ATTiny NFC Thermometer keychain with keys

Tiny NFC-Powered Keychain Thermometer

What if your keychain could tell you the temperature, all while staying battery-free? That’s the essence of this innovative keychain ‘NFC_temp’ by [bjorn]. This nifty gadget harnesses energy from an NFC field—like the one created by your smartphone—to power itself just long enough to take a precise temperature reading. Using components like an ATTiny1626 microcontroller, a TMP117 thermometer, and an RF430CL330H NFC IC, NFC_temp cleverly stores harvested power in a capacitor to function autonomously.

The most impressive part? This palm-sized device (18×40 mm) uses a self-designed 13.56 MHz antenna to draw energy from NFC readers. The temperature is then displayed on the reader, with an impressive accuracy of ±0.1 °C. Creator [bjorn] even shared challenges, like switching from an analog sensor due to voltage instability, which ultimately led to his choice of the TMP117. Android phones work best with the tag, while iOS devices require a bit more angling for reliable detection.

Projects like NFC_temp underscore the creativity within open source. It’s a brilliant nod to the future of passive, wireless, energy-efficient designs. Since many of us will all be spending a lot of time around the Christmas tree this month, why not fit it in a bauble?

Pixel mashup with Wasm-4 logo and retro graphics

WASM-4: Retro Game Dev Right In Your Browser

Have you ever dreamt of developing games that run on practically anything, from a modern browser to a microcontroller? Enter WASM-4, a minimalist fantasy console where constraints spark creativity. Unlike intimidating behemoths like Unity, WASM-4’s stripped-back specs challenge you to craft games within its 160×160 pixel display, four color palette, and 64 KB memory. Yes, you’ll curse at times, but as every tinkerer knows, limitations are the ultimate muse.

Born from the WebAssembly ecosystem, this console accepts “cartridges” in .wasm format. Any language that compiles to WebAssembly—be it Rust, Go, or AssemblyScript—can build games for it. The console’s emphasis on portability, with plans for microcontroller support, positions it as a playground for minimalist game developers. Multiplayer support? Check. Retro vibes? Double-check.

Entries from a 2022’s WASM-4 Game Jam showcase this quirky console’s charm. From pixel-perfect platformers to byte-sized RPGs, the creativity is staggering. One standout, “WasmAsteroids,” demonstrated real-time online multiplayer within these confines—proof that you don’t need sprawling engines to achieve cutting-edge design. This isn’t just about coding—it’s about coding smart. WASM-4 forces you to think like a retro engineer while indulging in modern convenience.

WASM-4 is a playground for anyone craving pure, unadulterated experimentation. Whether you’re a seasoned programmer or curious hobbyist, this console has the tools to spark something great.

KiCad render of µLind pcb

The 6809 8-Bit Microcomputer: A Father-Son Odyssey

If you’re nostalgic for the golden age of microprocessors and dream of building your own computer, this story might spark your imagination. [Eric Lind], passionate retro enthusiast and his 14-year-old son, embarked on a mission to craft a microcomputer from scratch, centred around the exotic Motorola 6809 chip: the µLind.

What sets this project apart is its ambition: bridging retro computing with modern enhancements. Starting with just a 6809 and some basic peripherals, the men designed a multi-stage roadmap to realize their dream. Each stage brought new challenges: debugging an address decoder, reworking memory management, and evolving glue logic into programmable GAL chips. Fascinatingly, the project isn’t just about nostalgia—it’s a playground for exploring multitasking operating systems and pushing the boundaries of 8-bit computing.

Their creativity shines in solutions like a C64-compatible joystick port, add-on expansion cards, and a memory overkill of 1MB RAM. With every setback—a missing pull-up resistor or a misrouted IRQ signal—their determination grew stronger. By combining old-school know-how with modern tools like KiCad, they’ve created something that is both personal and profoundly inspiring.

[Eric]’s hope and goal is to establish a community of people that want to expand beyond the traditional Z80 and 6502 based SBC’s. Interested? Read [Eric]’s project log on Hackaday.io and start crafting!

Brain on a chip setup with a hand and a dropper

Gray Matter On A Chip: Building An Artificial Brain With Luminol

Ever wondered if you could build a robot controlled by chemical reactions? [Marb] explores this wild concept in his video, merging chemistry and robotics in a way that feels straight out of sci-fi. From glowing luminol reactions to creating artificial logic gates, [Marb]—a self-proclaimed tinkerer—takes us step-by-step through crafting the building blocks for what might be the simplest form of a chemical brain.

In this video, the possibilities of an artificial chemical brain take centre stage. It starts with chemical reactions, including a fascinating luminol-based clock reaction that acts as a timer. Then, a bionic robot hand makes its debut, complete with a customised interface bridging the chemical and robotic worlds. The highlight? Watching that robotic hand respond to chemical reactions!

