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Hackaday Links: July 13, 2025

There’s interesting news out of Wyoming, where a coal mine was opened this week. But the fact that it’s the first new coal mine in 50 years isn’t the big news — it’s the mine’s abundance of rare earth elements that’s grabbing the headlines. As we’ve pointed out before, rare earth elements aren’t actually all that rare, they’re just widely distributed through the Earth’s crust, making them difficult to recover. But there are places where the concentration of rare earth metals like neodymium, dysprosium, scandium, and terbium is slightly higher than normal, making recovery a little less of a challenge. The Brook Mine outside of Sheridan, Wyoming is one such place, at least according to a Preliminary Economic Assessment performed by Ramaco Resources, the mining company that’s developing the deposit.

The PEA states that up to 1,200 tons of rare earth oxides will be produced a year, mainly from the “carbonaceous claystones and shales located above and below the coal seams.” That sounds like good news to us for a couple of reasons. First, clays and shales are relatively soft rocks, making it less energy- and time-intensive to recover massive amounts of raw material than it would be for harder rock types. But the fact that the rare earth elements aren’t locked inside the coal is what’s really exciting. If the REEs were in the coal itself, that would present something similar to the “gasoline problem” we’ve discussed before. Crude oil is a mixture of different hydrocarbons, so if you need one fraction, like diesel, but not another, like gasoline, perhaps because you’ve switched to electric vehicles, tough luck — the refining process still produces as much gasoline as the crude contains. In this case, it seems like the coal trapped between the REE-bearing layers is the primary economic driver for the mine, but if in the future the coal isn’t needed, the REEs could perhaps be harvested and the coal simply left behind to be buried in the ground whence it came.

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Tiny arcade machines on a tabletop

Tiny PONG, Big Ambitions: World’s Smallest Arcade

London, Ontario college student [Victoria Korhonen] has captured the attention of tech enthusiasts and miniaturization lovers with her creation of what might be the world’s smallest arcade machine. Standing just 64 mm tall, 26 mm wide, and 30 mm deep, this machine is a scaled-down marvel playing the classic Atari game PONG. While the record isn’t yet official—it takes about three months for Guinness to certify—it’s clear [Korhonen]’s creation embodies ingenuity and dedication.

[Korhonen], an electromechanical engineering student, took six months to design and build this micro arcade. Inspired by records within reach, she aimed to outdo the previous tiniest arcade machine by shaving off just a few millimeters During the project she faced repeated failures, but viewed each iteration as a step towards success. Her miniature machine isn’t just a gimmick; it’s fully functional, with every component—from paddle mechanics to coding—developed from scratch.

[Korhonen] is already eyeing new projects, including creating the smallest humanoid robot. She also plans to integrate her electromechanical expertise into her family’s escape room business. Her journey aligns with other hobbyist projects pushing the limits of miniaturization, such as this credit card-sized Tetris clone or [Aliaksei Zholner]’s paper micro engines.

Student-built rocket launch in Black Rock Desert, Nevada

Aftershock II: How Students Shattered 20-Year Amateur Rocket Records

When it comes to space exploration, we often think of billion-dollar projects—NASA’s Artemis missions, ESA’s Mars rovers, or China’s Tiangong station. Yet, a group of U.S. students at USC’s Rocket Propulsion Lab (RPL) has achieved something truly extraordinary—a reminder that groundbreaking work doesn’t always require government budgets. On October 20, their homemade rocket, Aftershock II, soared to an altitude of 470,000 feet, smashing the amateur spaceflight altitude and speed records held for over two decades. Intrigued? Check out the full article here.

The 14-foot, 330-pound rocket broke the sound barrier within two seconds, reaching hypersonic speeds of Mach 5.5—around 3,600 mph. But Aftershock II didn’t just go fast; it climbed higher than any amateur spacecraft ever before, surpassing the 2004 GoFast rocket’s record by 90,000 feet. Even NASA-level challenges like thermal protection at hypersonic speeds were tackled using clever tricks. Titanium-coated fins, specially engineered heat-resistant paint, and a custom telemetry module ensured the rocket not only flew but returned largely intact.

This achievement feels straight out of a Commander Keen adventure—scrappy explorers, daring designs, and groundbreaking success against all odds. The full story is a must-read for anyone dreaming of building their own rocket.

