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Build A Nixie Tube Clock 126

J Aldridge writes: "People are still using Nixie tubes. Their warm glow seems to be the digital equivalent of the warm sound of vacuum amplifiers. One person has constructed a tube wristwatch."
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Build A Nixie Tube Clock

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  • Pixie tubes (Score:1, Funny)

    by teasea ( 11940 )
    I love 'em. Just pure sugar though.
  • Mmmm (Score:1, Interesting)

    by Anonymous Coward
    reminds me of the Navy days...
    • Re:Mmmm (Score:3, Insightful)

      by digitalunity ( 19107 )
      sounds dangerous!

      When can I have one?
    • Re:Mmmm (Score:3, Interesting)

      by Shanep ( 68243 )
      Does Vacume Fluro Display constitute Nixie?

      I have a Casio Mini (Casio's first handheld electronic calculator) that has 6 x 7 segment VFD displays. The tubes are seperate, perfect for H:M:S.

      This calc is interesting as it has a fixed decimal point not shown on the display and is not capable of user entry of a decimal point.

      Good condition with a slight dent and little corrosion on battery terminals. It's up for sale if anyone is interested in it or it's small tubes? Collectors item and I'm not a collector of old calcs (I prefer my 48GX).

      shanep AT ign DOT com DOT au
  • hey (Score:2, Funny)

    Tube clocks? Weren't those out of style in the 80's?
  • by Anonymous Coward
    um, is this supposed to be a news post, or is it just a statement.

    after reading the blurb... "people are still using these things..." i just thought... ok. that's nice to know.
  • by Harumuka ( 219713 ) on Saturday February 02, 2002 @04:00AM (#2941244)
    I, too, was tempted to buy a few Nixies to revive my cold and dank cellar, but stopped dead in my tracks soon as I saw a notice at the respectable RepairFAQ []:
    This circuit was not isolated from the power line and has been removed due to the danger involved in such a setup.

    Although web archive's archives of the Repair FAQ only go back to 15 Feb 2K1 [], if I remember correctly the removed link went to the page Slashdot is linking too. Word from the wise: I'm not saying Nixies are inheirently dangerous, but many schmatics involving Nixie tubes do not isolate from the power line. And don't forget the big red warning on the page:

    Warning! As this design uses a transformerless power supply, the whole circuit is at mains potential. Disconnect before making any adjustments etc. If you need to use an oscilloscope for debugging, the circuit MUST be operated through an isolating transformer.
    • Personally, I think anyone who'd attempt to put something like this together and/or use it would have the knowledge or talent to realize what was involved. Well, at least I would.
    • Oh, sheesh ... a minute and a half with Google turned up the following if you really want to see the circuit. _asci2.htm []

      Warning, this circuit Really Is Dangerous.
    • the power supply of your computer is dangerous as well. But does that mean you should never take a piss because you might hit your precious linux running toy???
      • Where do you want your body sent?

        There is a big difference between a switching power supply designed by real engineers, with UL/CSA/TUV review and approval, and some random electronics project. Isolation transformers are a must for any electronic device that someone is going to poke around in with their bare hands.

        • You haven't been playing with PC power supplies for long have you?

          I work for a company that made bucketloads of cash reworking real IBM XT power supplies because while they were rated at 220/240VAC, their caps blew because someone at IBM forgot at 1.414x240+/-10% was. Can you say opps.

          And you might want to check to see just what it takes to get that UL/CSA/TUV rubber stamp of approval.
          • Those are safety certifications, not reliability or performance certifications.
            • Your starting to get a clue...
              If you are going to routinely put 375 volts into a device, it should not have a large number of components that exceed their ratings once the mains voltage exceeds 340. Things that can break down are caps (which have been known to catch fire, vent and genenly smell bad), wire insulation which can result in shorts, transformer insulation that can cause the windings to have less resistance, various types of surge proection devices that will attempt to trip 50 times a second.

              I've seen UL and TUV stamps of approval on lots of things for the Australian market based on testing at 220V. Sorry but Australia uses 240V and in places thats +/- 20%

    • All TV sets and computer monitors are this way too.

      If you work with the stuff it's a good idea to have an isolation transformer around (I've misplaced mine) There is a lot of High Voltage stuff in electronics. Know what you are dealing with, take all the right precautions, and hold one hand behind your back.

      • And wear rubber-soled shoes.

        (NOTE: Holding one hand behind one's back and wearing rubber-soled shoes is to prevent the current from getting a path across one's heart)
        • The rule I was taught was to consciously decide not only to put one hand behind your back, but to hold your belt. I was also encouraged to think about holding my belt, to avoid the unconscious, "I just need another hand on the other side of this" which ends up with one hand holding a negative terminal and the other a positive, and the current running straight across your heart.

          When I was 17 (before I'd been taught all that), I was helping a friend hook up an electric fence. The transformer had a wing nut on each side as a terminal, and was mounted to the wall by a nail at the top. For some IDIOTIC reason, I was trying to hook the fence up plugged in. Now, you often do have to work on live electrical equipment, but this was clearly not one of those cases.

