Modern Graphics Via DisplayLink For Your ISA-Era PC

The monitors used on older computers are now becoming difficult to find, as we doubt anything for MDA, CGA, Hercules, or EGA has been manufactured in decades. Even VGA, though there are plenty of surplus flat panels to be found, is not as ubiquitous as it once was. Where does that leave the retrocomputing enthusiast with an ISA PC and no screen? Perhaps [Ian Hanschen] has the answer with the PicoGraph, an ISA-to-USB-to-Displaylink adapter.

In hardware terms, it’s using a PicoMEM, a more general-purpose ISA card for emulating cards with a Pi Pico. The Pico hosts a USB DisplayLink adapter, which can connect to the screen of your choice. The software on the PicoMEM does the heavy lifting and provides MDA, Herc, EGA, and VGA support, as well as support for one of the 1990s Cirrus Logic SVGA chipsets. And yes, it appears to work with DOOM.

The practice of using 2020s microcontrollers to lend functionality to retrocomputers has revolutionised the art. We’ve seen many, with one of the more recent being a minimap add-on for an 8-bit Sinclair Spectrum.

A 3D printer hotend with four filament leads in positioned on an arm above a hole in a glass plate. Wires lead from a carbon fiber frame under the glass to four stepper motors with pulleys.

The Final Steps To A Sub-Minute Benchy

In 2024, [Jan Roetz] decided to see whether he could 3D print a Benchy – the boat-shaped benchmarking tool used in 3D printer calibration – in less than one minute. Two years later, after experiments with air bearing print beds, dry ice cooling, multi-filament hotends, and more, he’s finally broken the one-minute mark.

There are three primary factors limiting the speed of the printer: the extrusion flow rate, the cooling rate for extruded plastic, and the motion system itself. The printer’s hotend combines four strands of filament in one hotend and can extrude about 400 cubic millimeters of plastic per second. For cooling, an air duct around the nozzle could deliver about 400 liters of air per minute, which left the motion system as the only bottleneck.

The original print bed was on top of an air bearing on a granite base, and its motion could be controlled by cords connected to stepper motors. This whole system had very low friction, but its inertia was too high. [Jan] therefore replaced the build plate with a lighter carbon-fiber frame. This had no air bearing, but it slid between the base granite slab and a glass plate above it, which had an opening above the portion used as a build plate. Even the metal pulleys used on the stepper motors had too much inertia, so [Jan] replaced them with smaller, semi-circular plastic pulleys.

The first test was a sub-60-second dry run to make sure nothing would break. This revealed the need for cable guides to keep them from whipping around (not surprising when they were pulling the bed at an acceleration of 225 G). Finally, [Jan] was able to successfully print several successive 59-second Benchies. The prints weren’t photogenic, but they were mechanically sound and dimensionally correct. [Jan] could have gone even faster, but this degraded the print quality too much.

It’s quite an accomplishment, and an impressive conclusion to a major project; we covered the beginning of the project back when [Jan] was going for parallelization rather than speed. The final print didn’t use it, but he also experimented with dynamic temperature control.

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Poking Around With JTAG On A Guitar Amp

You would think a guitar amplifier would be a straightforward piece of analog electronics. But, of course, these days, everything has firmware, including [mforney]’s Yamaha THR10c. The service manual showed both a UART and JTAG header on the schematic, so as many of us would, he took that as a challenge.

Of course, the production board doesn’t have headers for these ports, but that’s not a real problem. The serial port seemed quiet, but the JTAG port was more productive. This revealed two binary images: a bootloader and the main firmware. Once you have the code, it is a straightforward, if not laborious, process to reverse engineer what the code does.

The next step is to figure out how to load new firmware. You can see in the post that this was done, and custom features sprang into life with custom-patched firmware.

We never get tired of seeing people dig into consumer devices like this. Things like JTAG and the wide availability of JTAG tools have made it easier but no less fun. Of course, there are even more features [mforney] has in mind, but now that’s just a matter of coding.

Keychain GameCube Controller Made Functional

Mini game controllers with buttons and joysticks that move like the real deal are a pretty cool keychain and fidget toy, but at least for some of us there’s this intrusive thought that tells us that it would be so much cooler if it actually was a functional game controller. Enter [Brux] tearing into a miniature GameCube controller and adding the required guts.

