Millivolt meter Nixie clock

Surprisingly, up until a year ago, [Jimmy] hadn’t seen a Nixie tube. Awful we know, but he has come around to the beauty of glowing numbers in a tube. He recently found an old millivolt meter in a junk pile that used Nixie tubes. The wondrous orange glow beckoned him, so [Jimmy] decided to build a clock.

Just about all of the Nixie clocks we’ve seen (including non-clock builds) rely on building a controller for the Nixie tubes. The controllers range from Nixie Arduino shields to the good ‘ol 74141 IC. [Jimmy] realized he didn’t need to bother with controlling the tubes in an already functional millivolt meter – he only needed to send the right voltage.

For his clock build, [Jimmy] used an Arduino to output a voltage through a bunch of resistor dividers. For example, if the time is 12:30, the output voltage will be 12.30mV. Using this technique, the values for the needed resistors don’t exist, so a little bit of PWM means the Arduino keeps fairly good time.

There’s one added bonus of [Jimmy]‘s clock – because the voltage varies around 0.01mV, the finished project acts like a digital version of Lord Vetinari’s clock. It may not be perfect, but at least a nice piece of equipment was saved from the trash.

Bottled Nixie clock


Who could not love the tender glow of a Nixie display? It isn’t a new concept for them to be used in clocks, and usually it’s how they are housed or encased for display that sets them apart. [crazy_phisic] did the near impossible by building his Nixie clock almost entirely inside of a glass bottle. The circuit boards and logic components were soldered outside, but the final combination of parts (sometimes requiring specialty homemade tools) were assembled inside. We wonder how long it took him from start to finish after learning boats in bottles can take from minutes to months. The original post is in polish, but if you want to find out more there is a Google translation.

[via Semageek]