SUNIX-S Nixie Controller

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What is the SUNIX-S ?

The term SUNIX stands for Swissnixie Universal Nixie Controller - which is a multifunctional independent electronic board for nixie clocks. The -S marks that the board is designed for small tubes like the Russian IN-8 or IN-14 and many other tubes like the ZM1080 etc.


This is page will be updated every time the board or code changes. The current version is R1.2 (PCB) & R1.2 (CODE), created on 7/May/2017


The idea was to develop an independent electronic board that can be used for multiple projects without the need to assemble or redesign the electronic board. The driver board can be used with any custom designed tube board.

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Design and Specifications

The board contains all necessary parts for a nixe clock: Input power regulation, microprocessor, RTC and EEPROM, high voltage drivers, high voltage power supply, control elements and connectors.

For the microcontroller an AtMega328 was chosen, because it can be used with the common Arduino IDE, is widely available and well-priced. With 20 general purpose I/O Pins and running at 16 MHz, it can provide all power and connectivity that is needed. Supported by a ultra-precise battery backed RealTimeClock (RTC) and an EEPROM it can take care of all program operations and storage space a clock needs.

The board has small low-profile connector for SPI (to connect GPS or anything else to it) and a built in USB-to-UART FT232 chip, which adds direct USB connectivity to the board.

For the cathode driving two HV5122 IC's are used, because they perfectly fit the requirements. Supported by a logic level shifter and a 5 to 12V charge pump controller (designed for flash memory programming! Awesome!) the provide 64 digital sink outputs that can be connected with up to 220V!

The built-in variable high efficiency power supply was designed with the MAX1771 DC-DC controller, allowing output voltages from 150 to 220V DC without modifications. A current up to 50mA can be supplied. The design and assembly of the power supply is very sensible, so the components must be chosen and assembled carefully.

Instead of a classical "button control" a modern rotary-encoder was used to manage various setting parameters

The board also has a switchmode power supply (5V@1A) that can operate from 9 to 18V DC input. The switchmode supply was chosen because it can supply a high current which is required to drive the six backlight LED's (Color "White" uses 60mA per LED!) and leave enough reserve for external components such as GPS antennas or similar. The Board is protected by a TPS2400 IC and a auto-reset fuse. When no power is present, a CR1220 Battery will keep the time of the RTC Module!

Here you can see a SUNIX-S controller board with an attached tube board and IN-8-2 nixies (R 1.2) and a complete clock in a case as well:

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In General, the current revision can drive up to six 10-digit nixie tubes and 2 neon-bulbs for separators or similar

Customized tube boards can be made, allowing many models of nixie tubes! Here is a list of common tubes:

  • IN-8 and IN-8-2
  • IN-14
  • ZM1080
  • LD-955A
  • CD71,CD72,CD78,CD81
  • Many other side-view and even top view nixie tubes!


Here you can find the schematic of the SUNIX-S Board, an IN-8-2 Tube board! Schematic of the tube board is available in the .zip file below.


The software for the SUNIX-S is coded in the Arduino language. The software is open source and freely usable for own projects. If you find errors or bugs, or if you have any ideas to improve the project i'm happy to hear about. Please understand that i cannot write software "on request" for own projects, because i'm really busy with my own life and projects. Alltrough, i'm happy to assist with minor problems ans questions.

The current version comes with the following features:

  • Display of Time
  • Manual and GPS Time setting
  • Anti-Cathode-Poisoning Routine (configurable each min, 10min, each hr)
  • Different Anti-Cathode-Posioning Patterns for selection
  • AM/PM Mode
  • Leading zero enable/disable eg. to display 08:30 or 8:30
  • Backlight Colors (16 different)
  • Backlight Brightness (0-99%)
  • Support vor NMEA GPS Timesync and full compatibility with "nwts" (read below)
  • All 39 Timezones selectable
  • Automatic DST Parameters for most of the worlds countries
  • Manual DST seting for unsupported location (Israel for example)
  • Activation input for a PIR or similar sensor to save power and tube life
  • Configurable time and input behaviour of the activation input

Time Setting

The time of the clock can be set manually over the parameters (this is explained in the "parameter_settings.pdf",which can be downloaded at the resources section) or via a external time provider. This could either be

- a GPS reciver that sends a standart NMEA GPS Signal
- a "nwts" device.

I recomment using the nwts, which is a network (ntp) time provider that works via wifi so you will not need to place the receiver in sight of satelites. The nwts can operate wherever your wifi is available, even if you live inside a concrete bunker!. The nwts is compatible with all sorts of networks (even with my custom ip and firewall one that i have!). Read more about the nwts

I'm currently working on a windows command-shell software that allows time-setting via serial

Parameter Setting

You will not have to set parameters by a number of buttons, pushing them so many times that it feels endless. A rotary encoder with integrated switch allows quick and easy selection and changing of parameters, even if they cover a large number of options, like 1-99% brightness. Also the encoder saves work and space in the casing, because only one hole is requiered for an encoder, instead of three or four buttons! The feeling is very natural and nice.
Find a pdf about the parameters and setting the time manually in the resources section!

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Here are the design-resources like Eagle files and arduino code. The includes the mainboard and the IN-8-2 with IN-3 tube board, but you can customize the board to your tube types! The part's for the tube-board are marked in the BOM.pdf.

The includes dxf drawings of the acrylic parts. The Code includes the Arduino .ino and required custom libraries. The Manual includes basic info how to use the settings.

Eagle, Case (dxf).zip