If you visit the Copenhagen City Hall, you’ll see an ornate mechanical clock. By itself, this is unremarkable, of course. There are plenty of ornate clocks in city halls around the world, but this one has a fascinating backstory that starts with a locksmith named Jan Jens Olsen. Unfortunately, Jens didn’t actually complete the clock before his death. It would take 12 years to put together the 15,448 individual parts. However, he did manage to see most of the clock that he had been designing for 50 years put together.
Jens was 60 when he started constructing the clock, but the story starts when he was only 25. In Strasbourg, the young locksmith saw an astronomical clock with a perpetual calendar in a cathedral. He was fascinated and returned several times to study the mechanism. Around the age of 30, Jens had moved to watchmaking and had a keen interest in astronomy — he was a founding member of the Danish Astronomical Society. Perhaps it was the combination of these two interests that made it inevitable that he would want to build a precise astronomically-correct clock.
Have you ever observed the project of another hacker and thought to yourself “I have got to have one of those!”? If so, you’re in good company with hacker [garberPark], the maker of the unusual chain clock seen in the video below the break.
While on a stroll past the Chicago Avenue Fire Arts Center in Minneapolis, MN, [garberPark] was transfixed by the clock seen to the right here. In the clock, two motors each drive a chain that has numbers attached to it, and the number at the top displays the current time. It wasn’t long before [garberPark] observed his own lack of such a clock. So they did what any hacker will do: they made their own version!
Using an ESP8266, and Arduino, and some other basic electronics, they put together a horizontal interpretation of the clock they saw. Rather than being continuous rotation, limit switches keep things in line while the ESP8266’s NTP keep things in time. Salvaged scanner stepper motors provide locomotion, and what appear to be bicycle cranks and chains work in harmony with cutoff license plates to display the current time- but only if there’s somebody around to observe it; A very nice touch and great attention to detail!
Pendulum clocks aren’t used quite as often these days as their cumbersome mechanics and timekeeping abilities have long been outshone by electronic alternatives. However, they’re still fun and they do work, so [PuzzLEGO] set about building a working example with Lego.
The core of the clock is the escapement, a linkage which the pendulum can only turn in one direction. As the pendulum swings once per second, it lets the escapement gear turn one notch forward at a time, turning the gears of the clock which drive the hands. It’s powered with a falling weight in the form of a drink bottle full of water, which turns the gears of the clock via a chain.
The clock can only run for approximately an hour, so it’s set up with a second and minute hand instead of the more usual minute and hour hand. However, with the pendulum tuned to the appropriate length and the weight fitted, it pleasantly ticks and tocks the seconds away.
[Keenan Rebera] recently found himself with an old racing clock (a chronoix cc3000) left behind by a roommate. How the roommate obtained such a clock seems murky at best, but undeterred [Keenan] set to work bringing the clock to life with Bluetooth functionality. The mechanical nature of the digits provided a satisfying auditory click, making it a good candidate for some upgrading. The new brain transplant is the venerable ESP32 with an RTC for good measure. He created a custom PCB with QWIC connectors to daisy chain together the driver boards together. Each PCB has four TBD62083 for driving the digits, two MCP expanders to increase the address space. This allows the ESP32 to address all the various segments over I2C. By soldering different pads together, he can change the address of each MCP, giving a maximum of 16 digits (9 possible MCP’s each driving 2 digits).
[wyojustin] was trying to think of projects he could do that would take advantage of some of the fabrication tech that’s become available to the average hobbyist. Even though he doesn’t have any particular interest in clocks, [wyojustin] discovered that he could learn a lot about the tools he has access to by building a clock.
[wyojustin] first made a clock based off of a design by [Brian Wagner] that we featured a while back. The clock uses an idler wheel to move the hour ring so it doesn’t need a separate hour hand. After he built his first design, [wyojustin] realized he could add a planetary gear that could move an hour hand as well. After a bit of trial and error with gear ratios, he landed on a design that worked.
The clock’s movement is a stepper motor that’s driven by an Arduino. Although [wyojustin] isn’t too happy with the appearance of his electronics, the drive setup seems to work pretty well. Check out [wyojustin]’s site to see the other clock builds he’s done (including a version with a second hand), and you can peruse all of his design files on GitHub.
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…)
Many have tried, but [Christoph Laimer] has succeeded in designing a working, (relatively) accurate clock nearly completely from 3D printed parts. Every gear, pulley, wheel and hand of [Christoph’s] clock is printed. Only a few screws, axles, a weight, and a string are non-printed. Even the crank to wind the clock is a 3D printed part.
[Christoph] designed his clock in Blender. It took quite a bit of design work to create parts that would work and be printable. Even more work was involved in printing over 100 failed prototype parts.
One might think that [Christoph] is using the latest printers from the likes of Makerbot or Utimaker to achieve this feat. It turns out he’s using a discontinued Rapman 3.2 printer. Further proof that even “older” printers are capable of great things! [Christoph] does run his printer rather slowly. Printing a single gear with 0.125 mm layers and a 0.4 mm nozzle takes him 2 or 3 hours.
Mechanically, the clock is gravity powered with an anchor escapement. Rather than a pendulum, [Christoph] chose to use a balance wheel and hairspringassembly to govern the escapement. Even the spring is printed from standard PLA. The weight is suspended from a pulley block. The clock isn’t particularly efficient. 70cm of height will run the clock for only 2 hours.
[Christoph’s] clock has proven to be accurate to within 1/4 second per hour. He hasn’t provided temperature stability data – but being PLA, we’d suggest not getting it too hot!