Nixie Tube Clock IN-12B (Bezel & High voltage guard)

thingiverse

This is an IN-12B Nixie Tube Clock, requiring approximately 170 Volts, which poses a risk of electrical shock; hence, protective covers are used to insulate the numerous live terminals. The bezel serves as a sturdy base for soldering wires onto Nixietube sockets, providing a clean separation between tube pairs. This design is generic and versatile, with plenty of mounting holes, making it adaptable to various enclosures. The Nixie tubes originate from Ukraine, labeled as New Old Stock (NOS), approximately 30 years old, still wrapped in original waxed paper. The bakelite bases, also circa 30 years old, have oxidized over time and required polishing with a Dremel polisher to restore their appearance. The IN-12B Nixie tubes require around 170 Volts to produce the desired glowing arc, which is achieved through a power FET switching an inductor on/off rapidly using an Atmega Chip. Given the presence of 170 Volts components, caution is advised during this stage of the project. The INS-1 separator colons are neatly designed and serve as an upgrade from standard "mains plug" types. To extend Nixie tube lifespan, dimming them reduces their usage time. A defective 10mm LED was modified by hollowing it out with a Dremel to contain an LDR, which was secured in place using epoxy glue; this setup effectively alters the PWM signal to the 170 Volt inverter circuit, enabling display dimming through duty cycle adjustment. To enclose the 170 Volts components, a 3D back/front shroud was created, providing adequate spacing for the tubes and allowing colon indicators to slot neatly between tube pairs. This design also offers each Nixie a sun shade, enhancing clarity. The mass of wiring is neatly contained within the protective shroud. The clock's enclosure is crafted from wood, carefully assembled to achieve a vintage look; however, cutting the front bezel was a challenging task. A small RTC module maintains timekeeping accuracy by keeping the clock in sync with current time.