          So, in any event, I hooked up one lead, and was tightning the wing nut for one lead. Of course, since the transformer was hung from a single point, it was flopping around. Without even thinking about it (a lot of not thinking going on, that day), I swung up my left hand to stabalize the transformer... And grabbed the oposite terminal.

          I remember standing there, with the muscles in my arms convulsing, and I thought, "I've got to do something." My chosen course of action was to yell "SHIIIIITTT!" at the top of my lungs. It didn't seem to improve my situation any, so I thought for a bit on what might be more productive. In one convulsive movement, I threw myself away from the transformer (my hands were locked to it by muscle spasms from the current).

          So, children, that is why you should grab your belt with one hand, and hang on for dear life.
      • by wowbagger ( 69688 ) on Saturday February 02, 2002 @11:22AM (#2941780) Homepage Journal
        Actually, all modern power supplies ARE isolated from the power line - that's the core of a switching power supply.

        First, the incoming AC is rectified to DC and filtered. This gives you 300VDC on about 10 to 1000 microfarads of capacitance - enough to kill you dead if it goes through your chest. That part of the circuit is directly connected to the power line.

        Then the DC is chopped by a transistor and fed into a transformer (this is the "switching" part of the power supply). This chopping is done at between 60 kHz and 1 MHz (depending upon the power supply). The other side of the transformer (the secondary) is completely isolated from the power line. This voltage is then rectified, filtered, and supplied to the rest of the device. The voltage is measured, and fed back to the switching controller, which drives the switching transistor through either an optocoupler or pulse transformer, closing the feedback loop and regulating the voltage.

        If you look at a modern switcher, you will usually see the "hot" side is completely isolated - even unto having sections of the PCB cut to prevent arc-over.

        So, the bulk of the power supply, and the rest of the chassis, are NOT electrically connected to the power line. In fact, less of the system is connected to the power line than in an old style line frequency tranformer design. (Now, there were some old designs that rectified the power line and used that directly. THOSE designs were "hot" chassis designs, and were widowmakers...)

        That said, you shouldn't go poking around inside a monitor or TV unless you know what you are doing. The anode voltage on the CRT is between 12kV and 25kV (although the source impedance is high enough that it won't kill you). However, the deflection circuits that sweep the electron beam across the CRT are at about 400V and have enough energy to knock you on your ass.

        I've worked on TVs, monitors, radio transmitters (including tube based 250 watt repeaters (3kV at .1 amp, never work alone, one hand in your back pocket)) I design these things [] for a living.
        • I'm no electrician, but I do have a degree in physics...

          How can you chop DC at any frequency? DC current has no frequency. And transformers only work on alternating current; it just makes a big electromagnet if you run DC through a transformer (and no current comes out the other side, except when you first apply the DC then again when you turn it off).

          What am I missing here? Or is it the original post that's off?
          • How can you chop DC

            no current comes out the other side, except when you first apply the DC then again when you turn it off

            Right. Do this over and over, really fast :)

            • Yes, but doing it over and over really fast is called AC.
              • is called AC.

                No. AC is alternating current, -AC Volts to +AC Volts. That is not quite the same as pulsed DC current.

                Going back to your older post:

                How can you chop DC at any frequency? DC current has no frequency.

                Read "chop" as "cut off". You can cut off DC current and turn it back on a number of times per second. That is the frequency. You get (ideally) a square wave between 0 Volts and +DC Volts.

                transformers only work on alternating current

                Transformers work on any change in current.

                • Good points all. I had a different (and wrong ;) definition of alternating current, and used sloppy verbage talking about transformers.

                  But my biggest stumbling block was not knowing what 'chopping' DC meant.

          • This is a bit of technojargon. As far as I know, it originated with op-amp developers. Alsee has it right, but perhaps you'd like a little more development of the idea.

            "Chopping" refers to turning the DC on and off so as to generate an alternating current that can be used in transformers. Modern power supplies do it the way described because higher frequencies allow smaller and lighter transformers for the same power level. Older-style, mains-frequency transformers are big and heavy, and aren't efficient -- largely because the low frequency means they need iron, and the iron has hysteresis and other losses.

            Really small, cheap, low-power power supplies don't even use transformers any more. They use capacitors and diodes in voltage-doubler circuits.

            • Ah, yup, this is exactly the info I was looking for. When he said chopping, I thought he was talking about low and high pass frequency filters, which didn't make sense for obvious reasons.

              Thanks much!
  • cool clocks (Score:5, Interesting)

    by Pathwalker ( 103 ) <> on Saturday February 02, 2002 @04:03AM (#2941250) Homepage Journal
    The coolest looking nixie tube based clocks I've seen on the web are these [] over at World Power Systems [].
    (Be sure to check out the Story Teller [] if you go to that site - extremely cool!)
    • Forgot one thing... (Score:3, Informative)

      by Pathwalker ( 103 )
      I hit submit rather than preview and neglected to add this:
      There is a good background writeup on nixie tubes here [] on part of the WPS site.

