Author: Lewin Day

3206 Articles

Adding Automatic Emergency Braking To An RC Car

July 2, 2025 by 1 Comment

Modern RC cars can be pretty darn fast. That’s fun and all, but it also makes it easy to crash them into things. This problem inspired [Narrow Studios] to whip up something to offer a bit of protection.

The concept is simple enough—the RC car just needs some way to detect obstacles and stop before hitting them. The build relies on ultrasonic sensors as rangefinders to spot solid objects in the path of the vehicle. An Arduino Nano is in charge of reading the sensors. When it appears the car is approaching a wall or similar obstacle, it fires off a PWM signal to the car’s motor controller commanding it to brake. The additional hardware is held to the car with a bunch of custom printed brackets.

The setup isn’t perfect; the video notes that if you insist on accelerating quickly when close to a wall, you still have a fair chance of hitting it. That’s largely put down to the refresh time of the sensors and the overall system, which could be improved with further work. Still, if you’re always crashing your RC car into walls or curbs, this kind of thing might appeal to you.

We’ve featured some other great RC projects before, too.

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There Are Better Lego-Compatible Universal Joints Out There

July 1, 2025 by 11 Comments

Lego’s Technic line features all kinds of mechanical devices, from cogs to gears to chains and even pneumatic components. However, the vast majority of these components are made out of plastic and are only capable of toy-like levels of performance. In the competitive world of Lego YouTube, builders often push these parts to their limits, breaking them more often than you might think. To that end, [Brick Experiment Channel] has been investigating stouter Lego-compatible universal joints from a variety of third-party manufacturers.

The video starts with a simple demonstration, showing that a Lego universal joint pops apart at just 0.4 Nm of torque. It’s no surprise, given it relies on tiny plastic pins in snap-fit joints. However, this means that it’s not that hard to build a stronger universal joint to outperform the stock parts.

The video steps through a range of other options available on the market. For example, CaDA builds a universal joint using aluminium sleeves, a copper center, and steel pins to join everything together. It’s so strong that the plastic Lego axles fail long before the joint does. Tested with third-party aluminum axles, it eventually fails at 2.3 Nm of torque when the aluminum sleeve snaps. An all-steel joint from MTP goes even harder, eventually stripping out its axle mount at 4 Nm. The rest of the video goes on to explore angular performance, size, and other design features.

It’s fair to say that if you’re swapping out universal joints and axles for aluminum steel parts, you’re not really playing with Lego anymore. At the same time, it’s neat that there exists a sort of defacto standard kit for mechanical experimentation that is now being expanded upon with stronger components. Video after the break.

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One Laptop Manufacturer Had To Stop Janet Jackson Crashing Laptops

July 1, 2025 by 32 Comments

There are all manner of musical myths, covering tones and melodies that have effects ranging from the profound to the supernatural. The Pied Piper, for example, or the infamous “brown note.”

But what about a song that could crash your laptop just by playing it? Even better, a song that could crash nearby laptops in the vicinity, too? It’s not magic, and it’s not a trick—it was just a punchy pop song that Janet Jackson wrote back in 1989.

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Blowtorching Electroplated 3D Prints For Good Reason

June 30, 2025 by 27 Comments

What if you electroplated a plastic 3D print, and then melted off the plastic to leave just the metal behind? [HEN3DRIK] has been experimenting with just such a process, with some impressive results.

For this work, [HEN3DRIK] prints objects in a special PVB “casting filament” which has some useful properties. It can be smoothed with isopropanol, and it’s also intended to be burnt off when used in casting processes. Once the prints come off the printer, [HEN3DRIK] runs a vapor polishing process to improve the surface finish, and then coats the print with copper paint to make the plastic conductive on the surface. From there, the parts are electroplated with copper to create a shiny metallic surface approximately 240 micrometers thick. The final step was to blowtorch out the casting filament to leave behind just a metal shell. The only problem is that all the fire tends to leave an ugly oxide layer on the copper parts, so there’s some finishing work to be done to get them looking shiny again.

