This Nixie Tube Clock is made out of 4 pieces IN-18 Nixie Tubes, driven by 5 TPIC6B595 High Voltage Shift Registers.
The microcontroller used in this project is an Atmel AT-mega88.
The Voltage input is 24V and for the Tubes a little Boost converter is used to step the input voltage up to 180V.
The Power drawn by the whole circuit is about 6Watts.