Are You Using Your Calipers Wrong?

August 20, 2024 by 50 Comments

It used to be that calipers were not a common item to have in an electronics lab. However, smaller parts, the widespread use of 3D printers and machining tools, and — frankly — cheap imported calipers have made them as commonplace as an ordinary ruler in most shops. But are you using yours correctly? [James Gatlin] wasn’t and he wants to show you what he learned about using them correctly.

The video that you can see below covers digital and vernier calipers. You might think digital calipers are more accurate, in practice, they are surprisingly accurate, although the digital units are easier to read.

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Pulling Hydrogen Out Of The Water

August 20, 2024 by 23 Comments

In theory, water and electric current will cause electrolysis and produce oxygen and hydrogen as the water breaks apart. In practice, doing it well can be tricky. [Relic] shows an efficient way to produce an electrolysis cell using a few plastic peanut butter jars and some hardware.

The only tricky point is that you need hardware made of steel and not zinc or other materials. Well, that and the fact that the gasses you produce are relatively dangerous.

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Remapping HID For Fun And… Well Fun

August 20, 2024 by 13 Comments

If you want to remap some mouse or keyboard keys, and you use Linux, it is easy. If you use Windows or another operating system, you can probably do that without too much trouble. But what if you use all of them? Or what if you don’t have access to the computer in question? Thanks to [jfedor2], you can reach for a Raspberry Pi Pico and make this handy key-and-mouse remapping hardware dongle.

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Open Source Liquid Rocket Reaches For The Sky

August 20, 2024 by 30 Comments

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

August 20, 2024 by 61 Comments

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

August 20, 2024 by 75 Comments

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

August 20, 2024 by 24 Comments

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.