A small keyboard form factor retrocomputer with blue keys on a black background sits in front of a display and a LEGO model of the Space Shuttle. There are a number of jumper wires and a breadboard coming from an open panel on the right side of the machine.

Aqua PCB Is A Big Upgrade For The Mattel Aquarius

October 15, 2022 by Navarre Bartz 9 Comments

In case you weren’t around in the 80s, or you happened to blink, you may have missed the Mattel Aquarius computer. [Nick Bild] has a soft spot in his heart for the machine though and built the Aqua cartridge to make the Aquarius into a more usable machine.

Originally equipped with a mere 4 KB of RAM and a small, rubbery keyboard, it’s not too surprising that the Aquarius only lasted five months on the market. [Nick] decided on the cartridge slot to beef up the specs of this little machine given the small number of expansion ports on the device. Adding 32 KB of RAM certainly gives it a boost, and he also designed an SD card interface called Aqua Write that connects to the Aqua cartridge for easily transferring files from a more modern machine.

The Aqua Write uses an Arduino Mega 2560 to handle moving data between the SD card and the system’s memory. This is complicated somewhat because a “PLA sits between the Z80 and data bus that XORs data with a software lock code (initialized to a random value on startup).” [Nick] gets around this by running a small program to overwrite the lock code to zero after startup.

Getting data on and off retrocomputers can certainly be a challenge. If you’re trying to get files on or off another old machine, check out this Simple Universal Modem or consider Using a Raspberry Pi as a Virtual Floppy Drive.

Why Learn Ancient Tech?

October 15, 2022 by Elliot Williams 69 Comments

The inner orbits of the Hackaday solar system have been vibrating with the announcement of the 2022 Hackaday Supercon badge. The short version of the story is that it’s a “retrocomputer”. But I think that’s somehow selling it short a little bit. The badge really is an introduction to machine language or maybe a programming puzzle, a ton of sweet blinky lights and clicky buttons, and what I think of as a full-stack hacking invitation.

Voja Antonic designed the virtual 4-bit machine that lives inside. What separates this machine from actual old computers is that everything that you might want to learn about its state is broken out to an LED on the front face, from the outputs of the low-level logic elements that compose the ALU to the RAM, to the decoder LEDs that do double-duty as a disassembler. You can see it all, and this makes it an unparalleled learning aid. Or at least it gives you a fighting chance.

So why would you want to learn a made-up machine language from a non-existent CPU? Tom Nardi and I were talking about our experiences on the podcast, and we both agreed that there’s something inexplicably magical about flipping bits, calling the simplest of computer operations into action, and nonetheless making it do your bidding. Or rather, it’s anti-magical, because what’s happening is the stripping away of metaphors and abstractions. Peering not just behind, but right through the curtain. You’re seeing what’s actually happening for once, from the bottom to the top.

As Voja wrote on the silkscreen on the back of the badge itself: “A programmer who has never coded 1s and 0s in machine language is like a child who has never run barefoot on the grass.” It’s not necessary, or maybe even relevant, but learning a complex machine in its entirety is simultaneously grounding and mind-expanding. It is simply an experience that you should have.

Building A Replica Of An Obscure Romanian Computer

September 29, 2022 by Zoe Skyforest 5 Comments

We’ve all seen emulated Apple II and Commodore 64 boards about the place. Few of us have heard of the Romanian ZX Spectrum clone known as the Cobra, let alone any efforts to replicate one. However, [Thomas Sowell] has achieved just that, and has shared the tale with us online.

The Cobra was named for its origins in the city of Brasov – hence, COmputer BRasov. The replica project was spawned for a simple reason. Given that sourcing an original Romanian Cobra would be difficult, [Thomas] realized that he could instead build his own, just as many Romanians did in the 1980s. He set about studying the best online resources about the Cobra, and got down to work.

The build started with board images sourced from Cobrasov.com, and these were used to get a PCB made. [Thomas] decided to only use vintage ICs sourced from the Eastern Bloc for authenticity’s sake, too. Most came from the former USSR, though some parts were of East German, Romanian, or Czechoslovakian manufacture. The project took place prior to the Russian invasion of Ukraine, so there weren’t any hassles shipping across borders.

With everything hooked up and the EEPROMs given a real Cobra ROM image, the computer burst into life. There were some hiccups, with an overheating video IC and some memory glitches. However, with some nifty tweaks and replacements subbed in, the computer came good. Other work involved adding a custom keyboard and modifying 3.5″ floppy drives to work with the system.

Overall, the build is a faithful tribute to what was an impressive piece of engineering from behind the Iron Curtain. [Thomas]’s work also embodies the DIY ethos behind many homebrew Cobra computers built back in the day.

If all this talk has got you curious about the full history of the Cobra and Romania’s underground computer movement, we have everything you’re looking for right here!

Tiny Dongle Brings The Hard Drive’s Song Back To Updated Retrocomputers

September 26, 2022 by Dan Maloney 28 Comments

Back in the “beige box” days of computing, it was pretty easy to tell what your machine was doing just by listening to it, because the hard drive was constantly thrashing the heads back and forth. It was sometimes annoying, but never as annoying as hearing the stream of Geiger counter-like clicks stop when you knew it wasn’t done loading a program yet.

