A black device with a monochrome LCD sits on a wooden table. It's keyboard extends below the frame. On the screen is the "Level 29" BBS service login.

Internet Appliance To Portable Terminal

August 8, 2024 by Navarre Bartz 2 Comments

Few processors have found themselves in so many different devices as the venerable Z80. While it isn’t powerful by modern standards, you can still use devices like this Cidco MailStation as a terminal.

The MailStation was originally designed as an email machine for people who weren’t onboard with this whole computer fad, keeping things simple with just an adjustable monchrome LCD, a keyboard, and a few basic applications. [Joshua Stein] developed a terminal application, msTERM, for the MailStation thanks to work previously done on decoding this device and the wealth of documentation for Z80 assembly.

While [Stein] designed his program to access BBSes, we wonder if it might be a good way to do some distraction-free writing. If that wasn’t enough, he also designed the WiFiStation dongle which lets you communicate over a network without all that tedious mucking about with parallel ports.

If you’d like something designed specifically for writing, how about an AlphaSmart? Wanting to build your own Z80-based project? Why not start with an Altoids-sized Z80 SBC, but don’t wait forever since Z80 production finally ended in June.

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Homebrew Reader Brings Paper Tape Programs Back To Life

June 15, 2024 by Dan Maloney 11 Comments

We may be a bit biased, but the storage media of yesteryear has so much more personality than that of today. Yes, it’s a blessing to have terabyte SD cards smaller than your pinky nail and be able to access its data with mind-boggling speed. But there’s a certain charm to a mass storage device that can potentially slice off your finger.

We’re overstating the dangers of the venerable paper tape reader, of course, a mass storage device that [David Hansel] recreated a few years back but we only just became aware of. That seems a bit strange since we’ve featured his Arduino-based Altair 8800 simulator, which is what this tape reader is connected to. Mechanically, the reader is pretty simple — just a wooden frame to hold the LEGO Technic wheels used as tape reels, and some rollers to guide the tape through a read head. That bit is custom-made and uses a pair of PCBs, one for LEDs and one for phototransistors. There are nine of each — eight data bits plus the index hole — and the boards are sandwiched together to guide the paper tape.

The main board has an ATmega328 which reads the parallel input from the read head and controls the tape motor. That part is important thanks to Altair Basic’s requirement for a 100- to 200-ms delay at the end of each typed line. The tape reader, which is just being used as sort of a keyboard wedge, can “type” a lot faster than that, so the motor speed is varied using PWM control as line length changes.

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Home Automation Terminal Has Great Post-Apocalyptic Look

May 21, 2024 by Lewin Day 18 Comments

If you use home automation these days, you’re probably used to using smart speakers, your smartphone, or those tabletop touchscreen devices. If you wanted something cooler and more personal, you could try building something like [Rick] did.

A Raspberry Pi 400 is the basis for the machine, and it still uses the original keyboard. It’s paired with a 3D-printed shell with a 7″ Waveshare HDMI touch display in it. The LCD is placed behind a Fresnel lens which provides some magnification. It displays a glowing blue command line which accepts text commands. It’s hooked up to the OpenAI API, so it’s a little smarter than just any old regular terminal. It’s hooked up to [Rick’s] home automation system, so he can use natural language queries to control lighting, music, and all the rest. Think Alexa or Siri, but in text form.

The design of the case, with its rounded edges, vents, and thick bezels gives it a strong retro-futuristic look, reminiscent of something out of Fallout. [Rick’s] neat application of weathering techniques helped a lot, too.

It reminds us of some of the cooler Pip Boy builds we’ve seen. Meanwhile, if you’ve got your own creative terminal build in the works, don’t hesitate to drop us a line!

Driving An OLED Screen With A 6502 Single-Board Computer

October 24, 2023 by Lewin Day 12 Comments

Twenty years ago, if you wanted an LCD for a project, you’d probably end up with something salvaged from a mobile phone or an HD44780 character display. These days, little OLEDs can be had for a few bucks and they’ve taken the maker world by storm. [Anders Nielsen] has recently been experimenting with driving these displays from the vintage 6502 CPU, and he’s even got scrolling operation down pat.

The best part is that [Nielsen] is doing all this on a single-board computer running his own assembly code. That’s right – there’s no compilers here. It’s bare metal coding at it’s best. The build uses a 6507 chip running at 1 MHz, paired with a 6532 RIOT and just 128 bytes of RAM—a similar setup to the Atari 2600.

The video explains how the code stacks up and drives the display, achieving the scrolling effect. It makes a huge difference to usability, especially compared to chunking pages at a time to the postage stamp-sized screen. He demonstrates a legitimate usage case too, using the setup as a serial terminal for a Raspberry Pi.

