Malfunctional Timekeeping With The Vetinari Clock

April 1, 2025 by Lewin Day 26 Comments

Lord Vetinari from the Discworld series is known for many things, but perhaps most of all a clock that doesn’t quite keep continuous time. Instead, it ticks away at random increments to infuriate those that perceive it, whilst keeping regular time over the long term. [iracigt] decided to whip up a real world version of this hilarious fictional timepiece.

The clock itself is an off-the-shelf timepiece purchased from Target for the princely sum of $5. However, it’s been deviously modified with an RP2040 microcontroller hidden away inside. The RP2040 is programmed to tick the clock at an average of once per second. But each tick itself is not so exact. Instead, there’s an erraticness to its beat – some ticks are longer, some shorter, in the classic Vetinari style. [iracigt] explains the nitty gritty of how it all works, from creating chaos with Markov chains to interfacing the RP2040 electronically with the cheap quartz clock movement.

If you’ve ever wanted to build one of these amusements yourself, [iracigt’s] writeup is a great place to start. Even better, it was inspired by an earlier post on these very pages! We love to see the community riff on a theme, and we’d love to see yours, too – so keep the tips coming, yeah? Video after the break.

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New Modelling Shows That Flat Protoplanets Might Be A Thing

February 20, 2024 by Maya Posch 23 Comments

Surface density of the benchmark run disc (in g cm−2). The disc becomes gravitationally unstable and fragments. Four of the fragments or protoplanets are followed until they reach density 10−3 g cm−3. (Credit: Fenton et al., 2024) — Surface density of the benchmark run disc (in g cm⁻²). The disc becomes gravitationally unstable and fragments. Four of the fragments or protoplanets are followed until they reach density 10⁻³ g cm⁻³. (Credit: Fenton et al., 2024)

While the very idea of a flat planet millions of years after its formation is patently ridiculous, recent modelling shows that during the protostar phase – where material from a nebula is drawn around a hydrostatic core into an accretion disc – it is likely that many of of the protoplanets which form inside a fragmentary protostar accretion disc take on a strongly oblate spheroid shape, rather than a spherical one. This according to [Adam Fenton] and [Dimitris Stamatellos], who ran half a million CPU hours worth of simulation time at the UK’s DiRAC HPC facility, per the University of Central Lancashire (UCLan) press release.

The research was published in the February 2024 issue of Astronomy & Astrophysics, titled The 3D structure of disc-instability protoplanets.

Where this research is essential is not just in our understanding of how our own solar system came to be – including our own oblate spheroid Earth – but also in interpreting what we observe via the Hubble Space Telescope, James Webb Space Telescope and others as we examine areas of the observable Universe such as the Orion Nebula, which is one of the regions with the most actively forming stars. By comparing these simulations with observations, we may find that the simulation matches perfectly, matches partially, or perhaps not at all, which provides data to refine the simulation, but also helps to reconsider how observations were previously interpreted.

Lord Vetinari’s Clock Strikes Again

February 12, 2013 by Mike Szczys 15 Comments

Inspired by the maddening timepiece from Discworld, this clock keeps time, but anyone watching the seconds tick by may be mentally unstable for it. [Renaud Schleck] built the stuttering clock using very few components. He undertook the build after being inspired by the version which [Simon Inns] built.

The clock itself is a run-of-the-mill item which uses one battery to keep time. We’re always impressed by how these dirt-cheap things remain so accurate over the long haul — but we digress. The method of attack uses coil injection to drive the hands. [Renaud] used one of the microcontrollers from the MSP430 Launchpad, along with the clock crystal which also shipped with the kit, to gain control of the mechanism. The crystal triggers an interrupt which does the actual time-keeping. The seconds hand is driven rather sporadically based on an algorithm explained in his write-up.

You can watch the uneven ticking in the video after the break. Despite that visually disturbing functionality, the short and long ticks balance each other and the correct time continues to be displayed.

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Building A Better Clock To Drive You Insane

October 12, 2011 by Brian Benchoff 24 Comments

[youtube=http://www.youtube.com/watch?v=YpqFU4SGe1Y&w=470]

[Simon] came up with an improved version of Lord Vetinari’s clock that begs to be installed in waiting rooms around the world.

Last week, we were introduced to a real-life Vetinari Clock that keeps regular time but ticks at irregular intervals. It’s a great way to turn someone’s mind into porridge, but the original build broke after a few weeks because of some limitations in the clock drive. [Simon] built a very minimal circuit does away with these problems.

Just as in the first build, a microcontroller pulses the second hand motor once every second. As for the random component of this build, the microcontroller has a puts 32 bytes into a 128 byte array. The array is checked 4 times a second, and if the byte is 1, the second hand is incremented. If the byte is 0, time stops for a little bit. [Simon] included the schematic, board layout and code if you’d like to build one yourself.

There are a few drawbacks to this design; the pattern of ticking and not ticking is hard-coded into the microcontroller. Even though the 32 second long pattern shouldn’t be noticeable by watching the clock, it’s not an entirely random solution. Judging from the comments on the original build, using radioactive decay to increment a second might be a bit uncalled for.

We would like to see a second hand that stops when you look at it though. Facial recognition, anyone?

Vetinari Clock Will Drive You Insane

October 6, 2011 by Brian Benchoff 47 Comments

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.

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