock on a low table or cupboard you'll hardly see the digits. I suggest to keep it on a shelf or near the TV so you can see it when seated.
You can also decide to insert tubes deeper in the case, so that only the half sphere glass surface protrudes, but consider that one of the best features of a nixie display is that digits lie on different planes, and you can see them much better from the side of a tube.

Step 25: Improvements list

Picture of improvements list
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This is not the end of the project, since there are some features to add to this new clock, maybe you can suggest more improvements:

  1. add a RTC (Real Time Clock) module so that the clock keeps the time also when PSU is disconnected
  2. add a cathode poisoning prevention routine to extend tubes life
  3. add a sensor to only turn the clock when you are near (sound sensor, ultrasonic proximity sensor...) and save tubes life
  4. add an alarm function using the multi-tone speaker
  5. substitute the push-button with a rotary encoder, to simplify surfing among the new functions
  6. remove in some way the wood knurl that seems a push-button on the lower left of the case ;-)
  7. add an internal 9V battery to keep the clock running wit no power-cord done, looking the pdf files you will see two pads marked to that purpose!
  8. add a bottom to protect the circuit and maybe cover the led light, or bend the led if light is annoying done!
  9. test the new crossfade code from Arduinix done!
  10. polish with dark wax the inside surface of the holes.
  11. as well explained on Threeneuron's page, multiplexing needs blanking intervals to avoid ghosting, and when I'll go deepen in the code I'll examine this function
  12. in my next version the third position of the ON/OFF switch will set the sleep function, so to turn off the displays leaving the controller working done, attached pdf files are updated!
I hope you liked my bigger electronic project so far, stay tuned for more features and clock models! And tell me if I forgot some detail.

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moire13 days ago

This is the most beautiful nixie design I have ever seen, congratulations!
Awesome project description too, thank you very much for sharing! :)
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)
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... :)
Keep up the good work!
Moire

andrea biffi (author)  moire13 days ago
Awesome! I'm really happy you like it, I've been inspired by a nice project too.
cityhawk25 days ago

Very nice project.
Could you please share an estimate cost for the parts for this project?

Thanks

sinaarian1 month 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)  sinaarian1 month 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.

blkadder1 month 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)  blkadder1 month 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.

vodkapom6 months ago

Hi,

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) ?

dumle29 vodkapom2 months ago

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 http://oshpark.com 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)  vodkapom3 months ago

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

janis.stals22 months ago

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?

davidm2002 months 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

GordonCrisp3 months ago
Awesome! I really want to build one!

Where do you get the 16khz crystal though?
andrea biffi (author)  GordonCrisp3 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
Garagebrand6 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)  Garagebrand3 months ago

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

sinaarian3 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)  sinaarian3 months ago

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

emil.godjaev made it!3 months ago

Andrea,
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.

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andrea biffi (author)  emil.godjaev3 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!

sinaarian3 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)  sinaarian3 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. . . .

jgluch7 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!8 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?

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andrea biffi (author)  lawrence.loblevyt8 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!

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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.loblevyt8 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.loblevyt8 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.

richb778 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!

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