That “happy sound” is getting harder to come by, even on retro machines, which increasingly have had their original thrash-o-matic drives replaced with compact flash and other solid-state drives. This HDD sound simulator aims to fill that diagnostic and nostalgic gap on any machine that isn’t quite clicky enough for you. Sadly, [Matthias Werner] provides no build details for his creation, but between the longish demo video below (by a satisfied customer) and the details of the first version, it’s easy enough to figure out what’s going on here. An ATtiny and a few support components ride on a small PCB along with a piezoelectric speaker. The dongle connects to the hard drive activity light, which triggers a series of clicks from the speaker that sound remarkably like a hard drive heading seeking tracks. A demo starts at 7:09 in the video below; the very brave — or very nostalgic — might want to check out the full defragmentation that starts at 13:11.

Sure, this one is perhaps a bit over-the-top, but in the retrocomputing world, no price is too high to pay in the name of nostalgia. And it’s still far from the most ridiculous hard drive activity indicator we’ve seen.

Continue reading “Tiny Dongle Brings The Hard Drive’s Song Back To Updated Retrocomputers” →

Hackaday Prize 2022: A Functional Commodore PET Tribute

July 28, 2022 by Zoe Skyforest 14 Comments

The C64 may be the best-selling computer of all time, but Commodore made several machines before that, too. [Mjnurney] always loved the Commodore PET, and set about building some new machines in the PET’s unique all-in-one form factor.

The case design started with measurements taken from an original Commodore PET, of which [Mjnurney] has three. Then, it was modified and extended to make room for a proper keyboard. The case also mounts a 14″ IPS display, two 15W speakers, and a gas strut enabling the case to be propped open for easy maintenance. It’s actually made out of real sheet metal, too!

The primary version mounts an Amiga 500 inside, including its classic keyboard. However, [Mjnurney] has developed a PC version, too. Both look great, and it’s wild to see Netflix displayed on a machine that looks more at home in 1977. Perhaps most of all, though, we love the dual floppy drives just below the screen.

Throwback cases pay tribute to some of our favorite machines. The tiny ones are perhaps the cutest of all.

Continue reading “Hackaday Prize 2022: A Functional Commodore PET Tribute” →

Pet Docking Station Was Two Decades In The Making

July 22, 2022 by Jenny List 14 Comments

There are some projects which once might have been entirely appropriate, but which now seem sacrilegious. [Dave Luna]’s PC docking station in a Commodore Pet 64 case might at first sight seem to be one of them, but there’s a little more to it than gutting a cherished retrocomputer.

A much younger [Dave] had a dead Pet 64, and because over two decades ago such a thing was considered junk, set about converting it to a PC case. In the way of all ambitious projects it stalled, so here in 2022 he was starting with the metal case and keyboard of a Pet 64 rather than the full computer.

Into the case went a small color TFT monitor, a USB3 hub, a DisplayLink adapter, and and an Arduino Micro doing the job of USB-ifying the Commodore keyboard. The result is a pretty cool docking station, but one which he admits isn’t as nice to use as he’d like. Viewed through rose tinted glasses any PET was an amazing machine in its day, but a slightly lackluster keyboard and a tiny screen don’t quite have the same allure in a world of 4K monitors. Still, we’d have one on our desk.

The Pet appears in quite a few projects that have made it to these pages, for example showing YouTube videos.

Continue reading “Pet Docking Station Was Two Decades In The Making” →

Modular Z80 Really Racks Up The Retrocomputer Cred

July 19, 2022 by Dan Maloney 24 Comments

Very few retrocomputing projects are anything other than a labor of love. There’s really no practical reason to build a computer that is woefully inadequate for just about any task compared to even an entry-level PC today. But the lack of a practical reason to do something rarely stops a hacker, as with this nifty modular Z80-based rack computer.

Actually, there’s at least one area where retrocomputers excel compared to their modern multi-core gigahertz counterparts — and that’s nostalgia. That’s what [Ricardo Kaltchuk] was going for with his build, which started by finding a Z80 and an Intel 8251 USART in his parts bin. Those formed the core of what would become the “Proton” computer, a modular beauty built around 7 cm by 10 cm PCBs that plug into a backplane inside a rack made from aluminum angle. Aside from the power supply and the Z80 CPU, other modules include a RAM card with a zero insertion force socket for an EPROM, a mass-storage module sporting a 128 MB Compact Flash card, plus modules for standard serial and I2C comms.

The fit and finish are excellent, and the performance is impressive. The Proton runs CP/M and boasts a ton of old applications that will bring back some memories, like SuperCalc and dBase. We’d venture a bet that WordStar is in there someplace, or easily could be. The video below is a little rough, but shows everything off really well.

In some ways, the Proton reminds us of the RC2014, but its fit and finish are what bring this build home. That’s not to take away from the work [Ricardo] obviously put into documentation, though. The 62-page manual has every detail of every module, plus instructions for building one of your own.

Continue reading “Modular Z80 Really Racks Up The Retrocomputer Cred” →