Hackaday Columns

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This excellent content from the Hackaday writing crew highlights recurring topics and popular series like Linux-Fu, 3D-Printering, Hackaday Links, This Week in Security, Inputs of Interest, Profiles in Science, Retrotechtacular, Ask Hackaday, Teardowns, Reviews, and many more.

Hackaday Podcast Episode 274: Capstan Robots, Avionics Of Uncertain Purpose, And What The Frack?

June 7, 2024 by No comments

What do capstans, direct conversion receivers, and fracking have in common? They were all topics Hackaday editors Elliot Williams and Al Williams found fascinating this week. If you wonder what makes an electrical ground a ground, or what a theodolite is, you should check it out.

This week, the hacks came fast and furious. Capstans, instead of gears, work well for 3D-printed mechanisms, a PI Pico can directly receive radio signals, and the guys saw a number of teardowns and reverse engineering triumphs. You’ll also find solid-state heat pumps, flying wings, spectroscopy, and more.

The can’t miss articles this week? Learn about theodolites, a surveying feat from ancient Greece, and how fracking works.

Check out the links below if you want to follow along, and as always, tell us what we’ve mispronounced — or any other thoughts on the episode — in the comments!

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This Week In Security: Recall, Modem Mysteries, And Flipping Pages

June 7, 2024 by 6 Comments

Microsoft is racing to get into the AI game as part of Windows 11 on ARM, calling it Copilot+. It’s an odd decision, but clearly aimed at competing with the Apple M series of MacBooks. Our focus of interest today is Recall, a Copilot+ feature that not only has some security problems, but also triggers a sort of visceral response from regular people: My computer is spying on me? Eww.

Yes, it really sort of is. Recall is a scheme to take screen shots of the computer display every few seconds, run them through character recognition, and store the screenshots and results in a database on the local machine hard drive. There are ways this could be useful. Can’t remember what website had that recipe you saw? Want to revisit a now-deleted tweet? Is your Google-fu failing you to find a news story you read last week? Recall saw it, and Recall remembers. But what else did Recall see? Every video you watched, ever website you visited, and probably some passwords and usernames you typed in.

Continue reading “This Week In Security: Recall, Modem Mysteries, And Flipping Pages” →

Retrotechtacular: TVO

June 6, 2024 by 18 Comments

Hardware hackers come from a variety of backgrounds, but among us there remains a significant number whose taste for making things was forged through growing up in a farm environment. If that’s you then like me it’s probable that you’ll melt a little at the sight of an older tractor, and remember pretending to drive one like it at pre-school age, and then proudly driving it for real a few years later before you were smart enough to realise you’d been given the tedious job of repeatedly traversing a field at a slow speed in the blazing sun. For me those machines were Ford Majors and 5000s, Nuffields, the ubiquitous red Fergusons, and usually relegated to yard duty by the 1970s, the small grey Ferguson TE20s that are in many ways the ancestor of all modern tractors.

The Black Art Of Mixing Your Own Fuel

There was something odd about some of those grey Fergies in the 1970s, they didn’t run on diesel like their newer bretheren, nor did they run on petrol or gasoline like the family Austin. Instead they ran on an unexpected mixture of petrol and heating oil, which as far as a youthful me could figure out, was something of a black art to get right. I’d had my first encounter with Tractor Vapour Oil, or TVO, a curious interlude in the history of agricultural engineering. It brings together an obscure product of the petrochemical industry, a moment when diesel engine technology hadn’t quite caught up with the on-farm requirement, and a governmental lust for a lower-tax tractor fuel that couldn’t be illicitly used in a car.

TVO is a fuel with a low octane rating, where the octane rating is the resistance to ignition through compression alone. In chemical terms octane rating a product of how many volatile aromatic hydrocarbons are in the fuel, and to illustrate it your petrol/gasoline has an octane rating in the high 90s, diesel fuel has one close to zero, and TVO has a figure in the 50s. In practice this was achieved at the refinery by taking paraffin, or kerosene for Americans, a heavier fraction than petrol/gasoline, and adding some of those aromatic hydrocarbons to it. The result was a fuel on which a standard car engine wouldn’t run, but which would run on a specially low-compression engine with a normal spark ignition. This made it the perfect tax exempt fuel for farmers because it could only be used in tractors equipped with these engines, and thus in the years after WW2 a significant proportion of those Fergies and other tractors were equipped to run on it. Continue reading “Retrotechtacular: TVO” →

