Author: Heidi Ulrich

142 Articles

Two hands working a TekaSketch

TekaSketch: Where Etch A Sketch Meets Graph Theory

September 29, 2025 by 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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Franke A600 coffee machine with PicoVoice

Coffee By Command: The Speech2Touch Voice Hack

September 24, 2025 by 1 Comment

If you were to troll your colleagues, you can label your office coffee maker any day with a sticker that says ‘voice activated’. Now [edholmes2232] made it actually come true. With Speech2Touch, he grafts voice control onto a Franke A600 coffee machine using an STM32WB55 USB dongle and some clever firmware hacking.

The office coffee machine has been a suspect for hacking for years and years. Nearly 35 years ago, at Cambridge University, a webcam served a live view of the office coffee pot. It made sure nobody made the trip to the coffee pot for nothing. The funny, but in fact useless HTTP status 418 was brought to life to state that the addressed server using the protocol was in fact a teapot, in answer to its refusal to brew coffee. Enter this hack – that could help you to coffee by shouting from your desk – if only your arms were long enough to hold your coffee cup in place.

Back to the details. The machine itself doesn’t support USB keyboards, but does accept a USB mouse, most likely as a last resort in case the touchscreen becomes irresponsive. That loophole is enough: by emulating touchscreen HID packets instead of mouse movement, the hack avoids clunky cursors and delivers a slick ‘sci-fi’ experience. The STM32 listens through an INMP441 MEMS mic, hands speech recognition to Picovoice, and then translates voice commands straight into touch inputs. Next, simply speaking to it taps the buttons for you.

It’s a neat example of sidestepping SDK lock-in. No reverse-engineering of the machine’s firmware, no shady soldering inside. Instead, it’s USB-level mischief, modular enough that the same trick could power voice control on other touchscreen-only appliances.

A piece of perovskite crystal

Perovskite Solar Cell Crystals See The Invisible

September 16, 2025 by 14 Comments

A new kind of ‘camera’ is poking at the invisible world of the human body – and it’s made from the same weird crystals that once shook up solar energy. Researchers at Northwestern University and Soochow University have built the first perovskite-based gamma-ray detector that actually works for nuclear medicine imaging, like SPECT scans. This hack is unusual because it takes a once-experimental lab material and shows it can replace multimillion-dollar detectors in real-world hospitals.

Current medical scanners rely on CZT or NaI detectors. CZT is pricey and cracks like ice on a frozen lake. NaI is cheaper, but fuzzy – like photographing a cat through steamed-up glass. Perovskites, however, are easier to grow, cheaper to process, and now proven to detect single photons with record-breaking precision. The team pixelated their crystal like a smartphone camera sensor and pulled crisp 3D images out of faint radiation traces. The payoff: sharper scans, lower radiation doses, and tech that could spread beyond rich clinics.

Perovskite was once typecast as a ‘solar cell wonder,’ but now it’s mutating into a disruptive medical eye. A hack in the truest sense: re-purposing physics for life-saving clarity.

Street with polluted smoggy air

Serious Chemical Threat Sniffer On A Budget

September 16, 2025 by 40 Comments

Chemical warfare detection was never supposed to be a hobbyist project. Yet here we are: Air Quality Guardian by [debdoot], the self-proclaimed world’s first open source chemical threat detection system, claims to pack lab-grade sensing into an ESP32-based build for less than $100. Compare that with $10,000+ black-box hardware and you see why this is worth trying at home, even if this project might not have the nut cracked just yet.

Unlike your air monitor from IKEA, the device aims to analyze raw gas sensor resistance – ohm-level data most devices throw away – combined with temporal spikes, humidity correlations, and a database of 35+ signatures. Of course, there is a lot of work to be done here on the calibration side, and we don’t have any chemical warfare agents on hand to test against, so we have no idea how well it works, and we’d expect false positives. Still, the idea of taking a more granular look at the data coming off the sensor may bear some fruit.

(Editor’s note: edited with a hefty dash of skeptical salt.)

Featured Image by Arjun Lama on Unsplash

Close up of a multi-USB tester PCB

Troubled USB Device? This Tool Can Help

August 26, 2025 by 18 Comments

You know how it goes — some gadgets stick around in your toolbox far longer than reason dictates, because maybe one day you’ll need it. How many of us held onto ISA diagnostic cards long past the death of the interface?

