For as long as I can remember, I have loved nixie tubes. I asked my father the other day and he said that I was fascinated with them as a child. About 6 months ago I found some neat nixie modules on eBay (from former Soviet Union). The module includes a nixie tube (0-9 digits), a binary decoder chip, and they are stackable. I bought several and they sat for a while.
I knew I would have some extra time over the holidays and planned to get this idea moving forward. I purchased a small power supply that buck-boosts 9-12V to 200V as this is needed to power the tubes.
So I wired one up...
Some people make clocks, I wanted to make a temp display. I knew of various special character tubes (deg C, Hz, omega, etc); I ordered a few of those as well. I had to de-soldier a digit display tube and install the special character tube (to display the degC character). Then I decided to include a leading + or - sign, I had to order a different special character tube and repeat the de-solder/tube swap scenario.
I prototyped using an Arduino however I am now using a stand alone micro-processor with a temperature sensor. I wrote an averaging algorithm to damped the change rate. This "averaged" data is shifted for proper display and sent to a couple of registers. Once the registers are full, the data is sent to the nixie tube modules. The included decoders covert the incoming binary numbers and light the proper segments.
My components are still on breadboards.
I am in the process of designing component placement and I will properly mount a single circuit board. The outer cover is from an old Apple ][ floppy drive
I built the inner tray using a bandsaw, dremel and a brake. Still thinking about painting that portion.
I am thinking about future expansion. Mainly mating a temperature sensor with a driveway solar light (for power) and using a small Xbee radio transceiver to periodically send outside temp data to this box (I will have to add an Xbee to this box as well to receive).