Author: Dan Maloney

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Hackaday Links: September 25, 2022

September 25, 2022 by 15 Comments

Looks like there’s trouble out at L2, where the James Webb Space Telescope suffered a mechanical anomaly back in August. The issue, which was just announced this week, involves only one of the six imaging instruments at the heart of the space observatory, known as MIRI, the Mid-Infrared Instrument. MIRI is the instrument on Webb that needs the coldest temperatures to work correctly, down to six Kelvins — we’ve talked about the cryocooler needed to do this in some detail. The problem has to do with unexpectedly high friction during the rotation of a wheel holding different diffraction gratings. These gratings are rotated into the optical path for different measurements, but apparently the motor started drawing excessive current during its move, and was shut down. NASA says that this only affects one of the four observation modes of MIRI, and the rest of the instruments are just fine at this time. So they’ve got some troubleshooting to do before Webb returns to a full program of scientific observations.

There’s an old saying that, “To err is human, but to really screw things up takes a computer.” But in Russia, to really screw things up it takes a computer and a human with a really poor grasp on just how delicately balanced most infrastructure systems are. The story comes from Moscow, where someone allegedly spoofed a massive number of fake orders for taxi rides (story in Russian, Google Translate works pretty well) through the aggregator Yandex.Taxi on the morning of September 1. The taxi drivers all dutifully converged on the designated spot, but instead of finding their fares, they just found a bunch of other taxis milling about and mucking up traffic. Yandex reports it has already added protection against such attacks to its algorithm, so there’s that at least. It’s all fun and games until someone causes a traffic jam.

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This Scratch-Built X-Ray Tube Really Shines

September 24, 2022 by 25 Comments

On no planet is making your own X-ray tube a good idea. But that doesn’t mean we’re not going to talk about it, because it’s pretty darn cool.

And when we say making an X-ray tube, we mean it — [atominik] worked from raw materials, like glass test tubes, tungsten welding electrodes, and bits of scrap metal, to make this dangerously delightful tube. His tool setup was minimalistic as well– where we might expect to see a glassblower’s lathe like the ones used by [Dalibor Farny] to make his custom Nixie tubes, [atominik] only had a small oxy-propane hand torch to work with. The only other specialized tools, besides the obvious vacuum pump, was a homebrew spot welder, which was used to bond metal components to the tungsten wires used for the glass-to-metal seals.

Although [atominik] made several versions, the best tube is a hot cathode design, with a thoriated tungsten cathode inside a copper focusing cup. Across from that is the anode, a copper slug target with an angled face to direct the X-rays perpendicular to the long axis of the tube. He also included a titanium electrode to create a getter to scavenge oxygen and nitrogen and improve the vacuum inside the tube. All in all, it looks pretty similar to a commercial dental X-ray tube.

The demonstration in the video below is both convincing and terrifying. He doesn’t mention the voltage he’s using across the anode, but from the cracking sound we’d guess somewhere around 25- to 30 kilovolts. The tube really gets his Geiger counter clicking.

Here’s hoping [atominik] is taking the proper precautions during these experiments, and that you do too if you decide to replicate this. You’ll also probably want to check out our look at the engineering inside commercial medical X-ray tubes.

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Hackaday Podcast 186: Weighing Cats, Slamming VU Meters, Slimmer Skimmers, And Clean Air On The Cheap

September 23, 2022 by 3 Comments

Hackaday Editor-in-Chief Elliot Williams took time out from Supercon planning to join Staff Writer Dan Maloney for a look through the hacking week that was. We always try to keep things light, but it’s hard sometimes, especially when we have to talk about wars past and present and the ordnance they leave behind. It’s also not a lot of fun to talk about a continent-wide radio outage thanks to our angry Sun, nor is learning that a wafer-thin card skimmer could be lurking in your ATM machine.

But then again, we did manage to have some fun by weighing cats to make sure they’re properly fed, and making music by pegging VU meters. We also saw how to use PCBs to make a beautiful yet functional circuit sculpture, clean up indoor air on a budget, and move microns with hardware store parts. And we also got to celebrate a ray of international hope by looking back on the year that taught us much of what we know about the Earth.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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Snooping On Starlink With An RTL-SDR

September 23, 2022 by 21 Comments

With an ever-growing constellation of Starlink satellites whizzing around over our heads, you might be getting the urge to start experimenting with the high-speed internet service. But at $100 or more a month plus hardware, the barrier to entry is just a little daunting for a lot of us. No worries, though — if all you’re interested in is tracking [Elon]’s birds, it’s actually a pretty simple job.

Now, we’re not claiming that you’ll be able to connect to Starlink and get internet service with this setup, of course, and neither is the delightfully named [saveitforparts]. Instead, his setup just receives the beacon signals from Starlink satellites, which is pretty interesting all by itself. The hardware consists of his “Picorder” mobile device, which sports a Raspberry Pi, a small LCD screen, and a host of sensors, including an RTL-SDR dongle. To pick up the satellite beacons, he used a dirt-cheap universal Ku-band LNB, or low-noise block downconverter. They’re normally found at the focal point of a satellite TV dish, but in this case no dish is needed — just power it up with a power injector and point it to the sky. The signals show up on the Picorder’s display in waterfall mode; curiously, the waterfall traces look quite similar to the patterns the satellites make in the night sky, much to the consternation of astronomers.

