I wanted a Nixie Tube based VU meter as a visual toy for my home theater so I took the easy way out and basically parted it all out.
The box is a reconditioned telephone ringer box - I love the finger splices at the joints and the patina of years of aged finish.
The tubes and driver are from the internet as a kit - Mr. Nixie.
And the internal power supply for the LEDs is from a old cell phone charger.
Step 1. - Build the Nixie kit and be careful to follow the directions carefully as errors are very hard to troubleshoot!
Be sure to dimension transfer to the telephone box lid for a close fit. Since the lid is quite thick compared to the profile of the Nixie motherboard, I had to route out the thickness. This also created an overheating issue so I was sure to design in a ventilation flow via convection. A raised cover and box allows for internal led light to shine out adding a nice touch.
Nixie kit - $125 USD
Telephone box - $14 USD eBay
Misc LEDs, toggle switch, and wire - $8.00 USD
Step 2. Prepare the telephone switch box. I pulled the box apart and cleaned the major grime off it with a bit of thinner on a rag. Then I followed up with a little Danish tongue oil on the wood to help recondition it.
The two way switch was very corroded and not making good contact for turning on and off the tubes (separately from the LEDs). So I disassembled it completely and cleaned up all the contact points with emery cloth.
To get the standoffs for the air flow gaps I ground brass nuts completely circular and then screwed them into the box. The brass gives it a nice classic look.
I used ribbin wire on the LED circuit which is nicely sized for flexible circuit wiring and appropriate for low voltage LED systems. Note I show the rear of the box with only the left and right cannels but not the ground (neg) pin. It hasn't been installed yet.
Step 3. Build the internals.
I used 10mm RGB LEDs for the interior lighting. To hold the leds in place I use plexiglass with holes drilled in it to hold the leads square and to be able to mount them inside with hot melt glue and not obscure the lens.
a package of 10 of these on eBay are about $5USD.
Then assemble all the parts inside, using shrink tube to protect the soldered wires from potential shorts when the lid is closed.
Lastly, I etched the brass plate to be in German for a different twist and used the conventional laser printer mask and acid etch technique (found elsewhere on the internet and my other instructables).
Verify all your wiring before powering up (especially ensure the resistors are correct for the LEDs) and secure any loose wires that may contact power points.
Viola! You have an underglow VU meter!