3D Printing A Big LEGO Christmas Tree

December 20, 2024 by Lewin Day 5 Comments

LEGO make lots of neat floral arrangements these days, and even little Christmas trees, too. While they’re fun to build out of tiny little blocks, they’re a little small for use as your main Christmas tree. Sadly, a bigger version simply doesn’t exist in the LEGO catalog, so if that’s your desire, you’ll have to build your own—as [Ruth] and [Ellis] did!

The concept behind the build is as you’d expect. The duo effectively just 3D printed giant versions of LEGO pieces, with which they then assembled a large Christmas tree. It sounds very straightforward, but scaling an existing LEGO design up by six times tends to come with some complications. A tactical decision was made early on to ease proceedings—the original LEGO tree had a large brown base that would take lots of printing. This was eliminated in the hopes that it would speed the build significantly. The long plastic shafts that supported the original design were also replaced with steel shafts since printing them would have been incredibly difficult to do well.

The rest of the video demonstrates the huge amount of work that went into actually 3D printing and assembling this thing. It’s pretty great to watch, and you’ll learn a lot along the way.

We’ve seen other creators try similar projects, where they 3D print their own building blocks from scratch. It normally turns out much harder than expected! No surprise when you think about all the engineering that went into perfecting LEGO all those years ago.

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Rudolph’s Sleigh On A North Pole PCB

December 20, 2024 by Heidi Ulrich 14 Comments

Each Christmas, [Adam Anderson], [Daniel Quach], and [Johan Wheeler] (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.

Where This Xmas Card’s Going, We Don’t Need Batteries!

December 19, 2024 by Jenny List 16 Comments

Energy harvesting, the practice of scavenging ambient electromagnetic fields, light, or other energy sources, is a fascinating subject that we don’t see enough of here at Hackaday. It’s pleasing then to see [Jeff Keacher]’s Christmas card: it’s a PCB that lights up some LEDs on a Christmas tree, using 2.4 GHz radiation, and ambient light.

The light sensors are a set of LEDs, but the interesting part lies in the RF harvesting circuit. There’s a PCB antenna, a matching network, and then a voltage multiplier using dome RF Schottky diodes. These in turn charge a supercapacitor, but if there’s not enough light a USB power source can also be hooked up. All of this drives a PIC microcontroller, which drives the LEDs.

Why a microcontroller, you ask? This card has an interesting trick up its sleeve, despite having no WiFi of its own, it can be controlled over WiFi. If the 2.4 GHz source comes via proximity to an access point, there’s a web page that can be visited with a script generating packets in bursts that produce a serial pulse train on the DC from the power harvester. The microcontroller can see this, and it works as a remote. This is in our view, next-level.

Left: the traces of a flashy paper Christmas tree. Right: the finished tree on cardstock.

Flashy Paper Christmas Tree Does It With A 555

December 13, 2024 by Kristina Panos 10 Comments

‘Tis the season for holiday hacks, and [Ben Emmett] is here to remind us that we don’t necessarily need a fancy microcontroller in order to make flashy fun things happen.

Smoothing down the copper traces with a guitar pick.

Take this Christmas tree for example, which uses a 555 timer and a CB4017 decade counter in order to drive some blinking LEDs. The ICs are through-hole, making the circuit fairly accessible to new players, but there are a few SMD components that need soldering as well. (More on that later.)

Here, the 555 acts like a clock and drives a square wave. Using the clock as input, the decade counter toggles the output pins one after the other, driving the LEDs to blink in turn. Since there are only eight lights, there is a pause in the light-up pattern, but that could be fixed by wiring decade counter output #9 to the reset pin.

Although function was the main focus circuit-wise, [Ben] managed to lay the traces in the shape of a Christmas tree, which looks great. Having done a similar project in the past, he discovered that the craft cutting machine prefers thick traces and wider spaces between them. This is largely why [Ben] chose to use through-hole ICs.

