Check out this Huge Nixie Clock that Jaroslaw Lupinski built after being wowed by the Union Square clock. I also love clock projects since there is lots of interesting changes just by being a clock.
Thanks for the tip Peter.
“The timekeeping circuit is identical to my previous nixie clock: an Atmega168 controls the show, with a DS1307 keeping time. The only difference is that the sheer number of tubes made for some creative problem solving. Each 74141 chip requires 4 data lines, for a total of 60 inputs, and the Atmega had only 17 spare ones, after SDA and SCL were used for RTC communication. Digging through my array of spare chips, I decided on using shift registers. 74141 chips are BCD->NixieSegment chips, so I can use one 8-bit shift register per two 74141 chips. I drive 12 of the 15 74141 chips with this method. The center three chips are driven directly by the ATMega, because they need to be updated much more often.”
