TechyMagThings

Solder stencils are a fantastic way to accurately apply solder paste to a PCB. Professionally-made stencils are cut from steel, but for the home hacker, soda cans continue to be the alternative of choice. The only trick is how to actually get those little holes made, and [Saheen Palayi] shows off both his method of laser-engraving the holes, as well as a tool for cutting the can in the first place.

To turn a soda can into a flat-ish aluminum sheet means cutting off the ends and slicing it open. Ideally, one achieves this without kinking or bending the thin metal. In practice, this is quite difficult. [Saheen]’s solution is something a little like a pipe cutter — a 3D printed tool that gradually presses a blade section from a utility knife into the empty can as it turns until it cuts through. Once the top and bottom are off, it’s easy enough to snip down the side to get a curved sheet.

The hole pattern comes from one’s PCB design software of choice, and the actual cutting is done by a fiber laser. The wavelength of fiber lasers makes them good at marking and cutting metal, and [Saheen]’s laser takes almost no time at all to cut the stencil into the thin metal.

Fiber lasers used to be the sort of tool that only industrial shops had, but they’re a prosumer-level tool that can be bought online nowadays. [Saheen] uses an xTool F1 Ultra to cut his solder stencil, and we’ve previously seen that same laser used to create a PCB by blasting away unwanted copper until only the traces remain.

We’ve seen aluminum cans etched and also machined to create stencils, and the laser is certainly the fastest. Watch it in action in the video below.

[Nick Bild] evidently has a soft spot for the 6502, given that his Vectron65 Plus home computer project uses at least one of them, depending on the add-ons. You see, he hasn’t just made a homebrew computer, he’s also produced multiple expansions. One of which, the VGA Plus Text Mode, has its own 6502 co-processor. He’s also produced two versions of a VGA graphics card capable of 640×480 output. We’re still not 100% sure how many entries we are going to count [Nick]’s work as for the contest, since the graphics cards can be used with just about anything, not just the Vectron65, but we do know they’re strong contenders every one.

We covered the start of the Vectron65 project back in 2019, and it’s only gotten more practical as it has moved off breadboard onto PCB, and into a new version as the 65 Plus with more RAM and GPIO ports. Considering that the original let you game in VR using an add-on we covered, we might have to drop the “nearly” from “nearly practical” when talking about the Plus. Especially when you consider the graphics — we covered first version of 7400-series based VGA graphics card, while the newer V2 differs mostly in doubling the RAM and producing a more stable output. The V2 VGA card can work in tandem with the Text Mode card to write 40-column text to the screen without using up all the 6502 CPU’s cycles, offloading them to the second 6502 on the card with the help of a character ROM. Hey, if Commodore could put a second 6502 in a disk drive, why not? You can check out the whole suite in action in the demo video below. We admit to being particularly tickled by the Hackaday Comment Generator he’s running in BASIC.

If you’re worried about competing with [Nick], don’t worry — the 2026 Retrocomputing contest has multiple categories. You still have a few weeks to do something retro-modern, restomod an old machine, or just do some old-school programming.

Internet radios have been a thing in some form for the last quarter century, and the advent of cheap networked microcontrollers has made them easier than ever to build. But just how small can one be made? [Milen] has made one that’s about as small as we’ve seen, and put it up on Instructables.

The hardware recipe is straightforward enough; take a microcontroller, connect it to the internet, and have your internet radio software squirt its output to a DAC. In this case the microcontroller is an ESP32-C£ on a very small dev board, and clipped to that is a custom PCB with a PCM5102A I2S DAC and an amplifier. The whole thing is tiny, small enough in fact that the two connectors are significant in size compared to it.

Whether or not it’s a practical device for listening remains to be seen, but it’s certainly tiny. But the question is, could it be made smaller? Perhaps eschewing the connectors would be an easy win, and in return for a loss in quality the ESP has a built-in DAC that’s not intended for audio but can be used. If you have any bright ideas, we’d be interested to hear them.

We’ve seen plenty of internet radios over the years, and for some reason this cassette-shaped one appeals to us.

A lot of the retrocomputing world is focused on the 1980s, and for good reason– the home computer revolution was in full swing in that decade, and there is a veritable Cambrian Explosion of capable hardware to play with, emulate or recreate. There’s plenty of retro to look back to before that halcyon decade, though, as [Michael Gardi]’s port of Lunar Lander to the PDP-1 reminds us.

Both Digital Equipment Corporation’s PDP series and the game Lunar Lander are probably iconic enough in their own right to need no introduction, but there’s actually a connection between them. While many people think the game started with Atari’s 1979 arcade cabinet, the first version– then only text based, and called the Lunar Landing Game–actually dates back 10 years before that, and was dreamed up at DEC on a PDP-8. If you’re of a certain vintage, odds are, you probably typed in the BASIC version of the Lunar Landing Game at some point.

