Because every engineer loves a good Nixie tube thermometer.
If you want to know the temperature, normal digital thermometers, or increasingly the Internet, are usually good enough. Visually though, it’s hard to beat the warm glow and retro look of a Nixie tube. What better way to display this than with a three-digit tube display like Luca Dentella’s build.
His process is outlined in a series of 10 posts that can be found here, or you can just skip to the completed version. The “brain” of this display is a Arduino Pro Micro (ATmega32U4). It uses a thermistor-style temperature sensor, which has a resistance than changes depending on the temperature, to tell how hot it is.
The display is, of course, three nixie tubes. The first thing that’s interesting about the setup is that the third tube shows “°C.” Dentella is using an “IN-19A” tube for this purpose, which can also reveal a number of other symbols. In this case, it shows the degrees Celsius value at all times.
The other interesting part of this design, besides the generally clean layout and printed circuit board use, is that each tube has a programmable LED under it. This allows for a unique coloring, and could certainly have produce many interesting visual effects. Perhaps in another life, this type of display could serve as a sound level meter, with the LEDs pulsing on and off to the beat of the music.