Vintage Plotter Gets Bluetooth Upgrade

December 2, 2019 by Tom Nardi 25 Comments

Recently [iot4c] stumbled upon this gorgeous Robotron Reiss plotter from 1989, brand-new and still in its original box. Built before the fall of the Berlin Wall in East Germany, it would be a crime to allow such a piece of computing history to go unused. But how to hook it up to a modern system? Bad enough that it uses some rather unusual connectors, but it’s about to be 2020, who wants to use wires anymore? What this piece of Cold War hardware needed was an infusion of Bluetooth.

While the physical ports on the back of the Robotron certainly look rather suspect, it turns out that electrically they’re just RS-232. In practice, this means converting it over was fairly straightforward. With a Bolutek BK3231 Bluetooth module and an RS-232 to UART converter, [iot4c] was able to create a wireless adapter that works transparently on the plotter by simply connecting it to the RX and TX pins.

A small DC buck converter was necessary to provide 3.3 V for the Bluetooth adapter, but even still, there was plenty of room inside the plotter’s case to fit everything in neatly. From the outside, you’d have no idea that the hardware had ever been modified at all.

But, like always, there was a catch. While Windows had no trouble connecting to the Bluetooth device and assigning it a COM port, the 512 byte buffer on the plotter would get overwhelmed when it started receiving commands. So [iot4c] wrote a little script in Node.js that breaks the commands down into more manageable chunks and sends them off to the plotter every 0.1 seconds. With this script in place the Robotron moved under its own power for the first time in ~30 years by parsing a HP-GL file generated by Inkscape.

If you’re interested in a plotter of your own but don’t have a vintage one sitting around, never fear. We’ve seen an influx of DIY plotters recently, ranging from builds that use popsicle sticks and clothespins to customizable 3D printed workhorses.

A Python Serial Terminal To Get You Out Of A Jam

November 28, 2019 by Tom Nardi 21 Comments

When fiddling around with old computers, you can occasionally find yourself in a sticky situation. What may be a simple task with today’s hardware and software can be nearly impossible given the limited resources available to machines with 20 or 30 years on the clock. That’s where [bison] recently found himself when he needed to configure a device over serial, but didn’t have any way of installing the appropriate terminal emulator on his Fujitsu Lifebook C34S.

His solution, since he had Python 2.6 installed on the Debian 6 machine, was to write his own minimal serial terminal emulator. He intended for the code to be as terse as possible so it could be quickly typed in, should anyone else ever find themselves in need of talking to a serial device on Linux but can’t get screen or minicom installed.

The code is very simple, and even if you never find yourself needing to fire up an impromptu terminal, it offers an interesting example of how straightforward serial communications really are. The code opens up the /dev/ttyS0 device for reading, and after appending the appropriate return character, pushes the user’s keyboard input into it. Keep looping around, and you’ve got yourself an interactive terminal.

With this program written, [bison] was able to connect the 266 MHz C34S to his Retro WiFi SI, a modem adapter that bridges the gap between a vintage computer and modern wireless network. Gadgets like these allow you to browse BBSes as the creator intended, and can be fashioned with nothing more exotic than an ESP8266 running some open source code.

Just In Time For Christmas: Apple Macintosh Prototype For Sale

November 27, 2019 by Al Williams 21 Comments

We do love a bit of retrotechnology around our workspace. But we have to admit, we really want to find this prototype Apple Mac under the tree this year. There’s only one problem. There’s only one for sale and only two like it known to exist, for that matter. The auction house thinks it will fetch up to $180,000. We will guess that number is low, but we will find out on December 4th.

The 1983 computer has a pre-production plastic housing and a 5.25 inch “twiggy” drive. Apple provided this machine, apparently, to Encore Systems so they could develop MacWrite ahead of the machine’s release date.

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ATX2AT Makes Retrocomputing Safer, Heads To Kickstarter

November 25, 2019 by Donald Papp 21 Comments

It’s easy to take power supplies for granted in modern computing, but powering vintage hardware is not always so simple or worry-free. The power supplies for old electronics are themselves vintage, and the hardware being powered can be quite precious. A power problem can easily cause fried components and burned traces on a board. As [Doc TB] observes, by the time you hear crackling, it’s already far too late.

To address this, [Doc TB] designed the ATX2AT Smart Converter as an open source project and recently decided to make it available through a Kickstarter campaign. ATX2AT is a way to safely and securely replace some vintage power supplies with a standard PC ATX power supply, and adds a large number of protection features such as current monitoring and programmable reaction time for overcurrent protection. All of this can help prevent a retrocomputer enthusiast’s precious vintage hardware from being damaged in the event of a problem. It’s not just for powering known-good hardware; it can be invaluable when testing or repairing hardware that might be in an unknown state.

When we first came across [Doc TB]’s ATX2AT project we recognized it as a well-made device to address a specific niche, and to do it well. Assessing risk takes into account not only the probability of a problem occurring, but also just how bad things would be if it did happen. If your old hardware is precious enough to warrant the extra protection, or you are into repairing or assessing old hardware, then an ATX2AT might be just what you need. You can see it in action in the video embedded below.

