Make your own 7 segment displays..With Neon light

Using a 3D printed frame and some Ne-2 neon lamps you can make your own impressive seven segment displays.

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Great visibility! Simple to make and very inexpensive. If you want a neon orange display but can't afford nixies you can churn these things out till the cows come home. Custom characters can also be made as demonstrated in the tube/relay computer photo showing +, - and Equals signs.
I am expanding the characters to include as many alphanumeric characters and symbols as I can thing up. An old technology can bring hope for the future!

If you are not familiar with the neon bulbs(Ne-2) here is a picture of one close up:

Note the long skinny package and leads exiting the base of the bulb.

It is important to note the dimensions of the bulb may vary a bit as to both length and girth The diameter is about 5.5 to 6mm.

I made sure to account for this variance in the shell holder designs for the printing.

These lamps(or bulbs) are widely available on Ebay and other sources for about 10 cents each to, well, the skies the limit for some vendors. It is important to shop carefully.

The lamps require about 90-100 volts(AC or DC) to fire, but best brightness is at a higher voltage ranging from 125 volts to 175. A dropping resistor is needed to limit the current in these lamps or they will self destruct quickly.. I use them in my projects at 160 volts or so and use a 47kohm resistor.

There are several color that these bulbs can be obtained, the glass shells are coated to produce a variety of colors. I prefer the orange glow myself, but you can select any color you please.

A great feature of this display system is that if a bulb burns out you can replace it instead of scrapping the whole display. These bulbs have a very long life but if one should fail you can simply replace it and the display is as good as new.


For clocks etc

Standard Tesselated Geometry - 252.28 kB - 03/14/2018 at 18:09


decimal point.stl

Decimal point shell

Standard Tesselated Geometry - 128.31 kB - 03/14/2018 at 18:09



File for the = sign display.

Standard Tesselated Geometry - 183.00 kB - 03/13/2018 at 15:25



File for the +/- display

Standard Tesselated Geometry - 280.42 kB - 03/13/2018 at 15:25



File for a character backframe

Standard Tesselated Geometry - 13.01 kB - 03/13/2018 at 15:24


View all 6 files

  • 1 × Ne2 Bulbs(as many as required) Neon lam
  • 1 × 47k ohm resistor(as many as required) Current limiting resistor
  • 1 × 3D printed shell-front and backframe see files for stl
  • 1 × 8 Pin female header input connector
  • 1 × E6000 or similar adhesive for tack holding bulbs in place

View all 6 components

  • My first application for the displays

    castvee803/13/2018 at 15:47 0 comments

    I originally built the displays for an old timey calculator made from vacuum tubes and relays. I wanted a vintage look for the machine but nice big and clear digits to display the numbers.

    This calculator uses rotary switches to input numbers to be add/subtracted. A s you can see even in a very brightly lit room the digits are clear and easy to read(despite my poor photography) This picture shows the input numbers, the = sign and equals and the resulting solution.

    I then built this all relay version of the calculator:

    This shows the same except the solution contains 2 digits.

    Both of these machines are using line voltage(120vac) rectified and filtered(170VDC) to power the digits.

  • Building the display characters

    castvee803/13/2018 at 15:23 0 comments

    Getting started.

    Gather the components or the display. Here is a photo of the basic components:

    The first step is to seat the bulbs in the frame. The front of the frame is the display bulb housing and has holes and slots already printed in to seat the bulbs. Each bulb is seated into a slot and the leads are brought out through the back. Add a small dab of glue to the inside of each slot to keep it in place during assembly. After all the bulbs are in place sit the assembly aside for a bit to allow the glue to tack up.

    One side of each bulb is the commonly connected. The other side is  connected to a 47k resistor and wired to the connector. Simple. I made the wires attach to the connector in order-a,b,c,d,e,f,g to keep it simple to connect and the bottom wire being the common.

    The neon lamps have no polarity so you can drive the display as common anode or cathode.

    After the wiring is complete glue the frame back on the display. This covers and protects the wiring inside and adds to making the display easy to mount.

    These are completed displays ready for testing.

    I will ad some more characters soon. I made the for an old time relay vacuum tube calculator originally and this was all I needed for the project.

    Note the +/- sign. Each bulb is connected individually so it can be switched form + to - electronically. I will produce a decimal point as well as a colon for clock making etc.

View all 2 project logs

  • 1
    Printing the parts

    Print the display housings in black for best results and contrast.I printed mine in ABS at 15% infill. If you print them lower you may have to open up the holes a bit to easily get the bulb leads through. Each front character face needs a back frame so print them as a set to reduce printing time.

  • 2
    Inserting the bulbs.

    Feed the bulb leads through the printed holes for each segment. Before pushing in place, add a dab of E6000 or similar glue to hold them in place and allow to dry a bit before proceeding.

  • 3
    Connecting the leads commonly

    The copper leads of the bulbs are very flexible and stay put when you bend them. Bend one lead from each bulb flat against the back of the shell and overlap them so every lead connects common to each lamp. There is no particular way to do this as long as they do not short out other leads. Solder each overlap and you can add a dab of glue here and there to keep them in place.

View all 10 instructions

Enjoy this project?



DeepSOIC wrote 03/16/2018 at 10:01 point

Ne2?? It's just Ne, these atoms won't stick to each other...

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castvee8 wrote 03/16/2018 at 11:36 point

They stick so bad it's repulsive........

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Dr. Cockroach wrote 03/15/2018 at 23:48 point

If I ever do a relay adder build then that is the display I want to use :-)

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[this comment has been deleted]

Dr. Cockroach wrote 03/16/2018 at 00:10 point

I am not the one to stop such a noble project, gota love it :-)

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castvee8 wrote 03/16/2018 at 00:09 point

Ha....I thought the same thing....jokingly at first....but then the disease of serious vintage bit me...and now I can't stop..Right now I am building an all vacuum tube version...Somebody stop me....Please!!!!!!

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Ted Yapo wrote 03/15/2018 at 14:08 point

Have you thought about using the storage capability of neon bulbs to make the display non-volatile?  The idea would be to bias the bulbs slightly above their maintaining voltage, but below their strike voltage.  You could turn on a segment with a capacitively-coupled pulse, and turn it back off by killing the supply.

I know these voltages aren't well-specified, and change as the bulb ages, but it might be an interesting way to make a multiplexed display that you just have to write once to store state.

  Are you sure? yes | no

castvee8 wrote 03/15/2018 at 14:31 point

Certainly something to explore. My first applications did not require multiplexing so I have not tried much in that direction. Hoping to get more feedback like this as the contest proceeds for future project logs.

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David Scholten wrote 03/13/2018 at 01:50 point

Brings a smile to my face :)

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castvee8 wrote 03/13/2018 at 14:38 point

Hopefully in a good way!

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