The project relies on a “lab-on-a-chip” approach, where microfluidics streamline the processes. Luminol isn’t just for forensic TV shows anymore—it’s the star of this experiment, with resources like this detailed explanation breaking down the chemistry. For further reading, New Scientist has you covered.

We’ve had interesting articles on mapping the human brain before, one on how exactly brains might work, or even the design of a tiny robot brain. Food for thought, or in other words: stirring the gray matter.

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PI Board chess board on a table in a room

Chess What: One More Pi-Powered Board

Chess is timeless, but automating it? That’s where the real magic begins. Enter [Tamerlan Goglichidze]’s Pi Board, an automated chess system that blends modern tech with age-old strategy. Inspired by Harry Potter’s moving chessboard and the commercial Square Off board, [Tamerlan] re-imagines the concept using a Raspberry Pi, stepper motors, and some clever engineering. It’s not just about moving pieces — it’s about doing so with precision and flair.

At its core, the Pi Board employs an XY stepper motor grid coupled with magnets to glide chess pieces across the board. While electromagnets seemed like a promising start, [Tamerlan] found them impractical due to overheating and polarity-switching issues. Enter servo linear actuators: efficient, precise, and perfect for the job.

But the innovation doesn’t stop there. A custom algorithm maps the 8×8 chess grid, allowing motors to track positions dynamically—no tedious resets required. Knight movements and castling? Handled with creative coding that keeps gameplay seamless. [Tamerlan] explains it all in his sleekly designed build log.

Though it hasn’t been long since we featured a Pi-powered LED chess board, we feel that [Tamerlan]’s build stands out for its ingenuity and optimization. For those still curious, we have a treasure trove of over fifty chess-themed articles from the last decade. So snuggle up during these cold winter months and read up on these evergreens!

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Receipt paper mural from above eye level

Massive Mural From Thermal Receipt Paper

Turning trash into art is something we undoubtedly all admire. [Davis DeWitt] did just that with a massive mural made entirely from discarded receipt paper. [Davis] got lucky while doing some light dumpster diving, where he stumbled upon the box of thermal paper rolls. He saw the potential them and, armed with engineering skills and a rental-friendly approach, set out to create something original.

The journey began with a simple test: how long can a receipt be printed, continuously? With a maximum length of 10.5 feet per print, [Davis] designed an image for the mural using vector files to maintain a high resolution. The scale of the project was a challenge in itself, taking over 13 hours to render a single image at the necessary resolution for a mural of this size. The final piece is 30 foot (9.144 meters) wide and 11 foot (3.3528 meters) tall – a pretty conversational piece in anyone’s room – or shop, in [Davis]’ case.

Once the design was ready, the image was sliced into strips that matched the width of the receipt paper. Printing over 1,000 feet of paper wasn’t without its issues, so [Davis] designed a custom spool system to undo the curling of the receipts. Hanging the mural involved 3D-printed brackets and binder clips, allowing the strips to hang freely with a kinetic effect.

Though the thermal paper will fade over time, the beauty of this project lies in its adaptability—just reprint any faded strips. Want to see how it all came together? Watch the full process here.

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Historical map of The Netherlands overlayed with clouds

Hacking Global Positioning Systems Onto 16th-Century Maps

What if GPS had existed in 1565? No satellites or microelectronics, sure—but let’s play along. Imagine the bustling streets of Antwerp, where merchants navigated the sprawling city with woodcut maps. Or sailors plotting Atlantic crossings with accuracy unheard of for the time. This whimsical intersection of history and tech was recently featured in a blog post by [Jan Adriaenssens], and comes alive with Bert Spaan’s Allmaps Here: a delightful web app that overlays your GPS location onto georeferenced historical maps.

Take Antwerp’s 1565 city map by Virgilius Bononiensis, a massive 120×265 cm woodcut. With Allmaps Here, you’re a pink dot navigating this masterpiece. Plantin-Moretus Museum? Nailed it. Kasteelpleinstraat? A shadow of the old citadel it bordered. Let’s not forget how life might’ve been back then. A merchant could’ve avoided morning traffic and collapsing bridges en route to the market, while a farmer relocating his herd could’ve found fertile pastures minus the swamp detour.

Unlike today’s turn-by-turn navigation, a 16th-century GPS might have been all about survival: avoiding bandit-prone roads, timing tides for river crossings, or tracking stars as backup. Imagine explorers fine-tuning their Atlantic crossings with trade winds mapped to the mile. Georeferenced maps like these let us re-imagine the practical genius of our ancestors while enjoying a modern hack on a centuries-old problem.

Although sites like OldMapsOnline, Google Earth Timelapse (and for the Dutch: TopoTijdreis) have been around for a while, this new match of technology and historical detail is a true gem. Curious to map your own world on antique charts? Navigate to Allmaps and start georeferencing!