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Cardboard Computer Replica Is Cheap And Easy To Make

November 22, 2019 by Zoe Skyforest 10 Comments

Replicating 1960s-era computer hardware can be a daunting task. Components can be hard to find, schematics thin on the ground, and software near-unobtainable. Of course, not every computer from the decade consisted of expensive high-end electronics – CARDIAC was built out of common cardboard, and making your own is a cinch!

CARDIAC stood for Cardboard Illustrative Aid To Computation. Consisting of a series of sliding cardboard parts, it acted as a basic guide to the principles of computation. Through the use of a pencil and the associated guidebook, students could run simple programs to learn how to program computers at the barebones level.

Finding the paper-based computational learning tool highly valuable in their youth, [megardi] wanted to bring it back for a new audience. Thankfully, there are plenty of resources on the web that made it easy to whip up art files to reprint the device. [megardi] then also wrote up the instructions on how to accurately reproduce a CARDIAC, with helpful tips on how to best put it together. For a quick test, any old paper will do, while using 110 g cardstock and a laminator makes a sturdier build that can be used with dry-erase markers.

CARDIAC remains an excellent tool for teaching the basics of Von Neumann architecture computing. We’ve discussed similar teaching tools before, too – from the days when “real” computers were too expensive to let students anywhere near them. How times change!

Building A Front Panel For The RC2014 Computer

November 21, 2019 by Tom Nardi 6 Comments

The RC2014 is a slick Z80 computer kit that’s graced these pages a number of times in the past. It allows anyone with a soldering iron and a USB-to-serial adapter to experience the thrill of early 1980s desktop computing. But what if you’re looking for an even more vintage experience? In that case, this custom RC2014 front panel from [James Stanley] might be just the thing to scratch that Altair itch.

The front panel allows you to view and alter the contents of memory with nothing more complex than toggle switches and LEDs, just like on the early microcomputers of the 1970s. If you’ve ever wanted to learn how a computer works on the most basic level, single-stepping through instructions and reading them out in binary is a great way to do it.

[James] says he was inspired to take on this project after reading a 1978 issue of Kilobaud Magazine (as one does), and seeing an article about building a homebrew Z80 machine with a front panel. Obviously he had to modify the approach a bit to mate up with this relatively modern variation on the venerable CPU, but the idea was essentially the same.

His documentation for the project is sure to be fascinating for anyone enamored with those iconic computers of yesteryear, but even readers with more modern sensibilities will likely find some interesting details. The way [James] coaxes the data and various status states out of the kit computer takes up the bulk of the write-up, but afterwards he talks about how he designed the PCB and wraps up with his tips for creating a professional looking front panel.

This isn’t the first time we’ve seen a modern Z80 computer kitted out with blinkenlights, but it’s certainly one of the most professional looking. If you combine the RC2014 kits available on Tindie with the details provided by [James], you’ll soon be learning the fine art of programming a computer with toggle switches.

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Teardown: VTech PreComputer 1000

November 19, 2019 by Tom Nardi 49 Comments

Back in the days before kids could be placated with a $50 Android burner phone, many a youngster was gifted a so-called “educational computer” to keep them occupied. Invariably looking like a fever dream version of the real computer their parents didn’t want to let them use, these gadgets offered monochromatic exploits that would make Zork look like Fortnite. Due equally to their inherent hardware limitations and the premise of being an educational toy, the “games” on these computers often took the form of completing mathematical equations or answering history questions.

The VTech PreComputer 1000 is a perfect specimen of this particular style of educational toy. Released in 1988, it was advertised as a way for pre-teens to become more comfortable with operating a real computer; since at that point, it had become abundantly clear that the coming decade would see a beige box on every professional’s desk. Its full-size QWERTY keyboard was specifically mentioned in the product’s accompanying literature as a way to get young hands accustomed to the ways of touch typing.

Words of wisdom from the PreComputer 1000’s manual.

By the mid-1990s these devices would have progressed far enough to include passable text-to-speech capabilities and primitive graphics, but the junior professional who found him or herself seated in front of the PreComputer 1000 was treated to a far more spartan experience. It’s perhaps just as well that this particular educational computer was listed as a training tool, because even in 1988, surely a session with this toy must have felt very much like work.

But that’s not to say the PreComputer 1000 is without its own unique charms. In an effort to help cement its role as a “trainer” for more conventional computers, VTech saw fit to equip the PreComputer with its own BASIC interpreter. They even included generous written documentation that walked young programmers through the various commands and functions. Even today, there’s something oddly appealing about a mobile device with a full keyboard that can run BASIC programs for better than 24 hours on batteries (even if they’re alkaline “C” cells).

Let’s take a look inside this more than 30 year old mobile device, and see how the designers managed to create a reasonable facsimile of actual computing on a kid-friendly budget.

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