Nixie Tube Speedometer In Motorcycle Handlebars

The handlebars of this Honda CL175 ended up being perfect for holding two Nixie tubes which serve as the speedometer. There are two circular cavities on the front fork tree which are the same size as the Nixies. Wrapping the tubes in a bit of rubber before the installation has them looking like they are factory installed!

This isn’t a retrofit, he’s added the entire system himself. It starts with a hall effect sensor and magnets on the rear wheel and swing arm. Right now the result is 4 MPH resolution but he plans to add more magnets to improve upon that. For now, the driver and speedometer circuitry are hosted on protoboard but we found a reddit thread where [Johnathan] talks about creating a more compact PCB. If your own bike lacks the fork tree openings for this (or you need help with the drivers) check out this other Nixie build for a slick-looking enclosure idea.

The link at the top is a garage demo, but last night he also uploaded a rolling test to show the speedometer in action. Check out both videos after the break.

[Thanks Crawdingle]

48 thoughts on “Nixie Tube Speedometer In Motorcycle Handlebars

    1. The tubes should hold up quite well — they’re pretty robust. I would think the circuitry could be packaged against the elements easily enough. I have no idea about the hall-effect sensor. Are there automotive-grade versions available from auto-parts stores? I would think it’s a common motorcycle part but I have no idea.

      1. I disagree. my gut feeling is that the vibration will kill this over time.

        I love nixies and I build with them. but the high voltage needed for them is too high for me to feel safe having them on a vehicle like this. if you crash and there is exposed circuitry, you could have a real safety/danger issue. not to mention the broken glass from the nixies.

        in short, I don’t think this is, AT ALL, a wise engineering decision. I applaud the creativity but this is not safe and responsible engineering.

        1. If at any point you plan on taking an unexpected leave of absence (a crash) from your motorcycle you will immediately discount any hazards that your motorcycle may possess in of itself. You will then pray to god your helmet will save your life because that will be the only thing still safely attached to you whilst your bike or you sliding several dozen feet away from one another.

        2. Remember when fuel pumps at gas stations had nixie tube displays, in the 80’s? An odd revival of an old tech when they first went away from mechanical counters. If someone crashed a car into such pumps, any spark and fire potential from the power supply for the display would be of much less worry than the rest of the disaster.

          1. Those were not nixies, they were either 7, 9, or 15 segment neon displays like the beckman panaplex modules. There were also numitron incandescent and vfd units as well.

          2. Panaplex and incandescent displays were used because of their high brightness (for daylight visibility) before LCDs could handle the temperature range needed in a gas pump.
            The high voltage wouldn’t be a problem, after all, the pumps had 120 or 240 volt AC power in them too.
            I have never seen a nixie gas pump, just segmented displays. When did you see them in use?

        3. Just riding a motorcycle makes you 16 times more likely to suffer an accident per road mile as opposed to a car. I believe that the hazards you have pointed out are statistically insignificant. Also what about the ignition system? It’s around 30kv. Broken glass in an automobile accident is a moot point. There is a a lot more glass in a car than is on a motorcycle.

      2. Automotive Hall effect sensor:, slot type with magnet built in.

        That’s a replacement for points in a distributor (motorcycles haven’t had distributors since Jesus gave up his leathers (may not apply to HD who still build bikes like it’s 1915)).

        Bike ignition is mostly CDI, triggered by a magnet going past a small coil (pulse generator).

        Speedo/tacho pickups may be Hall effect, but more likely to be simple reed switches, just like on your bicycle. One advantage the Hall effect sensor has is you may not need a magnet on the spinning bit (notch sensor).

          1. Lol, HD fans are so easy to troll.

            How long did it take them to discover water cooling? We’re still waiting for the day they discover oil gaskets.

        1. When HD’s V-Rod debuted, SPEED Channel had a long documentary/commercial on the development of the bike – sponsored by… Honda, or was it Yamaha? Was one of those two.

      3. Oh, I agree with [bl] that reliability may not be the best (time will tell), but dangerous? Eh. [bl] must have missed the class on ignition coils, spark plug, petrol and falling off said motorcycle.

        You can get ‘MilSpec’ nixies that handle vibration quite well, who knows what these are.

        1. I would not want to be on such a motorcycle if it had an accident, gas spilled out and the nixies broke and exposed 160v…

          the very thought of it goes against all I believe in, when it comes to responsible engineering.

          just not for me, I guess. and I would not have anyone I care about engage in such irresponsible designs. I’m being blunt, but engineers DO owe it to everyone to make their designs and creations safe and responsible.

          at the very least, I’d want to see a lexan guard over the nixies and some circuit that detects shock and immediately removes power to the dc/dc.

          1. 160 volts is nothing compared to the sparks from dragging pegs on the twisties…
            this would be totally irresponsible to put into an off the shelf product or stock bike, but as a customization? piffle —

          2. @mjrippe; I wonder if safety agencies would agree with your view that 160v == 12v in terms of danger level with flammable and combustable liquids.

            you call it fearmongering. I call it ‘being a responsible engineer’. sadly, a lot of the so-called engineers don’t think or care about danger, risk or safety; and that includes pure software products, too (which are not life-threatening but still, people are too keen to move forward with an idea without really thinking about all the repurcussions that may result if something fails or some data leaks out that could be very damaging). recklessness in software AND hardware designs are more common, especially with china making stuff that they could care less about, safety-wise.

            we need to be more sensitive to product safety. it seems to be a lost art, these days, and it saddens me when people try to play it down and make it sound like its unimportant or unessential.

