Hackaday Links: May 23, 2021

May 23, 2021 by Dan Maloney 10 Comments

The epicenter of the Chinese electronics scene drew a lot of attention this week as a 70-story skyscraper started wobbling in exactly the way skyscrapers shouldn’t. The 1,000-ft (305-m) SEG Plaza tower in Shenzhen began its unexpected movements on Tuesday morning, causing a bit of a panic as people ran for their lives. With no earthquakes or severe weather events in the area, there’s no clear cause for the shaking, which was clearly visible from the outside of the building in some of the videos shot by brave souls on the sidewalks below. The preliminary investigation declared the building safe and blamed the shaking on a combination of wind, vibration from a subway line under the building, and a rapid change in outside temperature, all of which we’d suspect would have occurred at some point in the 21-year history of the building. Others are speculating that a Kármán vortex Street, an aerodynamic phenomenon that has been known to catastrophically impact structures before, could be to blame; this seems a bit more likely to us. Regardless, since the first ten floors of SEG Plaza are home to one of the larger electronics markets in Shenzhen, we hope this is resolved quickly and that all our friends there remain safe.

In other architectural news, perched atop Building 54 at the Massachusetts Institute of Technology campus in Cambridge for the last 55 years has been a large, fiberglass geodesic sphere, known simply as The Radome. It’s visible from all over campus, and beyond; we used to work in Kendall Square, and the golf-ball-like structure was an important landmark for navigating the complex streets of Cambridge. The Radome was originally used for experiments with weather radar, but fell out of use as the technology it helped invent moved on. That led to plans to remove the iconic structure, which consequently kicked off a “Save the Radome” campaign. The effort is being led by the students and faculty members of the MIT Radio Society, who have put the radome to good use over the years — it currently houses an amateur radio repeater, and the Radio Society uses the dish within it to conduct Earth-Moon-Earth (EME) microwave communications experiments. The students are serious — they applied for and received a $1.6-million grant from Amateur Radio Digital Communications (ARDC) to finance their efforts. The funds will be used to renovate the deteriorating structure.

Well, this looks like fun: Python on a graphing calculator. Texas Instruments has announced that their TI-84 Plus CE Python graphing calculator uses a modified version of CircuitPython. They’ve included seven modules, mostly related to math and time, but also a suite of TI-specific modules that interact with the calculator hardware. The Python version of the calculator doesn’t seem to be for sale in the US yet, although the UK site does have a few “where to buy” entries listed. It’ll be interesting to see the hacks that come from this when these are readily available.

Did you know that PCBWay, the prolific producer of cheap PCBs, also offers 3D-printing services too? We admit that we did not know that, and were therefore doubly surprised to learn that they also offer SLA resin printing. But what’s really surprising is the quality of their clear resin prints, at least the ones shown on this Twitter thread. As one commenter noted, these look more like machined acrylic than resin prints. Digging deeper into PCBWay’s offerings, which not only includes all kinds of 3D printing but CNC machining, sheet metal fabrication, and even injection molding services, it’s becoming harder and harder to justify keeping those capabilities in-house, even for the home gamer. Although with what we’ve learned about supply chain fragility over the last year, we don’t want to give up the ability to make parts locally just yet.

And finally, how well-calibrated are your fingers? If they’re just right, perhaps you can put them to use for quick and dirty RF power measurements. And this is really quick and really dirty, as well as potentially really painful. It comes by way of amateur radio operator VK3YE, who simply uses a resistive dummy load connected to a transmitter and his fingers to monitor the heat generated while keying up the radio. He times how long it takes to not be able to tolerate the pain anymore, plots that against the power used, and comes up with a rough calibration curve that lets him measure the output of an unknown signal. It’s brilliantly janky, but given some of the burns we’ve suffered accidentally while pursuing this hobby, we’d just as soon find another way to measure RF power.

IRC Will Never Die

May 22, 2021 by Elliot Williams 51 Comments

The big kerfuffle in the open source world this week surrounds the biggest IRC server operator, Freenode. Wherever the dust settles, myriad important open source projects use Freenode’s IRC servers for their main channel of user feedback, and a number of vibrant communities call or called Freenode home. What you would call a 3D printer, and most of the software that drives it, for instance, was brainstormed up in Freenode’s #reprap. If you want help with a Linux distribution, you’ll be set straight within a few minutes in the relevant channel, because the people who wrote, packaged, or maintain it are probably on Freenode waiting to chat.

