You Can Run BASIC On An Old HP 4592 Protocol Analyzer

April 28, 2024 by 10 Comments

What do you do when you find an ancient piece of test gear and want to have fun? Well, you can always try getting BASIC running on it, and that’s precisely what [David Kuder] did.

The HP4952A Protocol Analyzer actually looks a lot like an old computer, even if it was never meant for general-purpose use. The heart of the machine is a Zilog Z80 CPU, though, so it shares a lot in common with microcomputers of its era.

Among other hacks, [David] worked to get Microsoft Basic-80 running on the machine. Initially, he was only able to get it up and running on the display, with no way to read the keyboard, disk, or access the serial port. Eventually, by diving into the nitty-gritty of the machine, he was able to at least get the keyboard working along with some basic BASIC programs. Usable memory is just 8KB, but you can do a fair bit with that when you’ve only got a 32×16 display for output anyway!

It’s a neat hack and one that was extendable to the HP4957A as well. We’ve seen similar machines on these pages before, too! If you’ve got your own neat retro hacks on the boil, don’t hesitate to drop us a line!

[Thanks to Christopher Zell for the tip!]

Corral Some Zippy Blue Flames Into 3D Printed Troughs

April 28, 2024 by 18 Comments

[Steve Mould] came across an interesting little phenomenon of blue flames zipping around a circular track. This led to diving down a bit of a rabbit hole about excitable mediums, ultimately leading him to optimize the shapes and come up with some pretty wild variations which he shows off in a video (also embedded below.)

After figuring out that the moving flame depended on combustion of fuel vapor in an environment that didn’t allow for the whole surface to stay lit at once, [Steve] tried to optimize the design of 3d-printed channels and raceways to encourage this effect, and he came up with some pretty novel ones. The 3D models are here if you’d like to try them for yourself (we especially like the “figure eight” and “rays” models.)

The video is an excellent show & tell of everything [Steve] dove into, complete with plenty of demonstrations of harnessing this effect to create some nifty running flames. Check it out in the video below, and if unintuitive physical effects are your thing, don’t miss [Steve]’s peeling apart of the turntable paradox.

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Boneblocker Is A Big LED Wall That Rocks

April 28, 2024 by 3 Comments

[Nick Lombardy] took on a job almost every maker imagines themselves doing at some point. He built a giant LED wall and he did a damn fine job of it, too. Introducing BoneBlocker.

BoneBlocker is an 8 x 14 wall of glass blocks that lives at a bar called The Boneyard. Each block was given a length of WS2812B LED strip. 30 LED/meter strips were chosen, as initial maths on the 60 LED/meter strips indicated the whole wall would end up drawing 1.5 kW. Discretion, and all that.

The glowing game controller.

The whole display is run from a WT32-ETH01 board, which is a fast ESP32-based module that has onboard Ethernet to boot. [Nick] used the WLED library as he’d seen others doing great things with it, performance-wise. He ended up using one board per column to keep things fast, but he reckons this was also probably a little bit of overkill.

His article steps through the construction of the wall, the electronics, and the software required to get some games working on the display. The final result is quite something. Perhaps the best bit is his explanation of the custom controller he built for the game. Dig into it, you won’t be disappointed.

In particular, we love how the glass blocks elevate this display to a higher aesthetic level. We’ve seen other great projects tread this same route, too. Video after the break.

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The Z80 Is Dead. Long Live The Free Z80!

April 28, 2024 by 27 Comments

It’s with a tinge of sadness that we and many others reported on the recent move by Zilog to end-of-life the original Z80 8-bit microprocessor. This was the part that gave so many engineers and programmers their first introduction to a computer of their own. Even though now outdated its presence has been a constant over the decades. Zilog will continue to sell a Z80 derivative in the form of their eZ80, but that’s not the only place the core can be found on silicon. [Rejunity] is bringing us an open-source z80 core on real hardware, thanks of course to the TinyTapeout ASIC project. The classic core will occupy two tiles on the upcoming TinyTapeout 7. While perhaps it’s not quite the same as a real 40-pin DIP in your hands, like all of the open-source custom silicon world, it’s as yet early days.

The core in question is derived from the TV80 open-source core, which we would be very interested to compare when fabricated at TinyTapeout’s 130nm process with an original chip from a much larger 1970s process. While It’s true that this project is more of an interesting demonstration of TinyTapeout than a practical everyday Z80, it does at least serve as a reminder that there may be a future point in which a run of open-source real Z80s or other chips might become possible.

