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Hackaday Links: September 21, 2025

Remember AOL? For a lot of folks, America Online was their first ISP, the place where they got their first exposure to the Internet, or at least a highly curated version of it. Remembered by the cool kids mainly as the place that the normies used as their ISP and for the mark of shame an “@aol.com” email address bore, the company nevertheless became a media juggernaut, to the point that “AOL Time Warner” was a thing in the early 2000s. We’d have thought the company was long gone by now, but it turns out it’s still around and powerful enough of a brand that it’s being shopped around for $1.5 billion. We’d imagine a large part of that value comes from Yahoo!, which previous owner Verizon merged with AOL before selling most of the combined entity off in 2021, but either way, it’s not chump change.

For our part, the most memorable aspect of AOL was the endless number of CDs they stuffed into mailboxes in the 90s. There was barely a day that went by that one of those things didn’t cross your path, either through the mail or in free bins at store checkouts, or even inside magazines. They were everywhere, and unless you were tempted by the whole “You’ve got mail!” kitsch, they were utterly useless; they didn’t even make good coasters thanks to the hole in the middle. So most of the estimated 2 billion CDs just ended up in the trash, which got us thinking: How much plastic was that? A bit of poking around indicates that a CD contains about 15 grams of polycarbonate, so that’s something like 30,000 metric tonnes! To put that into perspective, the Great Pacific Garbage Patch is said to contain “only” around 80,000 metric tonnes of plastic. Clearly the patch isn’t 37% AOL CDs, but it still gives one pause to consider how many resources AOL put into marketing.

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Photo of the Haasoscope Pro

Haasoscope Pro: Open-Everything 2 GHz USB Oscilloscope

Our hacker [haas] is at it again with the Haasoscope Pro, a full redesign of the original Haasoscope, which was a successful Crowd Supply campaign back in 2018.

This new Pro version was funded on Crowd Supply in April this year and increases the bandwidth from 60 MHz to 2 GHz, the vertical resolution from 8 to 12 bits, and the sample rate from 125 MS/s to 3.2 GS/s. Selling for $999 it claims to be the first open-everything, affordable, high-bandwidth, real-time sampling USB oscilloscope.

The firmware and software are under active development and a new version was released yesterday.

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2025 Hackaday Component Abuse Challenge: Let The Games Begin!

In theory, all parts are ideal and do just exactly what they say on the box. In practice, everything has its limits, most components have non-ideal characteristics, and you can even turn most parts’ functionality upside down.

The Component Abuse Challenge celebrates the use of LEDs as photosensors, capacitors as microphones, and resistors as heat sources. If you’re using parts for purposes that simply aren’t on the label, or getting away with pushing them to their absolute maximum ratings or beyond, this is the contest for you.

If you committed these sins against engineering out of need, DigiKey wants to help you out. They’ve probably got the right part, and they’re providing us with three $150 gift certificates to give out to the top projects. (If you’re hacking just for fun, well, you’re still in the running.)

This is the contest where the number one rule is that you must break the rules, and the project has to work anyway. You’ve got eight weeks, until Nov 11th. Open up a project over at Hackaday.io, pull down the menu to enter in the contest, and let the parts know no mercy!

Honorable Mention Categories:

We’ve come up with a few honorable mention categories to get your ideas flowing. You don’t have to fit into one of these boxes to enter, but we’ll be picking our favorites in these four categories for a shout-out when we reveal the winners.

  • Bizarro World: There is a duality in almost every component out there. Speakers are microphones, LEDs are light sensors, and peltier coolers generate electricity. Turn the parts upside down and show us what they can do.
  • Side Effects: Most of the time, you’re sad when a part’s spec varies with temperature. Turn those lemons into lemonade, or better yet, thermometers.
  • Out of Spec: How hard can you push that MOSFET before it lets go of the magic smoke? Show us your project dancing on the edge of the abyss and surviving.
  • Junk Box Substitutions: What you really needed was an igniter coil. You used an eighth-watt resistor, and got it hot enough to catch the rocket motor on fire. Share your parts-swapping exploits with us.

Inspiration

Diodes can do nearly anything.  Their forward voltage varies with temperature, making them excellent thermometers. Even the humble LED can both glow and tell you how hot it is. And don’t get us started on the photo-diode. They are not just photocells, but radiation detectors.

Here’s a trick to double the current that a 555 timer can sink. We’d love to see other cases of 555 abuse, of course, but any other IC is fair game.

Resistors get hot. Thermochromic paint changes color with temperature. Every five years or so, we see an awesome new design. This ancient clock of [Sprite_tm]’s lays the foundation, [Daniel Valuch] takes it into the matrix, and [anneosaur] uses the effect to brighten our days.

Of course, thin traces can also be resistors, and resistors can get really hot. Check out [Carl Bujega]’s self-soldering four-layer PCB. And while magnetism is nearly magic, a broken inductor can still be put to good use as a bike chain sensor.

Or maybe you have a new twist on the absolutely classic LEDs-as-light-sensors? Just because it’s been done since the early says of [Forrest Mims] doesn’t mean we don’t want to see your take.

Get out there and show us how you can do it wrong too.

