In what can only be described as a work of art, [suedbunker] has created a clock under a glass dome. Sporting Nixie tubes, a DS3223, BCD encoders, and MPSA43 transistors driven by an MCP23008 I/O expander it is truly a sight to behold. [suedbunker] has previously created the Circus Clock, a similar clock that celebrated a diversity of ways of displaying the time.
The dome clock represents a continuation of that idea. Reading the clock requires looking at the horizontal and vertical numbers separately. The hours are on the horizontal and minutes are on the vertical. Monday to Sunday is represented in the neon bulbs on the back. The power supply at the bottom provides a wide range of voltages including 5 V, 12 V, 24 V, 45 V, 90 V, 150 V, and -270 V for all the various types of lights. For safety, an optocoupler is used on the -270 volts to drive the clear seven-segment display.
An Arduino Nano controls the whole clock by communicating with the DS3232 real-time clock module and the port expanders via I2C. The soldering and wiring work, in particular, is tidy and beautiful. We look forward to future clocks by [suedbunker] and his wife.
Source: THE CLOCK UNDER THE DOME