This isn’t the first time we’ve featured a TinyTapeout project.

Train A GPT-2 LLM, Using Only Pure C Code

April 28, 2024 by 7 Comments

[Andrej Karpathy] recently released llm.c, a project that focuses on LLM training in pure C, once again showing that working with these tools isn’t necessarily reliant on sprawling development environments. GPT-2 may be older but is perfectly relevant, being the granddaddy of modern LLMs (large language models) with a clear heritage to more modern offerings.

LLMs are fantastically good at communicating despite not actually knowing what they are saying, and training them usually relies on PyTorch deep learning library, itself written in Python. llm.c takes a simpler approach by implementing the neural network training algorithm for GPT-2 directly. The result is highly focused and surprisingly short: about a thousand lines of C in a single file. It is a highly elegant process that does the same thing the bigger, clunkier methods accomplish. It can run entirely on a CPU, or it can take advantage of GPU acceleration, where available.

This isn’t the first time [Andrej Karpathy] has bent his considerable skills and understanding towards boiling down these sorts of concepts into bare-bones implementations. We previously covered a project of his that is the “hello world” of GPT, a tiny model that predicts the next bit in a given sequence and offers low-level insight into just how GPT (generative pre-trained transformer) models work.

Pi Pico Gets A ZX Spectrum Emulator

April 27, 2024 by 8 Comments

The Pi Pico is a capable microcontroller that can do all kinds of fun and/or useful things. In the former vein, [antirez] has ported a ZX Spectrum emulator to the Pi Pico.

ZX2040, as it is known, is a port of [Andre Weissflog’s] existing ZX spectrum emulator. It’s designed for use on the compact embedded Pi Pico platform, using ST77xx TFT displays. To that end, it has a UI optimized for small, low resolution screens and minimal buttons. After all, very few Pi Picos come with a full QWERTY keyboard attached.

Certain hacks are necessary to make it all work; the chip is overclocked to get things humming fast enough. The emulator also runs upscaling or downscaling in realtime as needed. This allows the emulator to run with a variety of displays, almost none of which are a direct match for the ZX Spectrum’s original resolution of 256×192 pixels.

Code is on Github for the curious, including a great run down from [antirez] on everything that makes it tick. If you want to play ZX Spectrum games on a keychain, you’d do well to start here. There are other projects to emulate it on the Pico, too! Video after the break.

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Wine In Beverage Cans Had A Rotten Egg Problem, Until Now

April 27, 2024 by 70 Comments

Aluminum beverage cans are used for all kinds of drinks, but when it comes to wine there are some glitches. Chief among them is the fact that canned wine occasionally smelled like rotten eggs. Thankfully, researchers have figured out why that happens, and how to stop it. How was this determined? As the image above hints at, lots and lots of samples and testing.

What causes this, and why don’t other beverages have this problem? Testing revealed that the single most important factor was the presence of molecular sulfur dioxide (SO2), a compound commonly used in winemaking as an antioxidant and antimicrobial.

It turns out that the thin plastic lining on the inside of beverage cans doesn’t fully stop molecular SO2 from reacting with the surrounding aluminum, creating hydrogen sulfide (H2S) in the process. H2S has a very noticeable rotten egg smell, even in low concentrations.

Researchers discovered that if a canned beverage contained more than 0.5 ppm of molecular SO2, a noticeable increase in hydrogen sulfide was likely to be present within four to eight months. The problem is that since most wines aim for around 0.5 ppm of SO2, the average can on wine sitting on a shelf will have a problem sooner rather than later. The more SO2 in the wine (reds tend to contain less, whites more), the worse the problem.

Simply increasing the thickness of the plastic liner is an imperfect solution since it increases manufacturing costs as well as waste. So, researchers believe the right move is to use a more durable liner formulation combined with a lower SO2 concentration than winemakers are usually comfortable with. Unlike bottles, cans can be hermetically sealed which should offset the increased oxidation risk of using a lower concentration of SO2. The result should be wine as a canned beverage, with a shelf life of at least 8 months.

The research is published here and gives a great look at just how one approaches this kind of scientific problem, as well as highlighting just how interesting the humble aluminum beverage can really is.