If You’re 3D Scanning, You’ll Want A Way To Work With Point Clouds

April 5, 2025 by Donald Papp 7 Comments

3D scanning is becoming much more accessible, which means it’s more likely that the average hacker will use it to solve problems — possibly odd ones. That being the case, a handy tool to have in one’s repertoire is a way to work with point clouds. We’ll explain why in a moment, but that’s where CloudCompare comes in (GitHub).

Not all point clouds are destined to be 3D models. A project may call for watching for changes in a surface, for example.

CloudCompare is an open source tool with which one can load up and do various operations on point clouds, including generating mesh models from them. Point clouds are what 3D scanners create when an object is scanned, and to become useful, those point clouds are usually post-processed into 3D models (specifically, meshes) like an .obj or .stl file.

We’ve gone into detail in the past about how 3D scanning works, what to expect from it, and taken a hands-on tour of what an all-in-one wireless scanner can do. But what do point clouds have to do with getting the most out of 3D scanning? Well, if one starts to push the boundaries of how and to what purposes 3D scanning can be applied, it sometimes makes more sense to work with point clouds directly instead of the generated meshes, and CloudCompare is an open-source tool for doing exactly that.

For example, one may wish to align and merge two or more different clouds, such as from two different (possibly incomplete) scans. Or, you might want to conduct a deviation analysis of how those different scans have changed. Alternately, if one is into designing wearable items, it can be invaluable to be able to align something to a 3D scan of a body part.

It’s a versatile tool with numerous tutorials, so if you find yourself into 3D scanning but yearning for more flexibility than you can get by working with the mesh models — or want an alternative to modeling-focused software like Blender — maybe it’s time to work with the point clouds directly.

Disney’s Bipedal, BDX-Series Droid Gets The DIY Treatment

April 5, 2025 by Donald Papp 4 Comments

[Antoine Pirrone] and [Grégoire Passault] are making a DIY miniature re-imagining of Disney’s BDX droid design, and while it’s still early, there is definitely a lot of progress to see. Known as the Open Duck Mini v2 and coming in at a little over 40 cm tall, the project is expected to have a total cost of around 400 USD.

The inner workings of Open Duck Mini use a Raspberry Pi Zero 2W, hobby servos, and an absolute-orientation IMU.

Bipedal robots are uncommon, and back in the day they were downright rare. One reason is that the state of controlled falling that makes up a walking gait isn’t exactly a plug-and-play feature.

Walking robots are much more common now, but gait control for legged robots is still a big design hurdle. This goes double for bipeds. That brings us to one of the interesting things about the Open Duck Mini v2: computer simulation of the design is playing a big role in bringing the project into reality.

It’s a work in progress but the repository collects all the design details and resources you could want, including CAD files, code, current bill of materials, and links to a Discord community. Hardware-wise, the main work is being done with very accessible parts: Raspberry Pi Zero 2W, fairly ordinary hobby servos, and an BNO055-based absolute orientation IMU.

So, how far along is the project? Open Duck Mini v2 is already waddling nicely and can remain impressively stable when shoved! (A “testing purposes” shove, anyway. Not a “kid being kinda mean to your robot” shove.)

Check out the videos to see it in action, and if you end up making your own, we want to hear about it, so remember to send us a tip!

3D Print (and Play!) The Super Mario Tune As A Fidget Toy

April 4, 2025 by Donald Papp 36 Comments

[kida] has a highly innovative set of 3D-printable, musical fidget toys that play classic video game tunes. Of course there’s the classic Super Mario ditty, but there’s loads more. How they work is pretty nifty, and makes great use of a 3D printer’s strengths.

To play the device one uses a finger to drag a tab (or striker) across the top, and as it does so it twangs vertical tines one-by-one. Each tine emits a particular note — defined by how tall the thicker part is — and plays a short tune as a result. Each one plays a preprogrammed melody, with the tempo and timing up to the user. Listen to them in action in the videos embedded just under the page break!

There are some really clever bits to the design. One is that the gadget is made in two halves, which effectively doubles the notes one can fit into the space. Another is that it’s designed so that holding it against something like a tabletop makes it louder because the surface acts like a sounding board. Finally, the design is easily modified so making new tunes is easy. [kida]’s original design has loads of non-videogame tunes (like the Jeopardy! waiting theme) as well as full instructions on making your very own versions.

Fidget toys are a niche all their own when it comes to 3D printed devices. The fidget knife has a satisfying snap action to it, and this printable linear toggle design is practically a fidget toy all on its own.

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DIY Linear Tubular Motor Does Precise Slides

March 31, 2025 by Donald Papp 25 Comments

We’ve seen plenty of motor projects, but [Jeremy]’s DIY Tubular Linear Motor is a really neat variety of stepper motor in a format we certainly don’t see every day. It started as a design experiment in making a DIY reduced noise, gearless actuator and you can see the result here.

Here’s how it works: the cylindrical section contains permanent magnets, and it slides back and forth through the center of a row of coils depending on how those coils are energized. In a way, it’s what one would get by unrolling a typical rotary stepper motor. The result is a gearless (and very quiet) linear actuator that controls like a stepper motor.

