The Heavy Disco-Ball Satellite Designed To Do… Nothing

September 12, 2026 by Donald Papp 19 Comments

Launched in 1976, LAGEOS-1 (LAser GEOdynamic Satellite) is unusual in that it contains no instrumentation, no electronics, no power supply, and no means of propulsion. It’s spherical, weighs just under 407 kg, and looks a bit like a disco ball. It may not be accurate to say it does nothing, but unlike most satellites its role is entirely passive. It’s also one of the oldest scientific satellites still in service.

The lens-like objects covering the surface of LAGEOS-1 are corner cube retroreflectors, which have the nifty effect of always reflecting incident light right back towards its source.

Ground stations fire short laser pulses at it and measure the time it takes for the light to return, a form of time-of-flight ranging. Since LAGEOS-1’s orbit is highly stable, it provides a reliable reference point for measuring even tiny changes in the Earth itself. The size, shape, rotation, and more of our planet can be measured as a result. LAGEOS data (LAGEOS-2 was launched in 1992) has also been used in tests of general relativity.

Its orbit and construction were deliberately chosen so that atmospheric drag and other disturbances would be minimal. The simple, maintenance-free design combined with an extraordinarily stable orbit means LAGEOS is expected to circle our world for millions of years to come.

LAGEOS-1 also contains a message to the future in the form of two identical plaques prepared by Dr. Carl Sagan just in case there’s anyone around to find it some day. Check out the short 1975 video from NASA, embedded just below.

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Looking At A TRS-80 12 MB External Hard Drive From 1983

September 12, 2026 by Maya Posch 17 Comments

Although hard disks weren’t a common feature yet in many home computers in the 1980s, they were becoming increasingly more affordable. For relative meanings of the word ‘affordable’, naturally. This is illustrated by the 12 MB HDD for the Radio Shack TRS-80 that [Clint] over at LGR recently took a peek at.

Costing a cool $3,495 in 1983 – or $11,932 in 2026 USD – this 12 MB storage wonder used a Tandon TM-603 full-height 5.25″ HDD inside. Lacking a working TRS-80 to try it out with, the video is limited to just a basic powering up and opening up of the unit, but [Clint] will be donating it to a computer museum who can hopefully put it to use again.

The connection to the TRS-80 computer is handled by a ribbon cable, while the HDD has its own built-in power supply, rated at 60 Watt.

On the main board for the external HDD controller there is a Signetics 8X300 microprocessor that forms the brains of what makes it into an external drive for the TRS-80. Despite its age, it still looks brand new inside, so despite the Rifa capacitors in the PSU, [Clint] decided to power it on. This resulted in an auditory experience that’s probably best compared to a very rusty jet engine spinning up after languishing for a decade prior to spooling up for take-off.

Hopefully we’ll find out whether this particular unit and its HDD are still working in 2026.

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How To Fold Curved Lines In Metal Without Fancy Tools

September 11, 2026 by Donald Papp 16 Comments

Folding a sheet of metal in a straight line is one thing, but how does one fold multiple curved lines into a sheet of aluminum without fancy machines? [John] demonstrates how to do exactly that with little more than hand tools and a fair bit of patience. The secret is drilling a lot of small holes along each fold line.

First, a bit of background. [John] wanted to fabricate a curved piece of aluminum as cover that would match the sleek aerodynamic lines of a Belly Tank Lakester. The trick is that there isn’t a single straight line to be found, and the fold lines are all curves. How can one do such folding with only hand tools?

[John] found that fabrication was possible by drilling small holes all along each fold line, then carefully bending as needed. The line of holes weakens the metal, acting like a score line, and allow the required curves to be made cleanly. There’s some finishing work and straightening involved, but the hard part of making the actual folds is taken care of.

One method that didn’t work was cutting a shallow groove in the metal to create something like a pre-scored fold line. [John] tried this and found that while the metal does indeed fold along the weakened line, the aluminum tends to crack in the process. When making a line of holes instead, the metal between each hole bends nicely.

This technique does mean the finished part ends up with small perforations along each fold, but the part is mounted on the bottom of the car and [John] says that he’d have to look quite closely to notice. A little polishing goes a long way, too.

We have covered many ways to bend sheet metal and while machinery exists to do it exceedingly well, great results can be had with little more than simple tools and some patience.

Watch [John] go through the process in the video embedded below, or skip to 7:55 if you just want to see the end result.

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Trying To Fix A Suspiciously Cheap Enterprise-Grade Network Switch

September 11, 2026 by Maya Posch 19 Comments

When you see a listing for an Ethernet switch whose specification list is in effect ‘yes’, with a four-digit price tag when new, and with the seller asking for less than 10% of said $3,000 asking price in an ‘untested’ condition, the only rational thing to do is of course to mash that ‘buy’ button. This is what [This Does Not Compute] did, and created a video about to show what a great investment decision this was.

Naturally this Juniper EX4100-F-12P switch came without power supply brick for its 48VDC input. Figuring out its pin-out and probing said input showed that the voltage rails had been shorted, giving a first clue as to why this switch had been on sale for so very cheap. Bravely hoping that it would be a straightforward fix, the unit was disassembled.

