A clock made with LED filaments inside clear plastic tubes

LED Filaments Make A Retro Clock Without Any Retro Parts

April 5, 2022 by Robin Kearey 9 Comments

We love clock projects here at Hackaday, and we’ve seen many beautiful designs based on a wide variety of display technologies. There are various types of glass tubes like Nixies, Numitrons and classic VFD displays, all of which have that warm “retro” glow to them. Then there’s LEDs, which are useful for making cool pixel-based timepieces and easy to drive with low-voltage electronics. So how about combining the best of both worlds, by using LEDs to make a Numitron-like display? That’s exactly what [Jay Hamlin] did when he built a digital clock based on LED filaments.

The heart of the project consists of orange LED filaments similar to the ones used in vintage-style LED light bulbs. [Jay] bought a bunch of them online and tried various ways of combining them into seven-segment displays, eventually settling on a small PCB with a black finish to give good contrast between the LEDs and the background. To make the displays look like they’re encased in glass, [Jay] bought a set of plastic test tubes and cut them to size.

The base of the clock is formed by a slick black PCB that holds an ESP32. The segments are driven through a set of 74LV595 shift registers to keep the required number of GPIOs to a minimum. There are no buttons: thanks to a WiFi connection and the Network Time Protocol the ESP32 automatically keeps the correct time.

The end result looks remarkably like a Numitron display at first glance, and remains a beautifully-made clock even if you notice that there’s no glass to be found. If you’re into LED filament clocks (and who isn’t?), check out this analog wall clock, or this spiderweb-like digital clock.

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Cool Mechanism Day: Two-Way To One-Way

March 14, 2022 by Dave Rowntree 8 Comments

The internal mechanisms that are used in timepieces have always been fascinating to watch, and are often works of art in their own right. You don’t have to live in the Watch Valley in Switzerland to appreciate this art form. The mechanism highlighted here (from Mechanistic on YouTube) is a two-way to one-way geared coupler (video, embedded below) which can be found at the drive spring winding end of a typical mechanical wristwatch. It is often attached to a heavily eccentrically mounted mass which drives the input gear in either direction, depending upon the motion of the wearer. Just a little regular movement is all that is needed to keep the spring nicely wound, so no forgetting to wind it in the morning hustle!

The idea is beautifully simple; A small sized input gear is driven by the mass, or winder, which drives a larger gear, the centre of which has a one-way clutch, which transmits the torque onwards to the output gear. The input side of the clutch also drives an identical unit, which picks up rotations in the opposite direct, and also drives the same larger output gear. So simple, and watching this super-sized device in operation really gives you an appreciation of how elegant such mechanisms are. Could it be useful in other applications? How about converting wind power to mechanically pump water in remote locations? Let us know your thoughts in the comments down below!

If you want to play with this yourselves, the source is downloadable from cults3d. Do check out some of the author’s other work!

We do like these super-sized mechanism demonstrators around here, like this 3D printed tourbillon, and here’s a little thing about the escapement mechanism that enables all this timekeeping with any accuracy.

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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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Daft Punk Word Clock Goes Stronger And Faster

March 8, 2022 by Matthew Carlson 12 Comments

What would you call a word clock that doesn’t tell time? The concept of a word clock is that all the words needed to be used are already there and then just selected. [Ben Combee] realized there were only 18 unique words to make up the song “Harder Faster Better Stronger” and with an extra PyBadge from Supercon 2021 on hand, it seems obvious to make a musical word clock of sorts.

The PyBadge is a 120 MHz ATSAMD51 based board with a screen, buttons, and a case that he 3d printed. To get reasonable sound quality while still fitting with the 2MB of flash storage on the device, MP3 compression was chosen. Since there was only one speaker, it was mixed down to mono and a lower bitrate, getting the size down to just 880KB. The mp3 is processed by the audiomp3 module in circuitpython with the volume level being sent to five NeoPixels to act as a VU. Getting the timing correct was the hardest part as the lyrics needed to be separated out and the timing figured out. Using Audacity’s label track feature, he had all the words tagged in the track and could export it into a format that could be massaged into a python friendly format.