      Please don't bother moderating this up - it's at a high enough level that people will see it, and I've been at the cap for quite a while.
      (now, if someone were to flip my rtbl [] flag I'd be thankful...
  • Reminiscent.. (Score:3, Interesting)

    by Xerithane ( 13482 ) <xerithane@n e r d f a r m . o rg> on Saturday February 02, 2002 @04:03AM (#2941251) Homepage Journal
    I used to date a girl whose fathers father worked for some government contract oufit (can't remember off the top of my head). He was part of the program to build the first digital clock. So, his team managed to do it and for about $60K in parts they built a clock that was slightly smaller than your desktop computers and used the nixie tubes for the display. This was by far the coolest clock I have ever seen, and probably ever will see. The girls dad ended up giving me the clock because of my fascination (and even he wasnt supposed to have it, funny story behind that for a later date) and the girl took it when we split up. One of those things I will never get over, but these clocks are so incredibly cool. I'm definitely not a compotent electrical engineer type person but would definitely consider buying one if anyone is in the building market.
  • These will look terrific in my underground laboratory. Maybe I can set up an array of them to count down to Armageddon, or St. Patrick's Day, or something.

    But where the hell would I get Nixie tubes if I don't happen to have any in the attic (I looked).
  • Another geek project I'll have to add to the list of things I HAVE to do to feel complete. *sigh*

    Damn you slashdot! :)

    • Another geek project I'll have to add to the list of things I HAVE to do to feel complete. *sigh*

      Damn you slashdot! :)

      I know the feeling. I currently have to many half [] finished [] projects [] on the plate.

  • Warning from site (Score:2, Interesting)

    by bryan1945 ( 301828 )
    "Warning! As this design uses a transformerless power supply, the whole circuit is at mains potential. Disconnect before making any adjustments etc.
    If you need to use an oscilloscope for debugging, the circuit MUST be operated through an isolating transformer."

    As cool as this looks (yet still too much for me to tinker with), just this warning would put me off. One small error at 340V could be an, ahh, inconvience! And I didn't see any mention of what type of currents are running. Crispy!

    But seriously, having the rough equivalent of neon tubes for "UK£10/US$15 (excluding nixies)" would be neat. But considering that my lab group for EE201 blew out every circuit/component we tried to build in lab, I wouldn't trust myself with a soldering iron on anything more dangerous than an unplugged PCB board.
    • "Warning! As this design uses a transformerless power supply, the whole circuit is at mains potential. Disconnect before making any adjustments etc. If you need to use an oscilloscope for debugging, the circuit MUST be operated through an isolating transformer."

      This reminds me of a Heathkit oscilliscope kit I put together 20 years ago. The beam intensity control circuit used a normal TTL gate chip that was attached to the back of the tube. The chip's power and ground were connected between -2000 and -2005 volts(!).

      It the input signal to the chip (which was always pulsing to cancel DC potential) was controlled by the rest of the circuitry at between 0 and 5 volts, and this was transferred to the control chip via a huge high-voltage rated capacitor with 2000 volts accross it, which would wiggle the other end between -2000 and -2005 volts. An impressive hardware hack.

      As it happened, when I finished the scope and fired it up, it didn't work. It was pretty hard to debug without an oscilliscope :-/, and I was afraid of shocking the crap out of myself poking around 2000V circuits. I eventually got it working. It still works to this day, but the lame 5MHz bandwidth isn't too impressive.

  • I was clued into this here recently at another website. Now, with all the other geeks exposed to Nixie tubes, it looks like my chances of getting something, at least on eBay, are far worse. Nixie clocks (or, really, the tubes) are so cool because they're so retro. The displays are incredible.

    Another new hobbie vanquished by the Slashdot Effect.
  • Coincidence. (Score:2, Interesting)

    by Stillman ( 185591 )
    Isn't life odd?
    Of all the obscure things to hit me twice in one day!

    A friend of mine has a page up detailing exactly this. []

    He's a valve lover, not a web designer, but he has lots of pictures, and would love feedback! :)

    His main page is here. []
  • Warm Memories (Score:2, Insightful)

    by Doomsdaisy ( 90430 )
    My uncle was a classic tech scrounger, and had all manner of things that used tubes and early transistors. I fondly remember when he once showed me one of his prized posessions, a nixie tube calculator. It was maybe 25x25cm and the warm glow of the numbers was much friendlier than the simple black on grey of the LCDs I grew up with.

    I could tell that even then it was something special by the way he treated it and obviously treasured it. It wasn't until I was older that I learned to appreciate the tech of yesteryear and the creativity and genius of those who created so much with the limited tools they had at the time.
  • 190 volts at... (Score:3, Informative)

    by Futurepower(tm) ( 228467 ) <M_Jennings @ not ...> on Saturday February 02, 2002 @04:28AM (#2941283) Homepage

    I seem to remember: 190 volts minimum at 3 to 5 milliamps. Discouraging if you want to use batteries.

