A Vintage ‘Scope Comes Back To Life

June 4, 2025 by Jenny List 1 Comment

We’re suckers for a vintage electronic teardown here at Hackaday, and thus it’s pleasing to see [Thomas Scherrer OZ2CPU] with a 1962 AEG oscilloscope on his bench. It’s definitely seen better days, and is a single-trace 10 MHz unit of the type you might have seen in a typical general purpose electronics lab back in the day.

Pulling the cover off, and as expected there’s a row of tubes each side of the centrally mounted CRT. No printed circuits in sight, and no transistors either, though the rectifiers are selenium parts. After a clean-up it’s time to look at the tubes, and they show the metallic deposits characteristic of long operation. We’re more used to that from older televisions than test equipment,

Gently bringing the power up it looks promising, but there’s a purple glow from one of the PCL82 triode-pentodes. Replacing that and a double-triode results in a ‘scope that surprisingly, is working. It was evidently a high quality device in the first place, with components capable of lasting for over six decades.

We’ve seen more from his bench involving tubes, including this device using a magic-eye tube as the heavy lifter.

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Spin-Casting This Telescope Mirror In Resin Didn’t Go To Plan

June 3, 2025 by Lewin Day 27 Comments

For most of us, mirrors are something we buy instead of build. However, [Unnecessary Automation] wanted to craft mirrors of his own for a custom telescope build. As it turns out, producing optically-useful mirrors is not exactly easy.

For the telescope build in question, [Unnecessary Automation] needed a concave mirror. Trying to get that sort of shape with glass can be difficult. However, there’s such a thing as a “liquid mirror” where spinning fluid forms into a parabolic-like shape. Thus came the idea to spin liquid resin during curing to try and create a mirror with the right shape.

That didn’t quite work, but it inspired a more advanced setup where a spinning bowl and dense glycerine fluid was used to craft a silicone mold with a convex shape. This could then be used to produce a resin-based mirror in a relatively stationary fashion. From there, it was just necessary to plate a shiny metal layer on to the final part to create the mirror effect. Unfortunately, the end result was too messy to use as a viable telescope mirror, but we learn a lot about what didn’t work along the way.

The video is a great journey of trial and error. Sometimes, figuring out how to do something is the fun part of a project, even if you don’t always succeed. If you’ve got ideas on how to successfully spin cast a quality mirror, drop them in the comments below. We’ve seen others explore mirror making techniques before, too.

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The Keyboard Sinclair Never Made

June 2, 2025 by Heidi Ulrich 17 Comments

For those of us who’ve spent far too long hammering rubber keys into submission, a glorious solution has arrived. [Lee Smith] designed the ZX Mechtrum Deluxe, the ultimate keyboard upgrade for your beloved ZX Spectrum 48k. Thanks to [morefunmakingit], you can see this build-it-yourself mechanical mod below. It finally brings a proper spacebar and Spectrum-themed Wraith keycaps into your retro life.

The Metrum Deluxe is a full PCB redesign: no reused matrices or clunky membrane adapters here. [Lee Smith] got fed up with people (read: the community, plus one very persistent YouTuber) asking for a better typing experience, so he delivered. Wraith keycaps from AliExpress echo the original token commands and BASIC vibe, without going full collector-crazy. Best of all: the files are open. You can download the case on Printables and order the PCB through JLCPCB. Cherry on top (pun intended): you’ll finally have a spacebar your thumbs can be proud of.

So whether you’re into Frankenstein rigs or just want your Spectrum to stop feeling like an air mattress, check this video out. Build files and link to the keycaps can be found on Youtube, below the video.

Tip: if you foster a secret love for keyboards, don’t miss the Keebin’ with Kristina’s series on all sorts of keyboards.

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Planetary Poetry With A Tiny Digital Core

June 2, 2025 by Heidi Ulrich 7 Comments

Some hacks just tickle the brain in a very particular way. They’re, for a change, not overly engineered; they’re just elegant, anachronistic, and full of mischief. That’s exactly what [Frans] pulls off with A Gentleman’s Orrery, a tiny, simple clockwork solar system. Composed of shiny brass and the poise of 18th-century craftsmanship, it hides a modern secret: there’s barely any clockwork inside. You can build it yourself.

