Vetinari Clock Will Drive You Insane

Sometimes we need more psy ops in our life. Being an eminent fan of the Discworld series, Reddit user [rdmiller3] decided he needed to build Lord Vetinari’s clock. This fictional clock was placed in the waiting room for Lord Vetinari in several of the Discworld books. Although the clock keeps accurate time overall, it sometimes tics irregularly and out of sync. The reason? To whittle away the minds of whoever waits for Lord Vetinari.

The build uses a standard battery-powered analog clockwork. The ticking mechanism is just a magnet mounted inside a coil driven iron core. The coil leads were disconnected from the clock circuit and connected to digital inputs of an Arduino. With a few random() calls, the clock keeps accurate but random time.

Unfortunately, the clock stopped working after a few weeks because the 5 V from the Arduino was, “pounding it way too hard.” [rdmiller3] says a few resistors and LEDs for the voltage drop would make for a more reliable circuit, though. Check out the hard to watch video of the clock in action after the break.


via buildlounge

47 thoughts on “Vetinari Clock Will Drive You Insane

    1. i 2nd everything you said. my only wish is that it had a shift bell for the hours…only the bell would be inconsistent also like the ticking (hammer hit times would be off or sometimes muted at random).

    1. Agreed there should be a smoother transition or less jitter. Like tick (1 second) tick (1.2 second) tick (1.8 second) tick (1.5 second) tick (1.1 second) tick (0.8 second) etc

    1. You can see it snap back one second near the begging of the video if you watch closely, whether this was intended or not, I’m not sure… but he did talk about doing that in his article.

  1. I’m reminded of the clock (was it here I saw it?) that runs fast for half an hour, then slow for the remaining half.

    Each hour is accurate, but it would allow someone to take a longer break than usual, unless someone else was paying attention to the time on another clock.

  2. Damn this is awesome!
    Got to order me a arduino tomorrow and start learning.
    Would be nice if it was just slightly off, to make people wondering if they’re just imagining it.

    Great idea! Nice job

  3. To completely destroy the mind of those waiting: make the ticking and the motion of the second hand out of sync and random.
    And keep the ticking just as loud as to be unavoidable in a room.

      1. Or place a second clock behind the first one somehow, maybe one with smaller hands, as to be easier to hide, so that you can hear a ticking, in between the ticking, even though it’s only actually ticking once on the first clock… lol.

        Anybody realized… that some people just have too much time on their hands???

  4. If I were going to build something like this (’cause it’s a pretty cool idea!), I’d use a Poisson random variable generator to generate the minute-hand movements. Poissons are positive, tick regularly on average, but are random otherwise (think radioactive decay, which follows a Poisson distribution). They’re not terribly hard to implement, either.

    1. I remember discussing the idea with friends a few years ago (although never with a plan to actually implement!), and we thought of using a Brownian bridge, in order to make each of the ticks identically distributed, yet still add up to a minute at a time (and with no particularly obvious correlation effects).

      Sadly, normally distributed variables can go negative, so a naive implementation won’t work. Never really got beyond that.

      Poisson, as a distribution, although nicely positive, doesn’t feel /quite/ right to me – number of events per unit time is its common significance, whereas what you really want is kind of like ‘time per event’ – more like an exponential process.

      If I had to have a go at it now, I’d probably try a log-normal distribution, with a bit of moment matching (tweaking sets of samples to make the average come out right) to avoid drift. Of course, I’ll never do it, but I do enjoy hypothesising in comments. =D

      1. With the Brownian thing, or indeed to use any distribution that is equally spaced on negative / positive, can’t you just knock the sign off, then divide by 2? Seems right to me. I’m not great with statistics or whatever branch of maths this is, but I’m a programmer, and it seems like what I’d do.

  5. Nice. Strange I have see clocks do this unmodified. I don’t know if it was me or the clock was crazy. The think I think this clock should do (what I saw) is to act normally a bit more and do strange hiccups once every while. That way when someone sees this then rubs their eyes it goes back to normal like nothing ever happened.

    1. ME TOO.

      I have often turned to look at my clock or watch and was sure the second hand had been sitting still for at least 2 seconds.

      Either it then compensates, or I’m crazy, because it never seems to lose time…

      1. The clocks in my high school would tick backwards before they went forwards. They’d sit there for a moment before they went to the correct position so that if you heard the tic and glanced at the clock you’d say “oh my god it feels like I’ve been in this class for an hour but it’s only been 15 minutes.” It was absolutely maddening.

        1. Only, in the case of clocks of this type, there’s a valid reason for it, because the movement is underdamped. Each second, when the second hand moves, it overshoots then rebounds back to the right position. I’ve seen some that overshoot by over half a second. So if you glance up at the clock at just the right moment, it looks like it just moved backward.

  6. Wouldn’t it be much funnier just having two clocks? One would drive the hour and minute, so tey’re on time. The other one would connected to the arduino. That way, we could make the clock slow down the seconds… Slower… Slower… Tick backwards… Then stop.

    And, after a while…

    Run again. Normally. Nothing hapened, are you accusing me?

    1. A clock I have to deal with already does what this clock is intended to do. It isn’t maddening, just bothersome. The gearing is worn and I cannot fix it.

      Your idea, well your idea would seem like a clock running down on batteries but has wonderful potential. If it started getting louder as it slowed at the same time the piped in music got quieter I would flip out as soon as it stopped. Once it got going again and everything instantly went to normal I would question whether to tell anyone.

  7. Here in germany, clocks at the trainstations stop and wait for two seconds on the 12 handle. You look at the second finger how it smoothly moves but then completely stops for two seconds!

    Actually, you need to be a bit one of us nerds and greeks to actually care, most I asked did not even notice.

    Well, I ckecked the time and it was actually running 1/59th of a second each other second.

    Up untill some days later where I found a guy who explained it to me: It is a older habbit of a socalled ‘Schleppsekunde’ that should hilight a certain time even from distance, back the days when the traindrivers were actually leaving on time. (todday we got GPS, digital clocks and everything and the Deutsche Bahn juts comes late regularly xD)

  8. A long-case / grandfather version of this would be awesome too – alter the speed of the pendulum on the fly somehow (electromagnet at the bottom perhaps?).

    Now if only someone could make a bell like “Old Tom” that rings out silences instead of chiming……

    1. There are battery-powered quartz clock movement modules which come with a pendulum. I’m pretty sure that the pendulum is just a moving decoration, so this idea might work.

  9. I’m waiting for someone to build a clock that runs on “Microsoft Time” where the time mostly runs forwards, but will stop for five minutes and then jump backwards three hours.

    You know, like the time estimations on WIndows file copies do.

    1. That is also true for iTunes and Apple Updates, only more like “mostly forward, stops at the 1 minute part, spends the next five minutes gradually saying that it takes 2 days in hours, then jumps ahead to what it will actually take, then does it”. Because that would be, though crazy and impossible, awesome.

  10. @Piku You owe me a new keyboard :-P

    That would be funny, just degauss the little magnetic sheet inside that you flip over to reverse the movement, then wind a second coil next to the first and apply DC bias current to set direction as the required current would likely burn out the existing coil.

    A lot of the time one of the wire ends comes loose, if you have a magnified its possible to repair this.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.