An electromechanical clock based on sliding frames

Watch Time Slide By With This Electromechanical Clock

February 27, 2023 by Robin Kearey 13 Comments

Back in the 18th century, clockmakers were held in high esteem, as turning pieces of metal and wire into working timepieces must have seemed like magic at the time. The advent of mass production made their profession largely obsolete, but today there are several hardware hackers whom you could consider modern heirs of the craft. [Hans Andersson] is one of them, and has made a name for himself with an impressive portfolio of electromechanical clocks. His latest work, called the Time Slider, is every bit as captivating as his previous work.

The mechanical display is almost entirely made of 3D printed components. Four flat pieces of red PLA form a basic 88:88 indicator, onto which the correct time is displayed by sliding frames that black out certain pixels. Those frames are moved up and down by a rack-and-pinion system driven by stepper motors. Evertyhing is controlled by an Arduino Mega, acoompanied by a DS3231 RTC and eight ULN2003-based stepper motor drivers.

[Hans] wrote a detailed assembly guide to go along with the STL files and Arduino code, so it should be easy make your own Time Slider if you have a decent supply of PLA filament. The display takes about ten seconds to update, but the process has certain hypnotic quality to it, helped by the mechanical whirring of the stepper motors in the background. Especially the hourly change of three or four digits at once is mesmerizing, as you can see in the video embedded below.

Time Slider is the latest in [Hans]’s long line of mechanical clocks, which includes the Time Twister series that evolved from a clever Lego-based design to a neat 3D-printed model. The rack-and-pinion system can also be used to make a compact linear clock.

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An electromechanical wall clock on a workbench, showing "8888"

Silent Stepper Motors Make Electromechanical Clock Fit For A Living Room

March 10, 2022 by Robin Kearey 13 Comments

Large mechanical seven-segment displays have a certain presence that you just don’t get in electronic screens. Part of this comes from the rather satisfying click-click-clack sound they make at every transition. Unfortunately, such a noise quickly becomes annoying in your living room; [David McDaid] therefore designed a silent electromechanical seven-segment clock that has all the presence of a mechanical display without the accompanying sound.

As [David] describes in a very comprehensive blog post, the key to this silent operation is to use stepper motors instead of servos, and to drive them using a TMC2208 stepper motor driver. This chip has a unique method of regulating the current that does not introduce mechanical vibrations inside the motor. A drawback compared to servos is the number of control wires required: with four wires going to each motor, cable management becomes a bit of an issue when you try to assemble four seven-segment displays.

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An Astronomical Mechanical Clock, In More Ways Than One

January 2, 2022 by Dan Maloney 29 Comments

If the workings of a mechanical timepiece give you a thrill, prepare to be blown away by this over-the-top astronomical clock.

The horological masterpiece, which was designed by [Mark Frank] as his “dream clock”, is a riot of brass, bronze, and steel — 1,200 pounds (544 kg) of it, in fact, at least in the raw materials pile. Work on the timepiece began in 2006, with a full-scale mockup executed in wood by Buchannan of Chelmsford, the Australian fabricator that [Mark] commissioned to make his design a reality. We have a hard time explaining the design, which has just about every horological trick incorporated into it.

[Mark] describes the clock as “a four train, quarter striking movement with the fourth train driving the astronomical systems,” which sounds far simpler than the finished product is. It includes 52 “complications,” including a 400-year perpetual calendar, tide clock, solar and lunar eclipse prediction, a planisphere to show the constellations, and even a thermometer. And, as if those weren’t enough, the clock sports both a tellurion to keep track of the Sun-Earth-Moon system and a full orrery out to the orbit of Saturn, including all the major moons. The video below shows the only recently finished masterpiece in operation.

[Mark]’s dream clock has been under construction for the better part of two decades, and we applaud not just his design but his patience. The skeletonized construction reminds us of the Clickspring clock from a few years back; now seems like a great time to go back and binge-watch that whole series again.

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Mechanical Clocks That Never Need Winding

February 25, 2018 by Elliot Williams 32 Comments

What is it about mechanical clocks? Maybe it’s the gears, or the soft tick-tocking that they make? Or maybe it’s the pursuit of implausible mechanical perfection. Combine mechanical clocks with “free” energy harvested from daily temperature and pressure variation, and we’re hooked.