The 6502 architecture still looms large in the collective consciousness; we’ve been talking about programming it in assembly for years. Video after the break.

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Bringing An ADM-3A Back To Life

August 16, 2023 by Chris Lott 22 Comments

[David] at Usagi Electric ended up with an old Lear Siegler ADM-3A terminal in a trade a couple of years ago. But the CRT face was plagued with so-called cataracts, and the condition of the insides was unknown. The video ( below the break ) shows the restoration process, which went quite smoothly. [David] was relieved that the CRT repair in particular was easy, a fact he attributes to the Texas weather —

The temperature was 110 F / 43 C when he set the CRT outside to bake in the sun for a few hours. Afterwards, removing the “integral implosion protection” plastic screen went better than expected. Everything cleaned up nicely and the screen reinstalled. Introduced in 1976, the main electronics board is chock full of TTL chips with nary a microprocessor in sight. Fortunately the board was substantially intact, and a single missing chip was found hidden underneath the board. [David] gets the terminal up and running in short order, and is confronted with an annoyance familiar to gray-haired programmers who grew up in this era. Most terminals had different sets of commands to control features such as cursor control and clearing parts or all of the screen. Programs often assumed a certain type of terminal. Some terminals could be configured to behave in different ways, and some programs offered the user a choice of terminals. Today your terminal emulator probably still has a few choices of which kind of terminal to emulate, VT-100 being the most common. And eventually some operating systems provided a terminal abstraction, like Unix’s termcap for example.

If you were around in the era where terminals like the ADM-3A were scattered everywhere, what was your favorite terminal and/or terminal feature? And today, do you have any favorite terminal emulator to recommend? Let us know in the comments below.

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Selectric Typewriter Goes From Trash Can To Linux Terminal

July 25, 2023 by Dan Maloney 19 Comments

If there’s only lesson to be learned from [alnwlsn]’s conversion of an IBM Selectric typewriter into a serial terminal for Linux, it’s that we’ve been hanging around the wrong garbage cans. Because that’s where he found the donor machine for this project, and it wasn’t even the first one he’s come across in the trash. The best we’ve ever done is a nasty old microwave.

For being a dumpster find, the Selectric II was actually in pretty decent shape. The first couple of minutes of the video after the break show not only the minimal repairs needed to get the typewriter back on its feet, but also a whirlwind tour of the remarkably complex mechanisms that turn keypresses into characters on the page. As it turns out, knowing how the mechanical linkages work is the secret behind converting the Selectric into a teletype, entirely within the original enclosure and with as few modifications to the existing mechanism as possible.

Keypresses are mimicked with a mere thirteen solenoids — six for the “latch interposers” that interface with the famous whiffletree mechanism that converts binary input to a specific character on the typeball, and six more that control thinks like the cycle bail and control keys. The thirteenth solenoid controls an added bell, because every good teletype needs a bell. For sensing the keypresses — this is to be a duplex terminal, after all — [alnwlsn] pulled a page from the Soviet Cold War fieldcraft manual and used opto-interrupters to monitor the positions of the latch interposers as keys are pressed, plus more for the control keys.

The electronics are pretty straightforward — a bunch of MOSFETs to drive the solenoids, plus an AVR microcontroller. The terminal speaks RS-232, as one would expect, and within the limitations of keyboard and character set differences over the 50-odd years since the Selectric was introduced, it works fantastic as a Linux terminal. The back half of the video is loaded with demos, some of which aptly demonstrate why a lot of Unix commands look the way they do, but also some neat hybrid stuff, like a ChatGPT client.

Hats off to [alnwlsn] for tackling a difficult project while maintaining the integrity of the original hardware.

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Mythic I: An Exploration Of Artisanal Computing

May 17, 2023 by Tom Nardi 14 Comments

While computers have become ever faster and more capable over the years, it’s hard to say they’ve become any more exciting. In fact, they’ve become downright boring. Desktop, laptop, or mobile, they’re all more or less featureless slabs of various dimensions. There’s not even much in the way of color variation — the classic beige box is now available with white, black, or metallic finishes.

Believing that such a pedestrian appearance isn’t befitting a device that puts the world’s collected knowledge at our fingertips, [Keegan McNamara] started exploring a more luxurious approach to computing. Gone is the mass produced injection molded plastic, in its place is hand-carved maple and Tuscan leather. Common computing form factors are eschewed entirely for a swooping console inspired by fine furniture and classic sports cars. The final result, called the Mythic I, is equal parts art and science. Not just a bold reimaging of what a computer can be, but an object to be displayed and discussed. Continue reading “Mythic I: An Exploration Of Artisanal Computing” →