Exploring VersaLOGIC Pre-LSI Logic Cards With The Data/620

August 2, 2025 by Maya Posch 3 Comments

Before the era of large-scale integration (LSI) semiconductor circuits, discrete logic circuits using the common diode-transistor logic (DTL) were still necessary and available in a format that was modular and reusable. [David Lovett] over at the Usagi Electric farm has two great examples that date back to the 1950s and 1960s, showing the jump in technology over the course of a mere decade.

The newer Varian Data Machines 620 from 1966 uses germanium diodes and transistors, while the 1956 Bendix G-15 uses germanium diodes with vacuum tubes, the latter effectively fulfilling the same purpose as the transistors. The main difference between the modules is the density, with a decade of technological improvements allowing for more than double the logic on similarly sized cards and a similarly impressive reduction in power usage.

Currently, [David] is working on reverse-engineering these so-called VersaLogic modules to be able to troubleshoot the Data/620 machine in his possession. The results of these efforts are being published on GitHub. Although you can think of these modules as more or less big versions of the 7400-logic ICs — which began to replace them in the Data/620I from 1967 — some of the circuits on the cards get pretty complex.

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2025 One Hertz Challenge: Learn Morse Code One Second At A Time

August 2, 2025 by Tyler August 3 Comments

Learning Morse Code is no longer a requirement for HAMs in many jurisdictions, but it’s still a nice skill to have. [I_void(warranties)] wanted to learn, but couldn’t find a trainer that fit his style. What to do but build it yourself? Since we’re in the midst of a challenge, he took up the gauntlet and turned his need to learn Morse into a 1 hertz Morse code game.

In concept it is quite simple: a message beeps out in Morse, with a corresponding LED flash, all in one second. The player then has one second to type think they heard. Get it done fast enough, and a character LCD will tell you if you scored.

The project is based around an Arduino Nano; thanks to easily-available libraries, a PS/2 keyboard can serve as input and a 2×16 LCD as feedback with no real effort expended. For the audible component of the Morse challenge, an 8-ohm speaker is driven right off a pin on the Arduino. We won’t claim this efficient design only took one second to put together, but it probably didn’t take too long.

Of course this trainer, unlike some we’ve seen, only helps you learn to listen to the stream of dots and dashes. None of the others ever tried to fit a One Hertz theme, or [I_void(warranties)]’s particular learning style. For some, decoupling send and receive might be just the ticket to finally learning Morse one second at a time.

This Plane Flies Slow Because Its Wings Really Blow

August 2, 2025 by Tyler August 19 Comments

The key to Short Takeoff and Landing (STOL) operations is the ability to fly slow– really slow. That’s how you get up fast without a long takeoff roll to build up speed. Usually, this involves layers of large flaps and/or leading edge slats, but [rctestflight] on YouTube decided he wanted to take a more active approach with a fully blown wing.

The airplane in question is R/C, of course, and good thing: these wings would be a safety nightmare for a manned aircraft. With a blown wing, air is blown out of a slot on the top end of the wing, producing a high-speed, high-pressure zone that keeps the wing flying when it would otherwise be completely stalled out. As long as everything works, that’s great! If an engine fails, well, suddenly you aren’t flying anymore — and you’re going too slow to glide. It ends badly.

[rctestflight] doesn’t have to worry about that, though, because this foamboard and pink styro R/C aircraft carries nothing that can’t survive a crash. (A couple of electric ducted fans (EDCs), an Ardupilot, a radio, and a battery are all pretty shock-resistant.) The EDCs sit midway down the chord of the wings, and blow air into a plenum carved into the foam. On each wing, the exhaust from the fans is driven rearward from a slot created by a piece of carbon fiber. This air serves not only as a lift-enhancement but also as the plane’s sole propulsion and a component of its control system.

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Thanks, Tamiya-san

August 2, 2025 by Elliot Williams 12 Comments

We’re saddened to report the passing of Shunsaku Tamiya, the man behind the Tamiya line of models. What was surprising about this, though, is how many of our readers and writers alike felt touched by the Tamiya model company. I mean, they made great models, and they’re definitely a quality outfit, but the outpouring of fond memories across a broad spectrum was striking.

For example, we originally ran the story as breaking news, but our art director Joe Kim spent a good part of his childhood putting together Tamiya kits, and felt like he absolutely had to do a portrait of Mr. Tamiya to pay his respects. I presume Joe is more on the painting-the-models end of the spectrum of Tamiya customers, given his artistic bent. Jenny’s writeup is absolutely touching, and her fond remembrances of the kits shines through her writing.

Myself, I’m on the making-small-robots end of the spectrum, and was equally well served. Back in the early ’90s, the “twin motor gearbox” was a moderately challenging and tremendously rewarding build for me, but it was also the only variable-ratio small motor gearbox that we had easy access to for making small bots to run around the living room.