This is not that game. Despite the 1959 PDP-1 being more restricted, hardware-wise, than the PDP-8, [Michael Gardi] manages to get Lunar Lander in all of its graphical glory running on the PDP-1. Of course, if you’ve seen SpaceWar you know DEC’s first minicomputer can handle the graphics. You can play the emulated version online, if you’d like, or download it yourself from the link above. There is one PDP-1 that survives in working order, and [Michael] hopes to get the chance to run it there one day on the machine that started hacker culture. We wish him luck!

In the meantime, this may be the most “retro” project in our ongoing retrocomputer contest. There’s no special prize for that superlative, but if you can do older, have at ‘er! There are three weeks left to go back in time and claim both bragging rights and fabulous prizes.

While you may not be familiar with the term “busy board”, you’ve almost certainly seen one. It’s the sort of toy with a bunch of buttons, switches, and of course LEDs, that are designed to keep young children entertained. As it so buttons, switches, buttons, and LEDs also keep hardware hackers entertained — doubly so if they are the ones designing said busy board in the first place.

That’s where we find [Andy], or should we say, [Uncle Andrew]. Last Christmas he decided to scratch build an electronic busy board for his nephew, and while it might not be a terribly complex piece of kit from a technical standpoint, it’s a fantastic multidisciplinary project in that it’s really equal parts hardware and software. While it would surely be possible to implement a gadget like this entirely in hardware, [Andy] took the modern hobbyist approach of offloading some of the task to a collection of carefully arranged ones and zeros.

In the write-up, [Andy] goes over the decisions he made while designing and building the device. This ranges from the extra effort put in to keep the PCB down to two layers and the logic behind LED multiplexing. This extends right into the software aspect of the project, with a surprisingly deep explanation of how the code uses timers and interrupts to run the show as efficiently as possible, maximizing the run time of the PIC18F67K40 microcontroller on a trio of AAA batteries.

It’s a fun read about a low-stakes project that’s made all the better by the personal touch. Just like the kids of makers and hardware hackers, [Andy]’s nephew is a lucky to have somebody like this in his life.

Homebrew computers don’t have to be retrocomputers, but [Just4Fun]’s all-through-hole, 68008-based “68k-MBC” certainly qualifies, so it is a worthy entry in our ongoing contest. While there are both “full” and “lite” hardware configurations, the three-IC “lite” configuration is what first caught our eye. Yes, three: the 68008, an SRAM chip, and a PIC microcontroller that acts as the ROM.

Software is provided by the suitably-retro CP/M68K, or standalone executables, which run on both hardware configurations. The “lite” option restricts you to a maximum of 512 KB of RAM and a single serial port, but it looks like you still get I2C and the option to plug in an SD “hard drive” or RTC module however you configure the machine. Through the serial port, you can of course connect a terminal of you choice, or even use a thermal printer. The “full” version has two serial ports, if you want to do both. [Just4Fun] also has a parallel adapter lets you plug in printers with that interface as well. The demo video is below, but be warned that the text-to-speech narration won’t be to everyone’s liking.

We’ve featured other single-board-computers using the 68k before, but this one is a worthy contender in our contest, not least for the impressively low chip count. This contest has gotten oodles of entries, but there’s still time for yours: entries close October 27th.

[Applied Science] has a new demo of an old 1970s patent for a portable generator that is both interesting and terrifying. The generator uses sodium and water, which, if you remember your old chemistry classes, will combust spontaneously. Turns out, though, it won’t if you draw power from it fast enough. Don’t draw enough power? BOOM, apparently. Check it out in the video below.

Of course, lithium-ion batteries might catch fire, too, but this looks a lot more likely. The patent made some wild claims about how much you could draw from the device, but the video shows that practical results are somewhat less.

Mechanically, a spinning metal disk has a sodium electrode extremely close to it. Water flows through the tiny gap, and electricity will flow between the two electrodes. This seems to be the only practical device built on this principle that is available to the public. We presume the original inventor built something, but there’s no record of it.

The mechanical challenges are obvious. You have to connect to the spinning disk. In addition, as the sodium electrode goes away, you have to keep narrowing the gap. The patent mentions a spring, but doesn’t provide any details.

We were expecting a slip ring arrangement, but the resistance was too high. That led him to use a liquid-metal contact with a homemade alloy of gallium, indium, and tin. The original disk was made with stainless steel. Later, he plated the disk with nickel to improve the conductivity.

This doesn’t seem very practical and certainly seems unsafe, but it is still pretty cool. If you do try to duplicate this from the data on GitHub, he has some ideas on how to make it work better.

Of course, there are sodium-ion batteries. We’ve even seen liquid sodium-based fuel.