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Longform articles, the best of what the Hackaday writing crew has to offer.

How Airspeed Sensors Work

June 30, 2026 by 28 Comments

When you’re driving your car, you’re probably regularly looking at the speedometer to make sure you comply with the local speed limits. The method by which it works is simple enough: the rotation of the wheels is sent mechanically via a cable to a dial on the dash, or an electronic sensor counts the rotations of the drivetrain and an electronically-controlled needle or display shows the speed.

But what about if you were in an aircraft, and the wheels had nothing to do with how fast you were going? How would you even begin to measure speed? There are two ways: there’s a convenient solution to this problem rooted in simple fluid mechanics, and a far-more-complex modern solution. Today, we’ll explore how planes and helicopters are able to figure out how fast they’re going, by the old ways and the new.

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The Teenage Angst Of 3D Printing: Solidoodle, Printrbot, And Bridges

June 29, 2026 by 42 Comments

Bridges are a part of our constructed landscape that we take for granted. And bridges by themselves aren’t especially important. What is important is that bridges let you get from one place to another. Technology is often the same. We get from point A to point B through some bridge technology that, probably, most normal people never even notice.

Years ago, point A was commercial 3D printing. Industry had stereolithography, selective laser sintering, fused deposition modeling, and other rapid-prototyping technologies. These were not toys. They were expensive industrial systems used by companies that needed prototypes badly enough to pay serious money for them.

Fast Forward to Today

Today, you can go to a big box store and buy a 3D printer for well under $1,000, and often far less. Modern machines are almost plug-and-play and tend to do all the hard parts for you. That’s point B. How we got between points is a story of hackers who had a dream, and many Hackaday readers lived through it and even played a part in that bridging.

For a long time, RepRap was synonymous with hobby-level 3D printing. The project, started by [Adrian Bowyer] at the University of Bath in 2005, was built around a powerful idea: a machine that could print many of its own parts, thereby helping make more machines. RepRap Darwin reached its early self-replicating milestones in 2008, and the movement produced a thicket of descendants, variants, and arguments about rods, belts, bearings, extruders, firmware, and what “self-replicating” really meant. Of course, the machine could only print some of the parts you needed, but it was still impressive how much of a printer you could make with one printer.

Without RepRap, the desktop 3D printer boom would have looked very different. It created a common pool of ideas: Cartesian frames, printed brackets, hobbed bolts, heated beds, RAMPS boards, Marlin firmware, and a whole common vocabulary. It also created the expectation that a 3D printer was something you could understand, modify, repair, and improve. That expectation would not survive everywhere, but it defined the early culture.

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Flying Cell Towers Are A Thing

June 25, 2026 by 20 Comments

Typically, when you’re sitting on a plane on the tarmac, you switch your phone to flight mode while you’re sitting through yet another “quirky” (boring) safety video. You’ll watch some inflight entertainment, read the airline magazine if you get really desperate, and wonder if anyone ever buys those random watches for sale in the “duty free” section. Then, finally, upon landing, you’ll be connected back to the Internet and you’ll finally feel like you can breathe again.

Only, this time, you forgot to set your phone to flight mode. You’re sitting at 30,000 feet, and… your phone has signal? You’re online, and you’re getting notifications and emails just like you’re on the ground. You’ve accidentally discovered that your flight has an on-board cell tower.

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The Trains With Rubber Tires

June 24, 2026 by 37 Comments

The train was one of the game-changing inventions that defined the Industrial Age. No more would humanity rely on tempestuous animals to haul goods and passengers great distances across the land. Fire and steam came along to rapidly increase the speed of travel and transformed the very fabric of society itself.

To this day, the vast majority of train networks rely on the same basic principle—heavy locomotives and carriages running steel wheels on steel tracks. Yet, there is a curious alternative twist on this concept that sees trains of carriages riding on tires instead. But what would possess anyone to build a rubber tired train?

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Linux Fu: Upcycling An Old Router

June 23, 2026 by 28 Comments

You’re wandering through a thrift store and spot an old router for ten bucks. Worthless, right? But in this case, it was a Google OnHub, which, at the time, was pretty premium and still isn’t anything to sneeze at. Of course, Google abandoned it long ago, and it runs Chrome, so pass, right? Of course I didn’t. In fact, I bought two for less than $20. The question is always the same: what do you do with it?

OpenWrt will run on the device. That’s a good start, but merely replacing the firmware isn’t much of a project. The more interesting question is whether the hardware can still do something useful. I had a specific need: connect a wired workstation to a reasonably distant WiFi network without running cable and without suffering the usual double-NAT headaches that come from turning the router into yet another subnet. For this, the OnHub turned out to be nearly perfect.

The Hardware

The OnHub was Google’s first Wi-Fi router, built by TP-Link and ASUS in different versions. Mine was the TP-Link model, and one was missing a bit of plastic cowl trim. Under the hood, it has a Qualcomm IPQ8064 dual-core processor — a dual-core ARMv7 — multiple radios, gigabit Ethernet, and enough memory to run OpenWrt comfortably: 1 GB of RAM and 4 GB of flash. The processor also has two network offload processors, but it isn’t clear to me that the stock OpenWrt build uses them.

These devices were expensive when new, but now show up regularly at thrift stores and surplus sales. Installing OpenWrt was straightforward. You do need to remove a screw that covers the magic switch at the bottom, but that’s not a big problem. You can just peel the rubber foot back if you don’t want to remove it. However, the interesting part came afterward.

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MSYS2 And The No-Fuss Way To Get More GNU Into Your Windows

June 22, 2026 by 37 Comments

As great and streamlined as the Windows desktop experience is, one area where it’s at best disappointing and at worst rage-inducing is when it comes to its command line interface (CLI) offerings. In Windows 9x/ME this could be excused by the fact that it was essentially just a dressed-up MS-DOS CLI experience, but on Windows NT-based OSes no such excuse exists.

Yet even after Microsoft finally acknowledged the shortcomings of the cmd.exe shell by 2006, they then proceeded to go their own way with PowerShell, industry standards be damned. Especially for those of us who have no beef with the UNIX/BSD/Linux CLI experience and the joys of shell scripting, this insistence was disappointing. Simultaneously, everyone from OS X/MacOS to Haiku were happily offering a familiar CLI environment alongside POSIX compatibility.

Although Windows NT OSes were POSIX compliant, they never offered a suitable shell along with it, nor any of the other things you’d expect in a modern-day BSD, Haiku or Linux CLI environment. In a recent article by my esteemed colleague Al Williams, these sore points were somewhat addressed as far as basic CLI tools go, but the issue goes obviously much deeper than just the basic userland tools. Which is where MSYS2 comes into the picture.

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What Happens If Russia Shuts The Door On Their Leaky ISS Module?

June 18, 2026 by 29 Comments

There was a particularly tense moment aboard the International Space Station earlier this month, with NASA directing their astronauts to secure themselves in the Dragon capsule and prepare for a potential return to Earth while their Russian counterparts engaged in what we now know to have been some impromptu demolition work on their side of the orbiting complex.

Despite objections from their American partners, Roscosmos had given their cosmonauts the go-ahead to drill and cut into the walls of the Zvezda module — one of the core components of the ISS which has been in orbit since 2000 — to try and identify and ultimately repair persistent leaks that have been venting the Station’s atmosphere out into space for several years. We may never know the exact nature of the behind-the-scenes communication that went on between the two space agencies, but in the end the Russians abandoned their plan and NASA’s personnel were told to resume their normal duties.

But where do things go from here? Although it’s true the International Space Station is entering its final years, the mission isn’t over yet, and that means the two countries need to continue to work together if they hope to get any science done in the time they have left.

At this point there hasn’t been any official word from either agency, but sources that wish to remain anonymous have been dropping hints, and that’s got the rumors swirling. With the understanding that anything is still possible, at this point it looks like Russia is going to abandon any further attempts to repair the leak and instead seal off the crippled compartment of the Zvezda module. This won’t solve all the problems, and in fact will create some new ones. But if that’s what it will take to keep the peace with NASA until Station operations wind down, it’s apparently a bargain they’re willing to make.

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