But suppose Freenode burns to the ground tomorrow, as some are suggesting. So what? My take is that is doesn’t matter. Freenode doesn’t own IRC, setting up an IRC server is essentially trivial, and what’s really important is the online community — they can just pick up and move somewhere else with very little hassle.

This is not to say that we don’t all benefit from the diligence that Freenode’s volunteer administrators and operators have donated to the cause over the years. IRC servers don’t run themselves, and Freenode’s admins fought and won an epic battle with spammers a couple years back. Keeping IRC running at scale is a different thing than setting up something for your friends, and so the Freenode folks definitely deserve our thanks.

But look, IRC is an old protocol and it’s a simple protocol. It’s so simple, in fact, that writing an IRC bot is just a few dozen lines in Python, using no external libraries. All you need to do is send plain text over a socket. You can do this — it makes a great networking hello world.

IRC is fun for hackers, but if you want a user-friendly GUI client, you ridiculously many to choose from. There are even no-install web clients if you just want to dip your toes in. Heck, you could install your own server in an hour or so.

So saying that the demise of Freenode is the end of IRC is a lot like saying that the end of Hotmail was the end of e-mail. In the grand scheme of things, almost nobody actually uses IRC — Freenode has 78,000 users while Slack has 10 million — and IRC users are very savvy, if not full-on geeky. These are the sort of people who can probably find the server field in a menu and change it from irc.freenode.net to irc.whatever.org.

In addition to our traditional #hackaday channel on irc.freenode.net, there’s also a channel set up on irc.libera.chat as well. There isn’t much action in either — IRC tends to be a slow conversation, so don’t freak out if someone responds to you an hour later — but if you want to swing by, we’re there. IRC will never die!

2021 Hackaday Prize Begins!

If you missed our announcement, this year’s Hackaday Prize is on! We’ve all had a rough year and a half, and it’s lead a lot of us to think seriously about our world. How would you want to change it going forward? Fifty entrants will rethink, refresh, and rebuild their way into $500, and the Grand Prize is $25,000. Get hacking!

Retrotechtacular: Double For Nothing

May 21, 2021 by Jenny List 52 Comments

If you are in the market for web hosting in 2021 and you sign up with one of the cloud computing providers, you’ll soon see how the different resources are priced. Storage and bandwidth are cheap, while CPU time is expensive. This reflects the state of a modern computer, in which a typical disk drive now holds a terabyte or more and rising by the year while a new processor is becoming a bottleneck whose performance hasn’t increased as much as the manufacturers would like over models from years ago.

Twice As Much Hardware From A Bit Of Software?

In the early 1990s though it was a different matter. A 486 or early Pentium processor was pretty powerful compared to the DOS or Windows 3.1 software it was expected to run, and it was the memory and disk space attached to it that limited performance… and cost an arm and a leg. There was a period in about 1995 when a supposed fire in a chip factory somewhere sent RAM prices into the hundreds of dollars per megabyte, briefly causing an epidemic of RAM raiding in which criminals would break into offices and take only the SIMs from the computers.

A solution to this problem came perhaps surprisingly from the software industry. Disk Doubler was a DOS driver that promised more disk space, achieving this seemingly impossible feat by compressing the disk to fit more data on it. Processor power swapped for disk space was a reasonable trade at the time so it became extremely popular, and eventually Microsoft incorporated their own disk compression into DOS. In some cases it could even speed up a computer with a slow disk drive, as I found out as a student with a 286 packing an MFM drive.

Something For Nothing, Perhaps It’s Too Good To Be True.

If compression could increase disk space then couldn’t it do the same for RAM? The industry came to the rescue once more with an array of RAM doubler products, first applying the disk doubling technique to on-disk virtual memory, and then doing the same with the contents of the memory itself. The first approach worked at the expense of a system slow-down, while the second, not so much. In fact it was little more than a scam, with software products promising much but delivering absolutely nothing behind the scenes.

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Hackaday Podcast 119: Random Robot Writing, Slithering Snake Shenanigans, And Phased Array Phenomena

May 21, 2021 by Mike Szczys 2 Comments

Hackaday editors Mike Szczys and Elliot Williams pick up on the neatest hacks you may have missed. We start off with another “What’s that Sound?” so put your geeky-ears to the test and win a Hackaday Podcast T-shirt. Here are a couple of classic hacks to bring you joy: music based on Markov chains, and a squiggly take on the classic Nokia game of snake. For the more hardcore science geeks we dive into the B Meson news coming out of CERN’s physics experiments. And after taking a detour in bristle-bot-based pen plotting, we unpack the hidden system of pipes that carry oil, gas, diesel, and more from the refinery to your region.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (The best 57 MB you’ll download all day!)

