I bought the Arduino Nixie Tube Shield from gra-afch.com on eBay for about $94 US. It comes fully assembled and tested. It has all of the high voltage circuitry, a RTC chip with backup battery and switches used to set the time and date. It is meant to be used with an Arduino Uno which is not supplied. This is one of the cheapest Nixie Tube clock assemblies I have come across.
|To verify that the shield worked I plugged on an Arduino Uno and loaded the code from gra-afch. As expected it worked perfectly. The shield seems to be well constructed with SMT components and uses quality parts. |
|I wanted to drive my Nixie Tube clock with an NodeMCU Amica module so that I could have a clock that automatically sets its time and date using the NTP protocol over the Internet. The custom software I wrote to accomplish this also knows about daylight saving time and adjusts itself automatically. |
To accomplish this I built the NodeMCU module onto a small piece of pref board that has the form factor of an Arduino Uno. This allows the NodeMCU module to plug directly onto the Nixie Tube Shield.
Of course this meant that I would not be using the RTC chip or any of its support circuitry on the shield itself.
I built a voltage regulator onto the pref board to reduce the 12 volt power from the shield down to 5 V for the NodeMCU. This was probably unnecessary but oh well.
|I did not want to build my state of the art Nixie Tube Clock into a boring rectangular box . I decided instead to build it into an elliptical shape. |
The process started by printing out an ellipse of the proper size and gluing it to 1/8" mdf. I then cut the mdf to shape and drilled a series of holes equal distant from the edge. This became a template for my router.
|I attached the template to a piece of 3/4" Baltic Birch using double sided tape and used a flush trim router bit with a bearing to cut the wood to shape. The bearing runs along the template making the router cut out the exact shape. I then drilled all of the hole in the template through the wood and then used a jig saw to saw out the middle of the ellipse. |
I made two of these that I glued together as the clock's base needed to be about 1 1/2" deep.
|I again used the template and double sided tape to create the top out of black 1/8" plastic. After carefully measuring the positions of the Nixie Tubes, I drilled holes in the top for the six tubes and the two smaller neon bulbs. |
I used the template to create the bottom as well out of the same plastic material.
|After gluing the two sections of the chassis together and sanding them to 240 grit I stained them with mahogany stain. |
I attached four cabinet knobs to the bottom to use as feet to give my clock a modern look.
Here I put all of the chassis pieces together to get an idea of how things fit.
The bottom screws onto the wooden chassis but there are no exposed screws anywhere else.
|Here is the finished clock. |
|Here is the rear view of the clock showing the power connector. |
Notice there are no switches to set the time or date or to indicate daylight savings time. Setting of the clock is all done automatically.
|Another view of the finished clock.|
|Here is the clock in operation. My clock runs in 12 hour time and I suppress leading zeros which is why the left most tube is off. The time is 5:58:14. The clock can also run in 24 hour time by making a small change in the software. |
The lightning at the bottom of the Nixie Tubes is provided by RGB LEDs that are software controllable.
Every 10 minutes the clock changes momentarily from the display of time to the display of the date. Every 15 minutes, the clock performs a little light show by running the RGB LEDs through all the colors of the rainbow.
At the top of each hour the clock performs what is called the anti-poisoning routine which runs each tube through all the numeric digits. If this is not done periodically, the unused digits will slowly darken.