After laying everything out in KiCad, [Ben] exported the copper layer image for use on the cutting machine. Once it was all cut out, he put it on transfer tape to weed out the extra copper, and get the traces onto cardstock, the final substrate.

This is such a fun project, and we love that the CR2032 that powers it also acts as the stand in its vertical holder. Hit up GitHub if you want to make one for yourself. Want something even more 3D? Check out this hollow tree we saw a few years ago.

British Spooks Issue Yearly Teaser

December 12, 2024 by Jenny List 17 Comments

As a British taxpayer it’s reassuring to know that over in Cheltenham there’s a big round building full of people dedicated to keeping us safe. GCHQ is the nation’s electronic spying centre, and just to show what a bunch of good eggs they are they release a puzzler every year to titillate the nation’s geeks. 2024’s edition is out if you fancy trying it, so break out your proverbial thinking caps.

The puzzle comes in several stages each of which reveals a British landmark, and we’re told there’s a further set of puzzles hidden in the design of the card itself. We know that Hackaday readers possess fine minds, so you’ll all be raring to have a go.

Sadly GCHQ would for perfectly understandable reasons never let Hackaday in for a tour, but we’ve encountered some of their past work. First the Colossus replica codebreaking computer at Bletchley Park was the progenitor of the organisation, and then a few years ago when they had an exhibition from their archive in the London Science Museum.

Tis The Season

December 7, 2024 by Elliot Williams 16 Comments

’Tis the season for soldering! At least at my house. My son and I made some fairly LED-laden gifts for the immediate relatives last year, and he’s got the blinky bug. We were brainstorming what we could make this year, and his response was “I don’t care, but it needs to have lots of LEDs”.

It’s also the season for reverse engineering, apparently, because we’re using a string of WS2812-alike “fairy lights”. These are actually really neat, they look good and are relatively cheap. It’s a string of RGB LEDs with drivers, each dipped in epoxy, and run on a common three-enameled-wire bus. Unlike WS2812s, which pass the data on to the next unit in the line and then display them with a latching pulse at the end of a sequence, these LED drivers seem to count how many RGB packets have been sent down the wire, and only respond to their own number.

This means that if you cut up a string of 200 LEDs, it behaves like a string of 200 WS2812s. But if you cut say 10 LEDs off the string, where you cut them matters. If you cut it off the front of the string, you only have to send 10 color packets. If you cut them off the other end, you need to send 290 dummy packets before they even start listening. Bizarre, but ’tis the season for bizarre hacks.

And finally, ’tis the season for first steps into “software architecture”. Which is to say that my son is appreciating functions for the first time in his life. Controlling one LED is easy, but making a light show is about two more abstraction layers on top of that. We’ve been having fun making them dim, twinkle, and chase so far. We only have two more weekends, though, and we don’t have a final light show figured out yet, but after all, ’tis the season for last minute present hacking.

A chocolate coating machine works in the round to enrobe mint Oreos.

Chocolate-Coating Machine Mk. 2: The Merry-Go-Round

November 28, 2024 by Kristina Panos 16 Comments

This holiday season, [Chaz] wanted to continue his family’s tradition of enrobing a little bit of everything in dark chocolate, and built an improved, rotating chocolate-coating machine.

You may remember last year’s offering, aka the conveyor belt version. Although that one worked, too much chocolate was ultimately lost to the surface of the kitchen table. [Chaz] once again started with a standard chocolate fountain and bought a round wire rack that fits the circumference of the bowl at the bottom. He snipped a hole in the center large enough to accommodate the business part of the fountain and printed a collar with holes that he cleverly zip-tied to the rack.

[Chaz] also printed a large gear to go around the bowl, a small gear to attach to a six RPM motor, a motor mount for the bowl, and an air blade attachment for a portable Ryobi fan. The air blade worked quite well, doing the double duty of distributing the chocolate and thinning out the coating. Plus, it gives things a neat rumpled look on the top.

Want to make some special chocolates this year, but don’t want to build an enrober? Get yourself a diffraction grating and make some rainbow goodies with melted chocolate.

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