my nixie clock project

introduction:
the obvious next step from my led clock was of course, a nixie clock. i became quite enraptured with the idea of designing and building my own nixie clock once i realized what nixie tubes were, so i bought some IN-8 (ИН-8) nixie tubes from ebay and went to work on a clock design.

at first, my design was crude. using eagle, i put together a clock which used cd4016 decade counters, mpsa42 cathode drivers, and an avr, as well as an integrated boost controller. my mistakes were numerous, and they resulted in the frying of an atmega8535 and an stk500. :/

my second design used a max1771 boost converter and an avr which drove six 74141 nixie drivers through sn74hc595 shift registers. this design was too expensive to even try, so i scrapped it. (i used an autorouter to route the traces on the board anyways, so it's a good thing it never went anywhere... never trust the autorouter! :P)

the nixer mainboard:
finally, i decided to rectify the (120vac) mains to 170vdc for the tube voltage and use a multiplexed setup: ten mpsa42 cathode drivers and six mpsa92+mpsa42 anode drivers. the atmega16 receives a pulse-per-second interrupt by prescaling the signal from a 32.768khz watch crystal. a second timer/counter is used to multiplex the nixie tubes at 31.25khz. of course, there are switches to increment the hour and minute.

nixer mainboard pics:
here are the designs for the main controller board of nixer:

mainboard materials listing:

nixer mainboard code:
the code for nixer is C linked against the avr-libc open-source library for avr micros. avrdude commands are already available through the makefile included. the gerber zipfile is ready for sending to batchpcb, if you were interested.

• nixer.tar.bz2
• gerber.zip

the boost converter:
testing the driver circuitry with the 170vdc from the wall, while it proved the driver circuits worked, fried a few switches and diodes along the way... so, as a quick fix to ensure the safe operation of the device for years to come (and in other countries) i designed a simple attiny13a-controlled boost converter to step up 12vdc from a wall-wort into the 170vdc required by the IN-8.

boost converter pics:
here are the designs for the power supply board of nixer:

boost converter materials listing:

boost converter code:
again, the code is in C. nothing special here...

• smps.tar.bz2

photos of the progress:

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video of the finished product: