TekaSketch: Where Etch A Sketch Meets Graph Theory

September 29, 2025 by Heidi Ulrich 6 Comments

The Etch A Sketch was never supposed to meet a Raspberry Pi, a camera, or a mathematical algorithm, but here we are. [Tekavou]’s Teka-Cam and TekaSketch are a two-part hack that transforms real photos into quite stunning, line-drawn Etch A Sketch art. Where turning the knobs only results in wobbly doodles, this machine plots out every curve and contour better than your fingertips ever could.

Essentially, this is a software hack mixed with hardware: an RPi Zero W 2, a camera module, Inkplate 6, and rotary encoders. Snap a picture, and the image is conveyed to a Mac Mini M4 Pro, where Python takes over. It’s stripped to black and white, and the software creates a skeleton of all black areas. It identifies corner bridges, and unleashes a modified Chinese Postman Algorithm to stitch everything into one continuous SVG path. That file then drives the encoders, producing a drawing that looks like a human with infinite patience and zero caffeine jitters. Originally, the RPi did all the work, but it was getting too slow so the Mac was brought in.

It’s graph theory turned to art, playful and serious at the same time, and it delivers quite unique pieces. [Tekavou] is planning on improving with video support. A bit of love for his efforts might accellerate his endeavours. Let us know in the comments below!

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Building A (Not Very) Portable Xbox

September 21, 2025 by Fenix Guthrie 24 Comments

Modern handheld game consoles are impressive feats of engineering, featuring full fledged computers in near pocket-sized packages. So what happens if you take an original Xbox and sprinkle on some modern electronics and create a handheld? Well, if you’re [James] of James Channel, you end up with this sandwich of PCBs held together with hot glue and duck tape.

The first order of miniaturization in this Xbox was replacing the hard drive. Because a CompactFlash card uses parallel ATA, that could be a simple drop in replacement. However, the Xbox locks the hard drive to the system requiring a mod chip for the CF card to work. Fortunately, the sacrificial Xbox came with a mod chip installed. After using an arcade machine to flash the card and copy over the contents of the drive, the CF card install was a breeze.

For the screen and batteries, a portable DVD player that had remained unused since 2006 was repurposed. The battery cells were rather unhappy, but managed to get resurrected with some careful charging. As it turns out, the iPod 30 pin connector inside the portable screen contains an S-Video line. By tapping into that and adding in some power management for the batteries, the Xbox became a pile of PCBs that could maybe be taken places.

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Two sides of a business-card shaped device are shown. On the left, it’s clear that the device is about half a centimeter thick, with a large scroll wheel visible in the center. The device cover is 3D-printed in black plastic, and has cutouts to mark where three buttons ar. On the right, the underside of the device is visible. It is a black PCB, with white text giving contact information.

Building A Macro Pad Into A Business Card

August 31, 2025 by Aaron Beckendorf 10 Comments

A business card is a convenient way to share your contact information, but it’s unfortunately prone to being thrown away or forgotten. PCB business cards try to get around this problem, but while impressive, most won’t keep the recipient engaged for a very long time. [Cole Olsen]’s macro pad business card, on the other hand, might actually get regular use.

The card has three buttons and a rotary encoder as controls, with an RGB LED to indicate the card’s current mode. It can perform three sets of functions: general productivity, serving as a presentation remote, and controlling music. The scroll wheel is the main control, and can switch through windows, desktops, and tabs, page through slides, and control music volume.

The card itself is made out of a PCB, the exposed side of which contains [Cole]’s contact information, and the other side of which is covered by a 3D-printed case. As thick as it is, this might be stretching the definition of “card” a bit, but as a mechanical engineer, [Cole] did want to demonstrate some mechanical design. A nice!nano wireless keyboard development board running ZMK firmware reads the sensors and sends commands. Conveniently for a presentation remote, the card is powered by a rechargeable battery and can work wirelessly (as a side benefit, if a recipient were minded to get rid of this card, the lithium-polymer battery would probably substantially delay disposal).

[Cole] writes that he was inspired by many of the other impressive business cards we’ve covered. Some of the macro pads we’ve seen have been marvels of miniaturization in their own right.

LEDs That Flow: A Fluid Simulation Business Card

August 12, 2025 by Matt Varian 18 Comments

Fluid-Implicit-Particle or FLIP is a method for simulating particle interactions in fluid dynamics, commonly used in visual effects for its speed. [Nick] adapted this technique into an impressive FLIP business card.

The first thing you’ll notice about this card is its 441 LEDs arranged in a 21×21 matrix. These LEDs are controlled by an Raspberry Pi RP2350, which interfaces with a LIS2DH12TR accelerometer to detect card movement and a small 32Mb memory chip. The centerpiece is a fluid simulation where tilting the card makes the LEDs flow like water in a container. Written in Rust, the firmware implements a FLIP simulation, treating the LEDs as particles in a virtual fluid for a natural, flowing effect.

