Faux Nixie Tube Clock

I love retro tech. It's so much fun to play with older tech since they are usually larger and more aesthetic than modern equivalents. The only problem with old tech such as Nixie tubes is that they are rare, expensive, and generally difficult to work with. Since the library near me just got a laser cutter for the public to use, I knew I had to make a project to learn how to use it. What better thing to do than combine my passion for old tech with lasers. These LED "Nixie" tubes are much cheaper, less dangerous, and can be powered off of USB power.

The template I used for my PCB was provided by Connor Nishijima on github (https://github.com/connornishijima/lixie-arduino)
My original inspiration for this was the version that Make did (https://makezine.com/projects/led-nixie-display/), but Connor's PCB was much cheaper to produce as the PCB's are smaller.

Step 1: Materials and Tools

Materials:

Electronics:

• Arduino Nano
• 10K Resistor
• Pushbutton
• Toggle Switch
• WS2812B LED's
• Misc Wire
• Mini USB cable
• USB-B extender (commonly used for 3D Printers)
• Coin Cell Battery
• DS3231 RTC module

Other:

• 3mm Plywood
• 1/16" Acrylic
• M3 Screws and Nuts

Tools:

• Laser Cutter
• Sandpaper (220 Grit)
• Mouse Sander
• Allen Keys
• Utility Knife
• Super Glue
• Solder Reflow Oven (A toaster oven will also work)
• Wire Cutters
• Soldering Iron
• 60/40 Lead solder
• Syringe and Tips
• Solder Paste
• Hot Glue and Glue Dun

Step 2: Laser Cutting

Using the SVG files (or Fusion360 file) that I have provided, cut out the pieces of the frame.

The pieces that have text on them have a separate svg file that includes the text in it. These pieces are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, Back, Bottom, Top.

You will need:

• 4 x 0 (acrylic)
• 4 x 1 (acrylic)
• 4 x 2 (acrylic)
• 4 x 3 (acrylic)
• 4 x 4 (acrylic)
• 4 x 5 (acrylic)
• 4 x 6 (acrylic)
• 4 x 7 (acrylic)
• 4 x 8 (acrylic)
• 4 x 9 (acrylic)

• 1 x Back (wood)
• 1 x Bottom (wood)
• 3 x Button (wood)
• 4 x Feet1 (wood)
• 4 x Feet2 (wood)
• 1 x Front (wood)
• 2 x Side (wood)
• 4 x Slot (wood)
• 1 x Spacer (wood)
• 2 x Top Cover (wood)
• 2 x Top Slot (wood)
• 1 x Top (wood)

In making this I used the Glowforge at my local makerspace, but any laser cutter will work (Duh!). If you are using a Glowforge these are the settings that worked for me. With the wood I used 250 speed, 100 power, and 2 passes (for the more delicate pieces you might want to use less power and slower). For cutting the acrylic I used 200 speed, 100 power, and 1 pass. For engraving the wood I used 250 speed, 10 power, and 1 pass. For engraving the acrylic I used 500 speed, 50 power, and 1 pass. I recommend messing with settings and find what works best for you before cutting out all of the pieces.

Don't peel the protective layer off the acrylic, leave it on until a later step.

Step 3: Making the Digits

Order or make the PCB's for the digits using the gerber or Eagle files I have provided. I used the PCB files developed by Connor Nishijima as a base, the only edits I made were to add the 5v line in (since the original files dint have a 5V line for some reason) and change the silkscreen a bit. Using either a syringe filled with solder paste (the method I chose) or a stencil and a spreader tool, apply solder paste to the pads on the PCB's. When applying the solder paste a little bit goes a long way, you only need just enough to coat the pads. You'll need to make four of these, and it might be a good idea to make an extra to test on or in case one of them breaks. Carefully place the WS2812B LED's on the pads, being careful to note the orientation of the LED's. They don't have to be perfect since when they are cooking the surface tension of the solder will straighten them out. It is very difficult to remove an LED if it is put on wrong (I did this on my first board and spent close to a half hour trying to fix it without ruining anything. After placing all the LED's on the board, put them in the reflow oven, or in my case a toaster oven and then turn it on AFTER placing the boards in. Keep a close eye on the oven when it cooking, you don't want to exceed 220 degrees Celsius or you'll start to damage the boards. The solder should start to melt around 200 degrees Celsius. Once the solder joints have melted, turn off the oven and wait for it to cool off. Don't try to remove the boards until the have cooled, if you don't the LED's will move and the board will be ruined. After they are complete I recommend plugging them into an arduino and using one of the NeoPixel example codes to verify that the boards indeed work.

Step 4: Programming the Arduino

Plug the arduino Nano into your computer and open up the Arduino environment. Open the sketch and upload the code, making sure that you have selected the right board and COM port. If you ever need to update the clock's firmware you can do it through the USB extension cable and not disassemble it.

To make sure you are using the most up to date code check my Github here: https://github.com/ZGoode/Faux-Nixie-Clock

Step 5: Electronics

Connect all of the wires to the Arduino Nano as shown in the Fritzing diagram. Double check all wiring before plugging in to power. Fixing a burnt Nixie display is very difficult and annoying to have to deal with.

When mounting the toggle switches you will need to sand off about a millimeter from the top side (the side that is facing the PCB's making up the Nixies). This is to make them fit properly without interfering with the PCB.

You will also need to splice together the USB-B cable and the Mini-B cable. This serves two purposes, one to power the clock, and two to give you USB access so as to reprogram or update it without disassembling.

DS3231 Pinout

• SCL - A5
• SDA - A4

Lixie Pinout

• DIN - 7

Buttons

• Hour - 9
• Minute - 8
• Color - 10

Switches

• Daylight Savings - 11
• Time Set - 12
• 24 Hour - 13

Step 6: Final Assembly

After all of the electronics are tested and working and the wires have been cleaned up, prepare to close up the box. Tape down or glue the Arduino and RTC so that they don't end up touching one of the bolts or other wires. Make sure that everything that should be plugged in is plugged in. Super Glue the box shut, putting the bottom piece on last. After closing the box insert the feet pieces into their slots on the bottom.

At this point you need to take careful precautions to keep the acrylic clean. Before peeling off the protective plastic I recommend using rubber gloves to keep your skin oils from getting on the digits. Peel off the plastic protection and insert the numbers in the slots in this order (from front to back): 3, 8, 9, 4, 0, 5, 7, 2, 6, 1. After the digits are in place put the top slot piece onto each side to keep the acrylic number aligned and then super glue the top piece on to finish the clock. At this point you are done with assembly and ready to start setting up the clock for use.

Step 7: How to Use It

• To set the time: Toggle the set switch to on (making sure the DST or Daylight Savings Time is set correctly) and press the hour and minute buttons to change the time. After the time is set toggle the set switch to off and it should function correctly.
• To change the color/pattern used in the digits: Press the button labeled color
• To turn on or off Daylight Savings Mode: Toggled the switch in the back labeled DST
• To change to 24 hour mode: Toggle the switch on the back labeled 24HR

Because of the RTC used, you should only have to set the time when either the battery dies or when plugging it in for the first time.