Spiral Connector Makes Fastener-Free Assemblies

June 20, 2025 by Donald Papp 11 Comments

[Anton Gaia]’s SPIRAL sculpture resembles an organizer or modern shelving unit, but what’s really interesting is how it goes together. It’s made entirely from assembling copies of a single component (two, if you count the short ‘end pieces’ as separate) without a fastener in sight. [Anton] made the 3D model available, so check it out for yourself!

The self-similar design of the joint, based on the golden spiral, makes a self-supporting joint that requires neither glue nor fasteners.

The ends of each part form a tight, spiral-shaped joint when assembled with its neighbors. Parts connect solely to themselves without any need of fasteners or adhesives.

The end result is secure, scalable, and with a harmonious structure that is very pleasing to look at. Small wonder [Anton] used it as the basis for artistic work. You can see more pictures here.

The design of the joint is based on the golden spiral (which it turns out is also a pretty useful chicken coop architecture.)

The parts lend themselves quite well to 3D printing, and we’d like to take a moment to appreciate that [Anton] shared the .step file instead of just an STL. STEP (or STP) files can be imported meaningfully into CAD programs, making it much easier to incorporate the design into one’s own work. STEP is also supported natively in many 3D printer slicers, so there’s no need to convert formats just to print them.

A brief video describing SPIRAL is embedded just below, with a closer look at how the pieces fit together.

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Dual RGB Cameras Get Depth Sensing Powerup

June 19, 2025 by Donald Papp 17 Comments

It’s sometimes useful for a system to not just have a flat 2D camera view of things, but to have an understanding of the depth of a scene. Dual RGB cameras can be used to sense depth by contrasting the two slightly different views, in much the same way that our own eyes work. It’s considered an economical but limited method of depth sensing, or at least it was before FoundationStereo came along and blew previous results out of the water. That link has a load of interactive comparisons to play with and see for yourself, so check it out.

A box of disordered tools at close range is understood very well, and these results are typical for the system.

The FoundationStereo paper explains how researchers leveraged machine learning to create a system that can not only outperform existing dual RGB camera setups, but even active depth-sensing cameras such as the Intel RealSense.

FoundationStereo is specifically designed for strong zero-shot performance, meaning it delivers useful general results with no additional training needed to handle any particular scene or environment. The framework and models are available from the project’s GitHub repository.

While products like Microsoft’s Kinect have struggled to keep the consumer’s attention, depth sensing remains an enabling technology that opens possibilities and gives rise to interesting projects, like a headset that allows one to see the world through the eyes of a depth sensor.

The ability to easily and quickly gain an understanding of the physical layout of a space is a powerful tool, and if a system like this one can deliver such fantastic results with nothing more than two RGB cameras, that’s a great sign. Watch it in action in the video below.

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Flopped Humane “AI Pin” Gets An Experimental SDK

June 19, 2025 by Donald Papp 11 Comments

The Humane AI Pin was ambitious, expensive, and failed to captivate people between its launch and shutdown shortly after. While the units do contain some interesting elements like the embedded projector, it’s all locked down tight, and the cloud services that tie it all together no longer exist. The devices technically still work, they just can’t do much of anything.

The Humane AI Pin had some bold ideas, like an embedded projector. (Image credit: Humane)

Since then, developers like [Adam Gastineau] have been hard at work turning the device into an experimental development platform: PenumbraOS, which provides a means to allow “untrusted” applications to perform privileged operations.

As announced earlier this month on social media, the experimental SDK lets developers treat the pin as a mostly normal Android device, with the addition of a modular, user-facing assistant app called MABL. [Adam] stresses that this is all highly experimental and has a way to go before it is useful in a user-facing sort of way, but there is absolutely a workable architecture.

When the Humane AI Pin launched, it aimed to compete with smartphones but failed to impress much of anyone. As a result, things folded in record time. Humane’s founders took jobs at HP and buyers were left with expensive paperweights due to the highly restrictive design.

Thankfully, a load of reverse engineering has laid the path to getting some new life out of these ambitious devices. The project could sure use help from anyone willing to pitch in, so if that’s up your alley be sure to join the project; you’ll be in good company.

Tune In To “Higher Lower”, The Minimal Handheld Electronic Game

June 4, 2025 by Donald Papp 8 Comments

[Tommy] has a great write-up about designing and building a minimalistic handheld electronic game called “Higher Lower”. It’s an audio-driven game in which the unit plays two tones and asks the player to choose whether the second tone was higher in pitch, or lower. The game relies on 3D printed components and minimal electronics, limiting player input to two buttons and output to whatever a speaker stuck to an output pin from an ATtiny85 can generate.

Fastener-free enclosure means fewer parts, and on the inside are pots for volume and difficulty. We love the thoughtful little tabs that hold the rocker switch in place during assembly.

