Quasi-Quantifying Qubits For 100 Quid

July 14, 2025 by Adam Zeloof No comments

As part of his multi-year project to build a quantum computer, hacakday.io poster [skywo1f] has shared with us his most recent accomplishment — a Nuclear Magnetic Resonance Spectrometer, which he built for less than $100.

The NMR spectrometer is designed to disturb protons, which naturally line up according to the Earth’s magnetic field, using an electric coil. Once disturbed, the protons nutate (a fancy physics word for wobble), and flip quantum spin states. [skywo1f]’s NMR device can detect these spin state changes, as he demonstrates with a series of control experiments designed to eliminate sources of false positives (which can be annoyingly prevalent in experimental physics). His newest experimental device includes a number of improvements over previous iterations, including proper shielding, quieter power topology, and better coil winding in the core of the device. Everything was assembled with cost in mind, while remaining sensitive enough to conduct experiments — the whole thing is even driven by a Raspberry Pi Pico.

Here at Hackaday, we love to see experiments that should be happening in million-dollar laboratories chugging along on kitchen tables, like this magnetohydrodynamic drive system or some good old-fashioned PCB etching. [skywo1f] doesn’t seem to be running any quantum calculations yet, but the NMR device is an important building block in one flavor of quantum computer, so we’re excited to see where he takes his work next.

Introducing PooLA Filament: Grass Fiber-Reinforced PLA

July 14, 2025 by Maya Posch 11 Comments

We’re probably all familiar with adding wood dust, hemp and carbon fibers to PLA filament, but there are so many other fillers one could add. During the completely unrelated recent heatwave in Germany, [Stefan] from CNCKitchen decided to give a new type of biodegradable filler type a shot by scooping some freshly dried cow patties off the very picturesque grazing fields near his place. In the resulting video a number of questions are answered about this ‘PooLA’ that nobody was asking, such as whether it makes for a good filler, and whether it smells bad while printing.

Perhaps unsurprisingly to those who have spent any amount of time around large herbivores like cows, cow dung doesn’t smell bad since it’s mostly composed of the grass fibers that are left over after the cow’s multiple stomachs and repeated chewing have done their thing. As [Stefan] and his colleagues thus found out was that printing with PooLA smells like printing with grass.

As for the practical benefits of PooLA, it adds a nice coloring, but like other ‘reinforced’ PLA filaments seems to trade flexibility for stiffness, so that at ratios of cow dung powder between 5 to 20% added to the PLA powder the test parts would break faster. Creating the filament was also a bit of a chore, for reasons that [Stefan] still has to figure out.

That said, aside from the technically unneeded bacterial corpses and other detritus in cow patties, using grass fibers in FDM filament isn’t a crazy idea, and might fit right in there with other fibers.

Continue reading “Introducing PooLA Filament: Grass Fiber-Reinforced PLA” →

Record Changer Spins Round And Round

July 14, 2025 by Al Williams No comments

There was a time when all the cool kids had a 45 RPM record player. [RF Burns] picked up a 1950s-era player from RCA. However, it needed a lot of work. The good news? We get to see the teardown and the result in a two-part video series, which you can see below. If you are looking for the schematic, you’ll have to wait for the second video.

These were made to be cheap, so there were many parts that needed replacement or, at least TLC. The automation of the record changer was all done with an eccentric wheel, which is satisfyingly low-tech. We were surprised that it still seemed to work after everything was cleaned up.

Inside were two active tubes and a rectifier tube to amplify the signal from the needle. A coat of paint made it look great, and a polarized power cord made it safer.

There was also an unamplified version of the player you can see at the end of the second video. All the same things except for the tube amplifier, of course.

If you are too young to have fond memories of 45s, here’s a primer on how records work. The record player we really want is mobile.

Do You Trust This AI For Your Surgery?

July 14, 2025 by Ian Bos 19 Comments

If you are looking for the perfect instrument to start a biological horror show in our age of AI, you have come to the right place. Researchers at Johns Hopkins University have successfully used AI-guided robotics to perform surgical procedures. So maybe a bit less dystopian, but the possibilities are endless.

Pig parts are used as surrogate human gallbladders to demonstrate cholecystectomies. The skilled surgeon is replaced with a Da Vinci research kit, similarly used in human controlled surgeries.