Indeed, the Tamiya line included a whole series of educational models and components that were just perfect for the budding robot builder. I’m sure I have a set of their tank treads or a slip clutch in a box somewhere, even today.

It’s nice to think of how many people’s lives were touched by their kits, and to get even a small glimpse of that, you just need to read our comment section. We hope the company holds on to Mr. Tamiya’s love for quality kits that inspire future generations, whether they end up becoming artists, engineers, or simply hackers.

An ATTiny GPU Fan Controller That Sticks

August 2, 2025 by Heidi Ulrich 12 Comments

When your GPU fan goes rogue with an unholy screech, you either shell out for a new one or you go full hacker mode. Well, [ashafq] did the latter. The result is a delightfully nerdy fan controller powered by an ATTiny85 and governed by a DS18B20 temperature sensor. We all know a silent workstation is golden, and there’s no fun in throwing money at an off-the-shelf solution. [ashafq]’s custom build transforms a whiny Radeon RX 550 into a cool, quiet operator. Best of all: it’s built from bits likely already in your junk drawer.

To challenge himself a bit, [ashafq] rolled his own temperature-triggered PWM logic using 1-wire protocol on an ATtiny85, all without libraries or bloated firmware. The fan’s speed only ramps up when the GPU gets toasty, just like it should. It’s efficient and clever, and that makes it a fine hack. The entire system runs off a scavenged 12V fan. He could have used a 3D printer, but decided to stick onto the card with double-sided tape. McGyver would approve.

The results don’t lie: idle temps at 40 °C, load peaking at 60 °C. Quieter than stock, smarter than stock, and way cheaper too. The double-sided tape may not last, but that leaves room for improvement. In case you want to start on it yourself, read the full write-up and feel inspired to build your own. Hackaday.io is ready for the documentation of your take on it.

Modifying fans is a tradition around here. Does it always take a processor? Nope.

Custom Bedroom Lighting Controlled By Alexa

August 2, 2025 by Lewin Day 3 Comments

[Arkandas] had a problem. They liked reading in bed, but their bedroom lamps weren’t cutting it—either too bright and direct, or too dim and diffuse. The solution was custom lighting, and a new project began.

The concept was simple—build a custom controller for a set of addressable LED lighting strips that would be installed in the bedroom. Specifically, in the headboard of the bed, providing controllable light directly where it was needed. The strips themselves were installed in aluminum channel with plastic diffusers to give a nice smooth light. [Arkandas] then tasked an ESP32 to control the strips, using the FastLED library to work with WS2812B LEDs, and also the Adafruit NeoPixel library for using SK6812 LEDs and their extra white channel. The ESP32 was set up to provide a web interface for direct control over the local network. [Arkandas] also made good use of the FauxmoESP library to enable the device to be controlled via Amazon Alexa, which fit nicely into their existing smarthome setup. Files are on Github for the curious.

The final build works well, creating a soft light in the habitable area of the bed that can also be readily controlled via voice commands or via web. We’ve seen the ESP32 do other great feats in this arena before, too, albeit of the more colorful variety. Meanwhile, if you’re cooking up your own smart lighting solutions, don’t hesitate to tell the tipsline!

Universal Control For The Last Mac You’d Ever Expect

August 1, 2025 by Tyler August 8 Comments

Universal control is a neat feature on Macintosh computers, allowing you to slide your mouse seamlessly from device to device. Of course you need a relatively recent version of MacOS to make it work, right? Not necessarily– thanks to [Bart Jackobs] MacFriends, universal control has come to the Macintosh Classic.

The Arduino is perfect for this purpose, but choosing it ruined a perfectly good pun and we can never forgive that.

Well, not exactly universal control, but similar functionality at any rate. [Bart] can slide his mouse from one side of his retina display over onto the glorious 512 x 342, 1-bit display of his Macintosh Classic, just as if the 68k powered antique was a modern device. As you might expect, the Motorola 68000 in that old Mac is getting a teensy bit of help– though sadly for our love of puns, from an Arduino Nano and not any kind of Teensy.

The Arduino is emulating a mouse and keyboard on the Apple Desktop Bus using code based on the abduino by [akuker]. [Bart]’s custom software on the modern Mac captures the mouse and keyboard inputs to pipe to the Arduino via USB serial. Apple’s Universal control doesn’t require a wired connection between the two machines, of course, but then, it doesn’t work on the Classic. One could imagine redoing this project for Bluetooth communication to have that a same Clarkian feeling of technological magic Apple has always wanted to convey– but nothing was wireless in 1990 except for telegrams and a handful of telephones, so the project is appropriate as-is.

As much as we might resent that micro-controller for ruining a pun, if you want to hook into the ADB– perhaps to use old peripherals with an emulated Macintosh— an Arduino will do the job. So would a Teensy, though, and then we’d have our pun.

Our thanks to [Bart Jakobs] for the tip. Don’t forget to send in your own: the endless maw of the tipsline is always hungry.