With a 280 Watt power brick, it’s little wonder that the top of the unit is a one massive aluminium heatsink, including a large heatpipe. Also visible on the lid near the power input was a very-bad-news black skid mark.

From that first discovery the news just got worse and worse, with clear signs of water ingression, rust and corrosion, along with the aftermath of a powered circuit meeting such bad corrosion. After some clean-up it’s clear that some components had violently exploded, ripping apart layers of the PCB and likely parts of traces in those inner sections too.

With no schematics available and no other good repair options via Juniper or anywhere else, it seems that unfortunately this gamble turned out to be merely a pile of e-waste and a few bucks worth of scrap metal. Caveat emptor, once more.

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Making A Neo Nuvistor Project In 2026

September 11, 2026 by Maya Posch 19 Comments

For a little while vacuum tubes and semiconductors were fighting a heated battle for dominance, with bipolar junction transistors and 1959’s RCA Nuvistor both allowing you to build a compact circuit with relatively low power usage and no high voltages. Although we now know that semiconductor technology won out overwhelmingly, that doesn’t mean that you cannot build a brand new Nuvistor board in 2026, as [Eric Schlaepfer] AKA [TubeTimeUS] recently did.

Nuvistors saw their most use in small-signal radio frequency applications, like VHF and UHF, with excellent low-noise characteristics that saw them used until the early 1970s in television sets, radios and oscilloscopes, as well as in space probes like the 1960s US Ranger Moon missions, so by that metric they had a good run.

Nothing so exciting is built in this video, sadly, but alongside a breakdown on how nuvistors work, we do see a discrete 555-style timer built using a gaggle of tetrode nuvistors, giving a pretty good idea of what using them in a project is like. Being a vacuum tube at its core, nuvistors still have the heater element, which is what gives vacuum tubes their reputation for being slow to start working and large current draw.

Despite their drawbacks, nuvistors still have a range of benefits compared to modern-day transistors, including being practically immune to electrostatic discharge (ESD) and electromagnetic interference (EMI) all the way up an EMP that will destroy most semiconductor electronics.

That said, the somewhat limited 8-nuvistor implementation of the 555 had to get a few extra pins for the heater supply, which burns up about 7.5 Watt just to allow the circuit to function. Terming it the ‘hollow-state 555 timer’, it works effectively just like any semiconductor 555, just with that extra power cost and of course no significant prospect of making it smaller, barring a semiconductor evolution as with the pixels-sized CRTs in the SED and FED type displays.

We covered the nuvistor before, including a great reference on this device, and its history that was much longer than people often assume today, as well as the vacuum tubes we use every day in for example our microwaves.

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Hand-Coded ASM Powers Homebrew SNES Game

September 11, 2026 by Tyler August 7 Comments

Nintendo has made many game consoles in its long history — one that famously overlaps that of the Ottoman Empire — but only one of them was ever Super. It’s that console, the Super Nintendo Entertainment System, that [Inkbox] has decided to delve deeply into as he crafts a game in assembly using all the hardware tricks he can.

Hardware tricks he’ll need, given he’s limited to the two 64 kB RAM banks and 3.58 MHz Ricoh 6502-based CPU. Even the 4 MB limit he sets for a historically-accurate homemade cartridge seems positively claustrophobic by modern standards. The game he’s after making is a top-down adventure game a la Zelda, and [Inkbox] gets right into the weeds explaining how the SNES works as he shows his work in this nearly hour long video. If you’re looking for a deep dive into the architecture, along with how it is meant to be used, you could certainly find worse sources. Everything from the different graphics modes to what registers handle sound are covered in this and the previous video in the series.

We can’t help but call out his dedication to open source — the SNES Sound Engine he has put up on GitHub looks like it could be a real asset to anyone else doing this kind of homebrew. The game itself is on itch.io and is pay-what-you-want.

[Inkbox] doesn’t just limit himself to the SNES’s 6502-esqe assembly — he’s done impressive work in x86 ASM, too. Continue reading “Hand-Coded ASM Powers Homebrew SNES Game” →

Hackaday Podcast Episode 386: Doomscroll Tamagotchis, Clavichords, And Vibrotrucks

September 11, 2026 by Kristina Panos No comments

In this specially-numbered podcast episode that lines up quite nicely with our Retrocomputing Challenge, Elliot Williams and Kristina Panos met over surprisingly low latency and loud beverages to bring you the best of the previous week’s hacks.

But first, the news. German company Isar Aerospace can now claim that they’ve launched the first spacecraft into orbit from Europe. Be sure to check out the in-link, where we reported on the building of the spaceport.

In Hackaday news, the aforementioned Retrocomputing Contest had 64 entries at last check, which is just perfect for Episode 386. Will yours be the 65th?

Supercon Ten tickets are selling out, and per Elliot, the talks have been chosen, pending approval by each submitter. Keep an eye on the blog for the official announcement!

After reviewing the news, Elliot reached into the ol’ Mailbag and found two missives, including another from [Vik Olliver] regarding the printing of LEGO. The other is from [Mendel Munkis], who has been enjoying Wikipedia offline since 2018, thanks to a 32-bit ARM9 processor. Then, it was on to the hacks.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download in lovely MP3.