A Holographic Seven-Segment Clock

November 30, 2025 by No comments

Seven-segment displays are one of the most ho-hum ways to display the time. They were cool for a little bit in the 70s, but by now, they’re a little bit old hat. That is, unless you get weird with it. This holographic seven-segment clock from [mosivers] qualifies neatly in that category.

The first step was to make the holographic segment displays, because they’re not really something you can just buy off the shelf. [mosivers] achieved this by using a kit from LitiHolo, which enables you to create holograms by shooting a laser at special holographic film. Only, a few upgrades were made to use the kit with a nicer red diode laser that [mosivers] had on hand for better performance. The seven-segment layouts were carefully recorded on to the film to form the basic numerals of the clock, such that illuminating the films from different angles would light different segments of the numeral. It’s quite involved, but it’s explained well in the build video.

As for the timekeeping side of things, an ESP32 was used, setup to query a network time server to stay accurate. The microcontroller then commands a series of LEDs to light up as needed to illuminate the relevant segments of the holographic film to show the time.

Ultimately, [mosivers] built a cool clock with a look you won’t find anywhere else. It’s a lot more work than just wiring up some classic seven-segment LEDs, but we think the result is worth it. If you fancy other weird seven-segment builds, though, we’ve got plenty of others in the till.

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Has Steampunk Delivered The Hoverboard?

November 29, 2025 by 1 Comment

The hoverboard, one of the teen crazes of the last decade, is both a marvel of technology and a source of hacker parts that have appeared in so many projects on these pages. It contains an accelerometer or similar, along with a microcontroller and a pair of motor controllers to drive its in-wheel motors. That recipe is open to interpretation of course and we’ve seen a few in our time, but perhaps not quite like this steampunk design from [Skrubis]. It claims a hoverboard design with no modern electronics, only relays, mercury switches, and neon bulbs.

The idea is that it’s a hoverboard from 1884 using parts available in that era, hence there’s talk of telegraph relays and galvanomic piles. The write-up is presented in steampunk-style language which if we’re honest makes our brain hurt, but the premise is intriguing enough to persevere. As far as we can see it uses a pair of relays and a transformer to make an oscillator, from which can be derived the drive for a 3-phase motor. This drive is sent to the motors by further relays operating under the influence of mercury tilt switches.

There are a full set of hardware designs once you wade past the language, but as yet it has no evidence of a prototype. We admit we kinda want it to work because the idea is preposterous enough to be cool if it ran, but we’d be lying if we said we didn’t harbor some doubts. Perhaps you our readers can deliver a verdict, after all presenting you with entertainment is what it’s all about. If a working prototype surfaces we’ll definitely be featuring it, after all it would be cool as heck.

Oddly this isn’t the first non-computerized balance transport we’ve seen.

Header: Simakovarik, CC BY-SA 4.0.

DIY Light Panels Work With Home Assistant

November 29, 2025 by 1 Comment

There are a few major companies out there building colorful LED panels you can stick on your wall for aesthetic purposes. Most commercial options are pretty expensive, and come with certain limitations in how they can be controlled. [Smart Solutions For Home] has whipped up a flexible DIY design for decorating your walls with light that is altogether more customizable.

In this case, the DIY light panels ape the hexagonal design made popular by brands like Nanoleaf. In this case, each hexagon panel runs an ESP32 microcontroller, which controls a series of WS2812 addressable LEDs. This allows each panel to glow whatever color you like, and they’re arranged in an XY grid to enable you to light individual panels with a range of different geometric effects. The benefit of having a full microcontroller on each panel is that they can act quite independently—each one able to be used as a smart light, an notification display, or even as a physical button, all integrated with Home Assistant.

If you’re a fan of DIY smart home products, these might be right up your alley. They’re supremely flexible and customizable, and can do a lot of things that commercial versions can’t easily replicate. Just don’t ignore the fact that they require a considerable amount of assembly, what with the custom PCBs, 3D printed enclosures, and front diffusers to deal with. That’s just the way the LED wall crumbles.

We’ve seen other similar builds before, too. Why? The simple fact is that a lot of people want cool glowy panels on their wall without having to pay through the nose for them.

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On The Benefits Of Filling 3D Prints With Spray Foam

November 29, 2025 by 14 Comments

Closed-cell self-expanding foam (spray foam) is an amazing material that sees common use in construction. But one application that we hadn’t heard of before was using it to fill the internal voids of 3D printed objects. As argued by [Alex] in a half-baked-research YouTube video, this foam could be very helpful with making sure that printed boats keep floating and water stays out of sensitive electronic bits.

