nixiedisp - USB nixie tube display

Nixiedisp is a 6-digit nixie tube numeric display, software-controlled over USB or RS232, that also functions standalone as a clock.

Features:

• Controlled over USB or RS232 serial port to display arbitrary numbers, set the time/date, change settings, and switch between modes of operation.
• Standalone operation as a clock or stopwatch timer with a battery-backed real-time clock (CR2032 coin cell).
• Designed to use soviet IN-14 nixie tubes.
• Powered by a 12v DC supply through a standard 2mm barrel jack (center-positive).

Excercise caution when operating without an enclosure, there are high voltages (180V DC) present in the power supply section of the board, and around the nixie tubes.

Project website: http://nuclear.mutantstargoat.com/hw/nixiedisp
Github repo: https://github.com/jtsiomb/nixiedisp

Project structure:

• hw/: hardware design
• fw/: firmware for the on-board AVR microcontroller
• sw/: end-user host-side software for controlling the device from a computer

License

Copyright (C) 2020-2021 John Tsiombikas nuclear@member.fsf.org

Hardware designs and software (firmware) in this project are free. Feel free to use, modify, and/or redistribute under the terms of the GNU General Public License v3, or at your option any later version published by the Free Software Foundation. See COPYING for details.

How to build a nixiedisp device

To build one of these for yourself, you need to:

1. Zip up the contents of the hw/gerber directory, and send them to a PCB manufacturer to get boards made. For my own boards I used jlcpcb.com.

2. Order the components listed in the bill of materials (hw/bom.ods). I ordered mine from mouser.com, and the spreadsheet contains the mouser reference number for each component, to make it easy to order the whole lot without too much searching. Make sure to order at least as many of each one of them, as specified in the bom.

3. Find 6 (optionally 4) soviet IN-14 nixie tubes. They tend to go for about $10 - $15 each on ebay.

4. Find a 12v DC power supply with a barrel jack (2mm center pin), center-positive (+ -o)- -), to power the board. It doesn't have to be regulated, but it must be able to provide about 500mA at 12v. Typical power consumption is 2-3W.

5. If you got the git version of this project, you'll need to build the firmware by changing into fw and typing make. You'll need to have avr-gcc, libc-avr, and GNU make installed for this. Release archives include a pre-built firmware image you can use (fw/nixiedisp.hex).

6. Assemble the board, and program the microcontroller with a suitable AVR ISP. If you have avrdude installed, you can simply change into fw and type make program, with the board powered up and the programmer connected.

If you don't need the serial port (RS232) option, you can leave J1 (the DB9 connector), U2 (max232 level converter) and all its surrounding electrolytic capacitors (C1, C2, C4, C8 and C15) unpopulated, and install a 10k pull-up resistor across the pads of J7 (usbpwr).

References

High-voltage power supply based on Michael Moorrees' nixie supply MK1.5: https://threeneurons.wordpress.com/nixie-power-supply