A Nixie tube can best be described as an electronic device that displays numerals and other information using glow discharge. The glass tube is packed with a wire-mesh anode and multiple cathodes, shaped like numerals or other symbols.
“I was digging around in my parts bins and came across most of the exotic bits required to build a GPS sync’d Nixie tube clock. Logic side is an ATTiny1634 with a surplus (old) SiRF GPS module. HV side is based on a surplus backlight inverter, rectified and filtered. At 3.3v it puts out around 140v under load, and around 270v if allowed to float,” the Reddit user explained.
“To switch the HV, I’m using a Supertex HV5122 high voltage shift register which gives me 32 channels. Since I only have 32, the high digit of the hour only has digits 1 and 2 connected, so to display ‘0’ I just leave it off. The 4 BS108 MOSFETs on the board are just level shifters for the control lines, since the HV5122 needs a minimum of around 10.5v for logic ‘high’ on its input.”
Additional information and schematics for the ATtiny1634-powered Nixie clock can be found here.
As previously discussed on Bits & Pieces, the high-performance Atmel picoPower 8-bit AVR RISC-basedATtiny1634 microcontroller features 16KB flash memory, 256B EEPROM, 1KB SRAM, 18 general purpose I/O lines, 32 general purpose working registers, one 8-bit timer/counter and one 16-bit timer/counter.
Additional key specs include two full duplex USARTs with start frame detection, universal serial interface (USI), I2C slave, internal and external interrupts, a 12-channel 10-bit A/D converter, programmable watchdog timer with Ultra Low Power internal oscillator and four software selectable power saving modes (the device operates between 1.8-5.5 volts).