Taser Ring Is Scary Jewelry You Shouldn’t Build

January 16, 2025 by Lewin Day 38 Comments

Officially, the term “taser” refers to a particular brand of projectile-firing electric stun gun. However, the word is also colloquially used to refer to just about any device intended for delivering electric shocks to an adversary. The taser ring from [Penguin DIY] definitely fits that description, though we’d strictly advise you not to consider building this at home.

The build is a hacky one. An arc generator circuit was pulled out from a jet cigarette lighter, and reconfigured to fit in a small ring-based form factor. It was hooked up with a power switch and a small bank of 30 mAh lithium polymer cell for power, and a compact USB-C charger board was installed to keep the batteries juiced. The electronics were then delicately assembled into a ring-shaped mold, which was injected with resin to produce the final ring. Once cast, a pair of small metal electrodes were installed on the outside. Activating the taser function is as simple as squeezing the ring—easy to do just by making a fist.

We’ve seen projects like these before; our advice is usually to avoid them unless you really know what you’re doing. Whether you end up shocking someone else or accidentally shocking yourself, the results tend to be bad. The latter seems particularly easy to do if you’re wearing this thing on your finger. Given it’s a ring, don’t expect to be able to pull it off in a hurry, either. It’s hard to see how that ends well.

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Gimbal Clock Relies On Servos For Its Cool Movements

January 16, 2025 by Lewin Day 1 Comment

In the annals of human history, clocks got boring there for a while. Most were just variations on hands spinning in a circle, with the occasional tweeting bird mechanism to liven things up. These days, we’re treated to all kinds of original and oddball designs, like this neat gimbal clock from [Twisted&Tinned].

The concept of the build is straightforward enough. It has four main vertical arms, each with a servo at the base that rotates about a vertical axis. Upon each arm are between one and three servos which rotate 3D printed structures in the shape of numbers. A Wemos D1 Mini microcontroller commands the servos to the correct positions to display the current time. It also uses its WiFi connection to get accurate time updates directly from a network time server.

It’s quite an artistic build—and it’s rather enjoyable to watch this one flex and twist its way into displaying the right time. It’s also easier to read at a glance than some of the more unintelligible designs out there. Indeed, we see all kinds of neat and innovative clocks around these parts.

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The Many Leaning Towers Of Santos, Brazil

January 14, 2025 by Lewin Day 55 Comments

If you’ve ever gazed at the shoreline of Santos, Brazil, and felt like something was tugging at your inner eye level, you’re not alone. In fact, you’ve spotted one of the world’s most bizarre architectural phenomena.

Santos is an interesting contradiction—it’s a sunny coastal city with pristine beaches that also plays host to a bustling port. What draws the eye, however, is the skyline—it’s decidedly askew. This isn’t a Photoshop job or some avant-garde urban planning experiment, either. It’s a consequence of engineering hubris, poor planning, and geology just doing its thing.

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Homebrew Retro Console Runs On PIC32

January 13, 2025 by Lewin Day 9 Comments

[Chad Burrow] decided to take on a noble task—building a “retro” style computer and video game console. Only, this one is built using somewhat modern hardware—relying on the grunt of the PIC32MZ2048EFH144 to get the job done. Meet the Acolyte Hand PIC’d 32.

It’s name might be a mouthful, but that chip can pull off some great feats! With a clock speed of 200 MHz, it’s not short on processing power, though RAM and flash storage are somewhat limited at just 512 KB and 2MB respectively. [Chad] was able to leverage those constraints to get a VGA output working at a resolutions up to 800 x 600, with up to 65,000 colors—though 256 colors is more practical due to memory concerns. The Acolyte Hand also rocks two 8-bit audio channels. It has a pair of Genesis-compatible controller ports as well as PS/2 and USB for keyboards and mice, along with more modern Xbox 360 controllers.

[Chad] cooked up some software to put it through its paces, too. It’s got a Tetris clone on board, and can also run Game Boy games at full speed via the Peanut-GB emulator. That provides for a pretty rich game library, though [Chad] notes he plans to develop more native video games for his system to demo at his local college. Design files are on Github for the curious.

