Your AI Ham Radio Buddy

July 18, 2026 by Al Williams 1 Comment

AI chatbots are everywhere these days, and they seem to “know” about everything. But while that is a strength, it can sometimes be a weakness because it isn’t laser-focused on one topic. Not so with this Ham-radio-centric chatbot called HamGPT. The service is clearly built on another GPT engine but understands how to retrieve data from common ham radio sources, such as the FCC database, propagation reports, and the like. It didn’t, however, seem to have access to ham radio-related books, magazine articles, or other “static” data that we could tell.

You do have to sign up for an account, which includes providing your callsign and location. There is a free tier that allows a limited number of queries per day, so you can try it to see if it is useful for you without subscribing.

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Calculator UI Is More Complex Than You Might Think

July 18, 2026 by Donald Papp 9 Comments

Calculators are so ubiquitous and so familiar that they are easy to take for granted in many different ways. [lcamtuf] points out one that has probably never occurred to many of us: the user interface for a calculator is an unexpectedly complex thing.

The internal logic to support sequential inputs and multiple operators in a way that feels intuitive is a complex thing.

Resolving something like 1 + 2 = is pretty straightforward but complexity compounds rapidly after that, with numerous special cases. Let’s imagine one decides to program a simple calculator UI as a weekend project. The development process might look a little like this:

User types in 1 + 2 = and the calculator displays 3. What happens if the user immediately presses -?
No problem, just consider the result of the previous operation as an already-there input. So we’ll have 3 - for this next operation, and wait for more.
Unless we should have treated that - as a negative sign for whatever number is coming next, making it a negative number? No, ignore that. Just treat whatever results from pressing equals as a pre-typed input.
Unless the user hits a number. Because if they hit 2 (for example) then we’ll have a 32 and not a 2 which they probably, definitely don’t expect. So that’s a special case and we should insert a clear if that happens.
Oh, better clear if the user enters a decimal, too.
I’m going to need a coffee…

And that’s just the tip of the iceberg. Imagine trying to figure all this out for the very first time, without the benefits of habit and history to fall back on.

The fact is that supporting the apparently trivial behavior of a simple calculator requires an underlying complex state machine that deals with all kinds of special cases in order to make the UI feel intuitive. And that’s just for a basic four-function calculator; we haven’t even touched on how special keys like % should behave.

We know [lcamtuf] speaks from experience, not just because of their deep knowledge of calculator history but because they rolled their own calculator that uses voltmeters as digit displays and there’s nothing like actually implementing something to make one appreciate it.

ESP32-driven Roulette Wheel Could Have Used A 555, But That Didn’t Have WiFi

July 18, 2026 by Tyler August 4 Comments

Sometimes you see a project and immediately, before going into the details, your mind throws up the old refrain: “coulda used a 555” — well, [Hulk] actually agrees when it comes to his ESP32-based, 3D printed roulette wheel. The first version did use a 555, but then feature creep kicked in and the final project ended up with an ESP32 instead. We’ve all been there.

The roulette wheel circuit is retained from the 555 version, with the ESP32 providing clock pulses instead of the venerable oscillator chip — it uses a pair of decade counters to create the chase effect of the LED around the wheel. With a handsome printed enclosure, [Hulk] could have stopped there, but then he’d have to keep track of scoring and the like manually like some kind of dark age peasant. It’s the 21st century, we have computers to to that for us!

Now, even though the ESP32 is still driving the LED chase via the decade counters, it can keep track of where the “ball” of light lands, and reports that via WiFi or serial. While it would have been an option to run the whole game on the ESP32. [Hulk] just has those values put into an SQL database on a server, which also runs the game front-end via PHP. The resulting web page lets two players make their bets and track their wins and losses over time. You can see that in action in the video embedded below.

Overkill? Sure, but we suspect [Hulk] already had the equipment and experience to make this the fastest way to get a playable game. There are easy ways to serve web content from an ESP32, but the easiest tool to use is always the one in your back pocket, right?

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Simple Games From A Simpler Time

July 18, 2026 by Elliot Williams 15 Comments

Modern video games are nothing short of amazing. My son and I were playing through the one of the latest Zeldas, which involve a mix of combat and puzzle-solving that’s pretty much the hallmark of the franchise. But the most recent open-world Zelda is simply massive. Made by around 1,000 people at a development expense of $150,000,000, it takes probably 60-80 hours to play through if you’re not rushing, and more if you’re taking it easy. It has layers of game mechanics, and worlds in the sky, on land, and underground. It’s big in every way.

Contrast the games of my youth, which were a lot smaller. Written by a pair of people or maybe a handful, with playtimes in the single-digit hours, and of course fitting in the limited computing resources of the time. But the low-stakes nature of the early phases of the industry meant that software developers could take risks, and many of the games were consequently kinda idiosyncratic in this more innocent time.

I think there’s something to be said for small games. They don’t require a lifestyle commitment just to get through. They can still be fun, without taking all of your time. And honestly, when you’re done with a game quickly, you have more time for other stuff. Granted, some of this spirit lives on in the small indie games of today, but even so, game developers have the big studios’ products in the backs of their minds when they are working on their smaller oeuvres.

We were talking about preserving old games for posterity around Hackaday and on the podcast, and our conversations reminded me of a couple of educational games that, despite their rudimentary graphics, are still pretty good today. Both were electronics related, and both are still playable today thanks to efforts on emulation and software preservation. To get a feel for the 1980’s, give Rocky’s Boots a try. (I like the TRS-80 Color Computer version the best, but that may just be nostalgia.) Most of you grownups out there will get through it in an hour or so.