    Liquid Crystal Displays: A few volts at almost zero milliamps. If you had designed with Nixies, the discovery of LCDs was like God was giving us a gift.
    • Re:190 volts at... (Score:5, Informative)

      by ( 463190 ) on Saturday February 02, 2002 @06:54AM (#2941361) Homepage
      I seem to remember: 190 volts minimum at 3 to 5 milliamps. Discouraging if you want to use batteries.

      Big whoop. It's not hard to make a switching power supply [] that will give you whatever voltage you want from a battery supply. Lots of sample circuits are out there.

      You can also buy inexpensive inverter modules that make 100VAC from a battery supply - typically used for powering LCD electroluminescent backlights. Seach on digikey [] for "backlight inverter".
      • Microamps versus milliamps (Which, by the way, that switching supply will consume a couple of milliamps as well- not to mention you just bulked up your device considerably...). If it takes 5 micrnoamps to operate something and another unit takes 5 milliamps the microampere consuming device will last much longer.

        I don't believe that he was saying that it was impossible or that someone didn't do it- it was just a godsend for the people having to develop devices with numeric displays to not have to mess with Nixies.
  • You know those tubes would make pretty good bongs....
    • Its only a matter of time before someone builds a bong out of an iCarumba. Its probably been done already. :)
  • Glad I already have enough for 5 or 6 clocks already cause they just got harder to locate now that /. geeks with electrical skills have been notified.

    *sigh* :)
  • This is so incredibly cool - and cheap in comparison:

    Nixie-Chronometer 01 []
  • by khaladan ( 445 ) on Saturday February 02, 2002 @04:37AM (#2941297) made out of vacuum tubes.

    Oh wait, that did end up being kind of useful :)

    Hurray for old tube things.
  • I would love to buy a nixie clock (I don't have the technical aptitude to build one), but I can't seem to find anyone who sells decent assembled, completed nixie clocks. Anyone know where I could get one? I have money to spend!
  • In my dad's basement I have an old calculator with about 11 of those tiny nixies. Something to remember next time I fly back for a visit.

    Projects already on the back burner:

    Dynakit STA-35 amp

    Pioneer vacuum tube receiver (needs some small caps replaced)

    Still enjoy my old Ampeg V7 tube amp, too. Digital circuits seem to take extreme proportions to replicate the functions of the simplest old analog circuits. Not alway for the better, either.

  • So that all the pixies that live inside my PC can tell the time when they come out at night to play.
  • Even Cooler... (Score:5, Interesting)

    by kzinti ( 9651 ) on Saturday February 02, 2002 @04:53AM (#2941305) Homepage Journal
    Wow, those nixie clocks bring back some fond memories. I always wanted to build a nixie project, but as a novice hardware hacker, couldn't even read the hookup schematic. Now, a little older, wiser, and with the help of these kits maybe I'll finally build one.

    However, while browsing some of the associated links, I came across this clock, which I find even cooler: []

    It uses an oscilloscope tube to draw the time in green phosphor arcs - no pixels. Way cool! And a kit is available with a guts-on-display plexiglass case. Awesome...

    • Re:Even Cooler... (Score:4, Interesting)

      by ( 463190 ) on Saturday February 02, 2002 @05:35AM (#2941330) Homepage
      It uses an oscilloscope tube to draw the time in green phosphor arcs - no pixels.

      Very nice!

      If you don't feel like figuring out how to drive a CRT directly, there are some interesting things you can do with just a regular oscilloscope set to XY mode. Next time you're at Fry's, go to the aisle where they have all the oscilloscopes and function generators. This works best on a CRT scope, not a digital sampling scope. Hook two function generators to the scope inputs and set it to XY mode. Set the function generators to a sine wave, and play with the frequencies. You can generate all sorts of interesting lissajous figures [].

      I once made a project using a PIC, a couple of DACs, and two stepper motors. The stepper motors were wired up like a "poor man's galvanometer" - the were driven by the DACs to move back and forth within a step. By mounting the motors at 90 degrees and hitting them with a laser pointer, I was able to make a pretty groovy portable laser show for about $40 worth of components.

      Another thing you can do if you don't feel like making your own hardware is to hook your sound card's left and right outputs to an oscilloscope. The you could write some simple software to draw these kinds of figures on the scope by just sending the wave forms out of your sound card. Unfortunately the frequency response is limited to the audible range so this is not ideal. A simple resistor-ladder DAC on the parallel port might work better because you could have <20HZ frequencies.

      It's amazing what you can do with a little geometry....
      • Another thing you can do if you don't feel like making your own hardware is to hook your sound card's left and right outputs to an oscilloscope.

        You don't even need a scope to do this kind of thing. When I was 16 or 17, I learned how to disconnect the yoke from a TV and connect the inputs to other sources - a poor man's X/Y scope. One time a friend and I connected the horizontal and vertical yokes to the left and right outputs of his stereo's B speaker channel and made all sorts of cool patterns while we played Aerosmith until our ears bled. There must have been some horrible kind of impedance mismatch, though, because after a couple of hours, we completely burnt out his expensive high-power amp. Oops.