While a tubular linear motor is at its heart a pretty straightforward concept, [Jeremy] found very little information on how to actually go about making one from scratch. [Jeremy] acknowledges he’s no expert when it comes to motor design or assembly, but he didn’t let that stop him from iterating on the concept (which included figuring out optimal coil design and magnet spacing and orientation) until he was satisfied. We love to see this kind of learning process centered around exploring an idea.

We’ve seen DIY linear motors embedded in PCBs and even seen them pressed into service as model train tracks, but this is the first time we can recall seeing a tubular format.

Watch it in action in the short video embedded below, and dive into the project log that describes how it works for added detail.

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How To Make A 13 Mm Hole With A 1/2″ Drill Bit

March 29, 2025 by Donald Papp 75 Comments

As everyone knows, no matter how many drill bits one owns, one inevitably needs a size that isn’t on hand. Well, if you ever find yourself needing to drill a hole that’s precisely 13 mm, here’s a trick from [AvE] to keep in mind for doing it with a 1/2″ bit. It’s a hack that only works in certain circumstances, but hey, it just may come in handy some day.

So the first step in making a 13 mm hole is to drill a hole with a 1/2″ bit. That’s easy enough. Once that’s done, fold a few layers of tinfoil over into a small square and lay it over the hole. Then put the drill bit onto the foil, denting it into the hole (but not puncturing it) with the tip, and drill at a slow speed until the foil wraps itself around the bit like a sheath and works itself into the hole. The foil enlarges the drill bit slightly and — as long as the material being drilled cooperates — resizes the hole a tiny bit bigger in the process. The basic idea can work with just about any drill bit.

It’s much easier demonstrated than described, so watch it in action in the video around the 2:40 mark which will make it all very clear.

It’s not the most elegant nor the most accurate method (the hole in the video actually ends up closer to 13.4 mm) but it’s still something worth keeping in the mental toolbox. Just file it away along with laying your 3D printer on its side to deal with tricky overhangs.

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Make DIY Conductive, Biodegradable String Right In Your Kitchen

March 28, 2025 by Donald Papp 3 Comments

[ombates] shares a step-by-step method for making a conductive bio-string from scratch, no fancy equipment required. She demonstrates using it to create a decorative top with touch-sensitive parts, controlling animations on an RGB LED pendant. To top it off, it’s even biodegradable!

The string is an alginate-based bioplastic that can be made at home and is shaped in a way that it can be woven or knitted. Alginate comes primarily from seaweed, and it gels in the presence of calcium ions. [ombates] relies on this to make a goopy mixture that, once extruded into a calcium chloride bath, forms a thin rubbery length that can be dried into the strings you see here. By adding carbon to the mixture, the resulting string is darkened in color and also conductive.

There’s no details on what the actual resistance of a segment of this string can be expected to measure, but while it might not be suitable to use as wiring it is certainly conductive enough to act as a touch sensor in a manner similar to the banana synthesizer. It would similarly be compatible with a Makey Makey (the original and incredibly popular hardware board for turning household objects into touch sensors.)

What you see here is [ombates]’ wearable demonstration, using the white (non-conductive) string interwoven with dark (conductive) portions connected to an Adafruit Circuit Playground board mounted as an LED pendant, with the conductive parts used as touch sensors.

Alginate is sometimes used to make dental molds and while alginate molds lose their dimensional accuracy as they dry out, for this string that’s not really a concern. If you give it a try, visit our tip line to let us know how it turned out!

Handheld Console Plays Original Pong With Modern E-Waste

March 24, 2025 by Donald Papp 8 Comments

[Simon] wrote in to let us know about DingPong, his handheld portable Pong console. There’s a bit more to it than meets the eye, however. Consider for a moment that back in the 1970s playing Pong required a considerable amount of equipment, not least of which was dedicated electronics and a CRT monitor. What was huge (in more than one way) in the 70s has been shrunk down to handheld, and implemented almost entirely on modern e-waste in the process.

The 1970s would be blown away by a handheld version of Pong, made almost entirely from salvaged components.

DingPong is housed in an old video doorbell unit (hence the name) and the screen is a Sony Video Watchman, a portable TV from 1982 with an amazing 4-inch CRT whose guts [Simon] embeds into the enclosure. Nearly everything in the build is either salvaged, or scrounged from the junk bin. Components are in close-enough values, and power comes from nameless lithium-ion batteries that are past their prime but still good enough to provide about an hour of runtime. The paddle controllers? Two pots (again, of not-quite-the-right values) sticking out the sides of the unit, one for each player.

At the heart of DingPong one will not find any flavor of Arduino, Raspberry Pi, or ESP32. Rather, it’s built around an AY-3-8500 “Ball & paddle” (aka ‘Pong’) integrated circuit from 1977, which means DingPong plays the real thing!

We have seen Pong played on a Sony Watchman before, and we’ve also seen a vintage Pong console brought back to life, but we’re pretty sure this is the first time we’ve seen a Sony Watchman running Pong off a chip straight from the 70s. Watch it in action in the video (in German), embedded below.

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