For any DIY projects to escape the cool lab environment and make it into the real world requires packaging with aesthetic approval.   The ETA Nixie tube clock  was no exception.   While I was totally happy with the PCB mount for the Nixie tubes shown in the previous blog entry, What is an ETA Nixie Tube Clock and How Do You Build One? , it would not get home display approval without a good looking enclosure.  Basically, I had some work to do.

ETA Nixie tube clock project that needs an enclosure

I didn’t have to look far for options to choose from.   there are literally hundreds of images on the web to choose from.      I found a few images I liked, modified the design to match my PCB, got HQ approval (i.e. the wife), and then executed on a design that could be displayed just outside the kitchen.   In this blog, I will describe the steps it took to take the ETA Nixie Tube clock from PCB concept into a complete project ready to be mounted anywhere inside the home.   Let me know your comments about the design in the sections below.

The ETA Nixie tube clock with Birch enclosure and wall mounted in home


  1. 3.5″x0.75″ birch plank.
  2. 1.5″x 0.75″ birch plank.
  3. Super Glue
  4. Hot glue
  5. Wood stain
  6. Wood glue
  7. M2 1/4″ standoff
  8. Keyhole frame mounts
  9. ETA Nixie Tube Clock

Step 1: Cut the base plank

Cut the 3.5″x0.75″ birch plank to 12″ in length. This is the faceplate that the Nixie tube PCD will be mounted.

Cut the birch plank to 12″ in length

Step 2: Drill the Nixie Tube holes

Use a 1 1/4″ drill to create the six Nixie tube holes. The PCB CAD drawing is a great way to dimension the hole locations.  Use the link to print it out and tape it to the piece of wood.  Then use a small drill to drill pilot holes for each of the larger holes including the PIR sensor hole.

IMG_6279 (1)
The PCB CAD drawing can used used as a template to center the Nixie tube holes

With a piece of scrap wood underneath, use the 1 1/4″ drill to drill out of the six Nixie Tube holes and the PIR sensor hole.

The faceplate with completed holes

Step 3: Drill the PCB mounting holes for the M2 wood mounts

With the faceplate cut and Nixie Tube holes cut out, now is the best time to drill holes for the M2 wood mounts.    Use a drill slightly larger than the M2 standoffs at the 3 corners of the ETA Nixie Tube Clock that are not being used.    Use the PCB as a guide.

Drill holes and glue the M2 standoffs into the wood

Step 4: Cut the frame pieces for the faceplate

Using Miter saw, cut 45-degree angles of the 1.5″ x 0.75″ plank to cut two 12″ length and two 3.5″ length edges.

I performed this by cutting each of the pieces one at a time and then seeing how they fit the faceplate.   Some adjustments may be required to get a truly flush fit.   I also learned that the miter saw will take would away a little wood due to the thickness of the blade.  So when I measured with a pencil, cut the wood using the blade on the outside of the pencil marking.

All Four sides of the frame cut using the miter saw

Step 5: Cut two frame pieces to fit the PIR sensor hole

This is a very sturdy frame with the frame pieces being 0.75″ wide.   The drawback is that for a compact display, the PIR sensor hole will be covered by the frame without some adjustments.

Drawing with a pencil where the frame needs to be cut so the PIR sensor can be mounted
IMG_6605 (2).JPG
Ensuring the cut section can fit the PIR sensor

For this project, I used a miter saw to do this, but a band saw would also be good.    To use the miter saw, the wood and saw were placed so that the miter blade was not allowed to cut all the way through the wood, but leave approximately a 1/4 inch. Here is a short video of how it is done.

Step 6: Cut a slot for the USB power cable

Also using a miter saw, a slot was as cut into the wood where the power cable was located.     In this design, I wanted the power cable to come out the back of the frame a allow a seem-less mounting on the wall.   This requires that power can be provided through the wall.

Making space for the USB power cab
Testing the fit of the final assembly
Testing the power cable fit of final assembly

Step 7: Use a router for the keyhole mounting hardware.

For a complete flush mounting of the frame to the wall, two keyhole mountings were added to the frame.    I just used a drill bit, but a router is the better choice.

IMG_6668 (2)_LI.jpg
Routing the wood to fit the keyhole mounts

Step 8: Screw and glue the frame pieces into the faceplate using 2″ screws

With a good glue, you don’t need to use screws for this step.  On my first clock, I used just glue, but it does require a good clamping system.    Without a good clamping system, while the glue dries, 2″ wood screws are another option.

With each piece lined up flush to the face place, drill two pilot holes all the way through the frame and into the face place.   Be careful not to drill all the way through the faceplate.

With the holes drilled, use wood glue and screw them into the faceplate with a 2″ wood screw.   The result is a super sturdy frame… maybe an overkill

IMG_6668 (3).JPG
Using 2″ wood screws and wood glue for the frame
IMG_6667 (2).JPG
The assembled and glued frame

Step 9: Stain the frame to fit the right color

I choose a dark Kona color stain for this project to contrast the orange glow of the Nixie Tubes.   Before staining, you will want to sand the frame down with 150 grit sandpaper, then something like 220 grit or higher to clean up the edges, pencil marks, errantly placed wood glue left on the wood.

Then using Acetone on a piece of cloth, rub each side of the frame to clean up the rest of the dirt and wood and get it ready for the stain.

I used a small wooden brush and applied the stain to the outside of the frame all at once.   Apply it evenly.    Wait just three minutes and using a clean rag, wipe off the excess stain.    The longer you wait the darker the stain, but three minutes worked perfectly for this wood.

The stained frame ready for assembly

Step 10: Add the keyhole mounts to the Frame

Try to get these two at the same level on the frame so that when you add mounts to the wall, you can use a simple level gauge.

Step 11: Assemble the ETA Nixie tube clock

Place and glue the PIR Sensor into the PIR Sensor hole with hot glue.    Then screw the ETA Nixie Tube Clock into the M2 standoff and connect the PIR sensor with the cable.   Add the power cable and it is ready to be mounted on the wall.

Step 12: Wall mounting the ETA Nixie tube clock

With the design, the clock can be flush mounted to the wall but will require that power is available.   In the design, I punched a USB cable through the wall and into a kitchen cabinet.    I actually had to do it twice because I hit a nail on the first try.  That is why there are two holes in the wall below.     Luckily, these holes are all hidden behind the frame when mounted.      From within the cabinet, the USB cable was attached to a power supply and connected to an AC outlet from within the cabinet.

The USB power cable

The wall mounted hardware was carefully positioned to match the keyhole mounts on the frame.   The picture below shows one of the mounts, but there is another one on the right now shown in picture.

IMG_6633 (2)_LI.jpg
Wall mounting holes measured to match the frame

References and help

I would like to thank my good friend Charles and brother Arpad for their help with tools and guidance on this build.   Woodworking is not one of my strengths yet, but I learned a lot from these two and got to use their cool tools.

Summary and some final thoughts

With the steps shown above, A sturdy, secure mount for the can be built. I hope you enjoyed the project and please let me know if you have any questions or comments. Building custom wooden enclosures take time, but the results are worth it.

The PIR sensor is an important part of this project to increase the lifetime of the Nixie Tubes and it took some time to find a decent mounting location. My original idea was to also cover the PIR sensor with a dark lens,  making it invisible to the viewer. All the lenses I have tried filter out the IR and the sensor did not detect movement. I would love to hear other ideas about where to mount this sensor.

The surf looks great this week, I’m glad I finished this blog in time.