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Hackaday Links: October 27, 2024

Problem solved? If the problem is supplying enough lithium to build batteries for all the electric vehicles that will be needed by 2030, then a new lithium deposit in Arkansas might be a resounding “Yes!” The discovery involves the Smackover Formation — and we’ll be honest here that half the reason we chose to feature this story was to be able to write “Smackover Formation” — which is a limestone aquifer covering a vast arc from the Rio Grande River in Texas through to the western tip of the Florida panhandle. Parts of the aquifer, including the bit that bulges up into southern Arkansas, bear a brine rich in lithium salts, far more so than any of the brines currently commercially exploited for lithium metal production elsewhere in the world. Given the measured concentration and estimated volume of brine in the formation, there could be between 5 million and 19 million tons of lithium in the formation; even at the lower end of the range, that’s enough to build nine times the number of EV batteries needed.

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Quest 3 VR Headset Can Capture 3D Video (Some Tampering Required)

The Quest 3 VR headset is an impressive piece of hardware. It is also not open; not in the way most of us understand the word. One consequence of this is the inability in general for developers or users to directly access the feed of the two color cameras on the front of the headset. However, [Hugh Hou] shares a method of doing exactly this to capture 3D video on the Quest 3 headset for later playback on different devices.

The Quest 3 runs Android under the hood, and Developer Mode plus some ADB commands does the trick.

There are a few steps to the process and it involves enabling developer mode on the hardware then using ADB (Android Debug Bridge) commands to enable the necessary functionality, but it’s nothing the average curious hacker can’t handle. The directions are written out in the video’s description, along with a few handy links. (The video is embedded below just under the page break, but view it on YouTube to access the description and all the info in it.)

He also provides some excellent guidance on practical things like how to capture stable shots, editing the videos, and injecting the necessary metadata for optimal playback on different platforms, including hassle-free uploading to a service like YouTube. [Hugh] is no stranger to this kind of video and camera handling and really knows his stuff, and it’s great to see someone provide detailed instructions.

This kind of 3D video comes down to recording two different views, one for each eye. There’s another way to approach 3D video, however: light fields are also within reach of enterprising hackers, and while they need more hardware they yield far more compelling results.

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I’ve Got Two Turntables And A Laser Engraver

Digital media provides us with a lot of advantages. For something like recording and playing back music, digital copies don’t degrade, they can have arbitrarily high quality, and they can be played in a number of different ways including through digital streaming services. That being said, a number of people don’t feel like the digital experience is as faithful to the original sound as it could be and opt for analog methods instead. Creating analog copies of music is a much tougher matter though, as [Marco] demonstrates by using a laser engraver to produce vinyl records.

[Marco] started this month-long project by assembling and calibrating the laser engraver. It has fine enough resolution to encode analog data onto a piece of vinyl, but he had to create the software. The first step was to generate the audio sample, then process it through a filter to remove some of the unwanted frequencies. From there, the waveform gets made into a spiral, accounting for the changing speed of the needle on the record as it moves to the center. Then the data is finally ready to be sent to the laser engraver.

[Marco] did practice a few times using wood with excellent success before moving on to vinyl, and after some calibration of the laser engraver he has a nearly flawless 45 rpm record ready to hit the turntable. It’s an excellent watch if not for anything than seeing a working wood record. We’ve actually seen a similar project before (without the wood prototyping), and one to play records from an image, but it’s been quite a while.

Thanks to [ZioTibia81] for the tip!

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Secret C64 Program Found On A Christian Rock Band’s Vinyl Record

How often do you find Easter eggs in old vinyl records?

It sure was a surprise for [Robin Harbron] when he learned about a Commodore 64 program hidden on one of the sides of a record from the 1985 album of Christian rock band Prodigal. The host of the YouTube channel 8-Bit Show and Tell shows the “C-64” etching on one side of the vinyl, which he picked up after finding out online that the record contained the hidden program.

The run-out groove on records is typically an endless groove that keeps the record player from running off the record (unless there is an auto-return feature, which just replays the record). On side one of the vinyl, the run-out groove looks normal, but on side two, it’s a little thicker and contains some hidden audio. Recording the audio onto a cassette and loading it onto a dataset reveals a short C64 program.

The process is a little more troublesome that that, but after a few tries [Harbron] reveals a secret message, courtesy of Albert Einstein and Jesus Christ. It’s not the most impressive program ever written, but it’s pretty cool that programmers 35 years ago were able to fit it into only a few seconds of audio.

Unfortunately, we won’t be hearing much actual music from the album – [Harbron] chose not to play the songs to avoid copyright issues on YouTube.

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