This eye-catching business card uses clever tricks to stay slim. The PCB is just 0.6mm thick—compared to the standard 1.6mm—and the 3.6mm-thick 3.7V battery sits in a cutout to distribute its width across both sides of the board. The USB-C connection for charging and programming uses clever PCB cuts, allowing the plug to slide into place as if in a dedicated connector.

Inspired by a fluid simulation pendant we previously covered, this board is just as eye-catching. Thanks to [Nick] for sharing the design files for this unique business card. Check out other fluid dynamics projects we’ve featured in the past.

Hands On: The Hacker Pager

July 31, 2025 by Tom Nardi 27 Comments

It should come as no surprise that the hacker community has embraced the Meshtastic project. It’s got a little bit of everything we hold dear: high quality open source software, fantastic documentation, a roll-your-own hardware ethos, and just a dash of counterculture. An off-grid communications network cobbled together from cheap parts, some of which being strategically hidden within the urban sprawl by rogue operators, certainly sounds like the sort of thing you’d read about it in a William Gibson novel.

But while the DIY nature of Meshtastic is one of its most endearing features for folks like us, it can also be seen as one of its weak spots. Right now, the guidance for those looking to get started is to pick a compatible microcontroller development board, 3D print a case for it, screw on an antenna from AliExpress, flash your creation with the latest firmware, and then spend some quality time with the documentation and configuration tools to actually get it on the air. No great challenge for the average Hackaday reader, but a big ask for the weekend adventurer that’s just looking for a way to keep in touch with their friends while camping.

Quality hardware that offers a turn-key experience will be critical to elevating Meshtastic from a hobbyist’s pastime to something that could actually be fielded for applications such as search and rescue. Plus, let’s be honest, even those of us who like to put together our own gadgets can appreciate a more consumer-oriented piece of hardware from time to time. Especially if that hardware happens to be open source and designed to empower the user rather than hold them back.

Enter the Hacker Pager from exploitee.rs. As the name implies, it’s still very much a device intended for hackers — a piece of hardware designed for the halls of DEF CON rather than trekking through the wilderness. But it’s also an important step towards a new generation of Meshtastic hardware that meets the high standard of quality set by the software itself.

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ATtiny-Powered Business Card Plays Cracktro Hits

July 29, 2025 by Matt Varian 11 Comments

PCB business cards are a creative way to show your tech skills while getting your name out there. This take on a PCB business card, sent in by [VCC], tackles one of the big challenges with them: making them in such a way that they are cheap enough to not feel bad about handing them out.

These cards plug into a USB port for power and have over a dozen small LEDs that light up the stars on the front, and a small buzzer that can play over ten minutes of cracktro music. To keep the cost down, [VCC] went with an ATtiny1616 microcontroller costing under 50 cents and still having plenty of outputs to drive the buzzer and LEDs. The final per-unit cost prior to shipping came out to only 1.5 euros, enabling them to be handed out without worrying about breaking the bank.

To aid in the assembly of the cards, [VCC] 3D printed a jig to apply material to the back of the USB connector, building up its thickness to securely fit in the USB port. He also wrote a small script for assembly-line programming the cards, getting the programming process down to around ten seconds per card and letting him turn through prepping the cards. Thanks, [VCC], for sending in your project—it’s a great addition to other PCB business cards we’ve featured.

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A Very Tidy Handheld Pi Terminal Indeed

July 27, 2025 by Jenny List 30 Comments

As single board computers have become ever smaller and more powerful, so have those experimenting with them tried to push the boundaries of the machines they can be used in. First we had cyberdecks, and now we have handheld terminals. Of this latter class we have a particularly nice example from [Random Alley Cat]. It takes a Raspberry Pi Zero 2W and a handful of other parts, and makes them with a 3D printed case into something very professional indeed.

One of the problems with these designs has always been tidily packing away all the parts with their cables, and it’s one she solves by making a chassis to hold all the parts, and a case which fits around that. In a stroke the case no longer has to provide a dual function, allowing for a much easier internal layout. Her screen is a Pimoroni Hyperpixel, the keyboard is an Xbox 360 accessory, and the power supply is an off the shelf Pi UPS board and battery.

We particularly like the accesses on the underside of this machine to access the Pi ports, and the ventilation holes and external case details. It’s not perfect, as she says in the video below it’s not the best Linux keyboard. but we could really see ourselves using this.

If you follow handheld cyberdecks, we have a few treats for you on these pages. Not all of them run Linux, for example.

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