This project is a great example of just how powerful modern microcontrollers have become. Once upon a time, just driving a simple black-and-white graphical LCD might have taken some real effort, but today, there are pixels and clock cycles to spare in projects like these. Truly a wonderous world we live in!

Electromechanical 7-Segment Display Is High Contrast Brilliance

January 13, 2025 by Lewin Day 10 Comments

The seven-segment display is most well known in LED form, but the concept isn’t tied to that format. You can build a seven-segment display out of moving parts, too. [tin-foil-hat] has achieved just that with a remarkably elegant design.

As you might expect, the build relies heavily on 3D-printed components—produced in white and black plastic to create a high-contrast display. It’s a simple choice that makes the display easy to read in a wide variety of lighting conditions, and far less fussy than toying with LEDs and diffusers and all that.

Actuation of each display segment is achieved electromagnetically. Effectively, each segment behaves like a flip dot, with the orientation controlled by energizing one of two electromagnets per segment. Controlling the electromagnets is an ESP32, which is hooked up to the various segments via a Darlington transistor array, with multiplexing used to minimize the number of IO pins required. A shift register was also employed to let the microcontroller easily drive four of these electromechanical digits.

It’s a simple build, well explained—and the final result is aesthetically pleasing. We’ve seen a few builds along these lines before, albeit using altogether different techniques. Lots of different techniques, in fact! Video after the break.

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How Nyan Cat Was Ported To UEFI

January 13, 2025 by Lewin Day 12 Comments

The Unified Extensible Firmware Interface (UEFI) took over from the classical BIOS some years into the new millenium. It’s typically used for running a computer at the basic pre-OS level, and most of us don’t even notice it past boot time. However, you can do some neat things in this space—you can even port over Nyan Cat if you’re talented like [Cornelius].

*That’s fun. Set your friend’s computer to boot into this instead of their OS by default and see how long it takes them to figure it out.*

Yes, Nyan Cat is now available as a UEFI application, running via the EFI Simple Text Output Protocol. [Cornelius] approached this creation by first learning Rust, before progressing to the Hello World stage. Before long, the computer was booting up to display a simple text message with no OS required.

From there, creating the Nyan Cat animation required figuring out how to display it as a bunch of dancing characters, which is where the Simple Text Output Protocol came in. Nyan Cat was really the perfect animation for the UEFI environment, since its simple pixel art style was easily recreated with text. With a bit of work, the animation came together, with a remarkable resemblance to the original artwork.

All that’s missing is a routine to play the music over a PC speaker; only, those are hardly a thing anymore. A pity! In any case, if you’ve been cooking up your own nifty UEFI hacks, don’t hesitate to drop us a line!

Using Audio Hardware To Drive Neopixels Super Fast

January 13, 2025 by Lewin Day 17 Comments

Here’s the thing about running large strings of Neopixels—also known as WS2812 addressable LEDs. You need to truck out a ton of data, and fast. There are a dozen different libraries out there to drive them already, but [Zorxx] decided to strike out with a new technique—using I2S hardware to get the job done.

Microcontrollers traditionally use I2S interfaces to output digital audio. However, I2s also just happens to be perfect for driving tons of addressable LEDs. At the lowest level, I2S hardware is really just flipping a serial data line really fast with a clock line and a word select line for good measure. If, instead of sound, you pipe a data stream for addressable LEDs to the I2S hardware, it will clock that data out just the same!

[Zorxx] figured that at with an ESP32 trucking out I2S data at a rate of 2.6 megabits per second on the ESP32, it would be possible to update a string of 256 pixels in just 7.3 milliseconds. In other words, you could have a 16 by 16 grid updating at over 130 frames per second. Step up to 512 LEDs, and you can still run at almost 70 fps.

There’s some tricks to pulling this off, but it’s nothing you can’t figure out just by looking at the spec sheets for the WS2812B and the ESP32. Or, indeed, [Zorxx’s] helpful Github page. We’ve featured some other unorthodox methods of driving these LEDs before, too! Meanwhile, if you’ve got your own ideas on how to datablast at ever greater speeds, don’t hesitate to let us know!