PicoGUS: For All Your ISA Sound Card Needs

November 21, 2023 by 23 Comments

Sound cards used to be a big part of gaming machines in the 90s and 2000s but have largely gone extinct in the wake of powerful CPUs doing the sound themselves. Sound cards were expensive back then and, because the good ones weren’t very common, are expensive still for the retro gamer. But if you don’t need the real thing, [polpo] has you covered with his RP2040-based ISA sound card.

The PicoGUS, as he calls it, primarily serves to replace the Gravis UltraSound with modern components at a low cost. It uses the RP2040’s PIO to attach to an ISA bus and the RP2040’s dual-core power to synthesize the audio for its primary target, but also the AdLib (OPL2), CMS/Game Blaster and Tandy 3-Voice. [polpo] sells the PicoGUS on his Tindie store, but since it’s open source, you can of course just make your own.

Although “work-in-progress”, the PicoGUS is very useful to the right person and a perfect demonstration of how the RP2040’s PIO can be used to interface with almost any type of protocol.

Of couse, that’s not the only way to use the PIO, you can also create a CAN bus or even add another USB port.

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Duplex Typewriter

November 21, 2023 by 10 Comments

The Coleco Adam? A not-so-great home computer that likely contributed to the downfall of the company. The keyboard, however, is a different story, and worth repurposing.

[Nick Bild] has created a USB adapter that uses a Teensy 4.1 and an RJ-12 breakout board. Now this wasn’t just a simple matrix to decode. No, the fine folks at Coleco rolled their own communications protocol called AdamNet.

The keyboard uses an RJ-12 connector and a single data line to communicate over a 62.5 kbit/s, half-duplex serial bus. Inside the keyboard is a Motorola 6801 that caches the key presses and sends them to the computer. So the BOM is limited to what you see above — an RJ-12 breakout and a Teensy 4.1. It’s great to see old keyboards come alive again, especially one with such cool sci-fi keycaps. Want to hear it clack? Of course you do.

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LiPo Replacement Keeps Portable Scanner In The Action

November 21, 2023 by 8 Comments

If there’s anything people hate more than being locked into a printer manufacturer’s replacement cartridges, it’s proprietary batteries. Cordless power tools are the obvious example in this space, but there are other devices that insist on crappy battery packs that are expensive to replace when they eventually die.

One such device is the Uniden Bearcat BC296D portable scanner that [Robert Guildig] found for a song at a thrift store, which he recently gave a custom LiPo battery upgrade. It came equipped with a nickel-cadmium battery pack, which even under the best of circumstances has a very limited battery life. Using regular AA batteries wasn’t an option, but luckily the space vacated by the OEM battery pack left a lot of room for mods. Those include a small module with BMS functions and a DC-DC converter, a 2,400 mAh 4.2 V LiPo pillow pack, and a new barrel connector for charging. With the BMS set for six volts and connected right to the old battery pack socket, the scanner can now run for seven hours on a one-hour charge. As a bonus, the LiPo pack should last a few times longer than the NiCd packs, and be pretty cheap to replace when it finally goes too. There’s a video after the hop with all the details.

If you’re looking at a similar battery replacement project, you might want to check out [Arya]’s guide to everything you need to know about lithium-ion circuitry.

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Zork Zcode Interpreters Appear Out Of Nowhere

November 21, 2023 by 27 Comments

Some of our readers may know about Zork (and 1, 2, 3), the 1977 text adventure originally written for the PDP-10. The game has been public domain for a while now, but recently, the interpreters for several classic 1980s machines have also appeared on the internet.

What’s the difference? Zork is not a PDP-10 executable, it’s actually a virtual machine executable, which is in turn run by an interpreter written for the PDP-10. For example, Java compiles to Java bytecode, which runs on the Java virtual machine (but not directly on any CPU). In the same way, Zork was compiled to “Z-machine” program files, called ZIP (which was of course used in 1990 by the much more well known PKZIP). To date, the compiler, “Zilch” has not been released, but the language specification and ZIP specifications have, which has led some people to write custom ZIP compilers, though with a different input language.

For more on the VM, check out Maya’s Zork retrospective. (And dig the featured art. Subtle!)

Of course, that’s not the only type of interpreter. Some programming languages are interpreted directly from source, like this BASIC hidden in the ESP32’s ROM.

A black motion system with two stepper motors. A green circuit board is fixed in a rotating cage in the center, and the entire assembly is on a white base atop a green cutting mat. Wires wind through the assembly.