Peek behind the polished face and you’ll find a mechanical sleight of hand. This isn’t your grandfather’s gear-laden planetarium. Instead of that, it operates on a pared-down system that relies on a stepper motor, driving planetary movement through a 0.8 mm axle nested inside a 1 mm brass tube. That micro-mechanical coupling, aided by a couple of bevel gears, manages to rotate the Moon just right, including its orientation. Most of the movement relies on clever design, not gear cascades. The real wizardry happens under the hood: a 3D-printed chassis cradles an ESP32-C6, a TTP223 capacitive touch module, STSPIN220 driver, and even a reed switch with magnetic charging.

You can even swap out the brass for a stone shell where the full moon acts as the touch control. It’s tactile, it’s poetic, and therefore, a nice hack for a weekend project. To build it yourself, read [Frans]’ Instructable.

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A weather forecast is shown on a blue monochrome cathode ray tube display. It is displaying current conditions, and displays a “The Weather Channel” graphic in the top left corner.

A CRT Display For Retro Weather Forecasting

May 31, 2025 by Aaron Beckendorf 16 Comments

It would be hard to find any electronics still in production which use CRT displays, but for some inscrutable reason it’s easy to find cheap 4-inch CRTs on AliExpress. Not that we’re complaining, of course. Especially when they get picked up for projects like this Retro CRT Weather Display from [Conrad Farnsworth], which recreates the interface of The Weather Channel’s WeatherStar 4000+ in a suitably 90s-styled format.

The CRT itself takes up most of the space in the enclosure, with the control electronics situated in the base behind the display driver. A Raspberry Pi Zero W provides the necessary processing power, and connects to the CRT through its composite video output.

A custom PCB plugs into the GPIO header on the Raspberry Pi and provides some additional features, such as a rotary encoder for volume and brightness display, a control button, a serial UART interface, and a speaker driver. The design still has one or two caveats: it’s designed to powered by USB, but [Conrad] notes that it draws more current than USB 2.0 can provide, though USB-C should be able to keep up.

On the software side, a Python program displays a cycle of three slides: local weather, regional weather, and a radar display. For the local and regional weather display graphics, [Conrad] created a static background image containing most of the graphics, and the program only generated the dynamic components. For the radar display, the regional map’s outlines come from Natural Earth, and a Python program overlays radar data on them.

We’ve seen other attempts at recreating the unique style of the WeatherStar system, but nothing quite beats the real thing.
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Bubble Displays Make A Neat Retro Clock

May 28, 2025 by Jenny List 6 Comments

In 2025 we are spoiled for choice when it comes to displays, with affordable LCDs, OLEDs, TFTs, and e-ink panels of all sizes only a few clicks away. But in decades past, such exotica were not on the menu for casual construction. Instead there were a range of LED seven segment displays which have now largely passed out of use.

Among them were HP’s bubble displays, assemblies of miniature LEDs on a PCB, topped with plastic bubble lenses. If you had a calculator in the 1970s it probably had one, but in the present, [Joshua Coleman] has incorporated one into a pleasingly retro digital clock.

Inside the 3D printed case is an ESP32 with a pair of 74HC595 shift registers to drive the display, and an 18650 battery with all associated charging and protection circuitry. It’s a surprisingly simple circuit, and the code is provided on the page. He makes an apology to non-Americans for his use of US date formats, but we think few readers will be unable to change it to reflect the only date format which really matters.

If you find a bubble display, hang on to it. They’re certainly something we’ve seen before here a few times.

Two hands soldering components on a purpble PCB

Vintage Intel 8080 Runs On A Modern FPGA

May 26, 2025 by Heidi Ulrich 5 Comments

If you’re into retro CPUs and don’t shy away from wiring old-school voltages, [Mark]’s latest Intel 8080 build will surely spark your enthusiasm. [Mark] has built a full system board for the venerable 8080A-1, pushing it to run at a slick 3.125 MHz. Remarkable is that he’s done so using a modern Microchip FPGA, without vendor lock-in or proprietary flashing tools. Every step is open source.

Getting this vintage setup to work required more than logical tinkering. Mark’s board supplies the ±5 V and +12 V rails the 8080 demands, plus clock and memory interfacing via the M2GL005-TQG144I FPGA. The design is lean: two-layer PCB, basic level-shifters, and a CM32 micro as USB-to-UART fallback. Not everything went smoothly: incorrect footprints, misrouted gate drivers, thermal runaway in the clock section; but he managed to tackle it.

What sets this project apart is the resurrection of a nearly 50-year-old CPU. It’s also, how thoroughly thought-out the modern bridge is—from bitstream loading via OpenOCD to clever debugging of crystal oscillator drift using a scope. [Mark]’s love of the architecture and attention to low-level detail makes this more than a show-off build.
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