pcb with santa sleigh racing circuit

Rudolph’s Sleigh On A North Pole PCB

Each Christmas, [Adam Anderson], [Daniel Quach], [Johan Wheeler], and [Gustav Abrahamsson] (going by ‘the Janky Jingle Crew’)—set themselves the challenge of outdoing their previous creations. Last year’s CH32 Fireplace brought an animated LED fire to life with CH32V003 microcontrollers.

This year, they’ve gone a step further with the North Pole Circuit, a holiday project that combines magnetic propulsion, festive decorations, and a bit of engineering flair. Inspired by a miniature speedway based on Friedrich Gauss’ findings, the North Pole Circuit includes sleighs and reindeer that glide along a custom PCB track, a glowing village with flickering lights, and a buzzer to play Christmas tunes.

The propulsion system works using the Lorentz force, where vertical magnets interact with PCB traces to produce motion. A two-phase design, similar to a stepper motor, ensures smooth operation, while guard rails maintain stability on curves. A separate CH32V003 handles lighting and synchronized jingles, creating a cohesive festive display. As we mentioned in the article on their last year’s creation, going from a one-off to a full batch will make one rethink the joy of repetitive production. Consider the recipients of these tiny Christmas cards quite the lucky ones. We deem this little gift a keeper to put on display when Christmas rolls around again.

This annual tradition highlights the Crew’s knack for combining fun and engineering. Curious about the details or feeling inspired to create your own? Explore the full details and files on their GitHub.

3D Printed Blaster Does It With Compliant Components

The ease of integrating bendy parts into designs is one of 3D printing’s strengths. A great example of this is [uhltimate]’s six-shot blaster which integrates several compliant mechanisms. The main blaster even prints in one piece, so there’s not even any assembly required.

The ergonomics are unconventional, but the design is pretty clever.

The blaster itself has three main parts: the trigger, the sear, and the striker. Each of them rely on compliant mechanisms in order to function. The user pulls back the trigger, which hooks into and pulls back the striker. When the trigger is pulled back far enough, the sear releases the striker. This zips forward and slams into a waiting projectile, sending it flying.

The other interesting part is the projectiles and magazine in which they sit. The magazine fits onto the front of the blaster and pulling the trigger allows the magazine to drop down, putting the next projectile into firing position. After the final round is fired, the empty magazine falls away. It’s a pretty clever design, even if the ergonomics are a little unusual and it relies on gravity in order to feed. Tilt it too far sideways or upside down, and it won’t load properly.

We’ve seen compliant mechanisms used for projectile firing before, but this design really raises the bar in the way it does more than just firing the striker.

3D printing allows rapid iteration of designs, which makes devices that rely on compliant mechanisms much easier to develop and fine-tune.

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Creators demonstrating their Jedi Watch

Walkie Talkies, Jedi Style: Building A Communicator

Playing Star Wars Outlaws sparked an idea with [3DSage]: why not recreate the game’s wrist communicator as a functioning gadget? Inspired by the relatively simplistic design, he and his friend Ben set out to build their own device to take to Galaxy’s Edge in Disneyland. Armed with an arsenal of tools—3D printers, CNC machines, and soldering irons—he aimed to turn imagination into reality.

After ordering multiple walkie-talkies, they meticulously tested each one for audio quality, circuit board size, and compatibility with custom components. The ‘world’s tiniest walkie-talkie’ had potential but demanded creative modifications, including disassembling and resoldering components. They crafted their own circuit board and designed a 3D printed housing to fit both electronics and style. For the finishing touch, they weathered the device with paints and even glow-in-the-dark accents, making it authentic to the Star Wars universe. Even Chewbacca himself gave one a thumbs-up!

Weathering goes a long way towards creating a convincing prop — it can turn a bundle of pipes and some foam blocks into a movie-ready WWII machine gun.

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Tiny arcade machines on a tabletop

Tiny PONG, Big Ambitions: World’s Smallest Arcade

London, Ontario college student [Victoria Korhonen] has captured the attention of tech enthusiasts and miniaturization lovers with her creation of what might be the world’s smallest arcade machine. Standing just 64 mm tall, 26 mm wide, and 30 mm deep, this machine is a scaled-down marvel playing the classic Atari game PONG. While the record isn’t yet official—it takes about three months for Guinness to certify—it’s clear [Korhonen]’s creation embodies ingenuity and dedication.