But unlike ISA, USB isn’t going away anytime soon. Which is exactly why this USB and more tester by [Iron Fuse] deserves a spot in your toolbox. This post is not meant to directly lure you into buying something, but seen how compact it is, it would be sad to challenge anyone to reinvent this ‘wheel’, instead of just ordering it.

So, to get into the details. This is far from the first USB tester to appear on these pages, but it is one of the most versatile ones we’ve seen so far. On the surface, it looks simple: a hand-soldered 14×17 cm PCB with twelve different connectors, all broken out to labelled test points. Hook up a dodgy cable or device, connect a known-good counterpart, and the board makes it painless to probe continuity, resistance, or those pesky shorts where D+ suddenly thinks it’s a ground line.

You’ll still need your multimeter (automation is promised for a future revision), but the convenience of not juggling probes into microscopic USB-C cavities is hard to overstate. Also, if finding out whether you have a power-only or a data cable is your goal, this might be the tool for you instead.

Digital prototype of Zeusfilter 1.0

How To Stop Zeus From Toasting Your Pi

August 22, 2025 by 18 Comments

If you’ve ever lost gear to lightning or power spikes, you know what a pain they are. Out in rural Arkansas, where [vinthewrench] lives, the grid is more chaos than comfort – especially when storms hit. So, he dug into the problem after watching a cheap AC-DC module quite literally melt down. The full story, as always, begins with the power company’s helpful reclosers: lightning-induced surges, and grid switching transients. The result though: toasted boards, shorted transformers, and one very dead Raspberry Pi. [vinthewrench] wrote it all up – with decent warnings ahead. Take heed and don’t venture into things that could put your life in danger.

Back to the story. Standard surge suppressors? Forget it. Metal-oxide varistor (MOV)-based strips are fine for office laptops, but rural storms laugh at their 600 J limits. While effective and commonly used, MOVs are “self-sacrificing” and degrade over time with each surge event.

[vinthewrench] wanted something sturdier. Enter ZeusFilter 1.0 – a line-voltage filter stitched together from real parts: a slow-blow fuse, inrush-limiting thermistor, three-electrode gas discharge tube for lightning-class hits, beefy MOVs for mid-sized spikes, common-mode choke to kill EMI chatter, and safety caps to bleed off what’s left. Grounding done right, of course. The whole thing lives on a single-layer PCB, destined to sit upstream of a hardened PSU.

As one of his readers pointed out, though, spikes don’t always stop at the input. Sudden cut-offs on the primary can still throw nasty pulses into the secondary, especially with bargain-bin transformers and ‘mystery’ regulators. The reader reminded that counterfeit 7805s are infamous for failing short, dumping raw input into a supposedly safe 5 V rail. [vinthewrench] acknowledged this too, recalling how collapsing fields don’t just vanish politely – Lenz makes sure they kick back hard. And yes, when cheap silicon fails, it fails ugly: straight smoke-release mode.

In conclusion, we’re not particularly asking you to try this at home if you lack the proper knowledge. But if you have a high-voltage addiction, this home research is a good start to expand your knowledge of what is, in theory, possible.

Close up of a DIY minimalist EDC multitool, a penny, and a paperclip

This Pocket Multitool Weighs Less Than A Penny

August 21, 2025 by 26 Comments

A multitool that weighs less than a penny? Yes, it exists. This video by [ToolTechGeek] shows his titanium flat-cut design tipping the scales at only 1.9 grams—lighter than the 2.5-gram copper penny jingling in your pocket. His reasoning: where most everyday carry (EDC) tools are bulky, overpriced, or simply too much, this hack flips the equation: reduce it to the absolute minimum, yet keep it useful.

You might have seen this before. This second attempt is done by laser-cutting titanium instead of stainless steel. Thinner, tougher, and rust-proof, titanium slashes the weight dramatically, while still keeping edges functional without sharpening. Despite the size, this tool manages to pack in a Phillips and flathead screwdriver, a makeshift saw, a paint-lid opener, a wire bender (yes, tested on a paperclip), and even a 1/4″ wrench doubling as a bit driver. High-torque screwdriving by using the long edges is a clever exploit, and yes—it scrapes wood, snaps zip ties, and even forces a bottle cap open, albeit a bit roughly.

It’s not about replacing your Leatherman; it’s about carrying something instead of nothing. Ultra-minimalist, featherlight, pocket-slip friendly—bet you can’t find a reason not to just have it in your pocket.

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