Our friend Muris from Elektronika.ba has been busy. He has created one of the coolest Nixie Clocks that I have seen in a long time. His inspiration is the Ice Tube Clock from Adafruit which uses a single tube that glows blue. You can tell that the board was laid out with great care to get everything to fit in such a compact space. If you are interested in making your own you can get the code at the bottom of the project page.
“The shield board has 4 RGB LEDs under the Nixies that can be turned off if you don’t like how it looks. It shows time, full date and temperature. There is also a “candle mode” in which all four tubes lit up and simulate the flickering of candles. This looks pretty cool in dark room and you can even put it on the dining table for a bit of romance.
The brain of the clock is ATmega328P AVR microcontroller (the datasheet says it works at low voltages as 1.8V, and this is great because it must continue working on 3V backup battery). The important thing to notice here is the external crystal of 32.768 kHz that is used to clock the internal Timer1. That timer is set with a prescaler of 128 so that it generates interrupt once per every second and that is used for internal RTC.”