        Another time, while my girlfriend's parents were in Europe, we reversed the connection to their TV's vertical yoke coil to turn the picture upside down. We were going to leave it that way for her parents to discover, and thought they would find that hysterically funny. But when we realized they probably wouldn't figure out how to fix it, and that they'd probably spend a bunch of money on a TV repairman, we chickened out and put the picture back right-side up. Instead we turned upside down the abstract metal sculpture that hung above their fireplace.

        • Re:Even Cooler... (Score:2, Interesting)

          by jcapell ( 144056 )
          made all sorts of cool patterns while we played Aerosmith until our ears bled

          One of my most prized posessions in college was an old B&W TV with 8 ohm vertical and horizontal coils.

          By FAR the coolest patterns were produced by Dire Straits from the Brothers in Arms LP - especially the song Telegraph Road. I still think it was all the pot smoke that eventually burned out my stereo, not the boob tube.

          At some point, I could actually look at the boob tube's patterns and identify what song was playing - I shite thee not!
          • By FAR the coolest patterns were produced by Dire Straits from the Brothers in Arms LP - especially the song Telegraph Road.

            Telegraph Road was on Love Over Gold. Great album, though. Hmmm... I've got an ancient 13" B&W TV... Hmmm... I wonder...

    • That reminds me of a very cool clock I saw in Hong Kong (of all places ;)

      It had a single row of LEDs, mounted along a pendulum. The pendulum would swing back and forth, and the LEDs would flash so as to make it look like the current time was 'hanging' in the air in front of you.

      Kind of like the way monitors work [], I guess, except with a very low refresh rate.

      You can rig one up with your parallel port [] (I think parallel ports can just put out enough current to drive LEDs, but you might blow your port outputs if you're not careful); get it to output a fixed sequence at a certain frequency and wave a bit of wood with your LEDs mounted on it back and forth, and you should see a nice pattern.

      I had a friend who was doing this, but I have no idea if he got it going or not.
      • It had a single row of LEDs, mounted along a pendulum. The pendulum would swing back and forth, and the LEDs would flash so as to make it look like the current time was 'hanging' in the air in front of you.

        An electronics store here has this kind of clock, except the "pendulum" is inverted and motor driven. It scans back and forth very fast, and the red LED characters really seem to be hanging in midair. It's programmable and can be made to display the time and a short custom message. Pretty cool for $99 or thereabouts. I'm pretty sure Slashdot has covered this kind of gadget in the past.

  • Woohoo! (Score:3, Funny)

    by trivialproductions ( 514318 ) on Saturday February 02, 2002 @06:06AM (#2941339)
    I can now finish my Goldfinger-style atom bomb!
  • Jaycar Electronics [] in Australia stocks some vacuum fluorescent displays, kind of like mini-Nixies.

    If you're lucky, this link [] will take you to the description (and might even give you my session cookie :), otherwise go to the Online Catalogue [] page and select '-LEDs/Displays' from the dropdown menu then 'Search'.

    The one you're after is '11 Digit Fluoro Bargain'. Here are the details:

    Vacuum fluorescent displays - still look the best. Once again Jaycar has purchased a substantial quantity of a quality Futaba brand vacuum fluorescent displays. Each digit measures 6.0mm(H) x 3.5mm(W), 11 digits in all. The display also features an apostrophe in the top right hand corner of the digits, and a semicolon (;) in the bottom in all 11 digits. Electrical and mechanical data is incl in the price.
    Only A$1.70 each - about US$1.20 or so. I got two of them a couple of years back. Needless to say, they're still sitting in the cupboard, waiting for me to get around to making something with them ...
  • Back in the late 70's - early 80's a number of pinball manufacturers used neon displays for the score, but they were flat and rectangular like vacuum fluorescents. Has anybody ever seen one with nixie tubes? That would look so cool.
    • as far as I know, the pinballs all used electro-mechanical displays until they switched to computers with LED or vacuum flourescent displays about 1977. I have a Gottlieb Royal Flush, ca 1976, one of the last em machines...and a classically good playing one too. The numbers are just silkscreened on round wheels, with a cheezy solenoid driven stepping mechanism to advance it. I suppose it would make a neat clock, though...not as simple as the mechanical "digital" clocks made in the 40s-60s.
    • Re:Pinball Machines (Score:2, Interesting)

      by KC7GR ( 473279 )
      I've seen the odd Bally machine that used the neon displays for scoring. Said displays are called 'PanaPlex,' and they were originally developed by Burroughs Corp.

      They're kind of interesting in that they're nothing more than complex neon lamps. They consist of metal segments, laid out in the pattern of a seven or fifteen-segment display, sealed in a glass enclosure that contains (of course) neon. Apply about +130VDC to the common anode, and then ground the appropriate lead for the segment that you want to light up.

      I don't see them much any more, at least not in pinball machines. The reason, I think, is that PanaPlex displays did not stand up to vibration and shock particularly well, and pinball machines dispense both in generous quantity.

      For trivia buffs: There was one other type of vacuum display tube made that consisted of individual incandescent filaments, in the familiar seven-segment pattern, sealed into what looked for all the world like a standard miniature tube envelope. I don't recall who made them, but their trade name was 'Numitron.'

