Dr. Scott M. Baker's Nixie Clock Is Driven by an Intel-Powered Multibus Microcomputer
Vintage-style clock build comes with a choice of period-appropriate real-time clock (RTC) module or shiny new GPS receiver module.
Engineer and vintage computing enthusiast Dr. Scott M. Baker is back on the Multibus train again, this time building an add-on board for the machine that turns it into a working Nixie tube clock — complete with room for a Global Navigation Satellite System (GNSS) receiver module for high-accuracy timekeeping.
"I like Nixie tubes, and I’ve made a fair number of projects — my Nixie Tube Calculator, a Nixie Tube Clock RC2014, even a PC Clone with a built-in Nixie tube display," Baker explains by way of background to the project. "I felt like it was finally time for another IN-12 Nixie tube project, so I added a Multibus Nixie tube board. The board features up to eight IN-12 Nixie tube displays, a built-in 170-volt DC power supply, and a couple multimodule slots (you can never have too many multimodule slots)."
The host for this add-in board is an Multibus system driven by an Intel 80/24A single-board computer — a standard, designed as a rival to the Altair/S-100 bus, which allows for the single-board computer to be expanded by one or more additional boards. In this case, that expansion is a numerical display powered by classic Nixie tubes — though Baker's design also includes room for two more boards to expand the expansion further.
The display board itself is based on socketed IN-12 Nixie tubes, a classic piece of display technology which holds glowing wires in the shape of the numerals zero through nine — lit on-demand with a cheery high-voltage glow. With additional space left over, Baker added room for the expansion board to have its own expansion boards — "multimodules," including a period-appropriate real-time clock or, for improve timing accuracy and automatic time setting, a GPS receiver module. A speech synthesizer module could turn it into a speaking clock, too, if desired.
More details are available in the video embedded above and on Baker's website; design files for the Nixie board and the multimodules have been uploaded to Baker's Multibus GitHub repository.