Places to follow Hackaday podcasts:

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This Week In Security: Watering Hole Attackception, Ransomware Trick, And More Pipeline News

May 21, 2021 by Jonathan Bennett 11 Comments

In what may be a first for watering hole attacks, we’ve now seen an attack that targeted watering holes, or at least water utilities. The way this was discovered is a bit bizarre — it was found by Dragos during an investigation into the February incident at Oldsmar, Florida. A Florida contractor that specializes in water treatment runs a WordPress site that hosted a data-gathering script. The very day that the Oldsmar facility was breached, someone from that location visited the compromised website.

You probably immediately think, as the investigators did, that the visit to the website must be related to the compromise of the Oldsmar treatment plant. The timing is too suspect for it to be a coincidence, right? That’s the thing, the compromised site was only gathering browser fingerprints, seemingly later used to disguise a botnet. The attack itself was likely carried out over Teamviewer. I will note that the primary sources on this story have named Teamviewer, but call it unconfirmed. Assuming that the breach did indeed occur over that platform, then it’s very unlikely that the website visit was a factor, which is what Dragos concluded. On the other hand, it’s easy enough to imagine a scenario where the recorded IP address from the visit led to a port scan and the discovery of a VNC or remote desktop port left open. Continue reading “This Week In Security: Watering Hole Attackception, Ransomware Trick, And More Pipeline News” →

Practical Sensors: The Hall Effect

May 20, 2021 by Al Williams 22 Comments

Measuring a magnetic field can be very easy with some pretty low tech, or it can be very high tech. It just depends on what kind of measurement you need and how much effort you want to expend. The very simplest magnetic sensors are reed switches. These are basically relays with no coil. Instead of a coil, an external magnet gets close enough to make or break the contacts in the reed. You see these a lot in, for example, door alarm sensors.

Then again, there’s no real finesse to a reed. It changes state when it sees enough of a magnetic field and that’s about all. You could use a compass with some sort of detection on the needle to get some more information about the field, but not much more. That was, however, how early magnetometers worked. Today, you have lots of options, including the nearly ubiquitous Hall effect sensor.

You might use a Hall effect to measure the magnetic button on a keyboard key coming down when you press it or the open and closed state of a valve. A lot of Hall effects see service as current monitors. Since a coil generates a magnetic field proportional to the current through it, a magnetic sensor can estimate the current in a coil of wire without any physical contact. Hall effects can also watch a magnet go by in a linear motion system or a rotating system to get an idea of position or speed. For example, check out this brushless motor controller that uses three sensors to understand the motor’s position.

History

Edwin Hall identified the effect in 1879. The basic idea is simple: an electrical conductor carrying current will exhibit changes due to an external magnetic field nearby. These changes show up as voltage you measure across the conductor. Normally, the voltage across a conductor will be nearly zero, but with a magnetic field, you’ll get a non-zero reading in proportion to the magnetic field strength in a particular plane, as we’ll see shortly.

Hall effect sensors are just one type of modern magnetometer. There are many different kinds including those that use inductive pickup coils that may or may not rotate or a fluxgate, which is a special type of coil. Some use a scale or a spring to measure force against another magnet — sometimes microscopically. You can even detect a magnetic field using optical properties like the Kerr effect or Faraday rotation.

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River Cleanup Aims To Expand In Earnest To Tackle Plastic Pollution

May 19, 2021 by Lewin Day 15 Comments

The Great Pacific Garbage Patch is just one of a number of pollution disasters affecting the world’s oceans. All over the globe, huge amounts of plastic enter waterways every day, causing havoc in delicate ecosystems.

Heading up the charge to deal with the problem, The Ocean Cleanup have been working on a variety of projects to help clean up plastic pollution. Chief among these is their river cleanup efforts, aiming to stop plastic pollution from reaching the ocean in the first place. The non-profit group intends to rapidly scale up its efforts, partnering with Finnish industrial manufacturer Konecranes in order to put its latest river cleaning design into series production.

We last reported on the group’s efforts in 2020, with their Interceptor craft operating in rivers in Malaysia, Indonesia, and the Dominican Republic. They’ve since refined the design for better functionality and easier deployment. Let’s jump in and see what they’ve learned and how their hunt for plastic pollution is shaping up.

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