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

GPS And Its Little Modules

September 8, 2025 by 17 Comments

Ever want to find your device on the map? Think we all do sometimes. The technology you’ll generally use for that is called Global Positioning System (GPS) – listening to a flock of satellites flying in the orbit, and comparing their chirps to triangulate your position.

The GPS system, built by the United States, was the first to achieve this kind of feat. Since then, new flocks have appeared in the orbit, like the Galileo system from the European Union, GLONASS from Russia, and BeiDou from China. People refer to the concept of global positioning systems and any generic implementation as Global Navigation Satellite System (GNSS), but I’ll call it GPS for the purposes of this article, and most if not all advice here will apply no matter which one you end up relying on. After all, modern GPS modules overwhelmingly support most if not all of these systems!

We’ve had our writers like [Lewin Day] talk in-depth about GPS on our pages before, and we’ve featured a fair few projects showing and shining light on the technology. I’d like to put my own spin on it, and give you a very hands-on introduction to the main way your projects interface with GPS.

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Psst… Got A Second? Here Are The 2025 One-Hertz Challenge Winners

September 5, 2025 by 20 Comments

Even with teachers with names like Kirchhoff and Helmholtz, old Heinrich Hertz himself likely didn’t have the slightest idea that his name would one day become an SI unit. Less likely still would have been the idea that Hackaday would honor him with the 2025 One-Hertz Challenge.

The challenge was deliberately — dare we say, fiendishly? — simple: Do something, anything, but do it once a second. Flash a light, ring a bell, click a relay, or even spam comments on a website other than Hackaday; anything at all, but do it at as close to one Hertz as possible. These are our favorite kinds of contests, because the simplicity affords a huge canvas for the creative mind to paint upon while still providing an interesting technical constraint that’s just difficult enough to make things spicy.

And boy, did you respond! We’ve received over a hundred entries since we announced the contest back in June, meaning that many of you spent 4,662,000 seconds of your summer (at least those of you above the equator) rising to the challenge. The time was well spent, with projects that pushed the limits of what we even expected.

While we loved ’em all, we had to winnow them down to the top three, each of which receives a $150 gift certificate from our sponsor, DigiKey. Let’s take a look at them, along with our favorite runners-up.

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Bootstrapping Android Development: A Survival Guide

September 4, 2025 by 24 Comments

Developing Android applications seems like it should be fairly straightforward if you believe the glossy marketing by Google and others. It’s certainly possible to just follow the well-trodden path, use existing templates and example code – or even use one of those WYSIWYG app generators – to create something passable that should work okay for a range of common applications. That’s a far cry from learning general Android development, of course.

The process has changed somewhat over the years, especially with the big move from the Eclipse-based IDE with the Android Development Tools (ADT) plugin, to today’s Jetbrains IntelliJ IDEA-based Android Studio. It’s fortunately still possible to download just the command-line tools to obtain the SDK components without needing the Google-blessed IDE. Using the CLI tools it’s not only possible to use your preferred code editor, but also integrate with IDEs that provide an alternate Android development path, such as Qt with its Qt Creator IDE.

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Field Guide To North American Crop Irrigation

September 3, 2025 by 26 Comments

Human existence boils down to one brutal fact: however much food you have, it’s enough to last for the rest of your life. Finding your next meal has always been the central organizing fact of life, and whether that meal came from an unfortunate gazelle or the local supermarket is irrelevant. The clock starts ticking once you finish a meal, and if you can’t find the next one in time, you’ve got trouble.

Working around this problem is basically why humans invented agriculture. As tasty as they may be, gazelles don’t scale well to large populations, but it’s relatively easy to grow a lot of plants that are just as tasty and don’t try to run away when you go to cut them down. The problem is that growing a lot of plants requires a lot of water, often more than Mother Nature provides in the form of rain. And that’s where artificial irrigation comes into the picture.

We’ve been watering our crops with water diverted from rivers, lakes, and wells for almost as long as we’ve been doing agriculture, but it’s only within the last 100 years or so that we’ve reached a scale where massive pieces of infrastructure are needed to get the job done. Above-ground irrigation is a big business, both in terms of the investment farmers have to make in the equipment and the scale of the fields it turns from dry, dusty patches of dirt into verdant crops that feed the world. Here’s a look at the engineering behind some of the more prevalent methods of above-ground irrigation here in North America.

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The Sense And Nonsense Of Virtual Power Plants

September 2, 2025 by 33 Comments

Over the past decades power grids have undergone a transformation towards smaller and more intermittent generators – primarily in the form of wind and solar generators – as well as smaller grid-connected batteries. This poses a significant problem when it comes to grid management, as this relies on careful management of supply and demand. Quite recently the term Virtual Power Plant (VPP) was coined to describe these aggregations of disparate resources into something that at least superficially can be treated more or less as a regular dispatchable power plant, capable of increasing and reducing output as required.

Although not actual singular power plants, by purportedly making a VPP act like one, the claim is that this provides the benefits of large plants such as gas-fired turbines at a fraction of a cost, and with significant more redundancy as the failure of a singular generator or battery is easily compensated for within the system.

The question is thus whether this premise truly holds up, or whether there are hidden costs that the marketing glosses over.

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The Browser Wasn’t Enough, Google Wants To Control All Your Software

August 28, 2025 by 170 Comments

A few days ago we brought you word that Google was looking to crack down on “sideloaded” Android applications. That is, software packages installed from outside of the mobile operating system’s official repository. Unsurprisingly, a number of readers were outraged at the proposed changes. Android’s open nature, at least in comparison to other mobile operating systems, is what attracted many users to it in the first place. Seeing the platform slowly move towards its own walled garden approach is concerning, especially as it leaves the fate of popular services such as the F-Droid free and open source software (FOSS) repository in question.

But for those who’ve been keeping and eye out for such things, this latest move by Google to throw their weight around isn’t exactly unexpected. They had the goodwill of the community when they decided to develop an open source browser engine to keep the likes of Microsoft from taking over the Internet and dictating the rules, but now Google has arguably become exactly what they once set out to destroy.

Today they essentially control the Internet, at least as the average person sees it, they control 72% of the mobile phone OS market, and now they want to firm up their already outsized control which apps get installed on your phone. The only question is whether or not we let them get away with it.

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Where There Is No Down: Measuring Liquid Levels In Space

August 26, 2025 by 40 Comments

As you can probably imagine, we get tips on a lot of really interesting projects here at Hackaday. Most are pretty serious, at least insofar as they aim to solve a specific problem in some new and clever way. Some, though, are a little more lighthearted, such as a fun project that came across the tips line back in May. Charmingly dubbed “pISSStream,” the project taps into NASA’s official public telemetry stream for the International Space Station to display the current level of the urine tank on the Space Station.

Now, there are a couple of reactions to a project like this when it comes across your desk. First and foremost is bemusement that someone would spend time and effort on a project like this — not that we don’t appreciate it; the icons alone are worth the price of admission. Next is sheer amazement that NASA provides access to a parameter like this in its public API, with a close second being the temptation to look at what other cool endpoints they expose.

But for my part, the first thing I thought of when I saw that project was, “How do they even measure liquid levels in space?” In a place where up and down don’t really have any practical meaning, the engineering challenges of liquid measurement must be pretty interesting. That led me down the rabbit hole of low-gravity process engineering, a field that takes everything you know about how fluids behave and flushes it into the space toilet.

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