Mechanical 7-Segment Display Uses A Single Motor

June 27, 2021 by Danie Conradie 29 Comments

Seven-segment displays have been around for a long time, and there is a seemingly endless number of ways to build them. The latest of is a mechanical seven-segment from a master of 3D printed mechanisms, [gzumwalt], and can use a single motor to cycle through all ten possible numbers.

The trick lies in a synchronized pair of rotating discs, one for the top four segments and another for the bottom three segments. Each disc has a series of concentric cam slots to drive followers that flip the red segments in and out of view. The display can cycle through all ten states in a single rotation of the discs, so the cam paths are divided in 36° increments. [gzumwalt] has shown us a completed physical version, but judging by CAD design and working prototype of a single segment, we are pretty confident it will. While it’s not shown in the design, we suspect it will be driven by a stepper motors and synchronized with a belt or intermediate gear.

Another 3D printed mechanical display we’ve seen recently is a DIY flip dot, array, which uses the same electromagnet system as the commercial versions. [gzumwalt] has a gift for designing fascinating mechanical automatons around a single motor, including an edge avoiding robot and a magnetic fridge crawler.

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Mechanical Seven-Segment Display, Smaller And Better Than The Original

February 4, 2021 by Dan Maloney 19 Comments

One thing we love here at Hackaday is when we get to track the evolution of a project over time. Seeing a project grow over time is pretty typical — scope creep is real, after all. But watching a project shrink can be a real treat too, as early versions get refined into sleeker and more elegant solutions.

This slimmed-down mechanical seven-segment display is a perfect example of that downsizing trend. When we saw [IndoorGeek]’s first vision of an electromechanical display, it was pretty chunky. Then as now, each segment is a 3D-printed piece with a magnet attached to the rear. The segments hover over solenoid coils, which when energized repel the magnet and protrude the segment, forming the desired digit. The old version used large, hand-wound coils, though, making the display pretty bulky front to back.

Version 2 of the display takes a page from [Carl Bugeja]’s playbook and replaces the wound coils with PCB coils. We’ve seen [Carl]’s coils on both rigid substrates and flex PCBs; [IndoorGeek] used plain old FR4 here. The coils occupy four layers so they have enough oomph to extend and retract each segment, and the PCB includes space for H-bridge drivers for each segment. The PCB forms the rear cover for the display, which is also considerably slimmed down for this version. What’s the same, though, is how good this display looks, especially with strong side-lighting — the shadows cast by the extended segments are striking against the plain white face of the display.

Congratulations to [IndoorGeek] on a great-looking build and a useful improvement over the original.

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Simple 3D Printed Seven-Segment Displays

February 2, 2021 by Zoe Skyforest 7 Comments

7-segment LED displays were revolutionary, finally providing a clear, readable and low-power numerical display solution. We’ve got plenty of other cheap display options now, but sometimes you just need the old nought-through-nine, and in a big, visible package, to boot. For those circumstances, consider whipping up a set of these 3D-printed seven-segment displays.

The build consists of a 3D printed frame, with each segment containing two WS2812B addressable LEDs. Each 7-segment assembly is then wired so they can be daisy chained, passing on data to the next digit in the chain. Paper is used to diffuse the LEDs for a smoother look, and a white 3D printed cover is printed for each digit to further spread the light and give a clean finish.

Being based on the WS2812Bs, it’s easy to drive such displays with just about any microcontroller or GPIO-equipped Linux board out there. We love big, beautiful displays – and the more artistic, the better. Video after the break.

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Big Workshop Clock Is 3D Printing Done Right

November 1, 2020 by Zoe Skyforest 7 Comments

Time is something uniquely important to humans, and they remain the only creatures on the planet to build devices to regularly track its progress. [Ivan Miranda] is one such creature, and built a giant 7-segment clock for his workshop that really ties the room together.

The clock is a testament to [Ivan]’s design skills in the 3D printed space. Taking advantage of his large format printer, each segment consists of a front panel, large single-piece diffuser, LED carrier, and backing plate. There are plenty of nice touches, from the interlocking ridges between each digit, to integral printed arrows on the inside that guide installation of the LED strips. Fit and finish approaches the level of a commercial product, a reward for [Ivan]’s years of practice in the field.