      Anyone remember any more about them? The BART system in the Bay Area (California) had loads of them in their old ticket machines and other digital readouts, such as those used on the station agent consoles.
      • I'd like to find a type of numeric display which had white-on-black numbers and which may have been manufactured by a company called IEE. The display operated by mechanically moving strips of black plastic or mylar in front of an incandescent lamp, the digit to be displayed was a translucent portion of the mylar. These displays were once widely used in government and military applications, and into the mid '80s were used in the video switching systems of the CBS-TV network. Does anybody remember the exact name of these devices, how they worked, or whether or if any are available to hobbyists.
        • The display operated by mechanically moving strips of black plastic or mylar in front of an incandescent lamp, the digit to be displayed was a translucent portion of the mylar. These displays were once widely used in government and military applications, and into the mid '80s were used in the video switching systems of the CBS-TV network.

          You mean like the last of the old TV sets with knobs that you turn to change the channel? Rather than having the numbers on the knobs, there was a wheel with the numbers on it, and the channel you were on showed in a small window, illuminated from behind by an incandescent light. Now that I think of it, that might have been my first ever electronic personalization (analogous to a case mod), when the incandescent lamp went out, I found a green neon lamp to install in its place.
    • My dad used to collect pinballs from the 50s & 60s -- I don't remember seeing a machine with Nixie tubes, but Wico, a Chicago-based supplier of parts for arcade machines, used to carry them in their catalogs, so someone must have been using them.
  • by insane ( 18348 )
    I don't mean to be nit picky, but I question the qualifications of the person who designed that circuit. First off, there is no reason not to isolate the power supply from the main line. It doesn't add much cost, and the safety is well worth it. Especially on home built projects, it's already easy enough to shock yourself or start a fire (don't ask...I have done either too many times...) Second, there is also no reason to use the frequency of the mains to drive the circuit. Any one who has ever looked into that has noticed that the mains frequency varies quite a lot over time. Isolating the circuit and using an updated digital circuit or even a small micro-controller (PIC or 8x51) you could build a better, more accurate clock with more features for cheaper. I might even design one myself, put my EE degree to use...
    • by Detritus ( 11846 ) on Saturday February 02, 2002 @07:04AM (#2941370) Homepage
      While I agree with you about the need for a transformer for safety reasons, the mains frequency is useful for a clock. I built a Heathkit digital clock, back when digital clocks were rare items, that used the mains frequency as the input to the logic circuits. It never drifted more than a few seconds from the time signals broadcast by WWV. The power grid operators would adjust the frequency of the grid to keep the long term average frequency at exactly 60 Hz. If the frequency dropped during the day, due to high load, they would run it a bit fast at night to compensate.
      • Frequency (Score:2, Interesting)

        by ESD ( 62 )
        In Europe the frequency actually can not deviate too much from 50 Hz, because all generators are locked into this frequency (if the frequency of one generator would be different an enormous current would flow from the other plants into this generator and it would most probably blow up). This system is used to cover peak loads:

        When a large load is applied to the grid, the frequency drops slightly and all generators in Europe deliver extra power to compensate for this (i.e. keep the frequency at 50 Hz), this is called frequency compensation.
        If the load persists longer, the plant/country/company responsible for the load increases its power output (thereby raising its frequency) to make sure the cost of this load is directed to the proper plant (power compensation).
        Due to the inertia of the entire European powergrid most of these frequency changes are no more than microHertzes, even when applying loads of megawatts.

        Just putting my "Process control in high-power electrical systems" course to use, I'm not an enormous expert in this field, and this course was a few years ago (my field is optical communications)..
        • (if the frequency of one generator would be different an enormous current would flow from the other plants into this generator and it would most probably blow up).

          A small power company where I useto live accidentally connected up a generator out of phase. They retreived the alternator core from the basement of a building over a half mile away. Thankfully no one was hurt. That was only a 1 Mega Watt generator. It weighed a few tons. Before it had left the power plant it had sheared off a 10 inch drive shaft and cracked the case on a huge diesel engine. The remains of the strator housing destroyed the generators on both side of it.

        • Your both right. frequency drift happens, but its tiny, due to load and a complicated power grid, it can not be changed during a full load, so its done at night, at about 3:00 am on a the western seaboard of the US atleast. Lowest power draw at that time.
    • Since an isolating transformer was mentioned numerous times, I have to ask what exactly it gains you in terms of safety. Is it meant to step down the voltage of the mains to a much safer level? Or is it one-to-one, and if so, what is the "isolation" intended to do?

      Sorry, I'm a software guy...
  • I built a Nixie tube meter when I was a schoolboy in the early 1970s, on account of 90v Nixie tubes being lots cheaper than any other display technology (and I only shorted the 90v line to something else and blew up all the electronics once).

    Home made A/D - basically an op-amp integrator which ramped up to the voltage to be measured, whilst the Nixie tubes counted up time.

