Nixie Clock 1

From neurotica.com

I built this very small Nixie clock in 2005 for myself. It uses Nixie tubes (a gas-discharge display device from the 1950s) and is built around a Philips P89C660 microcontroller, which is an 8051 variant. It runs from a 12V power supply and uses a step-up switching converter to generate 170V to drive the Nixie tubes.

The microcontroller is clocked at 3.6864MHz. The RTC functionality is built around a Philips PCF8583 chip, which is interfaced to the microcontroller via I2C. The Nixie tubes are tiny Russian IN-17s. The switching converter is built around an MC34063 DC-DC converter controller chip. The tubes are driven directly by Russian K155 chips (74141 equivalent) and are not multiplexed. The firmware is written in a mix of C (using the SDCC compiler) and assembly language.

Photos

The completed clock.

Rear view showing wiring.