Electronically, an ESP8266 runs the show, synchronizing the time over its in-built WiFi connection. Each segment contains 9 WS2812B LEDs, wired up in a single long strip that’s addressed by the microcontroller. This means that the segments can be lit up to any color of the rainbow, though [Ivan] is a man who best appreciates the look of classic red.

[Ivan]’s long been a proponent of big 3D-printed builds — his tank-tracked electric skateboard is a particularly good example. Video after the break.

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Palm-Sized Sixteen Segments Light The Way To Our Hearts

August 20, 2020 by Kerry Scharfglass 20 Comments

It’s no secret that we here at the Hackaday are suckers for cool display. LEDs, OLEDs, incandescent, nixie or neon, you name it and we want to see it flash. So it fills us with joy to discover a new way to build large, daisy-chainable 16-segment digits, and even more excited to learn how easy they are to fab and assemble.

A cousin of the familiar 7 segment display, the 16 segment gives so many more possibilities (128% more possibilities to be exact) for digit display. To be specific, those extra segments unlock the ability to display upper and lowercase latin characters as well as scads of punctuation.

But where the character set is complex, the assembly is anything but thanks to a great design from [Kolibri] called klais-16. They’re available fully assembled if you want to jump straight to code, but thanks to thorough documentation (seriously, check this out) assembly is a snap.

Each module is composed a very boring PCBA base layer which should be inexpensive from the usual sources, even when ordering one fully assembled. A stackup of three more PCBs are used for spacing and diffusion with plans for die-cut or injection mold layers if a larger production run ends up happening. Board dimensions for each character are 100 mm x 66.66 mm (about 4″ x 2.5″). Put together, each module can stand on its own or be easily daisy-chained together to make a longer single display.

Addressing all those bits with an elaborate, ugly control scheme would be a drag but fortunately the firmware for the onboard STM8 microcontroller exposes a nice boring serial interface which can be used without configuration to display strings. There’s even an example Windows Batch script!

Mechanical Seven-Segment Display Really Sticks Out From The Pack

July 27, 2020 by Dan Maloney 20 Comments

We’ve been displaying numbers using segmented displays for almost 120 years now, an invention that predates the LEDs that usually power the ubiquitous devices by a half-dozen decades or so. But LEDs are far from the only way to run a seven-segment display — check out this mechanical seven-segment display for proof of that.

We’ve been seeing a lot of mechanical seven-segment displays lately, and when we first spotted [indoorgeek]’s build, we thought it would be a variation on the common “flip-dot” mechanism. But this one is different; to form each numeral, the necessary segments protrude from the face of the display slightly. Everything is 3D-printed from white filament, yielding a clean look when the retracted but casting a sharp shadow when extended. Each segment carries a small magnet on the back which snuggles up against the steel core of a custom-wound electromagnet, which repels the magnet when energized and extends the segment. We thought for sure it would be loud, but the video below shows that it’s really quiet.

While we like the subtle contrast of the display, it might not be enough for some users, especially where side-lighting is impractical. In that case, they might want to look at this earlier similar display and try contrasting colors on the sides of each segment.

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Ultra-Cheap Microcontroller Powers Addressable 7-segment Display

May 16, 2020 by Jenny List 35 Comments

Since their being revealed to our community over a year ago, the various ultra-cheap microcontrollers in the sub-ten-cent price range have attracted a lot of interest but not so many projects. Their slightly annoying programming and PIC12-derived architectures present a barrier not mitigated by their price, when picking up an Atmel or other processor represents a much easier choice. That’s not to say that they aren’t slowly making an appearance though, and a cracking example comes from [Tim], who’s used a Padauk microcontroller to make an addressable 7-segment display. If you’re used to addressable multi-colour LEDs, this extends the idea into the world of numerical information.

The result is a PCB little bigger than the 7-segment display it serves, with interlocking 0.1″ pin connectors allowing daisy-chaining of modules. The extreme low cost of the parts makes it an attractive solution. Software wise it’s driven in a similar manner to addressable LEDs, and he goes into significant detail on its protocol. The firmware can be found in a GitHub repository. He directs readers to the Easy PDK programmer and the Small Device C compiler, which should be of interest to anyone tempted by these processors.