    Yeah, sure, it took a hell of a lot of calibration to get any accuracy out of the thing, but the boxfull of 0.1% resistors I'd "acquired" from somewhere helped a lot.

    And hooked into a couple of amplifiers in my (analogue) computer I could measure currents in the single figures of microamps - rather better than my moving coil meter could manage.
  • by Anonymous Coward on Saturday February 02, 2002 @07:06AM (#2941372)
    The idea dates from around 1915--there were several patents for similar
    cold-cathode gas display devices before WWII.
    National Union made such numeric displays around 1940,
    the GI series tubes used bent wires to form numerals and
    had large 9-pin bases.

    The Haydu Brothers Co. developed what we call Nixies today
    circa 1947/48--
    Burroughs bought the Haydus out in 1952, making all their
    display tubes (and their complex "Trochotron" counter tubes)
    into Burroughs products. After Burroughs
    was absorbed by Unisys, tube manufacture ceased--however,
    companies such as Richardson/National and Philips were making
    Nixies well into the 1980s. Richardson still has the special
    tooling to make them, and could make more if demand
    appears. Prices for NOS Nixies are rising, because so many people
    are building clocks and fooling with old test equipment....

    --Eric Barbour
  • I prefer the seven segment neon display tubes myself. They still provide the warm glow of neon but are driven more or less like LED displays. I have had one or two Heathkit digital clocks that use these tubes and they see to last about as long as nixie tubes before they wear out and need replacement..

    rm -r windows
  • Here's a link [] to Memepool's search page that will turn up the 1/22 post where the poster most likely got this. The Memepool post is more informative -- it has several other links, including a page where someone will build one of these clocks for you at what look like reasonable prices for anyone who really wants one of these but isn't a hardware hacker, and where to buy Nixie tubes (and other old displays) for someone who is.

    And personally, I think the combination of 30-year old Nixie tubes and modern PIC16F84 microcontrolers is simultaneously creepy and wonderful.

  • An excellent source of information is located at Sphere Research Corporation's Nixie Page []. They have datasheets, pinouts, excellent links and, yes, you can buy all manners of Nixies from 'em! Ken
  • ...instead of taking the lazy (and dangerous) route of making the thing transformerless. Other than that, I have no complaints about it.

    It would not have been hard to design a proper power supply for that clock. In fact, I question the designer's wisdom, maybe even their competence, in not going with said supply. Transformerless designs, I thought, went out with the old tube-type clock radios.

    For those that are thinking of making the thing, I'd strongly suggest doing it right. You'll probably need a couple of amps worth of 5V, and the tubes should run on anything from +130-170VDC.

    If you can't find an appropriate transformer that contains the requisite HV winding, try using two transformers: One for the low-V stuff, and the other being, say, a 12V filament transformer, wired such that the secondary winding is hooked to a 12V winding on the first transformer. The step-up effect should be enough to drive your tubes (you don't need a lot of current for Nixies).
    • (from the designer) The choice of power supply was carefully considered, and certainly not 'lazy'. The primary design goals were to produce something that could be built very small if required, and use only easily obtainable components. This project started as something for myself, that I made available for others, not a magazine-style project for electronics newbies - the warnings on the page clearly indicate the potential dangers, which would not be significantly less with an isolated version. I resent the comment questioning my competence from someone who doesn't appear to know what they are talking about. Transformerless PSUs are far from dead in real commercial products. when appropriately designed and packaged, they are no less inherently safe than transformer-based ones, and are commonly used where a small amount of low-voltage power is required. You will typically find them in rechargeable shavers, bathroom fan timers, Electric showers, electronic timeswitches, washing machines, power drill chargers amongst numerous other consumer and industrial products (some of which I design for a living, incidentally, with and without transformers). Transformerless PSUs are neither 'Bad' nor 'Wrong' - it's just that their appropriateness for any given application needs careful consideration. If you want to get really picky, there are some aspects of this design that are actually safer than a 'conventional' design - the anode and other limiting resistors from the high voltage line limit the maximum amount of power that could be dissipated under fault conditions to below that which would be likely to present a fire hazard. The only component which could dissipate a significant fault energy is the bridge rectifier, which is protected by a fusible resistor. Also, the original 240v version has NO stored engergy at high voltage after power is disconnected. By all means add an isolating transformer (as I have recommended on the page when faultfinding), but it will still bite you, badly, if you're not careful, and don't let isolation lull you into a false sense of security. If something looks dangerous, people will treat it with respect, if they think it is 'safe' that's where the accidents occur.
  • My first computer work was as an operator on a Burroughs B-4700... the front panel had 8 (I think) nixies and a keypad to enter machine instructions. Most of the time, it was to enter the instructions to read the bootstrap deck from the card reader for a coldstart. If the mainframe crashed, that was where you could debug, etc. In later models, the bootstrap level was moved to the console, which had a cpu, 8" floppy and a CRT.

    Later, I went to work for Burroughs Corp at their large systems manufacturing plant. I was around when Burroughs aquired (read: bet the farm) Sperry Univac under CEO and former Treasury Sect W Michael Bluementhau creating Unisys. As I recall, nixie technology has not been used in any new (B) products since 1980-1981 - they probably kept manufacturing a few years for spares, etc.