Of course, you don’t have to have a Picorder to snoop in on Starlink — any laptop and SDR should work, despite [saveitforparts]’ trouble in doing so. You shouldn’t have much trouble replicating the results by following the video below, which also has a few tips on powering an LNB for portable operations.

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Metric And Inch Threads Fight It Out For Ultra-Precise Positioning

September 21, 2022 by 20 Comments

When you’re a machinist, your stock in trade is precision, with measurements in the thousandths of your preferred unit being common. But when you’re a diemaker, your precision game needs to be even finer, and being able to position tools and material with seemingly impossibly granularity becomes really important.

For [Adam Demuth], aka “Adam the Machinist” on YouTube, the need for ultra-fine resolution machinist’s jacks that wouldn’t break the bank led to a design using off-the-shelf hardware and some 3D printed parts. The design centers around an inch-metric thread adapter that you can pick up from McMaster-Carr. The female thread on the adapter is an M8-1.25, while the male side is a 5/8″-16 thread. The pitches of these threads are very close to each other — only 0.0063″, or 161 microns. To take advantage of this, [Adam] printed a cage with compliant mechanism springs; the cage holds the threaded parts together and provide axial preload to remove backlash, and allows mounting of precision steel balls at each end to make sure the force of the jack is transmitted through a single point at each end. Each full turn of the jack moves the ends by the pitch difference, leading to ultra-fine resolution positioning. Need even more precision? Try an M5 to 10-32 adapter for about 6 microns per revolution!

While we’ve seen different thread pitches used for fine positioning before, [Adam]’s approach needs to machining. And as useful as these jacks are on their own, [Adam] stepped things up by using three of them to make a kinematic base, which is finely adjustable in three axes. It’s not quite a nanopositioning Stewart platform, but you could see how adding three more jacks and some actuators could make that happen.

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It’s Pi All The Way Down With This Pi-Powered Pi-Picking Robot

September 20, 2022 by 14 Comments

While most of us live in a world where the once ubiquitous Raspberry Pi is now as rare as hens’ teeth, there’s a magical place where they’ve got so many Pis that they needed to build a robotic dispenser to pick Pi orders. And to add insult to injury, they even built this magical machine using a Raspberry Pi. The horror.

This magical place? Australia, of course. There’s no date posted on the Pi Australia article linked above, but it does mention that there’s a Pi 4 Model B running the show, so that makes it at least recent-ish. Stock is stored in an array of tilted bins that a shuttle mechanism accesses via an X-Y gantry. The shuttle docks in front of a bin and uses a stepper-controlled finger to flip a box over the lip holding them in its bin. Once in the shuttle, the order is transported to an array of output bins, where a servo operates a flap to unceremoniously dump the product out for packing and shipping. There’s a video of a full cycle below, but a word of warning — the stepper motors on the X-Y gantry really scream, so you might want to lower the volume.

The article goes into more detail on not only the construction of “Bishop” — named after the heroic synthetic organism from Aliens — but also the challenges faced during construction. It turns out that even when you try to use gravity to simplify a system like this, things can go awry very easily. There’s also a fair bit of detail on the software, which surprisingly centers around LinuxCNC. And there are plans to take this further, with another bot to do the packing, sealing, and labeling of the order. If they need all that automation down there, we guess we found all the missing Pis.

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Hackaday Links: September 18, 2022

September 18, 2022 by 21 Comments

We always love when people take the trouble to show information in new, creative ways — after all, there’s a reason that r/dataisbeautiful exists. But we were particularly taken by this version of the periodic table of the elements, distorted to represent the relative abundance on Earth of the 90 elements that make up almost everything. The table is also color-coded to indicate basically how fast we’re using each element relative to its abundance. The chart also indicates which elements are “conflict resources,” basically stuff people fight over, and which elements go into making smartphones. That last bit we thought was incomplete; we’d have sworn at least some boron would be somewhere in a phone. Still, it’s an interesting way to look at the elements, and reminds us of another way to enumerate the elements.

It’s wildfire season in the western part of North America again, and while this year hasn’t been anywhere near as bad as last year — so far — there’s still a lot of activity in our neck of the woods. And wouldn’t you know it, some people seem to feel like a wildfire is a perfect time to put up a drone. It hardly seems necessary to say that this is A Really Bad Idea™, but for some reason, people still keep doing it. Don’t misunderstand — we absolutely get how cool it is to see firefighting aircraft do their thing. The skill these pilots show as they maneuver their planes, which are sometimes as large as passenger jets, within a hundred meters of the treetops is breathtaking. But operating a drone in the same airspace is just stupid. Not only is it likely to get you in trouble with the law, but there’s a fair chance that the people whose property and lives are being saved by these heroic pilots won’t look kindly on your antics.

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