Open Source Liquid Rocket Reaches For The Sky

Since the very beginning, solid-propellants have been the cornerstone of amateur rocketry. From the little Estes rocket picked up from the toy store, to vehicles like the University of Southern California’s Traveler IV that (probably) crossed the Kármán line in 2019, a rapidly burning chunk of solid propellant is responsible for pushing them skyward. That’s not to say that amateur rockets powered by liquid propellants are completely unheard of … it’s just that getting them right is so ridiculously difficult that comparatively few have been built.

But thanks to [Half Cat Rocketry], we may start to see more hobbyists and students taking on the challenge. Their Mojave Sphinx liquid-fueled rocket is not only designed to be as easy and cheap to build as possible, but it’s been released as open source so that others can replicate it. All of the 2D and 3D CAD files have been made available under the GPLv3 license, and if you’re in the mood for a little light reading, there’s a nearly 370 page guidebook you can download that covers building and launching the rocket.

Now of course we’re still talking about literal rocket science here, so while we don’t doubt a sufficiently motivated individual could put one of these together on their own, you’ll probably want to gather up a couple friends and have a well-stocked makerspace to operate out of. All told, [Half Cat] estimates you should be able to build a Mojave Sphinx for less than $2,000 USD, but that assumes everything is done in-house and you don’t contract out any of the machining.

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Australia Didn’t Invent WiFi, Despite What You’ve Heard

Wireless networking is all-pervasive in our modern lives. Wi-Fi technology lives in our smartphones, our laptops, and even our watches. Internet is available to be plucked out of the air in virtually every home across the country. Wi-Fi has been one of the grand computing revolutions of the past few decades.

It might surprise you to know that Australia proudly claims the invention of Wi-Fi as its own. It had good reason to, as well— given the money that would surely be due to the creators of the technology. However, dig deeper, and you’ll find things are altogether more complex.

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Learning How A Nuclear Missile Stays On Target

In 1962, unlike today, most things didn’t have computers in them. After all, the typical computer of the day was a fragile room-sized box that required a gaggle of high priests to service it. But the Minuteman I nuclear missile was stuffed full of pre-GPS navigation equipment and a computer. In a few years, by 1970, the Minuteman III could deliver a warhead 13,000 km with an accuracy of 200 meters. Each one cost about a half million dollars, but that’s almost five million in today’s money. [Ken] takes on a very detailed tour of the computers and avionics that were nothing short of a miracle — and a highly classified miracle — in the 1960s.

The inertial navigation relied on a gyroscope, which in those days, were large and expensive. The Minuteman I required alignment with a precise angle relative to the North Star which naturally wasn’t visible from inside the silo. By the time Minuteman II arrived, they’d figured out an easier way to orient the missiles.

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Close-Up On The RP2350 HSTX Peripheral

The new Raspberry Pi Pico 2 with its RP2350 microcontroller has only been with us for a short time, and thus its capabilities are still being tested. One of the new peripherals is HSTX, for which the description “High speed serial port” does not adequately describe how far it is from the humble UART which the name might suggest. CNX Software have taken a look at its capabilities, and it’s worth a read.

With a 150 MHz clock and 8 available pins, it’s a serial output with a combined bandwidth of 2400 Mbps, which immediately leaves all manner of potential for streamed outputs. On the RP2040 for example a DVI output was made using the PIO peripherals, while here the example code shows how to use these pins instead. We’re guessing it will be exploited for all manner of pseudo-analogue awesomeness in the manner we’re used to with the I2S peripherals on the EP32. Of course, there’s no corresponding input, but that still leaves plenty of potential.

Have a quick read of our launch coverage of the RP2350, and the Pico 2 board it’s part of.

A Lunar Lander-meets-Flappy-Bird game where you must rescue puppies from a Moon base, on an OLED display.

2024 Tiny Games Contest: Save The Stranded Puppies Of Moon Base P!

Usually, if something is tiny, it’s probably pretty cute to boot. [Luke J. Barker]’s lunar navigation game is no exception to this unwritten rule. And as far as contest rules go, this one seems to fit rather nicely, as it is tiny on more than one level.

Moon Base P (for Puppies) is built upon a XIAO ESP32-C3, an SSD1306 OLED display, and a single button to keep the BOM tidy. In this riveting side-scroller which sort of marries Lunar Lander and Flappy Bird, the top bar is always yellow and displays fuel and such, and the bottom is a rough, blue lunar surface over which you must maneuver your lunar lander. Keep pressing the button to stay up and avoid mountains, or let off the gas to cool the engine.

Fly that thing over the terrain, avoiding stray meteors and picking up free fuel, and then land gently at Moon Base P to save the stranded puppies. But you must keep flying — touch down anywhere but where you’re supposed to, and it’s game over! Once you’ve picked up the puppies, you must fly them safely onward to the rescue pod in order to win. Don’t miss the walk-through and demo after the break.

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An Amiga 2000 on a carpet floor

Amiga, Interrupted: A Fresh Take On Amiga OS

Serena OS is not just another operating system—it’s a playground for hackers, tinkerers, and Amiga enthusiasts pushing vintage hardware to new limits. Born from modern design principles and featuring pervasive preemptive concurrency and multi-user support, [dplanitzer]’s Serena OS is far from ordinary.

Running on Amiga systems with a 68030 or better CPU, it challenges traditional OS concepts by ditching threads in favor of dispatch queues, akin to Apple’s Grand Central Dispatch. The result? A dynamic, flexible kernel that combines forward-thinking design with retro charm.

The real innovation in Serena is its kernel, which uses a virtual processor concept to manage system resources efficiently. Instead of threads, Serena dynamically adjusts a pool of virtual processors based on dispatch queue needs, ensuring tasks are executed with precision and speed. Interrupt handling is also unique: interrupts are converted into semaphore signals, allowing the code to handle these signals at its convenience without missing any, making hardware interactions more controlled, especially where timing is critical.

For Amiga enthusiasts already customizing their setups, Serena OS offers new possibilities. It shares some spirit with projects like AROS (Amiga Research Operating System) but adds its own twist with object-oriented design and cross-platform goals. Whether you’re developing software for your classic Amiga or exploring new hardware interfaces, Serena OS provides a robust and adaptable foundation.

A very wide beige laptop sits on a wooden table. A hand manipulates a teal ball in a semicircle attached to the right sided of the device. The track ball and hand are outlined in white.

A Trackball Retro Laptop

While track pads and mice dominate the pointing device landscape today, there was a time when track balls were a major part of the scene. In order to really sell the retro chops of his portable computer, [Ominous Industries] designed a clip-on style track ball for his retro Raspberry Pi laptop.

Starting with a half circle shape, he designed the enclosure in Fusion360 to house the guts of a USB trackball. Using the pattern along a path feature of the software, he was able to mimic the groovy texture of the main device on the trackball itself. Flexures in the top of the track ball case with pads glued on actuate the buttons.

We appreciate the honesty of the cuts showing how often the Pi can get grumpy at the extra wide display in this video as well as the previous issues during the laptop build. The bezel around the screen is particularly interesting, being affixed with magnets for easy access when needing to work on the screen.

Retro portables are having a moment. We just covered the Pi Portable 84 and previously saw one inspired by the GRiD Compass . If you’re more interested in trackballs, maybe give this trackball ring or the Ploopy trackball a look?

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