Gameplay may be straightforward, but working with so little raises a number of design challenges. How does one best communicate game state (and things like scoring) with audio tones only? What’s the optimal way to generate a random seed when the best source of meaningful, zero-extra-components entropy (timing of player input) happens after the game has already started? What’s the most efficient way to turn a clear glue stick into a bunch of identical little light pipes? [Tommy] goes into great detail for each of these, and more.

In addition to the hardware and enclosure design, [Tommy] has tried new things on the software end of things. He found that using tools intended to develop for the Arduboy DIY handheld console along with a hardware emulator made for a very tight feedback loop during development. Being able to work on the software side without actually needing the hardware and chip programmer at hand was also flexible and convenient.

We’ve seen [Tommy]’s work before about his synth kits, and as usual his observations and shared insights about bringing an idea from concept to kit-worthy product are absolutely worth a read.

You can find all the design files on the GitHub repository, but Higher Lower is also available as a reasonably-priced kit with great documentation suitable for anyone with an interest. Watch it in action in the video below.

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Add Wood Grain Texture To 3D Prints – With A Model Of A Log

June 3, 2025 by Donald Papp 34 Comments

Adding textures is a great way to experiment with giving 3D prints a different look, and [PandaN] shows off a method of adding a wood grain effect in a way that’s easy to play around with. It involves using a 3D model of a log (complete with concentric tree rings) as a print modifier. The good news is that [PandaN] has already done the work of creating one, as well as showing how to use it.

The model of the stump — complete with concentric tree rings — acts as a modifier for the much-smaller printed object (in this case, a small plate).

In the slicer software one simply uses the log as a modifier for an object to be printed. When a 3D model is used as a modifier in this way, it means different print settings get applied everywhere the object to be printed and the modifier intersect one another.

In the case of this project, the modifier shifts the angle of the fill pattern wherever the models intersect. A fuzzy skin modifier is used as well, and the result is enough to give a wood grain appearance to the printed object. When printed with a wood filament (which is PLA mixed with wood particles), the result looks especially good.

We’ve seen a few different ways to add textures to 3D prints, including using Blender to modify model surfaces. Textures can enhance the look of a model, and are also a good way to hide layer lines.

In addition to the 3D models, [PandaN] provides a ready-to-go project for Bambu slicer with all the necessary settings already configured, so experimenting can be as simple as swapping the object to be printed with a new 3D model. Want to see that in action? Here’s a separate video demonstrating exactly that step-by-step, embedded below.

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This BB Shooter Has A Spring, But Not For What You Think

June 2, 2025 by Donald Papp 24 Comments

[It’s on my MIND] designed a clever BB blaster featuring a four-bar linkage that prints in a single piece and requires no additional hardware. The interesting part is how it turns a trigger pull into launching a 6 mm plastic BB. There is a spring, but it only acts as a trigger return and plays no part in launching the projectile. So how does it work?

There’s a spring in this BB launcher, but it’s not used like you might expect.

The usual way something like this functions is with the trigger pulling back a striker of some kind, and putting it under tension in the process (usually with the help of a spring) then releasing it. As the striker flies forward, it smacks into a BB and launches it. We’ve seen print-in-place shooters that work this way, but that is not what is happening here.

With [It’s on my MIND]’s BB launcher, the trigger is a four-bar linkage that transforms a rearward pull of the trigger into a forward push of the striker against a BB that is gravity fed from a hopper. The tension comes from the BB’s forward motion being arrested by a physical detent as the striker pushes from behind. Once that tension passes a threshold, the BB pops past the detent and goes flying. Thanks to the mechanical advantage of the four-bar linkage, the trigger finger doesn’t need to do much work. The spring? It’s just there to reset the trigger by pushing it forward again after firing.

It’s a clever design that doesn’t require any additional hardware, and even prints in a single piece. Watch it in action in the video, embedded just below.

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A Simple Tip For Gluing Those LED Filaments

May 29, 2025 by Donald Papp 6 Comments

[Boylei] shows that those little LED filament strips make great freeze-frame blaster shots in a space battle diorama. That’s neat and all, but what we really want to highlight is a simple tip [Boylei] shares about working with these filament strips: how to glue them.

Glue doesn’t stick to LED filament strips, so put on a small piece of heat-shrink and glue to *that* instead.

The silicone (or silicone-like) coating on these LED filament strips means glue simply doesn’t stick. To work around this, [Boylei] puts a piece of clear heat shrink around the filament, and glues to that instead. If you want a visual, you can see him demonstrate at 6:11. It’s a simple and effective tip that’s certainly worth keeping in mind, especially since filament strips invite so many project ideas.

When LED filament strips first hit the hobbyist market they were attractive, but required high operating voltages. Nowadays they are not only cheaper, but work at battery-level voltages and come in a variety of colors.

These filaments have only gotten easier to work with over the years. Just remember to be gentle about bending them, and as [Boylei] demonstrates, a little piece of clear shrink tubing is all it takes to provide a versatile glue anchor. So if you had a project idea involving them that didn’t quite work out in the past, maybe it’s time to give it another go?

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