Author: Al Williams

4318 Articles

Calipers: Do You Get What You Pay For?

August 11, 2025 by 53 Comments

Generally, you think that if you pay more for something, it must be better, right? But that’s not always true. Even if it is true at the lower end, sometimes premium brands are just barely better than the midrange. [Project Farm] looks at a bunch of different calipers — a constant fixture around the shop if you do any machining, 3D printing, or PCB layout. The price range spans from less than $10 for some Harbor Freight specials to brands like Mitutoyo, which cost well over $100. Where’s the sweet spot? See the video below to find out.

The first part of the video covers how much the units weigh, how smooth the action is, and how much force it takes to push it down. However, those are not what you probably care most about. The real questions are how accurate and repeatable they are.

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Neon Bulbs? They’re A Gas!

August 11, 2025 by 39 Comments

When you think of neon, you might think of neon signs or the tenth element, a noble gas. But there was a time when neon bulbs like the venerable NE-2 were the 555 of their day, with a seemingly endless number of clever circuits. What made this little device so versatile? And why do we see so few of them today?

Neon’s brilliant glow was noted when William Ramsay and Morris Travers discovered it in 1898. It would be 1910 before a practical lighting device using neon appeared. It was 1915 when the developer, Georges Claude, of Air Liquide fame, received a patent on the unique electrodes suitable for lighting and, thus, had a monopoly on the technology he sold through his company Claude Neon Lights.

However, Daniel Moore in 1917 developed a different kind of neon bulb while working for General Electric. These bulbs used coronal discharge to produce a red glow or, with argon, a blue glow. This was different enough to earn another patent, and neon bulbs found use primarily as indicator lamps before the advent of the LED. However, it would also find many other uses.

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Cheap Thermal Camera Fits The Bill

August 10, 2025 by 14 Comments

If you want to save a little money on a thermal camera, or if you just enjoy making your own, you should have a look at [Evan Yu’s] GitHub repository, which has a well thought out project built around the MLX90640 and an ESP32. The cost is well under $100. You can watch it do its thing in the video below.

There’s a PCB layout, a 3D-printed case, and — of course — all the firmware files.  The code uses the Arduino IDE and libraries. It leverages off-the-shelf libraries for the display and the image sensor.

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SparcStation 1+ Finally Gets Attention

August 9, 2025 by 12 Comments

We can’t throw stones. [Leaded Solder] picked up a SparcStation 1+ in 2018 and found it only produced illegal instruction errors. We’re sure he’s like us and meant to get back to it, and, instead, it sat on the bench, taking up space. You eventually have to move it, though, so seven years later, it was time for another go at it.

The first pass back in 2018 revealed that the machine had an interesting life. The full-sized hard drive was salvaged from an Apple computer. Removing the drive resolved the illegal instruction error. The drive seemed to work, but there was still nothing that suggested the machine would fully boot up. The next step was to try booting from a floppy, but that didn’t work either. The floppy cable had been surgically altered, again hinting this machine had seen some tough love.

Fast forward to 2025. This time, a Pi Pico-based SCSI emulator would stand in for the aging and suspect hard drive. Unfortunately, as noted, this machine has undergone some extensive and strange surgery. The power cable feeding the emulator had been rewired backwards, exposing the poor Pi Pico to 12 V, with predictable results. Luckily, it didn’t seem to phase the SparcStation.

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Learn C With A Lisp

August 9, 2025 by 19 Comments

One reason Forth remains popular is that it is very simple to create, but also very powerful. But there’s an even older language that can make the same claim: LISP. Sure, some people think that’s an acronym for “lots of irritating spurious parenthesis,” but if you can get past the strange syntax, the language is elegant and deceptively simple, at least at its core. Now, [Daniel Holden] challenges you to build your own Lisp as a way to learn C programming.

It shouldn’t be surprising that LISP is fairly simple. It was the second-oldest language, showing up in the late 1950s with implementations in the early 1960s. The old hardware couldn’t do much by today’s standards, so it is reasonable that LISP has to be somewhat economical.

With LISP, everything is a list, which means you can freely treat code as data and manipulate it. Lists can contain items like symbols, numbers, and other lists. This is somewhat annoying to C, which likes things to have particular types, so that’s one challenge to writing the code.

While we know a little LISP, we aren’t completely sold that building your own is a good way to learn C. But if you like LISP, it might be good motivation. We might be more inclined to suggest Jones on Forth as a good language project, but, then again, it is good to have choices. Of course, you could choose not to choose and try Forsp.

Student Drone Flies, Submerges

August 5, 2025 by 17 Comments

Admit it. You’d get through boring classes in school by daydreaming of cool things you’d like to build. If you were like us, some of them were practical, but some of them were flights of fancy. Did you ever think of an airplane that could dive under the water? We did. So did some students at Aalborg University. The difference is they built theirs. Watch it do its thing in the video below.

As far as we can tell, the drone utilizes variable-pitch props to generate lift in the air and downward thrust in water. In addition to the direction of the thrust, water operations require a lower pitch to minimize drag. We’d be interested in seeing how it is all waterproofed, and we’re unsure how deep the device can go. No word on battery life either. From the video, we aren’t sure how maneuverable it is while submerged, but it does seem to have some control. It wouldn’t be hard to add a lateral thruster to improve underwater operations.

This isn’t the first vehicle of its kind (discounting fictional versions). Researchers at Rutgers created something similar in 2015, and we’ve seen other demonstrations, but this is still very well done, especially for a student project.

We did see a submersible drone built using parts from a flying drone. Cool, but not quite the same.

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AI Code Review The Right Way

August 1, 2025 by 29 Comments

Do you use a spell checker? We’ll guess you do. Would you use a button that just said “correct all spelling errors in document?” Hopefully not. Your word processor probably doesn’t even offer that as an option. Why? Because a spellchecker will reject things not in its dictionary (like Hackaday, maybe). It may guess the wrong word as the correct word. Of course, it also may miss things like “too” vs. “two.” So why would you just blindly accept AI code review? You wouldn’t, and that’s [Bill Mill’s] point with his recent tool made to help him do better code reviews.

He points out that he ignores most of the suggestions the tool outputs, but that it has saved him from some errors. Like a spellcheck, sometimes you just hit ignore. But at least you don’t have to check every single word.

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