You’ve Got All Year To Print This Marble Machine Ornament For Your Christmas Tree

February 20, 2025 by Zoe Skyforest 11 Comments

Most Christmas ornaments just hang there and look pretty. [Sean Hodgins] decided to whip up something altogether fancier and more mechanical. It’s a real working marble machine that hangs from the tree!

The build is simple enough, beginning with a translucent Christmas ornament shell readily available from most craft stores. Inside, a small motor spins a pinion, which turns a larger gear inside the body. As the larger gear spins, magnets embedded inside pick up steel balls from the base of the ornament and lift them up to the top. As they reach their zenith, they’re plucked off by a scoop, and then they roll down a spiral inside. As for power, [Sean] simply handled that with a couple of wires feeding the motor from a USB power bank. Just about any small battery pack would do fine.

The build is beautiful to watch and to listen to, with a gentle clacking as the balls circulate around. Files are on MakerWorld for the curious. We’ve featured some great Christmas decorations before, too. Video after the break.

Reconstructing 3D Objects With A Tiny Distance Sensor

February 20, 2025 by Zoe Skyforest 8 Comments

There are a whole bunch of different ways to create 3D scans of objects these days. Researchers at the [UW Graphics Lab] have demonstrated how to use a small, cheap time-of-flight sensor to generate scans effectively.

Not yet perfect, but the technique does work…

The key is in how time-of-flight sensors work. They shoot out a distinct pulse of light, and then determine how long that pulse takes to bounce back. This allows them to perform a simple ranging calculation to determine how far they are from a surface or object.

However, in truth, these sensors aren’t measuring distance to a single point. They’re measuring the intensity of the received return pulse over time, called the “transient histogram”, and then processing it. If you use the full mathematical information in the histogram, rather than just the range figures, it’s possible to recreate 3D geometry as seen by the sensor, through the use of some neat mathematics and a neural network. It’s all explained in great detail in the research paper.

The technique isn’t perfect; there are some inconsistencies with what it captures and the true geometry of the objects its looking at. Still, the technique is young, and more work could refine its outputs further.

If you don’t mind getting messy, there are other neat scanning techniques out there—like using a camera and some milk.

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Water Jets Will Carve Your Pumpkin

February 20, 2025 by Zoe Skyforest 8 Comments

Carving pumpkins by hand is hot, sweaty, messy work, and a great way to slice your way into a critical artery. Why not let a water jet do it for you? It’ll be cleaner and more precise to boot, and [Jo_Journey] is here to show us how.

Obviously, you’ll need a water jet machine, there’s no getting around that. You’ll also still have to do the basic preparation of the pumpkin yourself—cutting a porthole into the top and mucking it out is your job. With that done, you must then mount the pumpkin on two metal rods which will be used to mount it in the water jet machine’s working area.

You can then create a vector file of your design, and use your chosen software to generate the G-code to run the water jet. [Jo_Journey] uses Scribe, and recommends cutting at a speed of around 200 in/min at low pressure. Remember, it’s pumpkin you’re cutting, not high-strength steel.

There is some inaccuracy, of course—your pumpkin’s surface is not a flat plane, after all—but the results are good enough for most Halloween-related purposes. Even despite the geometrical issues, though, [Jo_Journey] shows us that you can get pleasantly sharp edges on your design. That’s very hard to achieve by hand!

We do love a good holiday hack around these parts, even if it’s out of season. If you’ve been cooking up your own pumpkinous plans, don’t hesitate to let us know! Earlier is sometimes better—after all, who has time to hack together a project if you’ve just read about it on October 29?

The “Unbreakable” Beer Glasses Of East Germany

February 17, 2025 by Zoe Skyforest 80 Comments

We like drinking out of glass. In many ways, it’s an ideal material for the job. It’s hard-wearing, and inert in most respects. It doesn’t interact with the beverages you put in it, and it’s easy to clean. The only problem is that it’s rather easy to break. Despite its major weakness, glass still reigns supreme over plastic and metal alternatives.

