clock hacks

906 Articles

Oscillator Needs Fine-Tuning

November 3, 2024 by 23 Comments

Since their invention more than a century ago, crystal oscillators have been foundational to electronic design. They allow for precise timekeeping for the clocks in computers as well as on our wrists, and can do it extremely accurately and inexpensively to boot. They aren’t without their downsides though; a quartz watch might lose or gain a few seconds a month due to variations in temperature and other non-ideal environmental situations, but for working in the world of high-frequency circuits this error is unacceptable. For that you might reach for something like an oven oscillator, a circuit with a temperature controlled chamber able to keep incredibly precise time.

[IMSAI Guy] found this 10 MHz oven oscillator on a site selling bulk electronics at bargain basement prices. But as is unsurprising for anyone who’s used a site like this to get cheap circuits, it didn’t quite hit its advertised frequency of 10.000000 MHz. The circuit design is capable of this amount of accuracy and precision, though, thanks to some cleverly-designed voltage dividers and filtering. One of those voltage dividers allows a potentiometer to control a very narrow range of output frequencies, and from the factory it was outputting between 9.999981 and 9.9999996 MHz. To get it to actually output a 10 MHz wave with eight significant digits of accuracy, a pull-up resistor on the voltage divider needed to be swapped out.

While this was a fairly simple fix, one might wonder how an off-the-shelf component like this would miss the mark in such an obvious way but still go into production. But that’s one of life’s great mysteries and also the fun of sourcing components like this. In this case, the oven oscillator was less than $10. But these circuits aren’t always as good of a deal as they seem.

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Geochron world time clock

Geochron: Another Time, Another Timeless Tale

October 26, 2024 by 10 Comments

The Geochron World Time Indicator is a clock that doubles as a live map of where the sun is shining on the Earth. Back in its day, it was a cult piece that some have dubbed the “Rolex on the wall.” Wired’s recent coverage of the clock reminded us of just how cool it is on the inside. And to dig in, we like [Attoparsec]’s restoration project on his own mid-1980s Geochron, lovingly fixing up a clock he picked up online.

[Attoparsec]’s recent restoration shares insights into the clock’s fascinating mechanics. Using a synchronous motor, transparent slides, and a lighted platen, the Geochron works like a glorified slide projector, displaying the analemma—a figure-eight pattern that tracks the sun’s position over the year.

But if you’re looking for a digital version, way back in 2011 we showcased [Justin]’s LED hack of FlorinC’s “Wise Clock”, which ingeniously emulated the Geochron’s day-night pattern using RGB LEDs, swapping out the faceplate for a world map printed on vellum. That’s probably a much more reasonable way to go these days. Why haven’t we seen more remakes of these?

The 1983 Clock Four Decades In The Making

October 21, 2024 by 13 Comments

In 1983, a 14-year-old [Will] saw an LED clock in The Sharper Image store. At $250, it stayed in the store. That was a lot of money back then, especially for most teenagers. But [Will] didn’t forget. After high school, he and a friend planned to build one from scratch. They worked out how they would do it and did a little prototyping, but never really finished. Well, they never really finished at the time. Because 33 years later, [Will] decided to finally put it together. Check it out in the video below.

[Will’s] learned a lot since his original design, plus we have tech today that would have seemed like magic in the late 1980s. But he wanted to stay true to the original design, so there’s no microcontroller or smart LEDs. Just binary counters and a lot of LEDs. There’s even a 555 doing duty as a reset timer.

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A Flip Digit Clock, Binary Style

October 8, 2024 by 7 Comments

Flip digit clocks are a prized piece of consumer electrical ephemera, providing as they do a digital display without significant electronics. Making your own flip digit display involves some drudgery in the production of all those flip cards, but how would it seem if the complexity was reduced? Go from base 10 to base 2 for example, and a binary flip digit display can be made from flip dot display parts. [Marcin Saj] has done just that, resulting in a timepiece that’s a few bits out of the ordinary.

Under the hood though it’s slightly more conventional, with the trusty ATmega328 and Arduino bootloader, whose software drives the dot electromagnets via a set of MOSFET drivers. It’s a nice project which if you want there’s a Kickstarter to buy one, but the files are also available from a GitHub repository if you’d like to have a go for yourself. Meanwhile you can see it in action in the video below the break.

We like this clock, as it’s different from the norm in Arduino clocks. It’s not however the first flip dot clock we’ve seen, this one has a full dot matrix display.

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Seven Day Movement Makes A Rubbish Clock

September 29, 2024 by 10 Comments

We see a lot of clocks here at Hackaday. Some of them are better than others, but this one from [John Graham-Cumming] is definitely a rubbish clock. It performs the simple yet vital task of keeping track of which day is which when it comes to trash collection.

The big revelation for us from this project is that the standard plastic battery clock mechanism which you’ll  no doubt be familiar with from many cheap clocks can also be bought with gearing for a weekly rather than daily revolution. The physical hack is therefore a pretty simple one of mounting the movement with a single hand over a face showing the waste collections, and the write-up goes into more depth about the code for creating custom SVG clock faces. We’re already thinking of interesting stuff that can be done with one of these movements.

Meanwhile, we like this clock, but it’s certainly not the first trash indicator we’ve seen.

Recreating A Popular Faux-Nixie Clock

September 13, 2024 by 15 Comments

There’s a good chance you’ve seen “Nixie clocks” on the Internet that replace the classic cold cathode tubes with similarly sized LCD panels. The hook is that the LCDs can show pictures and animations of Nixie tubes — or pretty much anything else for that matter — to recreate the look of the real thing, while being far cheaper and easier to produce. It’s a hack for sure, and that’s the way we like it.

[Trung Tran] liked the idea, but didn’t just want to buy a turn-key clock. So he’s decided to build his own version based on the ESP32-S3. The WiFi-enabled microcontroller syncs up to the latest time via NTP, then uses a PCF8563 real-time clock (RTC) module to keep from drifting too far off the mark. The six displays, which plug into the custom PCB backplane, can then show the appropriate digits for the time. Since they’re showing image files, you can use any sort of font or style you wish. Or you could show something else entirely — the demo video below shows off each panel running the Matrix “digital rain” effect.

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Globe-Shaped World Clock Is A 3D-Printed Mechanical Marvel

August 12, 2024 by 5 Comments

Time zones are a complicated but necessary evil. Humans like the numbers on the clock to vaguely match up with what the sun is doing in the sky outside. To that end, different places in the world keep different time. If you want to keep track of them in a very pretty fashion, you might consider building a fancy and beautiful World Clock like [Karikuri] did. 

The design is based around a globe motif, mimicking the world itself. Only, on the surface of the globe, there are clock faces instead of individual countries. Each clock runs to its own time, directed by a complicated assemblage of 3D-printed gears. Mechanical drive is sent to the globe from a power base, which itself carries a mechanical seven-segment display. This too can display the time for different regions by using the controls below. It’s also useful for setting the clock to the correct time.

It’s a little difficult to follow the build if you don’t speak Japanese. However, quality subtitles are available in English if you choose to enable them.

We’ve seen [Karikuri’s] work before. We’ve also featured a great many world clocks over the years, including this particularly beautiful example that tracks night and day. Just don’t expect it to keep track of moon time. Video after the break.

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