Something’s Rotating In The State Of Denmark: A Clock

January 4, 2023 by Al Williams 15 Comments

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.

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Motion-Activated Clock Only Lights Up On Command

December 16, 2022 by Lewin Day 8 Comments

While some of us can fall asleep anywhere from a noisy auditorium to a brightly lit train station, others are more fussy, requiring quiet and dark to nod off. [Craig Lindley] likes to minimize light when he’s trying to sleep, and decided to build himself a simple clock that wouldn’t disturb his rest.

The basic concept was to build a clock that would only display the time on command. In this case, that command would be a wave of a hand in front of the clock. The build is based around a Lilygo ESP32 T-Display unit, which combines the ESP32 with an LCD display and a battery management system. The ESP32’s WiFi connection provides accurate time via querying an NTP server. A passive infrared motion sensor is used to detect the motion of the user’s hand in front of the clock.

While all kinds of clocks and clock radios are available out there, few are motion activated. [Craig]’s work is a great demonstration of building your own solutions to your problems. We’ve seen some other neat motion-sensing convenience hacks before, too!

Magnet Clock Makes Field Lines Visible

December 14, 2022 by Robin Kearey 1 Comment

The traditional method for visualizing magnetic fields, which your science teacher probably demonstrated at some point, is to sprinkle some iron filings onto a piece of paper and hold it over a magnet. It’s a bit of a messy process though, and nowadays there’s a more modern method available in the form of magnetic viewing films. These work thanks to tiny nickel particles suspended in an oily medium, and come in very handy if you want to examine, say, the magnetic field pattern of a DC electric motor. [Moritz v. Sivers] had another idea for this magic material however, and used it to make a Magnet Viewing Clock.

The clock’s front panel looks very similar to a large monochrome LCD, but is actually a big slab of magnetic viewing film. Four disks are mounted behind it, each carrying number-shaped magnetic stickers that are cleverly hidden from view. An Arduino Uno keeps track of time through a real-time clock and operates four stepper motors that rotate the number wheels. When they move into position, their magnetic stickers become visible through the film and you can read the time.

The clock’s mechanical parts are 3D printed, while the digits were cut from a sheet of sticky magnetic foil using a vinyl cutter. If you’d like to try making something similar you’re in luck: [Moritz] made the design files and the Arduino sketch available on his GitHub page. Magnetic viewing films are pretty neat things to play with anyway, and can even be used to read hidden messages.

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HUD-Like Clock Is A Transparent Time Display

December 14, 2022 by Lewin Day 13 Comments

While we have all types of displays these days, there’s something special about those that appear to float in the air. This HUD clock from [Kiwi Bushwalker] is one such example.

The build relies on four 8×8 LED matrixes to display the four digits that make up the time, run by the MAX7219 driver chip. However, the LEDs aren’t viewed directly — that would be too simple. Instead, the matrixes shoot their light up at an angle towards a tilted piece of clear acrylic. This creates a “heads-up display” look where the numbers appear to float in the air. The clock gets accurate time from an NTP time server over WiFi, thanks to the ESP32 microcontroller that runs the show.

It’s a straightforward clock build in many ways, but we particularly like the use of the heads-up display technique. It’s almost surprising we don’t see these projects more often, for things like car dashboard displays or targeting womp rats in a T-16 landspeeder. If you’ve been whipping up your own HUD projects, don’t hesitate to notify the tipsline!

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A dekatron-based clock with a GPS receiver and a plastic dinosaur on top

Dekatron Clock Tells The Time, Sans Semiconductors

December 5, 2022 by Robin Kearey 19 Comments

Over the years, there have been several memory and display technologies that served a particular niche for a while, only to be replaced and forgotten when a more suitable technology came along. One of those was the dekatron: a combination memory and display tube that saw some use in the 1950s and ’60s but became obsolete soon after. Their retro design and combined memory/display functionality make them excellent components for today’s clock hackers however, as [grobinson6000] demonstrates in his Dekaclock project.

A dekatron tube is basically a neon tube with ten cathodes arranged in a circle. Only one of them is illuminated at any time, and you can make the tube jump to the next cathode by applying pulses to its pins. The Dekaclock uses the 50 Hz mains frequency to generate 20 ms pulses in one tube; when it reaches 100 ms, it triggers the next tube that counts hundreds of ms, which triggers another one that counts seconds, and so on with minutes and hours.

The Dekaclock uses no semiconductors at all: the entire system is built from glass tubes and passive components. However, [grobinson6000] also built an auxiliary system, full of semiconductors, that makes the clock a bit easier to use. It sits on top of the Dekaclock and automatically sets the correct time using a GPS receiver. It also keeps track of the time displayed by the dekatrons, and tells you how far they have drifted from their initial setting.

Both systems are housed in sleek wooden cases that perfectly fit the tubes’ retro aesthetic. [grobinson6000] was inspired to make the Dekaclock after watching another dekatron clock we featured earlier, and designed the GPS receiver to work alongside it. Dekatrons are surprisingly versatile devices: you can use them to make anything from internet speed gauges to kitchen timers.

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A Timepiece Straight Out Of Back To The Future

December 2, 2022 by Lewin Day 20 Comments

[Stephen Holdaway] needed a desk clock, and decided to whip something up from scratch. The result is a beautiful tribute to the DeLorean’s time circuits from legendary 1985 film Back to the Future.

We say it’s a tribute rather than an exact replica, as it only implements the “present time” section of the time circuits. However, for those of us without time machines, that’s more than enough. In any case, the build is a very faithful recreation. It uses a lovely sheet metal enclosure complete with era-appropriate sticky labels.

Naturally, the numerals are all shown on green segment displays, though [Stephen] used 16-segment devices instead of the more typical 7-segment parts. What really helps add to the look is the shaded acrylic windows, which adds a very nice effect.

It’s a nice tribute piece that any fan would instantly recognize. We’ve seen some other great builds, too, like this replica of the RC controller that first gets the DeLorean up to 88 mph. If you’ve been whipping up your own neat prop project, don’t hesitate to hit us up on the tipsline!

Weasley Clock For Magically Low Cost

November 24, 2022 by Bryan Cockfield 12 Comments

For those unfamiliar with the details of the expansive work of fiction of Harry Potter, it did introduce a few ideas that have really stuck in the collective conscious. Besides containing one of the few instances of time travel done properly and introducing a fairly comprehensive magical physics system, the one thing specifically that seems to have had the most impact around here is the Weasley family clock, which shows the location of several of the characters. We’ve seen these built before in non-magical ways, but this latest build seeks to drop the price tag on one substantially.

To do this, the build relies on several low-cost cloud computing solutions and smartphone apps to solve the location-finding problem. The app is called OwnTracks and is an open-source location tracker which can report data to any of a number of services. [Simon] sends the MQTT data to a cloud-based solution called HiveMQCloud, but you could send it anywhere in principle. With the location tracking handled, he turns to some very low-cost Arduinos to control the stepper motors which point the clock hands to the correct locations on the face.

While the build does rely on a 3D printer for some of the internal workings of the clock, this does bring the cost down substantially when compared to other options. Especially when compared to this Weasley family clock which was built into a much larger piece of timekeeping equipment, having an option for a lower-cost location-tracking clock face like this one is certainly welcome.