Pi-lomar Puts An Observatory In Your Hands

November 20, 2023 by 5 Comments

Humans have loved looking up at the night sky for time immemorial, and that hasn’t stopped today. [MattHh] has taken this love to the next level with the Pi-lomar Miniature Observatory.

Built with a Raspberry Pi 4, a RPi Hi Quality camera, and a Pimoroni Tiny2040, this tiny observatory does a solid job of letting you observe the night sky from the comfort of your sofa (some assembly required). The current version of Pi-lomar uses a 16mm ‘telephoto’ lens and the built-in camera libraries from Raspbian Buster. This gives a field of view of approximately 21 degrees of the sky.

While small for an observatory, there are still 4 spools of 3D printing filament in the five different assemblies: the Foundation, the Platform, the Tower, the Gearboxes and the Dome. Two NEMA 17 motors are directed by the Tiny2040 to keep the motion smoother than if the RPi 4 was running them directly. The observatory isn’t waterproof, so if you make your own, don’t leave it out in the rain.

If you’re curious how we might combat the growing spectre of light pollution to better our nighttime observations, check out how blinking can help. And if you want to build a (much) larger telescope, how about using the Sun as a gravitational lens?

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Easy Hackintosh With Docker-OSX: Soon To Be Impossible?

November 20, 2023 by 44 Comments

The Docker-OSX project has to be among one of the easiest ways to get a fully functional Hackintosh off the ground on any Linux or Windows (10+) system, with the Docker image handling the heavy lifting of keeping the copy of MacOS happy and satisfied, even as the legality remains questionable, as we previously reported on in 2021. Officially, Apple’s software license for MacOS states that it can only be installed and use on Apple-branded hardware, which precludes the installation in e.g. a Docker container. This has left Docker-OSX in a gray zone where it’s technically illegal, but as it’s being advertised by its developer [Sick Codes] to be for use by security researchers who participate in Apple’s Bug Bounty program (including iOS, which requires XCode, which requires MacOS, etc.), it seems to slip through the cracks.

An obvious issue which may soon spell the end of MacOS-on-x86_64 and with it this use of Docker-OSX is that MacOS is now straddling Apple Silicon and Intel’s x86_64 architecture, with the latter no longer being sold by Apple’s in any of its systems after the recent introduction of its Apple Silicon-based Mac Pro. Although MacOS Sonoma (14) still supports x86_64, this support could be cut in MacOS 15 or 16, at which point running Docker-OSX with an Apple Silicon-only MacOS image would at the very least require an AArch64-based ARM system, though likely with an ISA extension level that matches the lowest-end Apple Silicon (ARMv8.5-A for M1).

Although this should not make it impossible to run Docker-OSX on future Linux (and perhaps Windows) systems on AArch64-based systems, it would make it more complicated and expensive as using one’s existing x86_64-based PC is no longer an option aside from adding a sluggish Qemu layer in between, which would add a significant performance penalty. If you are using Docker-OSX, what are your experiences and plans here?

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DIY Loading Coil Shortens Antenna Lengths

November 20, 2023 by 24 Comments

A newly licensed amateur radio operator’s first foray into radios is likely to be a VHF or UHF radio with a manageable antenna designed for the high frequencies in these radio bands. But these radios aren’t meant for communicating more than a double-digit number of kilometers or miles. The radios meant for long-distance communication use antennas that are anything but manageable, as dipole antennas for the lowest commonly used frequencies can often be on the order of 50 meters in length. There are some tricks to getting antenna size down like folding the dipole in all manner of ways, but the real cheat code for reducing antenna size is to build a loading coil instead.

As [VA5MUD] demonstrates, a loading coil is simply an inductor that is placed somewhere along the length of the antenna which makes a shorter antenna behave as a longer antenna. In general, though, the inductor needs to be robust enough to handle the power outputs from the radio. There are plenty of commercial offerings but since an inductor is not much more than a coil of wire, it’s entirely within the realm of possibility to build them on your own. [VA5MUD]’s design uses a piece of PVC with some plastic spacers to wind some thick wire around, and then a customized end cap with screw terminals attached to affix the antenna and feedline to. Of course you’ll need to do a bit of math to figure out exactly how many turns of wire will be best for your specific situation, but beyond that it’s fairly straightforward.

It’s worth noting that the coil doesn’t have to be attached between the feedline and the antenna. It can be placed anywhere along the antenna, with the best performance typically being at the end of the antenna. Of course this is often impractical, so a center-loaded coil is generally used as a compromise. Coils like these are not too hard to wind by hand, but for smaller, lower-current projects it might be good to pick up a machine to help wind the coils instead.

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