Displays We Like Hacking: HDMI

June 5, 2024 by 26 Comments

I don’t like HDMI. Despite it being a pretty popular interface, I find crucial parts of it to be alien to what hackers stand for. The way I see it, it manages to be proprietary while bringing a lot of the old cruft in. It doesn’t have a native alternative like DisplayPort, so portable implementations tend to suffer power-wise; the connector situation is interesting, and the HDMI Foundation has been doing some weird stuff; in particular, they are pretty hostile to open-source technology.

This article is not the place for such feelings, however, especially since I’ve expressed them enough in the DisplayPort article. We the hackers deserve to be able to handle the interfaces we stumble upon, and I firmly believe in that way more than in my right to animosity towards HDMI.

The HDMI interface is seriously prominent wherever you look, in part because it’s the interface created by the multimedia-involved companies for the multimedia-involved companies. Over the years we’ve had it, it’s been more than sufficient for basically everything we do video-wise, save for the highest resolutions.

It’s also reasonably simple to wire up, hack on, and even bitbang. Let’s go through what makes it tick.

The Core

HDMI is, at its core, three differential pairs for data, plus one pair to clock them and in the darkness bind them. It’s a digital interface, though it is a fun one. This makes it way more suitable for higher-distance video transmissions than interfaces like VGA, and as long as you stick to relatively low resolutions, HDMI won’t have as many asks in terms of PCB layout as DisplayPort might, thanks to HDMI link speeds scaling proportionally with the display resolution.

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Pasteurisation: Probably Why You Survived Childhood

June 4, 2024 by 124 Comments

There’s an oft-quoted maxim that youngsters growing up on farms have a much stronger immune system than those growing up in cities. The idea is that they are exposed to far more dirt and eat food much closer to the field than their urban cousins. Without the help of a handy microbiologist or epidemiologist it’s difficult to judge its veracity, but personal experience suggests that the bit about dirt may be true at least.

It’s Dangerous To Idealise The Past.

It’s likely that the idea of rural kids seeing more bugs may come from the idea that those in the cities consume sterile processed food from the supermarket, it plays into a notion of an idealised past in which a somehow purer diet came more directly from its source. Somehow so the story goes, by only eating pasteurised and preserved foods, city dwellers are eating something inferior, stripped of its goodness. There’s a yearning for a purer alternative, something supermarkets are only too happy to address by offering premium products at elevated prices. So, was the diet of the past somehow more wholesome, and are those kids having their future health ruined by Big Food? Perhaps it’s time to turn back the clock a little to find out.

A mostly black cow in a field of green grass
Even clean cows have bugs. Carolyn Parsons, CC BY-SA 4.0.

It’s likely everyone knows that food  spoils if left unattended for long enough. Some foods, such as grain, can last a long time if kept dry, while others such as milk will go bad quite quickly. Milk in particular goes bad for two reasons; firstly because it’s an excellent bacterial growth medium, and secondly because it contains plenty of bacteria by its very nature. Even very clean cows have bugs.

If you lived in most large cities in the nineteenth century, the Industrial Revolution had likely placed you far enough from the nearest cow that your milk had a significant journey to make to reach you even with up-to-date rail transport. Without refrigeration, during that journey it had become a bacterial soup to the extent that even though it might not yet have gone sour, it had certainly become a bacterial brew. It was thus responsible for significant numbers of infections, and had become a major health hazard. So much for the purer diet consumed by city kids of the past. Continue reading “Pasteurisation: Probably Why You Survived Childhood” →

Tech In Plain Sight: Theodolites

June 3, 2024 by 23 Comments

We take it for granted that you can look at your phone and tell exactly where you are. At least, as exact as the GPS satellites will allow. But throughout human history, there has been a tremendous desire to know where here is, exactly. Where does my farm end and yours start? Where is the border of my city or country? Suppose you have a flagpole directly in the center of town and a clock tower at the edge of town. You know where they are precisely on a map. You also know how tall they are. What you need is a theodolite, which is an instrument that measures angles very precisely.

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