Researchers used an architecture that uses live imaging and human corrections to input into a high-level language model, which feeds into the controlling low-level model. While there is the option to intervene with human input, the model is trained to and has demonstrated the ability to self-correct. This appears to work fairly well with nothing but minor errors, as shown in an age-restricted YouTube video. (NOTE: SURGICAL IMAGERY WATCH AT YOUR OWN RISK)

It’s noted that the robot performed slower than a traditional surgeon, trading time for precision. As always, when talking about anything medical, it’s not likely we will be seeing it on our own gallbladders anytime soon, but maybe within the next decade. If you want to read more on the specific advancements, check out the paper here.

Medical hacking isn’t always the most appealing for anyone with a weak stomach. For those of us with iron guts make sure to check out this precision tendon tester!

2025 One Hertz Challenge: Valvano Clock Makes The Seconds Count

July 14, 2025 by Tyler August 2 Comments

A man named [Jim Valvano] once said “There are 86,400 seconds in a day. It’s up to you to decide what to do with them.” — while we couldn’t tell you who [Jim Valvano] was without a google search*, his math checks out. The quote was sufficiently inspirational to inspire [danjovic] to create a clock count those seconds precisely.

It’s a simple project, both conceptually and electrically. All it does is keep time and count the seconds in the day– a button press switches between counting down, counting up, and HH:MM:SS. In every mode, though, the number displayed will change at one Hertz, which we appreciate as being in the spirit of the challenge. There are only four components: an Arduino Nano, a DS3231 RTC module, a SSD1306 128×64 OLED module, and a momentary pushbutton. At the moment it appears this project is only on breadboard, which is a shame– we think it deserves to have a fancy enclosure and pride of place on the wall. Wouldn’t you be more productive if you could watch those 86,400 seconds ticking away in real time? We think it would be motivating.

Perhaps it will motivate you to create something for our One Hertz Challenge. Plenty of seconds to go until the deadline on August 19th, after all. If you’d rather while away the time reading, you can check out some of [danjovic]’s other projects, like this Cistertian-inspired clock, or this equally-inscruitable timekeeper that uses binary-coded octal.

*Following a google search, he was an American college basketball coach in the mid-20th century.

Robots Want The Jobs You Can’t Do

July 14, 2025 by Al Williams 7 Comments

There’s something ominous about robots taking over jobs that humans are suited to do. Maybe you don’t want a job turning a wrench or pushing a broom, but someone does. But then there are the jobs no one wants to do or physically can’t do. Robots fighting fires, disarming bombs, or cleaning up nuclear reactors is something most people will support. But can you climb through a water pipe from the inside? No? There are robots that are available from several commercial companies and others from university researchers from multiple continents.

If you think about it, it makes sense. For years, companies that deal with pipes would shoot large slugs, or “pigs”, through the pipeline to scrape them clean. Eventually, they festooned some pigs with sensors, and thus was born the smart pig. But now that it is possible to make tiny robots, why not send them inside the pipe to inspect and repair?

Continue reading “Robots Want The Jobs You Can’t Do” →

Coroutines In C

July 14, 2025 by Al Williams 14 Comments

It is virtually a rite of passage for C programmers to realize that they can write their own cooperative multitasking system. C is low-level enough, and there are several ways to approach the problem, so, like Jedi light sabers, each one is a little bit different. [Christoph Wolcher] took his turn, and not only is his system an elegant hack, if that’s not an oxymoron, it is also extremely well documented.

Before you dig in, be warned. [Christoph] fully admits that you should use an RTOS. Or Rust. Besides, after he finished, he discovered the protothreads library, which does a similar task in a different way that is both more cool and more terrible all at the same time.

Once you dig in, though, you’ll see the system relies on state machines. Just to prove the point, he writes a basic implementation, which is fine, but hard to parse and modify. Then he shows a simple implementation using FreeRTOS, which is fine except for, you know, needing FreeRTOS.

Using a simple set of macros, it is possible to get something very similar to the RTOS version that runs independently, like the original version. Most of the long code snippets show you what code the macros generate. The real code is short and to the point.

Multiprocessing is a big topic. You can have processes, threads, fibers, and coroutines. Each has its pros and cons, and each has its place in your toolbox.