ISS Mimic Brings Space Station Down To Earth

October 6, 2023 by Tom Nardi 20 Comments

Built at a cost of more than $150 billion over the last twenty-five years, the International Space Station is arguably one of humanity’s greatest engineering triumphs. Unfortunately, unlike Earthly construction feats such as the Hoover Dam, Burj Khalifa, or the Millau Viaduct, you can’t visit it in person to really appreciate its scale and complexity. Well, not unless you’ve got the $50 million or so to spare to buy a seat on a Dragon capsule.

Which is why the team behind the ISS Mimic project are trying to make the ISS a bit more relatable. The open source project consists of a 3D printable 1:100 model of the Station, which is linked to the telemetry coming down from the real thing. A dozen motors in the model rotate the solar arrays and radiators to match the positions of their full-scale counterparts, while LEDs light up to indicate the status of various onboard systems.

To learn more about the ISS Mimic, team members Bryan Murphy, Sam Treadgold, and Tristan Moody stopped by this week’s Hack Chat to bring us up to speed on the past, present, and future of this fascinating project.

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Hackaday Podcast 239: Overclocking, Oscilloscopes, And Oh No! SMD Out Of Stock!

October 6, 2023 by Al Williams 2 Comments

Elliot Williams and Al Williams got together again to discuss the best of Hackaday for a week, and you’re invited. This week, the guys were into the Raspberry Pi 5, CNC soldering, signal processing, and plasma cutting. There are dangerous power supplies and a custom 11-bit CPU.

Of course, there are a few Halloween projects that would fit in perfectly with the upcoming Halloween contest (the deadline is the end of this month; you still have time). OpenSCAD is about to get a lot faster, and a $20 oscilloscope might not be a toy after all. They wrap up by talking about Tom Nardi’s latest hardware conversion of DIP parts to SMD and how TVs were made behind the Iron Curtain.

Did you miss a story? Check out the links below. As always, tell us what you think about this episode in the comments!

Go ahead and download it!

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Just When You Think Everything In Robotic Combat Has Been Tried Before…

October 6, 2023 by Jenny List 15 Comments

Since the first combat robots emerged around three decades ago, it seems as though every conceivable configuration has been tried at some point or other. Whether it’s a two-wheeled wedgebot, a walker, a four-wheeled flip-bot, or whatever, someone’s already been there. But how about a self-righting taco with a novel two-wheel drive system? It’s called Taco Tuesday, its team lead [Carter Hurd] has sent us the video below the break, and it’s worth a second look because the technique might find a place outside the arena.

So what exactly is novel about this bot? It has a single big fat wheel near the front in a longitudinal direction, and a larger slimmer one at the back in a transverse direction. The former wheel propels it around the arena while the latter wheel acts as a rear-wheel steering system, allowing it to pivot round and face an attacker very quickly indeed.

It’s this maneuverability which we think could find an application in other machines, though the same problem they have of sideways friction on that rear wheel would need to be overcome.

The video follows the bot through a BattleBots competition in Las Vegas, and shows us some of the damage they receive in combat. The drive system needs a bit more refinement, but this outing certainly proves it has plenty of potential.

Some of us here at Hackaday have a bit of a soft spot for fighting robots.

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This Week In Security: Looney Tunables, Not A 0-day*, And Curl Warning

October 6, 2023 by Jonathan Bennett 8 Comments

This week starts out with a nifty vulnerability in the glibc dynamic loader. This is an important step in running a binary executable on Linux, as it pulls the list of required shared libraries, and loads those libraries into memory. Glibc also includes a feature to adjust some runtime settings, via the GLIBC_TUNABLES environment variable. That’s where the vulnerability resides, and researchers from Qualsys obviously had a bit of fun in taking inspiration to pick the vulnerability name, “Looney Tunables”.

The problem is memory handling in the sanitizing parser. This function iterates through the environment variable, looking for strings of tunable1=aa, separated by colons. These strings get copied to the sanitized buffer, but the parsing logic goes awry when handling the malformed tunable1=tunable2=AAA. The first equals sign is taken at face value, copying the rest of the string into the buffer. But then the second equals sign is also processed as another key=value pair, leading to a buffer overflow.

The reason this particular overflow is interesting is that if the binary to be run is a Set-User-ID (SUID) root application, the dynamic loader runs as root, too. If the overflow can achieve code execution, then it’s a straightforward privilege escalation. And since we’re talking about it, you know there’s a way to execute code. It turns out, it’s possible to overwrite the pointer to the library search path, which determines where the dynamic loader will look for libraries. Tell it to look first in an attacker-controlled location, and you can easily load a malicious libc.so for instant code execution.

This vulnerability affects many Linux distros, and there’s already a Proof of Concept (PoC) published. So, it’s time to go check for updates for cve-2023-4911. Continue reading “This Week In Security: Looney Tunables, Not A 0-day*, And Curl Warning” →

Wok Your Way To The Center Of The Galaxy

October 6, 2023 by Dan Maloney 14 Comments

The round bottom of a proper wok is the key to a decent stir fry, but it also makes it hard to use on traditional Western stoves. That’s why many woks end up in a dark kitchen cabinet, unused and unloved. But wait; it turns out that the round bottom of a wok is the perfect shape for gathering something else — radio waves, specifically the 21-cm neutral hydrogen emissions coming from the heart of our galaxy.