          3. I would worry more about broken glass than sparks in an accident as the tubes are not covered with something like a polycarbonate top. Also wonder about getting an electrical shock when the circuits get wet in the rain. :P

          4. Don’t the ignition coils for the spark plugs generate close to a kV anyways? I think an appropriate current limit or short circuit detection on the tube supply would be sufficient safety.

          5. 5ma at 160v versus several amps at 12v? Which is more likely to cause a spark? Broken glass from nixies being dangerous? No more than any other bit of debris from a motorcycle accident.

    1. The speedometer is probably the least important gauge on a motorcycle. The only time I really pay attention to mine is if I know there’s a speed trap ahead or something…otherwise the rule is ride safely with the flow of traffic. It’s much safer to ride at a speed that you, being an experienced rider, feel comfortable with, than to attempt to follow some semi-arbitrary number assigned by politicians and frightened grandmothers.

      *Incidentally, all of the motorcycles I’ve owned have consistently read 10% higher than the actual GPS-verified speed.

      If I had only one gauge on my bike, it’d be an oil pressure indicator.
      Two, oil pressure and coolant/head temperature.
      Three, oil pressure, temperature and a tachometer.
      Nothing beyond that is really that important.

    1. You should see where they put the spark plugs!

      How many volts are they again?

      Even worse, they put the engine underneath the tank! Have you seen how hot those things get?

      Madness, I tell ya, just madness!

      Even worse, the fuel tank is right between the riders legs!


      Sheer insanity!

      [Weirdwhit] is right, the HAD / motorcyclist overlap is pretty small.

  1. There is 20,000volts under that gas tank, gas runs down when it leaks. Filling a motorcycle gas tank is quite dangerous. Hot engine, a spill or drips.
    Air blowing at hurricane levels with rain and road crud can get into almost anything.
    Cars and such have to be about 2/3 mil spec levels of robustness.

    1. “Cars and such have to be about 2/3 mil spec levels of robustness.”

      That number brought to you by NumerousBumholio™, when you need a random number backed by absolutely no facts, think NB.

      1. I don’t know what orifice [echodelta] pulled that 2/3rd number from (I’ve always wanted a milspec cupholder) but you can get parts rated for automotive use.

        ‘Auto spec’ sometimes exceeds mil spec (higher temperature range etc).

  2. I have to say that the timidity of some my American friends on here is a bit surprising. People from a land that brought us monster trucks, lunar landings, the wild west, muscle cars, the Manhattan Project, etc saying “ooh, that’s a bit scary, having sparks near volatile hydrocarbons”!
    Surely if somebody has made the decision to use a mode of transport that will give them a nasty experience given enough time, we should just admire their guts and applaud their flaming nixies?

    1. I think if you get the nixies inside the top yoke (top triple to the usa people) to meet the fuel tank, you’ve probably died in the full frontal that has just happened anyway and bent the frame spine like a banana, so I am a bit nonplussed at all the handwaving at fuel and nixies too.
      I think they’d be better off objecting on the basis that its very silly, a bugger to read in sunlight, liable to be interesting to ride in a downpour and impractical and will fall apart from vibration in short order.

      1. Fair play … glad it’s not just me.
        Also, although I haven’t ridden a bike for ages now, my recollection of riding a CB125 (Jonathon’s bike’s little brother?) is that it’s probably not a choice for today’s saftey minded commuter.

        1. Rigidly mounted clipons on a tiny vintage 175. The only commuting the owner will be doing is to the chiropracter to have their inexplicable wrist pain relieved :-)

    2. there is a thing called the darwin award.

      ’nuff said?

      you should be free to harm youself all you want; but encouraging people to take stupid chances is irresponsible.

      1. Thought it was just his own bike he was modding … didn’t realise he was a Honda Temporal SWAT.

        BTW, have you seen one one these bikes? They would likely disintegrate before harming another road user.

        1. The most dangerous thing about that bike is the 40 year old drum brakes.

          Weird that for a lot of small capacity bikes the US market gets drums while the rest of the world gets discs.

  3. I’m going to guess, based off the comments, that the hackaday croud and the motorcycle crowd don’t overlap much. I’ve never met someone who customized their bike with safety as their first concern. That’s not what it’s about. It’s about building something unique and cool. Otherwise we’d work on volvos.

    1. even unmodded bike owners aren’t as concerned about safety, since if they were they’d be in car/tank/bus/suv/truck ;)

      pretty much same for car/quad/rc/cnc/etc crowd too. its really nothing to do with the people doing it crowd, its more to do with the anoraks saying you don’t wanna do that..

      it’s a cool idea.

  4. Broken glass is irrelevant. Asphalt vs. Asphalt with broken glass = Pretty much the same thing. As for ‘high voltage.’ Mmm. Possibility of that adding some danger. But generally speaking, yes, most bike wrecks separate the operator and the machine pretty quickly. But not all. I think the concerns about what happens when you wreck are more or less irrelevant. Concerns about the wiring being safe while the bike is running make more sense.

    My opinions are based on the view point of riding a motorcycle, and forgoing the safety of the cage on occasion, and realizing that all of life is a balance of safety/sanity. And having wrecked said motorcycles on occasion.

  5. Very cool. I started (and subsequently back-burnered) a very similar project ( almost two years ago, now. Intended as part of a vaguely-dieselpunk CB77 gauge assembly, I had thoughts of expanding it to a friend’s XS650 – using the handlebar bushing holes just as done here. Even had a thought to use tubes with decimal points as half-digit indicators (to make each tube a 1.5 digit display), allowing a single tube to be sufficient as a tach or speedo.

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