The keychain/fidget toy is made by Backpack Buddies and is one of a range of similar toys that feature buttons you can press and joysticks that move, giving a pretty good start on the externals of the controller. Once cracked open at the seam, some interior redecorating had to be performed to clear space and add something to mount switches onto. Here [Brux] opted to glue SMD switches to custom 3D components in lieu of a PCB. These were subsequently wired up with thin enameled wire, before attaching the original buttons to them following some more plastic surgery.

Some tiny joystick innards were then installed before gluing on the final buttons and joystick caps. As for how it all connects to a real GameCube, here an RP2040 was used to handle the translation of control inputs to the GameCube controller protocol. Then a GameCube controller was sacrificed for its cable and controller connector, but as can be seen in the video it does all work and creates the perfect controller for guests.

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Breaking Enigma With An FPGA, Just Like At Bletchley Park

The pioneering work done by Alan Turing and others at Bletchley Park in England was perhaps as important in the history of technology as it was the history of the war. Given the last 80-odd years of technological development, their revolutionary work should be within the realms of a student project — which it was, specifically in ECE 5760 at Cornell University. The work was done by [Erica Jiang], [Kelvin Resch], and [Isabella Frank].

Nowadays if someone told you there was a code to be broken, you wouldn’t be reaching for electromechanical devices, but you just might think of trying an FPGA. After all, the programmable gate arrays allow for much faster execution of fixed logic than software running on a traditional CPU. That won’t help much with modern RSA schemes, and for Enigma, it’s massively overkill, but doing it that way was a great learning opportunity for the students.

Their project emulates the whole Bletchley Park cryptography apparatus, not just the Bombe Machine, and if you’re interested in learning about this piece of history you could absolutely do worse than to examine their documentation. If you’re into video, you can check out the final presentation and demo video below. Meanwhile if you’re wondering what the opposition was up to, we have good explainer of the enigma machine here.

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The Uncooperative Mirror Will Not Help You

The value of a mirror is in its clarity. If the reflection is cast by [danicakostic17]’s Uncooperative Mirror though, you’ll find anything but. It’s described as a useless machine, because it appears as a tiled mirror. As you approach it though, the tiles shake around and make it very difficult to follow what’s in front of you. It’s an art piece and a prank all in one, and we like it.

Behind the mirror is a 3D printed frame and a set of small servos with what look like some belts to hitch them up. There’s an ultrasonic sensor and an Arduino Uno, that sets those servos going as soon as the ultrasonic sensor sees anything. We can see this thing would be fun at a party.

Everything you’ll need is on the Instructables page linked above should you be foolhardy enough to want your own, and there’s even a YouTube video which we’ve placed below.

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Testing Various Ways To Waterproof FDM Printed Parts

Along with layer lines, FDM printers are notorious for being neither air- nor water-tight due to the countless very small gaps between the layers. This is very unfortunate if you are trying to FDM print something that should keep water either inside or outside. Although a variety of potential solutions exist, it’s hard to easily compare them. Correspondingly [Half-Baked-Research] decided that the best approach here was to just try everything and pit them against each other.

These solutions include various coatings either in- or outside the part, as well as the foam solution that he tried previously joined by a number of community-suggested alternatives that should not get waterlogged. To properly test them, the water pressure at a depth of about 10 meters would be good enough, but rather than find a really deep swimming pool or try his luck at nearby bodies of water, compressed air was used to ramp up the pressure of a what is basically a big bucket of water.

For the pressure chamber a Vevor vacuum chamber was modified to contain the 1 bar (103 kPa) of pressure, which was a fair bit of work and required a CNCed metal top plate. Among the printed and treated samples were also a couple of wild cards: a PETG cube with a TPU printed cover, a PU molded part and PETG with thicker walls.

Along with the long soak, percussive testing was also performed to see how it’d affect the water intrusion resistance. After all that, there were three winners: internal epoxy coating and two types of internal PU coating, though epoxy held up the best after repeated abuse. PU rubber also got a thumbs-up if you don’t need as high a pressure resistance but are more concerned with resisting physical abuse.

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