We’ve featured [HEN3DRIK]’s work before, particularly involving his creation of electroplated 3D prints with mirror finishes. That might be a great place to start your research if you’re interested in this new work. Video after the break.

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Sand Drawing Table Inspired By Sisyphus

June 30, 2025 by 7 Comments

In Greek mythology, Sisyphus was a figure who was doomed to roll a boulder for eternity as a punishment from the gods. Inspired by this, [Aidan], [Jorge], and [Henry] decided to build a sand-drawing table that endlessly traces out beautiful patterns (or at least, for as long as power is applied). You can watch it go in the video below.

The project was undertaken as part of the trio’s work for the ECE4760 class at Cornell. A Raspberry Pi Pico runs the show, using TMC2209 drivers to command a pair of NEMA17 stepper motors to drag a magnet around beneath the sand. The build is based around a polar coordinate system, with one stepper motor rotating an arm under the table, and another panning the magnet back and forth along its length. This setup is well-suited to the round sand pit on top of the table, made with a laser-cut wooden ring affixed to a thick base plate.

The trio does a great job explaining the hardware and software decisions made, as well as showing off how everything works in great detail. If you desire to build a sand table of your own, you would do well to start here. Or, you could explore some of the many other sand table projects we’ve featured over the years.

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Building A Piezo Noise Box

June 29, 2025 by 3 Comments

The humble piezo element is often used as little more than a buzzer in many projects. However, you can do more with them, as [Something Physical] demonstrates with their nifty piezo noise box. Check out the video (and audio) below.

The construction is simple enough, attractive in its own way, with a rugged junk-assembly sort of style. The video starts out by demonstrating the use of a piezo element hooked up as a simple contact microphone, before developing it into something more eclectic.

The basic concept: Mount the piezo element to a metal box fitted with a variety of oddball implements. What kind of implements? Spiralled copper wires, a spring, and parts of a whisk. When struck, plucked, or twanged, they conduct vibrations through the box, the microphone picks them up, and the box passes the sound on to other audio equipment.

It might seem frivolous, but it’s got some real value for avant-garde musical experimentation. In particular, if you’re looking for weird signals to feed into your effects rack or modular synth setup, this is a great place to start.

We’ve seen piezos put to other percussive uses before, too.

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Ancient SoundBlaster Cards Just Got A Driver Update

June 28, 2025 by 11 Comments

Old hardware tends to get less support as the years go by, from both manufacturers and the open-source community alike. And yet, every now and then, we hear about fresh attention for an ancient device. Consider the ancient SoundBlaster sound card that first hit the market 31 years ago. [Mark] noticed that a recent update squashed a new bug on an old piece of gear.

Jump over to the Linux kernel archive, and you’ll find a pull request for v6.16-rc3 from [Takashi Iwai]. The update featured fixes for a number of sound devices, but one stands out amongst the rest. It’s the SoundBlaster AWE32 ISA sound card, with [Iwai] noting “we still got a bug report after 25 years.” The bug in question appears to have been reported in 2023 by a user running Fedora 39 on a 120 MHz Pentium-based machine.

The fixes themselves are not particularly interesting. They merely concern minutiae about the DMA modes used with the old hardware. The new updates ensure that DMA modes cannot be changed while the AWE32 is playing a PCM audio stream, and that DMA setups are disabled when changing modes. This helps avoid system lockups and/or ugly noises emanating from the output of the soundcard.

It’s incredibly unlikely this update will affect you, unless you’re one of a handful of users still using an ISA soundcard in 2025. Still, if you are — and good on you — you’ll be pleased someone still cares about your user experience. Meanwhile, if you’re aware of any other obscure old-school driver updates going on out there, don’t hesitate to let us know on the tips line. Want to relive your ISA card’s glory days? Plug it into USB.

Image credit: Gona.eu, CC BY-SA 3.0

[Thanks to Meek Mark for the tip!]