Both the Beverly Clock, built by Arthur Beverly in 1864, and the Atmos series of clocks built between 1929 and 1939, run exclusively on the expansion and contraction of a volume of air (Beverly) or ethyl chloride (Atmos) over the day to wind up the clock via a ratchet. The Beverly Clock was apparently a one-off, and it’s still running today. And with over 500,000 Atmos clocks produced, there must be some out there.

Although we had never heard of it, this basic idea is really old. Clicking through Wikipedia (like you do!) got us to Cox’s Timepiece, which is powered by the movement of 68 kg of mecury under atmospheric pressure. It is currently not running, but housed in the Victoria and Albert Museum in London. Even older is a clock that we couldn’t find any info on that dates from 1620, invented by Cornelius Drebbel. Anyone know anything?

We’ve had energy harvesting on our mind lately, and the article on the Beverly Clock says that it gets 31 μWh over a day when the temperature swings by 3.3 °C. Put into microcontroller perspective, this is 0.39 μA at 3.3 V, so you’ll have to be pretty careful about your sleep modes, and an LED is out of the question. How amazing is it, then, that this can power a mechanical clock?

Thanks [Luke], [hex4def6], and [Wallace Owen] for tipping us off to these in the comment section!

Mechanical Clock Designed For A CNC Router Gets New Life Using A 3D Printer

June 10, 2014 by James Hobson 4 Comments

[Madis Kaasik] designed a clock a while back using Solid Edge (3D CAD) — but never got a chance to build it — until he became an exchange student at a university in Norway with access to a big industrial 3D printer!

He had originally intended for it to be cut out using a CNC router or with a laser cutter, but when discovered he could use the university’s 3D printer he decided to give it a shot — it’s actually the very first thing he’s ever printed! The designs had to be modified a little bit for 3D printing, but now that it’s done he’s also uploaded them to Thingiverse for anyone to use.

It took quite a bit of fine tuning with the pendulum, weights, and gears to get it ticking properly, but what [Madis] enjoyed most about this project was the realization of just how vast the possibilities of 3D printing are — he’s excited to begin his next big 3D printing endeavor!

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Mechanical Clock Relies On Marbles To Tick

May 28, 2014 by James Hobson 24 Comments

As fun as micro-controllers and RTCs are, sometimes it’s truly fascinating to see a completely mechanical clock. Using only gravity this Pendulum Marble Clock (German version) by [Turnvater Janosch] runs for 12 hours at a time and has an accuracy error of less than one second per day!

It works by raising a 2.5kg weight which sinks approximately 1 meter during that 12 hours. A series of steel ball bearings count the minutes, 5 minute increments, and hours. Every minute one ball is released on the track — when the track fills up, trap doors open releasing the balls to the next level. The first level is minutes, the second, 5 minutes, and the third, hours.

The entire thing is made out of wood, plastic gears, brass and steel wire, and an old flat iron (although we’re really not too sure what that’s used for…)

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Designing And Building A Wooden Mechanical Clock

March 19, 2013 by Jeremy Cook 16 Comments

Electronics are undoubtedly the basis for our modern society. Leaving out transistor-based devices, and a mechanical clock would be one of the most intricate devices man has come up with. As a Mechanical Engineer, I thought it would be a fun challenge to design and build my own gear-driven clock.

Because clocks have obviously been invented, I wouldn’t be starting from scratch, and I don’t think I could have figured out an escapement on my own. I explain my initial clock escapement and gear reduction design thoughts in this post, and originally getting the escapement to work was my biggest fear.

As seen in the first video after the break, the escapement gear is still a big problem, but not really for the reason I expected. The shaft that the gear sits on seems to be bent, so it allows the escapement to “go free” for part of it’s cycle, losing any sense of accurate timekeeping. Be sure to also check out the second video, especially around 1:50 when I show what happens when an escapement gear goes much faster than a normal clock. Continue reading “Designing And Building A Wooden Mechanical Clock” →