    I love the clock idea - sounds like a cool project.

  • I won't some of them tubs. Thay would be a cool looking case mod. What the computers look like in the 60's SCI-FI movies.
  • Around 35 years ago, ur company used to build frequency counters using Nixie Tubes. One of our engineers got hold of some Nixie tubes that displayed dollar-signs. He built a device called "ExecuMeetingCounter". It had a couple digital thumbwheel switches labelled "attendees". You dialed in the number of people in the meeting and the device sat on the conference table and tallied up the cost of the meeting (using some arbitrary per-person cost).

    Another fellow employee built a Nixie tube clock, but it used a 3-foot long glass PENDULUM as the rate determining device. A photodetector sensed the passing of the pendulum, incrementing the clock counters and sending a pulse to a coil to give the pendulum a "kick" to keep it going. It was an amusing mixture of old and new (at that time) technology.
  • by tomjennings ( 226406 ) on Saturday February 02, 2002 @04:58PM (#2943207) Homepage
    Yes, technologically, Nixies & related are a pain to interface to +5V CMOS logic, but that's not the point. LCDs are clearly superior in sooo many ways, but they are... well, boring.

    Pretty much all instrumentation these days looks the same, membrane switch, LCDs, a few LEDs, a pile of nifty software, an order-of-magnitude more accurate than the previous model, runs on a AA cell for 2 years until you throw it out.

    However, our lovely bodies are physical, and they like being enticed with 'interface' (sic) that connects with more than just yore brane. You can *touch* nixies, the glass is nice to touch, and so are heavy bakelite knobs, switches you can *feel* change state.... Nixie digits jump around. The orange color works well with your eyes. There's no blinky multiplex updates to dazzle.

    In general, pre-photomicrolithography electronic stuff was more fun to touch and use (though largely sucked when it came to power consumption, reliability, size, heat output, portability, ad nauseum) as is quite obvious.

    A Tektronix scope is an excellent example of technology and interface design and of paradigms lost -- they use first-principle physics (the cathode ray tube is more than just a display, it's an integral measurement component), a mixture of solid-state and state-of-the-art electron tubes, analog computing components (verniers), big clicky knobs, coded by color, size, shape and placement, nice colors and shape, a manual that contains data and meta-data (operating, maintenance, design! and curious gratuitous cartoon graphic characters walking along signal paths...) Like other targetd instrumentation, it embodied and defined a culture of use that was far more ... fun.

    But performance-wise, my TDS-220 software'n'LCD 100MHz BW gigasample scope, the size of an old table radio, is incomparable. It's a pretty amazing contrast for only 30 years of development.

    But now we get the best of both worlds (sic), teensy micros under the nice part of the old stuff. I think it's a pretty normal development, culturally, this re-use of the "outsides" of old equipment to achieve a revisionist view.

    Interface is always where the interesting stuff is.

    The best nixie and 'scope clock technology out there today, is hands-down, David's (, surface mount, AC power line isolation, small, low-power, software driven, switcher HV supply, reasonable price (no I get no kickback frmo his sales).

    I wrote a brief history of nixie and decimal tube history here:, nothing exhaustive, but a good start.

    For home-brew, a transformer/diode bridge/series regulator with zener is somewhat crude, but easy to make, reliable, and reasonably low power. For a transformer I use a Thordarson-Meissner # 26R60 transformer from Allied Electronics (web order) around $19 each (provides 6.3V and 150V outputs). This is no where near as elegant as David's but for one-off it's fine.

    I too make clocks ( but I'm not in the clock business per se, mine are simply art (more accurately craft) objects, though I'll make more. My emphasis is more on a functional, tactile artifact, a Nice Thing to hold and use. I've only made a half dozen so far, I've got another half-dozen in the works. After I use up my stock of PCBs I'll end up buying guts from David, it's a much better design.
  • I found a nixie tube multimeter in a government surplus pallet that I purchased last year. I remembered the nixie tubes from a calculater in our math room from high school and also from some of the frequency counters we used in college.

    I took it out and plugged it in. It didn't work. I then got curious and took it apart to find a fuse blown. I replaced it and it lit up like a brand new multimeter.

    There is something about the 3-Dimensionality of it. The numbers that it comes up with literally jump out at you or jump away from you. It's soo cool...even if its got a beige plastic case.

    Unfortunately people at work didn't share my admiration for it(Something about being out of date). I had to take home here where it commands a distinguished place on my bookshelf.
  • small Nixie display modded to show RPMS, temp, or the time of the day, mounted on the front of a puter. Now with the higher voltages required to drive the unit, some wiring modifications will be needed to make it happen. It would be quite retro and modern at the same time.
    Now i know that there are TRUE small nixies out there for i've seen them in a old medical diagonstic display (a hemocrit counter to be exact) not just a modded vacuum flourescent display.
  • I have this clock running, it keeps time ok, but I need to build the cabinet. Pics are a bit out of date, sorry! k.html


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