Off To The Races With ESP32 And EInk

Off to the races? Formula One races, that is. This project by [mazur8888] uses an ESP32 to keep track of the sport, and display a “live” dashboard on a 2.9″ tri-color LCD.

“Live” is in scare quotes because updates are fetched only every 30 minutes; letting the ESP32 sleep the rest of the time gives the tiny desk gadget a smaller energy footprint. Usually that’s to increase battery life, but this version of the project does not appear to be battery-powered. Here the data being fetched is about overall team rankings, upcoming races, and during a race the current occupant of the pole-position.

There’s more than just the eInk display running on the ESP32; as with many projects these days, micro-controller is being pressed into service as a web server to host a full dashboard that gives extra information as well as settings and OTA updates. The screen and dev board sit inside a conventional 3D-printed case.

Normally when talking Formula One, we’re looking into the hacks race teams make. This hack might not do anything revolutionary to track the racers, but it does show a nice use for a small e-ink module that isn’t another weather display. The project is open source under a GPL3.0 license with code and STLs available on GitHub.

Thanks to [mazur8888]. If you’ve got something on the go with an e-ink display (or anything else) send your electrophoretic hacks in to our tips line; we’d love to hear from you.

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Hackaday Links: September 14, 2025

Is it finally time to cue up the Bowie? Or was the NASA presser on Wednesday announcing new findings of potential Martian biosignatures from Perseverance just another in a long line of “We are not alone” teases that turn out to be false alarms? Time will tell, but from the peer-reviewed paper released simultaneously with the news conference, it appears that biological activity is now the simplest explanation for the geochemistry observed in some rock samples analyzed by the rover last year. There’s a lot in the paper to unpack, most of which is naturally directed at planetary scientists and therefore somewhat dense reading. But the gist is that Perseverance sampled some sedimentary rocks in Jezero crater back in July of 2024 with the SHERLOC and PIXL instruments, extensive analysis of which suggests the presence of “reaction fronts” within the rock that produced iron phosphate and iron sulfide minerals in characteristic shapes, such as the ring-like formations they dubbed “leopard spots,” and the pinpoint “poppy seed” formations.

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ESP32 Hosts Functional Minecraft Server

If you haven’t heard of Minecraft, well, we hope you enjoyed your rip-van-winkle nap this past decade or so. For everyone else, you probably at least know that this is a multiplayer, open world game, you may have heard that running a Minecraft server is a good job for maxing out a spare a Raspberry Pi. Which is why we’re hugely impressed that [PortalRunner] managed to squeeze an open world onto an ESP32-C3.

Of course, the trick here is that the MCU isn’t actually running the game — it’s running bareiron, [PortalRunner]’s own C-based Minecraft server implementation. Rewriting the server code in C allows it to be optimized for the ESP32’s hardware, but it also let [PortalRunner] strip his server down to the bare essentials, and tweak everything for performance. For example, instead of the multiple octaves of Perlin noise for terrain generation, with every chunk going into RAM, he’s using the x and z of the corners as seeds for the psudorandom rand() function, and interpolating between them. Instead of caves being generated by a separate algorithm, and stored in memory, in bareiron the underground is just a mirror-image of the world above. Biomes are just tiled, and sit separately from one another.

So yes, what you get from bareiron is simpler than a traditional Minecraft world — items are simplified, crafting is simplified, everything is simplified, but it’s also running on an ESP32, so you’ve got to give it a pass. With 200 ms to load each chunk, it’s playable, but the World’s Smallest Minecraft Server is a bit like a dancing bear: it’s not about how well it dances, but that it dances at all.

This isn’t the first time we’ve seen Minecraft’s server code re-written: some masochist did it in COBOL, but at least that ran on an actual computer, not a microcontroller. Speaking of low performance, you can’t play Minecraft on an SNES, but you can hide the game inside a cartridge, which is almost as good.

Thanks to [CodeAsm] for the tip. Please refer any other dancing bears spotted in the wild to our tips line.

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6502 Puts On An SDR Hat

The legendary 6502 microprocessor recently turned 50 years old, and to celebrate this venerable chip which brought affordable computing and video gaming to the masses [AndersBNielsen] decided to put one to work doing something well outside its comfort zone. Called the PhaseLoom, this project uses a few other components to bring the world of software-defined radio (SDR) to this antique platform.

The PhaseLoom is built around an Si5351 clock generator chip, which is configurable over I2C. This chip is what creates the phase-locked loop (PLL) for the radio. The rest of the components, including antenna connectors and various filters, are in an Arduino-compatible form factor that let it work as a shield or hat for the 65uino platform, an Arduino-form-factor 6502 board. The current version [Anders] has been working on is dialed in to the 40-meter ham band, with some buttons on the PCB that allow the user to tune around within that band. He reports that it’s a little bit rough around the edges and somewhat noisy, but the fact that the 6502 is working as an SDR at all is impressive on its own.

For those looking to build their own, all of the schematics and code are available on the project’s GitHub page. [Anders] has some future improvements in the pipe for this project as well, noting that with slightly better filters and improved software even more SDR goodness can be squeezed out of this microprocessor. If you’re looking to experiment with SDR using something a little bit more modern, though, this 10-band multi-mode SDR based on the Teensy microcontroller gets a lot done without breaking the bank.