The Cogwheel Nixie System

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The Devil is in the Details

Preparing to manufacture stuffed circuit boards involves allot of work having everything to do with excel spreadsheets and nothing to do with electrical engineering; Once the countless hours of prototyping, design, layout, PCB generation, stuffing, and first article board bring-up are over with the fun has just begun.

Block Diagram

For my latest design I choose to use an Atmel ATMEGA processor, in a configuration compatible with the very popular Arduino line of development/hobbyist boards. This means there is an integrated USB interface which can be used to control the clock from a PC, or to update the firmware. High-voltage is generated with discrete power JFET and coil in a boost-converter  configuration. Most nixie designs use discrete transistors to switch the displays on and off. I used Supertex HV513 8 channel push-pull high-voltage drivers, intended for use to drive print heads in dot matrix printers. This reduces the size required for the board.

The clock section uses the very common Dallas DS1302 real-time clock combined with a Maxim DS32HKZ TXCO, which provides accuracy to within one minute per year at room temperatures.

Project Background

I've been building nixie tube clocks for the last 9 years; I always had an interest in them since I was a kid, and even had a few laying around from that time. My goal has been to build and sell a quality nixie tube clock system, however, the project has been a very low priorty over other real-world obligations.

More recently (2010), I have had the time to revisit the project, and update it. As of 7/2010, I am about to fabricate the first run of 25 boards. I will test market these, and if there is sufficient interest, I hope to produce more.