But what if you could make glassware that didn’t break? Surely, that would be a supreme product that would quickly take over the entire market. As it turns out, an East German glassworks developed just that. Only, the product didn’t survive, and we lumber on with easily-shattered glasses to this day. This is the story of Superfest.

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Magnetic Vise Makes Positioning Your Workpiece Easier

February 14, 2025 by Zoe Skyforest 12 Comments

[Chris Borge] was doing some fine tapping operations, and wanted a better way to position his workpieces. This was critical to avoid breaking taps or damaging parts. To this end, he whipped up a switchable magnetic vice to do the job.

The key to the build is that the magnetic field can be switched on and off mechanically. This is achieved by having two sets of six magnets each. When the poles of both sets of magnets are aligned, the magnetic field is effectively “on.” When the poles are moved to oppose each other, they effectively cancel each other out, turning the field “off.” [Chris] achieved this functionality with 12 bar magnets, 12 M12 nuts, and a pair of 3D-printed rings. Rotating the rings between two alignments serves to switch the set up on or off. The actual switching mechanism is handled with a cam and slider setup which allowed [Chris] to build a convenient vice with a nice large working area. He also took special effort to ensure the device wouldn’t pick up large amounts of ferrous swarf that would eventually clog the mechanism.

It’s a neat build, and one you can easily recreate yourself. [Chris] has supplied the files online for your printing pleasure. We’ve featured some other types of magnetic vise before, too. Video after the break.

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Home Depot Lamp Gets A Rainbow Upgrade

February 14, 2025 by Zoe Skyforest 14 Comments

Home Depot has at times sold a neat spiral lamp that relies on LEDs to supply its soothing white glow. When [Craig Lindley] saw some modified versions on YouTube he decided he had to build one himself. The result is a charming rainbow lamp that really lights up a room (pardon the pun).

[Craig] first set about stripping the lamp of its white LED strips, replacing them with addressable WS2812B LEDs. No more would the lamp just output white light—any color in the RGB gamut was now on the table.

A powerful 10 amp 5 volt power supply was then installed to provide the necessary juice. A Wemos D1 Mini was pressed into service as the controller, which was also hooked up to an HC-SR04 infrared motion sensor. This provided the capacity to trigger the lamp when it detects someone moving nearby.

Alternatively, the lamp was given a time-activated mode as well. Either way, when activated, the lamp displays a range of colorful patterns on its elegant spirals, all with the aid of the popular FastLED library.

The final result is impressive—it looks almost stock, except it’s far more colorful and interesting to look at than the original. It’s also amusingly hard to display in our usual image formats because it’s so tall and narrow. In any case, we’ve seen some great lamp builds before, too. If you’re working on your own charming illuminations, don’t hesitate to drop us a line!

3D Printed Air Raid Siren Sounds Just Like The Real Thing

February 14, 2025 by Zoe Skyforest 11 Comments

Air raid sirens have an important job to do, and have been a critical piece of public safety infrastructure in times of geopolitical turmoil. They sound quite unlike anything else, by virtue of their mechanical method of generating an extremely loud sound output. They’re actually remarkably simple to build yourself, as [MarkMakies] demonstrates.

[Mark’s] build relies almost entirely on 3D printed components and ex-RC gear. The sound itself is generated by a rotor which spins inside a stator. Each is designed with special slots, such that as the rotor turns at speed, it creates spikes of air pressure that generate a loud wail. The rotor and stator are fitted inside a housing with a horn for output, which helps direct and amplify the sound further.

To spin the rotor, [Mark] used a powerful brushless motor controlled by a common hobby speed controller. The actual speed is determined by a potentiometer, which generates pulses to command the speed controller via a simple 555 circuit. By ramping the speed of the motor up and down, it’s possible to vary the pitch of the siren as is often done with real air raid sirens. This action could be entirely automated if so desired.

If you do decide to build such a siren, just be wary about how you use it. There’s no need to go around agitating the townsfolk absent an actual air raid. It’s worth noting that sirens of this type aren’t just used for air raids, either. They’re often used for tornado warnings, too, such as in Dallas, for example. But why not for music?

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