Monday, August 14, 2017

Resurrecting an Old Technology

A friend sent me this interesting video of a guy from the Czech Republic recreating the process to build Nixie Tubes.  Nixie tubes are vacuum tubes that were used most often in the late 60s to early 70s as a numeric display.  They used separate elements shaped like the numbers 0-9, each element switched on when desired.  They were largely replaced by seven-segment LED displays by the mid-70s; seven segment LEDs only needed seven control wires vs. the nine wires for a Nixie. 



I recommend watching in full screen, but it's  almost 40 minutes long and I know that's "TL:DW" for many.

I find the story fascinating.  Dalibor Farny, ran across a Nixie tube in 2011.  He became enchanted by the technology and decided he needed to learn how to make them.  He built a garden shed and started adding machines.  Eventually he had to rent space in a nearby castle.  Along the way, he found that most of the secrets to successfully making Nixie tubes had been lost to time, having passed away with the engineers and technicians that built them.  That knowledge had to be recreated.

Today, his business is expanding and a success story.  The story of his road from interest to production is at his website.

Edit at 1922 EDT: the old Typo monster


21 comments:

  1. I had seen the video - the whole thing. It was really neat.

    ReplyDelete
  2. Replies
    1. Oops. Thanks.

      There are 10 control wires, 0-9. There's another couple needed, too. My point was there's one wire per digit, unlike the 7 (with proper coding) for a 7 segment display.

      Delete
  3. I got started on the video and couldn't turn it off...watched it to the end. What I appreciate is the skill set and patience required to complete a set. indyjonesouthere

    ReplyDelete
    Replies
    1. And you've just got to believe the first few times someone tries to blow glass, cut the tubes, or attach two pieces of molten glass, that it doesn't just work right. I'd bet it takes a while to learn those skills. And there's a lot of skills to learn.


      Delete
    2. I thought
      this guy who recreated the Houskeeper copper to glass metal joint was pretty cool.




      Delete
    3. Arthur - that is pretty cool. Thanks.

      Delete
  4. My first exposure to Nixie tubes was in the late 1960's when I had a summer job as a tester at the Western Electric plant in Aurora, Illinois.

    They had a DMM built by Non Linear Systems that used them, and we used it to test circuit packs with resistor arrays on them.

    ReplyDelete
  5. That was absolutely beautiful, thank you! I had nixies on a high precision voltmeter from the 60's, rack mount. It had all of six digits (but the last one was mostly noise).

    I love seeing people figure out how civilization was made. Now, if you can just find a video on how to make 7-segment displays...

    ReplyDelete
  6. The first time I saw them was in Data Precision DVMs back in the 1970s. It was a transitional time because around the same time I was a technician working on 7-segment LED displays.

    How to make 7-segment LEDs? Simple. First make seven LEDs, then put them in plastic case ;-) Oh, yeah. How do you make LEDs? Tough question.

    There are some hints that it's a project that can be done at home. On YouTube, "make OLED" returns a handful of projects, like this one: https://www.youtube.com/watch?v=DL5jdmJi7k0 It's not for the home hobbyist - unless you have quite a lot of equipment.

    You tube "star" Jeri Ellsworth made transistors from silicon wafers in a demo, so I looked up her channel and found a video. She doesn't get as impressive a light as the other guys, but seems to use more primitive (low end) equipment:
    https://www.youtube.com/watch?v=CAgRF8TibJ0

    ReplyDelete
  7. You'll hate me for this question: What were Edge Light Displays? The term popped up when I saved the Dalibor Farny website to Pocket. And there we go down another rabbit hole.

    ReplyDelete
    Replies
    1. Well, you're going to hate me for the answer: never heard of them.

      The only thing that comes close to "Edge Light Display" to me is things like a plastic sign that sits in a base that shines a light onto its edge, and has something etched or cut into the plastic that stands out in strong contrast because of the edge light.

      Something like this.

      Delete
    2. Also, LED back lights for liquid crystal displays are opalescent plastic lit from the sides. They use to make slide light tables this way with high intensity fluorescents, also.

      Delete
    3. Also, the signs in restaurants with the glowing ink work by changing the glass/air impedance, thus ruining the TIR (total internal reflection) angle and causing light to radiate out where the ink is.

      Delete
    4. It helps to use the exact, correct term. Edge-lit.

      Solomon had it right, there is nothing new under the sun, but ol' skool is kool. (That last part is my corollary.)

      BEFORE THERE WERE NIXIE TUBES, THERE WERE EDGE-LIT DISPLAYS?
      https://hackaday.com/2017/03/23/before-there-were-nixie-tubes-there-were-edge-lit-displays/

      Not sure why the headline is phrased as a question.

      Delete
    5. Oh, OK. It looks just like one of those edge-lit signs. They had numbered plastic pieces in a 0-9 "stack" (row? column?) and switched the light on the desired one with those funky rotary switches behind them. Fancy decoding, for sure.

      Delete
    6. It's fascinating to contemplate that as soon as they figured out how to make large sheets of glass, this could have been done using any light source, and shutters.

      Delete
  8. Thank you for posting this, I watched the whole thing!

    ReplyDelete
  9. I remember nixies and something like them with more than 7 segments, they probably were used for generating alpha characters as well. I even remember the 7400 series logic elements used to decode a BCD set of 4 bits into individual 0..9 output lines. You need some analog magic to interface to the nixie tube though.

    ReplyDelete
  10. The 7447 was the BCD to 7 segment display. 4 bits of data in and the corresponding lines for the segment LEDs went low. You needed current limiting resistors in line with the LEDs - typically 330 ohms.
    I built many displays like that back in my hobbyist days of the mid 70's.

    I still have Don Lancaster's "TTL Cookbook" (1975) on my bookshelf. It was sold by the Howard W. Sams company. (Remember them?)

    ReplyDelete
    Replies
    1. I worked on 7-segment LED displays with the 7447 driver in about '76. It was in a mobile radio that turned on one digit at a time to conserve power, just to keep the heat down. Of course, the multiplexing rate and persistence of vision made it look like all 6 of the 7-segment LEDs were always on.

      Delete