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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Custom built RGB laser firing beam

Lasers, Galvos, Action: A Quest For Laser Mastery

If you’re into hacking hardware and bending light to your will, [Shoaib Mustafa]’s latest project is bound to spike your curiosity. Combining lasers to project multi-colored beams onto a screen is ambitious enough, but doing it with a galvanomirror, STM32 microcontroller, and mostly scratch-built components? That’s next-level tinkering. This project isn’t just a feast for the eyes—it’s a adventure of control algorithms, hardware hacks, and the occasional ‘oops, that didn’t work.’ You can follow [Shoaib]’s build log and join the journey here.

The nitty-gritty is where it gets fascinating. Shoaib digs into STM32 Timers, explaining how modes like Timer, Counter, and PWM are leveraged for precise control. From adjusting laser intensity to syncing galvos for projection, every component is tuned for maximum flexibility. Need lasers aligned? Enter spectrometry and optical diffusers for precision wavelength management. Want real-time tweaks? A Python-controlled GUI handles the instruments while keeping the setup minimalist. This isn’t just a DIY build—it’s a work of art in problem-solving, with successes like a working simulation and implemented algorithms along the way.

If laser projection or STM32 wizardry excites you, this build will inspire. We featured a similar project by [Ben] back in September, and if you dig deep into our archives, you can eat your heart out on decades of laser projector projects. Explore Shoaib’s complete log on Hackaday.io. It is—literally—hacking at its most brilliant.

Large gears on a bridge in Geneva, Switzerland

Gear Up: A 15-Minute Intro On Involute Gears

If you’re into CNC machining, mechanical tinkering, or just love a good engineering rabbit hole, you’re in for a treat. Substack’s [lcamtuf] has written a quick yet insightful 15-minute introduction to involute gears that’s as informative as it is accessible. You can find the full article here. Compared to Hackaday’s more in-depth exploration in their Mechanisms series over the years, this piece is a beginner-friendly gateway into the fascinating world of gear design.

Involute gears aren’t just pretty spirals. Their unique geometry minimizes friction and vibration, keeps rotational speeds steady, and ensures smooth torque transfer—no snags, no skips. As [lcamtuf] points out, the secret sauce lies in their design, which can’t be eyeballed. By simulating the meshing process between a gear and a rack (think infinite gear), you can create the smooth, rolling movement we take for granted in everything from cars to coffee grinders.

From pressure angles to undercutting woes, [lcamtuf] explores why small design tweaks matter. The pièce de résistance? Profile-shifted gears—a genius hack for stronger teeth in low-tooth-count designs.

Whether you’re into the theory behind gear ratios, or in need of a nifty tool to cut them at home, Hackaday has got you covered. Inspired?

[James] and his Lemontron portable 3D printer

If Life Gives You Lemons, Build This Lemontron

What if your 3D printer could fit in a box of filament but still rival the build plate size of heavyweights? Enter the Lemontron, a free and open source portable printer making waves in the maker community for its compact form factor and budget-friendly price. Watch [James]’ video on his build story here. Built around the Positron drive—a unique mechanism introduced by [Kralyn] in 2022—the Lemontron is the latest evolution of this innovative design. Although Kralyn mysteriously disappeared, their work inspired other projects like the Positron JourneyMaker and this Lemontron.

The Lemontron started as a unibody chassis mod for the JourneyMaker but grew into a complete redesign, cutting costs in half without sacrificing performance. By eliminating expensive CNC parts, it’s entirely made from off-the-shelf components, bringing the build cost to just $413. Compare that to $800 for the JourneyMaker and $699 for the Positron v3.2 kit.

Overhead photo of [James]' hands assembling the Lemontron Portable 3D printerRecent video updates show the Lemontron in action, printing impressively large and complex models. It tackled a marble run with 80-degree unsupported overhangs and a ‘comically large’ Benchy, proving its capability. Its compact design, paired with robust performance, is an exciting alternative for tinkerers seeking quality on a budget.

The Lemontron is in its final development stages, with frequent updates dropping on its YouTube channel. If you’re in the market for a more “traditional” mini-printer, check out this cool suitcase model from 2014.