It’s pretty common knowledge by now that 3D printed objects from FDM printers aren’t really watertight. Due to the way that these printers work, there’s plenty of opportunity for small gaps and voids between layers to permit moisture to seep through. This is where the use of this self-expanding foam comes into play, as it’s guaranteed to be watertight. In addition, [Alex] also tests how this affects the strength of the print and using its insulating properties.

The test prints are designed with the requisite port through which the spray foam is injected as well as pressure relief holes. After a 24 hour curing period the excess foam is trimmed. Early testing showed that in order for the foam to cure well inside the part, it needed to be first flushed with water to provide the moisture necessary for the chemical reaction. It’s also essential to have sufficient pressure relief holes, especially for the larger parts, as the expanding foam can cause structural failure.

As for the results, in terms of waterproofing there was some water absorption, likely in the PETG part. But after 28 hours of submerging none of the sample cubes filled up with water. The samples did not get any stronger tensile-wise, but the compression test showed a 25 – 70% increase in resistance to buckling, which is quite significant.

Finally, after tossing some ice cubes into a plain FDM printed box and one filled with foam, it took less than six hours for the ice to melt, compared to the spray foam insulated box which took just under eight hours.

This seems to suggest that adding some of this self-expanding foam to your 3D printed part makes a lot of sense if you want to keep water out, add more compressive strength, or would like to add thermal insulation beyond what FDM infill patterns can provide.

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A Flexible Light Inspired By IKEA

November 29, 2025 by 8 Comments

The IKEA SMÅSNÖRE is a flexible silicone rod with an embedded LED strip, attached at each end to a base. It’s eye-catching enough, and it has the useful property of providing a diffuse light from multiple angles that makes it a promising candidate for a work lamp. That’s enough for [Daniel James] to create his own lamp on a similar vein.

The electronics of his lamp are straightforward enough: a 12 volt LED strip whose brightness is controlled by a Pi Pico in response to a potentiometer as a brightness control. It’s not quite stiff enough to form the arch itself, so he’s created a 3D printed chain that forms the structure of the lamp. Similar to a bicycle chain in the way it’s constructed, it has individual links that slot together and pivot. The electronics are in the printed base at one end.

We like this lamp a lot, for the light it gives on the bench and for the ingenuity of the printed chain. We might even make one for ourselves.

Building A Simple Ribbon Synth

November 29, 2025 by 1 Comment

The usual input device for playing a synthesizer is the good old piano keyboard. However, you don’t have to stick to such pedestrian interfaces when making music. [Daisy] has a fun build that shows us how to put together a ribbon synth that makes wonderful little noises.

Naturally, the heart of the build is a ribbon potentiometer (also known as soft pots). It’s essentially a touch sensitive strip that changes in resistance depending on where you touch it. You can slide your finger up and down to vary the output continuously; in musical contexts, they can behave rather like a fretless instrument. [Daisy] employs one of these potentiometers in such a role by hooking it up to a Daisy Seed microcontroller board, which reads it with an analog-to-digital converter (ADC). The resistance values are used to vary the pitch of a dual-saw synthesizer programmed in the plugdata framework.

We’ve featured some other great ribbon synths over the years, too, like this tribute to the Eowave Persephone. They’re not the ideal choice for those that prefer their notes on pitch, but they’re beautifully fun to play with when you’re getting a little more experimental.

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Hacky Thanksgiving

November 29, 2025 by 8 Comments

It’s that time of year when we eat perhaps a little too much food, and have maybe just a few too many sips of red wine. But it’s also when we think about what we’ve been grateful for over the past year. And here at Hackaday, that’s you all: the people out there making the crazy projects that we get the pleasure of writing about, and those of you just reading along. After all, we’re just the hackers in the middle. You are all Hackaday.

And it’s also the time of year, at least in this hemisphere, when the days get far too short for their own good and the weather gets frankly less than pleasant. That means more time indoors, and if we play our cards right, more time in the lab. Supercon is over and Hackaday Europe is still far enough in the future. Time for a good project along with all of the festive duties.

So here we sit, while the weather outside is frightful, wishing you all a pleasant start to the holiday season. May your parts bin overflow and your projects-to-do-list never empty!

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