And if you want a challenge, try Rocky’s harder sequel: Robot Odyssey. If you already have a background in digital circuits, you’ll find it doable. Younger me hit a wall about two-thirds of the way through.

Both of these games stick with me because they taught me something, but also because they were simply quirky in a way that a game can only be when it’s written by a small team of folks who are just having fun programming it. If you pitched “a puzzle game about a raccoon who builds logic circuits to activate robot boots”, the boardroom would look at you like you’re out of your mind. But it’s just exactly the quirkiness and individuality of some of these early games that I cherish the most.

If you find yourself knee-deep in an endless modern game, take a side-quest off into a more naive time, and you’ll appreciate why people are putting efforts into archiving them.

Spidery Drone Goes Near-invisible By Spinning Really, Really Fast

July 18, 2026 by Donald Papp 11 Comments

Researchers demonstrate that something interesting happens when a small drone with a spindly airframe spins at a high speed: it very nearly turns invisible. The spidery device is shown mounted in its launcher in the image above. The dark blur at the rightmost side is an outlet on the wall behind the drone, not motion blur from a moving part.

There’s not much to do about the noise, but a high-speed spin becomes nearly invisible.

It’s called the Phantom Twist, and while we’ve seen single-motor drones that spin around a central axis before, they have always incorporated a wing-like structure or cleverly leverage the magnus effect to generate lift.

There’s not a lot of detail about the Phantom Twist’s hardware design but it appears to use a downward-angled motor for lift, relying on a high-speed control system to maneuver and maintain altitude.

This does away with the need for a wing, at the cost of only being stable while rotating at a high speed. We imagine it is also a touchy design that depends greatly on being balanced just so.

A hand launcher spins the device up before releasing it for flight. The visual effect once it is up and running is pretty striking; see for yourself in the short video, embedded just below.

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A scanning-electron micrograph is shown of a cricket's body, focusing on the head, which has been sliced off just above the eyes.

Cross-Sectioning Crickets With A Femtosecond Laser

July 18, 2026 by Aaron Beckendorf 8 Comments

Unlike most cutting lasers, femtosecond lasers don’t vaporize materials; rather, they produce such short, intense bursts of light that the affected region is ablated without having the chance to heat its surroundings. This makes them good at cutting away material without damaging the surroundings, something [Ben Krasnow] exploited to cut cross-sections of samples while still in a scanning-electron microscope.

In this case, the samples were crickets, and before imaging they had to be prepared. First, the bodies were soaked in glutaraldehyde to cross-link the proteins and stabilize the structure. Next, a series of solvent exchanges replaced the water in the bodies with a low-surface-tension solvent; this meant that during the next step, drying, surface tension wouldn’t distort the crickets’ internal structure. Finally, the insect bodies were charred under argon, which made the bodies conductive and more absorptive to laser light.

The laser itself and the scanning galvo are mounted outside the microscope, and shine in through a transparent window. To protect the detector and electron optics from a spray of ablated carbon, a servo motor swings an aluminium shutter between these and the sample while the laser is active. This caused some mysterious problems during testing: after the first ablation run, the electron microscope’s image would contain so much noise as to be unusable, but it would improve over time. As it turned out, the shutter was painted, and the other side of the paint was getting coated with charged carbon particles. This created a small capacitor which disrupted the electron optics as it discharged. Eventually, after solving this and a few other strange problems, [Ben] was able to take several time-lapse videos of the laser gradually ablating a cricket, 30 microns at a time, revealing its inner structure.

Although scanning-electron microscopes are unfortunately shard to come by, it’s still possible to restore a secondhand microscope or, as [Ben] did, build your own. Femtosecond lasers are yet more inaccessible, though they can be used to replicate themselves.

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Flex Filament Stuck To Your Build Platform? Reach For The Isopropanol

July 17, 2026 by Donald Papp 6 Comments

3D printing has been around long enough that everyone’s heard at least one weird trick regarding 3D prints. [Angus] of [Maker’s Muse] puts a few to the test, and came away with one solid tip for releasing TPU from a build platform to which it has unfortunately welded itself.

Flexible filaments tend to stick too well to build plates, which is why an interface layer like a thin layer of glue stick is called for. But what if one forgets to apply it before starting a print job? That can result in a print that is well and truly stuck. Peeling flex filament off a textured PEI bed is a bad time, because the print can tear and tends to leave little bits behind.

[Angus] heard that applying isopropyl alcohol helps release things in that case, so he gives it a try. Lo and behold, it seems to work! See for yourself at 18:10 in the video and keep it in mind if you end up in a similar situation. The print doesn’t exactly fall off on its own, but it does remain in one piece which is more than one can expect otherwise.

Watching isopropyl alcohol help release a stuck print is reminiscent of the way it also removes hot glue from just about any surface. The trick is getting the alcohol to wick in underneath for best results, and the same seems to be true with releasing TPU from a build plate.

One thing to keep in mind when evaluating tips and tricks from over the years is that the landscape changes. Something that maybe seemed to have potential years ago might not make much sense today. A good example is sugar as a bed adhesive, which [Angus] tries out. What started as an experiment in getting PLA to play better with glass build plates years ago doesn’t really carry over to now, with PEI-coated magnetic build platforms pretty much a solved problem. The more likely result nowadays is just a mess.

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