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Bioelectronic implants with size reference

Batteries Not Included: Navigating The Implants Of Tomorrow

Tinkerers and tech enthusiasts, brace yourselves: the frontier of biohacking has just expanded. Picture implantable medical devices that don’t need batteries—no more surgeries for replacements or bulky contraptions. Though not all new (see below), ChemistryWorld recently shed new light on these innovations. It’s as exciting as it is unnerving; we, as hackers, know too well that tech and biology blend a fine ethical line. Realising our bodies can be hacked both tickles our excitement and unsettlement, posing deeper questions about human-machine integration.

Since the first pacemaker hit the scene in 1958, powered by rechargeable nickel-cadmium batteries and induction coils, progress has been steady but bound by battery limitations. Now, researchers like Jacob Robinson from Rice University are flipping the script, moving to designs that harvest energy from within. Whether through mechanical heartbeats or lung inflation, these implants are shifting to a network of energy-harvesting nodes.

From triboelectric nanogenerators made of flexible, biodegradable materials to piezoelectric devices tapping body motion is quite a leap. John Rogers at Northwestern University points out that the real challenge is balancing power extraction without harming the body’s natural function. Energy isn’t free-flowing; overharvesting could strain or damage organs. A topic we also addressed in April of this year.

As we edge toward battery-free implants, these breakthroughs could redefine biomedical tech. A good start on diving into this paradigm shift and past innovations is this article from 2023. It’ll get you on track of some prior innovations in this field. Happy tinkering, and: stay critical! For we hackers know that there’s an alternative use for everything!

Close-up of a woman's neck with a haptic patch

Hacking Haptics: The 19-Sensor Patch Bringing Touch To Life

On November 6th, Northwestern University introduced a groundbreaking leap in haptic technology, and it’s worth every bit of attention now, even two weeks later. Full details are in their original article. This innovation brings tactile feedback into the future with a hexagonal matrix of 19 mini actuators embedded in a flexible silicone mesh. It’s the stuff of dreams for hackers and tinkerers looking for the next big thing in wearables.

What makes this patch truly cutting-edge? First, it offers multi-dimensional feedback: pressure, vibration, and twisting sensations—imagine a wearable that can nudge or twist your skin instead of just buzzing. Unlike the simple, one-note “buzzers” of old devices, this setup adds depth and realism to interactions. For those in the VR community or anyone keen on building sensory experiences, this is a game changer.

But the real kicker is its energy management. The patch incorporates a ‘bistable’ mechanism, meaning it stays in two stable positions without continuous power, saving energy by recycling elastic energy stored in the skin. Think of it like a rubber band that snaps back and releases stored energy during operation. The result? Longer battery life and efficient power usage—perfect for tinkering with extended use cases.

And it’s not all fun and games (though VR fans should rejoice). This patch turns sensory substitution into practical tech for the visually impaired, using LiDAR data and Bluetooth to transmit surroundings into tactile feedback. It’s like a white cane but integrated with data-rich, spatial awareness feedback—a boost for accessibility.

Fancy more stories like this? Earlier this year, we wrote about these lightweight haptic gloves—for those who notice, featuring a similar hexagonal array of 19 sensors—a pattern for success? You can read the original article on TechXplore here.

Close-up of a CPU

Register Renaming: The Art Of Parallel Processing

In the quest for faster computing, modern CPUs have turned to innovative techniques to optimize instruction execution. One such technique, register renaming, is a crucial component that helps us achieve the impressive multi-tasking abilities of modern processors. If you’re keen on hacking or tinkering with how CPUs manage tasks, this is one concept you’ll want to understand. Here’s a breakdown of how it works and you can watch the video, below.

In a nutshell, register renaming allows CPUs to bypass the restrictions imposed by a limited number of registers. Consider a scenario where two operations need to access the same register at once: without renaming, the CPU would be stuck, having to wait for one task to complete before starting another. Enter the renaming trick—registers are reassigned on the fly, so different tasks can use the same logical register but physically reside in different slots. This drastically reduces idle time and boosts parallel tasking. Of course, you also have to ensure that the register you are using has the correct contents at the time you are using it, but there are many ways to solve that problem. The basic technique dates back to some IBM System/360 computers and other high-performance mainframes.

Register renaming isn’t the only way to solve this problem. There’s a lot that goes into a superscalar CPU.

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