Building A Custom Swiss Army Knife

December 21, 2024 by Lewin Day 15 Comments

The Swiss Army knife is the most well-known multitool, combining a bunch of functionality into a compact package. [Jeff Gough] decided to build a custom example featuring a selection of his favorite tools.

He documents the build in a video series on YouTube (see below). [Jeff] decided to take on the project as a gift for his mother after she’d mentioned she’d wanted a Swiss Army-style knife with a horse’s hoof tool and finished in the classic shade of British Racing Green.

[Jeff] starts by disassembling an existing knife, taking care not to damage it in the process. He then makes and installs multiple custom tools, including the aforementioned horse hoof tool and a RADAR/NKS key for opening disabled toilets in the UK. He even crafts a bespoke Philips head screwdriver, too. Finally, he assembles everything back together and gives the build a beautiful green finish.

A Swiss Army knife can be a neat gift, but it’s even nicer when it’s got a personal touch like this one. We’ve featured some other nifty multitools before, too. Not all Swiss Army knives actually contain a, you know, knife. No kidding.

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Training A Self-Driving Kart

December 21, 2024 by Bryan Cockfield 1 Comment

There are certain tasks that humans perform every day that are notoriously difficult for computers to figure out. Identifying objects in pictures, for example, was something that seems fairly straightforward but was only done by computers with any semblance of accuracy in the last few years. Even then, it can’t be done without huge amounts of computing resources. Similarly, driving a car is a surprisingly complex task that even companies promising full self-driving vehicles haven’t been able to deliver despite working on the problem for over a decade now. [Austin] demonstrates this difficulty in his latest project, which adds self-driving capabilities to a small go-kart.

[Austin] had been working on this project at the local park but grew tired of packing up all his gear when he wanted to work on his machine-learning algorithms. So he took all the self-driving equipment off of the first kart and incorporated it into a smaller kart with a very small turning radius so he could develop it in his shop.

He laid down some tape on the floor to create the track and then set up the vehicle to learn how to drive by watching and gathering data. The model is trained with a convolutional neural network and this data. The only inputs that the model gets are images from cameras at the front of the kart. At first, it could only change the steering angle, with [Austin] controlling the throttle to prevent crashes. Eventually, he gave it control of the throttle as well, which behaves well except at the fastest speeds.

There were plenty of challenges along the way, especially when compared to the models trained at the park; [Austin] correctly theorized that the cause of the hardship in the park was a lack of contrast at the boundary between the track and any out-of-bounds areas. With a few tweaks to the track, as well as adding some wide-angle lenses to his cameras, he was able to get a model that works fairly well. Getting started on a project like this doesn’t have as high of a barrier to entry as one might imagine, either. Take a look at this comprehensive open-source Python library for self-driving projects. If you want to start smaller, perhaps don’t start with a self-driving kart.

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3D Printing A Big LEGO Christmas Tree

December 20, 2024 by Lewin Day 8 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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It’s Official: The North Pole Is Moving

December 20, 2024 by Al Williams 43 Comments

Every scout knows how to read a compass, and that there is a magnetic north and a true north. That’s because the Earth’s magnetic field isn’t exactly aligned with the North Pole. Every five years, the US National Oceanic and Atmospheric Administration (NOAA) and the British Geological Survey (BGS) get together to decide if magnetic north is still the same as it was before. This time, it isn’t.

The update is to the WMM — the World Magnetic Model. Magnetic north has shifted away from Canada and towards Siberia, a trend that has been ongoing for the last 20 years.

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Rudolph’s Sleigh On A North Pole PCB

December 20, 2024 by Heidi Ulrich 18 Comments

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.

Making A Mechanical Watch From Scratch Is Fine Work

December 20, 2024 by Lewin Day 7 Comments

There are plenty of hard jobs out there, like founding your country’s nuclear program, or changing the timing chain on a BMW diesel. Making your own mechanical watch from scratch falls under that umbrella, too. And yet, [John Raffaelli] did just that, and prevailed!

Only a handful of components were purchased—[John] grabbed jewels, sapphire crystals, the strap, and the hairspring and mainspring off the shelf. Everything else, he made himself, using a fine touch, a sharp eye, and some deft work on his machine tools. If you’ve never worked at this scale before, it’s astounding to see—[John] steps through how he produced tiny pinions and balance wheels that exist at sub-fingertip scale. Even just assembling something this tiny would be a challenge, but [John] was able to craft it all from scratch and put it together into a functioning timepiece when he was done.

The final piece doesn’t just look great—we’re told it keeps good time as well. People like [John] don’t come along every day, though we do have one similar story in our deep archives from well over a decade ago. If you’re cooking up your own bespoke time pieces in your home workshop, don’t hesitate to drop your story on the tipsline!

Building A Diet Coke Button

December 20, 2024 by Lewin Day 53 Comments

[mars91] had an interesting problem to solve—his girlfriend often requested Diet Coke, but yelling for one across the apartment was frustrating and impractical. A dedicated Diet Coke button seemed like the perfect solution, so that’s precisely what he built.

The Diet Coke Button is a relatively simple device. A small silver push-button activates an Adafruit Feather M0 to send out a signal via its RFM95 LoRa radio. That signal is picked up by the receiver device, which runs on an ESP32. It’s got an RFM95 LoRa module, which receives signals from the button and sounds an alarm to indicate the request for a Diet Coke. The ESP32 also hosts a basic website which allows Diet Coke requests to be submitted via the web, as well as general submissions of a textual nature. The latter are displayed on a small OLED display. If you’re feeling bold, you can even set up the ESP32 to be accessible from the outside Internet, with [mars91] explaining how to do so using a Cloudflare tunnel for your own protection.

The only problem is that delivering the Diet Coke is still something you have to do by hand. Perhaps a future upgrade would involve some kind of small apartment-spanning railway for the delivery of ice-cold cans to designated stations.

It’s a unique project, and one that recalls us of an interesting talk about a different type of call button.

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