Turning a wok into an entry-level radio telescope doesn’t appear to be all that hard, at least judging by what [Leo W.H. Fung] et al detail in their paper (PDF) on “WTH” or “Wok the Hydrogen.” Aside from the wok, which serves as the main reflector, you’ll need a bit of coaxial cable and some stiff copper wire to fashion a small dipole antenna and balun, plus some plastic tubing to support it at the focal point of the reflector. Measuring the wok’s shape and size, which in turn determines its focal point, is probably the hardest part of the build; luckily, the paper includes tips on doing just that. The authors address the controversy of parabolic versus spherical reflectors and arrive at the conclusion that for a radio telescope fashioned from a wok, it just doesn’t matter.

As for the signal processing chain, WTH holds few surprises. A Nooelec Sawbird+ H1 acts as preamp and filter for the 1420-MHz hydrogen line signal, which feeds into an RTL-SDR dongle. Careful attention is paid to proper grounding and shielding to keep the noise floor as low as possible. Mounting the antenna is a decidedly ad hoc affair, and aiming is as simple as eyeballing various stars near the center of the galactic plane — no need to complicate things.

Performance is pretty good: WTH measured the recession velocity of neutral hydrogen to within 20 km/s, which isn’t bad for something cobbled together from scrap. We’ve seen plenty of DIY hydrogen line observatories before, but WTH probably wins the “get on the air tonight” award.

Thanks to [Heinz-Bernd Eggenstein] for the tip.

Creating An Automated Hydrogen Generator At Home

October 6, 2023 by Maya Posch 34 Comments

Everyone and their pet hamster probably knows that the most common way to produce hydrogen is via the electrolysis of water, but there are still a number of steps between this elementary knowledge and implementing a (mostly) automated hydrogen generator. Especially if your end goal is to create liquid hydrogen when everything is said and done. This is where [Hyperspace Pirate]’s latest absolutely not dangerous project commences, with the details covered in the recently published video.

Automated hydrogen generator setup, courtesy of [Hyperspace Pirate]'s dog drinking bowl. — Automated hydrogen generator setup, courtesy of [Hyperspace Pirate]’s dog drinking bowl.

Since electrolysis cannot occur with pure water, sodium hydroxide (NaOH) is used in the solution to provide the ions. The electrodes are made of 316 stainless steel, mostly because this is cheap and good enough for this purpose. Although the original plan was to use a stacked series of electrodes with permeable membranes like in commercial electrolysers, this proved to be too much of a hassle to seal up leak-tight. Ergo the demonstrated version was attempted, where an upturned glass bell provides the barrier for the produced hydrogen and oxygen. With this system it’s easy to measure the volume of the produced hydrogen due to the displaced water in the bell.

Once enough hydrogen gas is produced, a vacuum pump is triggered by a simple pair of electrodes to move the hydrogen gas to a storage container. Due to hydrogen embrittlement concerns, an aluminium tank was used rather than a steel one. Ultimately enough hydrogen gas was collected to fill a lot of party balloons, and with the provided information in the video it should be quite straightforward to reproduce the system.

Where the automation comes into play is with a control system that monitors for example how long the vacuum pump has been running, and triggers a fail safe state if it’s more than a set limit. With the control system in place, [Hyperspace Pirate] was able to leave the hydrogen generator running for hours with no concerns. We’re hopeful that his upcoming effort to liquify this hydrogen will be as successful, or the human-rated blimp, or whatever all this hydrogen will be used for.

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Just What Is Tone, In A Microphone?

October 5, 2023 by Jenny List 23 Comments

As long-time Hackaday readers will know, there is much rubbish spouted in the world of audio about perceived tone and performance of different hi-fi components. Usually this comes from audiophiles with, we’d dare to suggest, more money than sense. But oddly there’s an arena in which the elusive tone has less of the rubbish about it and it in fact, quite important. [Jim Lill] is a musician, and like all musicians he knows that different combinations of microphones impart a different sound to the recording. But as it’s such a difficult property to quantify, he’s set out to learn all he can about where the tone comes from in a microphone.

He’s coming to this from the viewpoint of a musician rather than an engineer, but his methodology is not diminished by this. He’s putting each mic on test in front of the same speaker at the same position, and playing a standard piece of music and a tone sweep through each. He doesn’t have an audio analyser, reference speaker and microphone, or anechoic chamber, so he’s come up with a real-world standard instead. He’s comparing every mic he can find with a Shure SM57, the go-to general purpose standard in the world of microphones for as long as anyone can remember, being a 1960s development of their earlier Unidyne series. His reasoning is that while its response is not flat the sound of the SM57 is what most people are used to hearing from a microphone, so it makes sense to measure the others against its performance.

Along the way he tests a huge number of microphones including famous and expensive ones from exclusive studios and finally one he made himself by mounting a cartridge atop a soda can. You’ll have to watch the video below the break for his conclusions, we can promise it’s worth it.

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