A display based on magnetic viewing film

Moving Magnet Draws Stylish Shapes On Flexible Film

March 8, 2023 by Robin Kearey 2 Comments

[Moritz v. Sivers] has a knack for making his own displays, which are typically based on some obscure physical effect. Magnetic viewing films, those thin plastic sheets that change color in response to a magnetic field, are his latest area of interest, as you can see in his Magnetic Kinetic Art Display.

The overall idea of the display is similar to a kinetic sand art table, in which a ball traces out shapes in a pile of sand. In [Moritz]’s project, the magnetic viewing film is the sand, and a 2 mm diameter magnet is the ball. The magnet is moved along the film by two sets of coils embedded inside a flex PCB mounted just below the film. One set of coils, on the top layer of the PCB, moves the magnet in the x direction, while a second set on the bottom layer moves it in the y direction.

A flex PCB with coils on both sides — The flex PCB is small, but carries lots of windings

[Moritz] used a flex PCB not because it had to be bendy, but to keep the two sets of coils as close together in the z direction as possible. This helps to avoid a big difference in strength between the two directions. To drive the coils, he used a pair of TB6612FNG stepper motor drivers, controlled by a Wemos D1 Mini.

The housing was 3D printed mostly from PLA, but with a few bits done in PETG. This was for structural rigidity as well as thermal performance — the coils can carry up to two amps and get pretty warm as a result.

The video, embedded below, shows some of the shapes that can be drawn: squares, spirals and even digits to turn the display into a clock. [Moritz] got the PCB coil idea from a project by [bobricius], and cleverly extended it into a useful product. It’s not the first time [Moritz] used magnetic viewing film to make a clock, either.

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Displaying The Time Is Elemental With This Periodic Table Clock

March 7, 2023 by Dan Maloney 8 Comments

We see a lot of clocks here at Hackaday, so many now that it’s hard to surprise us. After all, there are only so many ways to divide the day into intervals, as well as a finite supply of geeky and quirky ways to display the results, right?

That’s why this periodic table clock really caught our eye. [gocivici]’s idea is a simple one: light up three different elements with three different colors for hours, minutes, and seconds, and read off the time using the atomic number of the elements. So, if it’s 13:03:23, that would light up aluminum in blue, lithium in green, and vanadium in red. The periodic table was designed in Adobe Illustrator and UV printed on a sheet of translucent plastic by an advertising company that specializes in such things, but we’d imagine other methods could be used. The display is backed by light guides and a baseplate to hold the WS2812D addressable LEDs, and a DS1307 RTC module gives the Arduino Nano a sense of time. The 3D printed frame of the clock has buttons for setting the time and controlling the clock; the brief video below shows it going through its paces.

We really like the attention to detail [gocivici] showed here; that UV printing really gave some great results. And what’s not to like about the geekiness of this clock? Sure, it may not be as action-packed as a game of periodic table Battleship, but it would make a great conversation starter.

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PCB Makes 7 Segment Displays

March 3, 2023 by Al Williams 9 Comments

Of course, there’s nothing unusual about using 7-segment displays, especially in a clock. However, [Edison Science Corner] didn’t buy displays. Instead, he fabricated them from a PCB using 0805 LEDs for the segments. You can see the resulting clock project in the video below.

While the idea is good, we might have been tempted to use a pair of LEDs for each segment or used a diffuser to blur the LEDs. The bare look is nice, but it can make reading some numerals slightly confusing.

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The Curved Nature Of Time Clock

March 3, 2023 by Al Williams No comments

While we’re told that space-time curves, we aren’t sure that was what [andrei.erdei] was going for when he built a great-looking curved LED clock. The LEDs are courtesy of a strip of 84 WS2812 smart LEDs, the curve comes from a 3D printed part, and a Wemos D1 mini provides the brains.

Like all of our favorite clocks, this one has a unique way of displaying the time. If you find the description in the post hard to understand, the video below makes it a bit easier to wrap your head around. Note the time appears in the top left corner of the video in several cases — so you can check to see if you’re reading it correctly.

The secret sauce, of course, is the curved plastic grid that holds the LEDs. Because of the unusual shape, supports are a must and there are notes in the post about the settings used to get the best results. With 84 LEDs, the software has to be careful not to turn them to full brightness at one time, or else the clock would need a 6 amp power supply. Instead, the software limits the brightness to a little less than half of the maximum. No LED is ever white, and not all LEDs are on at once. The clock works easily, according to [andrei], with a 2 A supply. The clock has a WiFi connection where you can set things up easily.

Overall, a nice-looking project that would look at home on a science fiction movie set. We’ve seen color clocks before. If you want to economize on LEDs, we’ve seen a clock with only five!

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Morse Code Clock For Training Hams

March 1, 2023 by Bryan Cockfield 13 Comments

It might seem antiquated, but Morse code still has a number of advantages compared to other modes of communication, especially over radio waves. It’s low bandwidth compared to voice or even text, and can be discerned against background noise even at extremely low signal strengths. Not every regulatory agency requires amateur operators to learn Morse any more, but for those that do it can be a challenge, so [Cristiano Monteiro] built this clock to help get some practice.

The project is based around his favorite microcontroller, the PIC16F1827, and uses a DS1307 to keep track of time. A single RGB LED at the top of the project enclosure flashes the codes for hours in blue and minutes in red at the beginning of every minute, and in between flashes green for each second.

Another design goal of this build was to have it operate with as little power as possible, so with a TP4056 control board, single lithium 18650 battery, and some code optimization, [Cristiano] believes he can get around 60 days of operation between charges.

For a project to help an aspiring radio operator learn Morse, a simple build like this can go a long way. For anyone else looking to build something similar we’d note that the DS1307 has a tendency to drift fairly quickly, and something like a DS3231 or even this similar Morse code clock which uses NTP would go a long way to keeping more accurate time.

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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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A clock with an e-paper display in a 3D-printed case

Low Power Challenge: E-Paper Shelf Label Becomes Ultra-Frugal Clock

February 24, 2023 by Robin Kearey 12 Comments

Over the past two decades, e-paper has evolved from an exotic and expensive display technology to something cheap enough to be used for supermarket price tags. While such electronic shelf labels are now easy to find, actually re-using them is often tricky due to a lack of documentation. Luckily, [Aaron Christophel] has managed to reverse engineer many types of shelf labels, and he’s demonstrated the results by turning one into an ultra-low-power clock called Triink. It’s based on a 128×296 pixel e-ink display paired with an nRF52832 BlueTooth Low-Energy SoC and uses just 65 micro-amperes on average: low enough to keep it running for more than a year on a single battery charge.

A PCB for an e-ink clock — Power on the left, e-ink on the right: the custom PCB is clever and compact, too

The clock is housed in an enclosure that’s simple but effective: a 3D-printed triangular prism with a slot for the screen and space for the 18650 lithium battery. One side can be opened to access the internal components, although that’s really only needed to charge the battery. You can see how cleverly everything snaps together in the video embedded below. Continue reading “Low Power Challenge: E-Paper Shelf Label Becomes Ultra-Frugal Clock” →