[Korhonen], an electromechanical engineering student, took six months to design and build this micro arcade. Inspired by records within reach, she aimed to outdo the previous tiniest arcade machine by shaving off just a few millimeters During the project she faced repeated failures, but viewed each iteration as a step towards success. Her miniature machine isn’t just a gimmick; it’s fully functional, with every component—from paddle mechanics to coding—developed from scratch.

[Korhonen] is already eyeing new projects, including creating the smallest humanoid robot. She also plans to integrate her electromechanical expertise into her family’s escape room business. Her journey aligns with other hobbyist projects pushing the limits of miniaturization, such as this credit card-sized Tetris clone or [Aliaksei Zholner]’s paper micro engines.

3D scanned image of LEGO sheep

Do 3D Printers Dream Of LEGO Sheep?

Imagine the power to clone your favorite LEGO piece—not just any piece, but let’s say, one that costs €50 second-hand. [Balazs] from RacingBrick posed this exact question: can a 3D scanner recreate LEGO pieces at home? Armed with Creality’s CR-Scan Otter, he set out to duplicate a humble DUPLO sheep and, of course, tackle the holy grail of LEGO collectibles: the rare LEGO goat.

The CR-Scan Otter is a neat gadget for hobbyists, capable of capturing objects as small as a LEGO piece. While the scanner proved adept with larger, blocky pieces, reflective LEGO plastic posed challenges, requiring multiple scans for detailed accuracy. With clever use of 3D printed tracking points, even the elusive goat came to life—albeit with imperfections. The process highlighted both the potential and the limitations of replicating tiny, complex shapes. From multi-colored DUPLO sheep to metallic green dinosaur jaws, [Balazs]’s experiments show how scanners can fuel customization for non-commercial purposes.

For those itching to enhance or replace their builds, this project is inspiring but practical advice remains: cloning LEGO pieces with a scanner is fun but far from plug-and-play. Check out [Balazs]’s exploration below for the full geeky details and inspiration.

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A variety of LEGO and the damage they've done to cardboard.

Stepping On LEGO For Science

You might say that the worst LEGO to step on is any given piece that happens to get caught underfoot, but have you ever thought about what the worst one would really be? For us, those little caltrops come to mind most immediately, and we’d probably be satisfied with believing that was the answer. But not [Nate Scovill]. He had to quantitatively find out one way or another.

The damage done to cardboard by both broken brittle brown LEGO, and angled LEGO.And no, the research did not involve stepping on one of each of the thousands of LEGO pieces in existence. [Nate] started by building a test rig that approximated the force of his own 150 lb. frame stepping on each piece under scrutiny and seeing what it did to a cardboard substrate.

And how did [Nate] narrow down which pieces to try? He took to the proverbial streets and asked redditors and Discordians to help him come up with a list of subjects.

If you love LEGO to the point where you can’t bear to see it destroyed, then this video is not for you. But if you need to know the semi-scientific answer as badly as we did, then go for it. The best part is round two, when [Nate] makes a foot out of ballistics gel to rate the worst from the first test. So, what’s the worst LEGO to step on? The answer may surprise you.

And what’s more dangerous than plain LEGO? A LEGO Snake, we reckon.

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Barbie’s Video Has Never Looked So Good

For those who missed it, there’s been something of a quiet revolution in the world of analogue video over the last year, due to the arrival of inexpensive “MiniDVR” devices. These little modules are a complete video recorder including battery, recording PAL or NTSC composite video and audio to SD card. They’ve become the box of choice for camcorder enthusiasts, but that’s not where the fun ends. [Max Vega] has taken a Barbie video camera toy from 2001 and added a MiniDVR to make it into a fully self-contained novelty camcorder. But this isn’t a simple case of duct-taping the DVR to the toy, instead it’s a comprehensive upgrade resulting in a device which could almost have been a real product.

The original toy had a small transmitter which could send over a short distance to a receiver that connected to a domestic VCR, so all that circuitry had to go. The camera itself is a small enough module in the fake lens assembly, with an easily identifiable output cable with the required composite signal. The video below the break steps through the proces of making the space for the MiniDVR module, and putting in extensions for all its buttons, and the SD card. Finally it has a new power supply module with an associated USB-C input, providing juice to both DVR and camera.

The result has what we can only describe as a pleasingly retro feel, in that it’s not of high quality and the colour is, well, Never The Same. But when a smartphone can record HD video that’s not the point, instead it’s there to be a retro toy, and in that it succeeds completely.

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