The music and the text cues becoming desynchronized became a larger issue as the file plays. Increasing the MP3 buffer helped but the real trick was to peek inside the music decoder and figure out how many samples had been decoded and cue the words based on that, rather than the time since it wasn’t as accurate. All the code and files are up on his Hackaday.io page if you feel the need to make your own. If you’re sticking with Daft Punk, make sure to have your helmet ready when you rock. Though based on this summary of the compressibility of pop songs, there are a few other songs with a small enough number of unique words that they too could get the word clock treatment. Video after the break.

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Sprockets And Chains Drive This Unique Mechanical Digital Clock

March 1, 2022 by Dan Maloney 17 Comments

When it comes to mechanical timepieces, we’re used to seeing mechanisms stuffed with tiny gears and wheel, often of marvelous complexity and precision. What we’re perhaps less used to seeing is a clock that uses chains and sprockets, and that looks more like what you’d find on a bicycle on your typical bicycle.

We can’t recall seeing anything quite like [SPE]’s “Time Machine” before. It’s one of those builds that explains itself by watching it work, so check out the video below and you’ll see where this one is going. The clock has three loops of roller link chain, each of which has a series of numbers welded to the links. The loops of chain are advanced around sprockets by a trio of geared-down motors, with the numbers standing up straight at the top of each loop. A microcontroller keeps track of the time and starts the clock advancing every minute, but a series of microswitches that are activated by the passing chain do all the rest of the control — sounds like a perfect time to say, “Could have used a 555,” but we still think it’s great the way it is.

Surprisingly, [SPE]’s clock seems like it wouldn’t be that hard to live with. Many unique electromechanical clocks that we feature, like a clock that’s nothing but hands or The Time Twister, are a little on the noisy side. While “Time Machine” isn’t exactly silent, its whirring isn’t terrible, and even though its clicks are a little loud, they’ve got a satisfying mechanical sound to them.

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Unique Clock Is All Hands, No Dial, And Does The Worm

February 17, 2022 by Dan Maloney 12 Comments

Back in the old days, we didn’t have fancy digital clocks. No, we had good analog clocks with a big hand and a little hand, and if you wanted to know the time you had to look at the clock and figure out which number each hand was pointing at, or kind of pointing at. It wasn’t easy, and we liked it that way.

So now, along comes an analog clock that’s nothing but the hands — no dial, no numbers, just hands. How is such a thing possible? The clue is in the clock’s name: AKUROBATTO, and in the video below, which shows the acrobatic movements of the clock’s hands as it does its thing. Serial improbable-clock maker [ekaggrat singh kalsi] clearly put a lot of thought into this mechanism, which consists of the hands and a separate base. The hands are joined together at one end and powered by small stepper motors. The base has two docking areas, where servo-driven claws can grasp the hand assembly, either at the center pivot or at the tip of either hand. With a little bit of shuffling around at transition points, the hands sweep out the hours and minutes in a surprisingly readable way.

For as cool as the design of AKUROBATTO is, the internals are really something else. There are custom-built slip rings to send power to the motors and the Arduinos controlling them, sensors to determine the position of each hand, and custom gearboxes for the steppers. And the locking mechanisms on the base are worth studying too — getting that right couldn’t have been easy.

All in all, an impressive build. Whether displaying the time on a phosphorescent screen or a field of sequins, it seems like [ekaggrat] has a thing for unique clocks. Continue reading “Unique Clock Is All Hands, No Dial, And Does The Worm” →

Accurately Track Your Mains Frequency

February 15, 2022 by Jenny List 27 Comments

Depending upon where in the world you live, AC mains frequency is either 50Hz or 60Hz, and that frequency is maintained accurately enough over time that it can be used as a time reference for a clock. Oddly it’s rarely exactly that figure though, instead it varies slightly with load on the network and the operators will adjust it to keep a constant frequency over a longer period. These small variations in frequency can easily be measured, and [jp3141] has created a circuit that does exactly that.

It’s a surprisingly straightforward device, in which a Teensy takes its power supply from a very conventional if now a little old-school mains transformer, rectifier, and regulator. A sample of the AC from the transformer passes through a low-pass filer and a clamp, and thence to the Teensy where it is fed into one of the on-board comparators from which its period is measured using one of the timers. Even then the on-board crystal isn’t considered accurate enough, so it is in turn disciplined by a 1 pulse per second (PPS) signal from a GPS receiver.

The Teensy then reports its readings over a serial line every five seconds to a Raspberry Pi, which collates and graphs the data. In case you are wondering what the effect of mains frequency variations might be, we once covered the story of how an entire continent lost six minutes.