TechyMagThings

The Universe is a large place, yet despite it being mostly empty space, there are still a lot of things to find and catalogue. This includes mildly terrifying things like supermassive black holes (SMBHs), one of the study subjects of the Sloan Digital Sky Survey (SDSS) project. In their 20th data release of the fifth all-sky survey (SDSS-V), the results of the Black Hole Mapper (BHM) program provides a lot of new insights into these SMBHs.

For a good primer on the SDSS’s ongoing survey, you can read this paper by [Kollmeier] et al. from 2017 in which this fifth survey and its three programs, including the BHM, are explained. This comes after four previous phases of the SDSS, all of them focusing on multispectral imaging and spectroscopic redshift survey with the 2.5 m Apache Point Observatory (APO) in New Mexico.

With SDSS-V a second 2.5 m observatory at Las Campanas (LCO) was added, with both observatories combined able to observe the entire sky, not just as static images, but also any changes over time. While these observations are in the near-infrared, combined with the data from other observatories this gives us probably one of the most comprehensive maps of the Milky Way and everything therein, including black holes.

This 20th data release gives us one of the clearest glimpses yet at the formation, growth and behavior of SMBHs and similar objects over time. A big part of this achievement are the automatic positioning robots at the observatories that handle the fiber optics that feed spectrographs, enabling faster and more accurate observations.

The TermDriver 2 is a USB-to-serial interface with a twist—it has a built-in screen for displaying relevant information. It can run at anywhere from 100 bit/s to 2Mbit/s, while showing you what’s happening on the wire. [James Bowman] worked on the TermDriver 2, and paid special attention to one feature—the visual look of the status indicators on the display.

[James] had hoped to make the status indicators look a little more old-school, a little more analog. His inspiration was the classic indicator panels from Apollo-era space hardware, which used bulbs behind plastic indicators. Incandescent bulbs don’t switch instantly on and off; they take time to warm and cool. This behaviour is both more pleasant, visually speaking, and would aid in making short-duration events on the TX, RX and other indicators more visible. Thus, [James] set about giving the LCD UI elements sixteen steps of brightness from off to fully on. The simulated bulbs get brighter the more rapidly activity is happening on a given pin. The indicator graphics, while tiny, are also given a nice superellipse shape, to recreate the warm centered glow of an incandescent indicator.

If you’re a UI fanatic who loves to make things as visually pleasing as possible, the work [James] has done is well worth looking at. We’ve featured other great GUI projects before, too, like this particularly visually pleasing effort. If you’ve had grand ideas in this space, be sure to tell us over on the tipsline.

These days there are emulators for all the great consoles of yesteryear, as well as old retrocomputers and arcade machines and so much else to boot. Now, though, a particularly popular MP3 player has an emulator of its own—by the name of clicky!

The name is a reference to the click wheel of the venerable Apple iPod, and as you might imagine, that’s precisely what clicky is built to emulate. [daniel5151] started the project as a neat technical challenge, following on from earlier work he’s done in the NES emulation space. The iPod is a bit of a difficult prospect to emulate, being very much a closed-source device that is very poorly documented in the public space. There are few projects to look to for help, since a complete open-source iPod emulator doesn’t already exist; however, various alternative firmware projects have offered a guiding light.

For now, clicky can boot into RetailOS, which is what you would have used on an iPod you bought from the factory. It can also run Rockbox and iPodLinux, though for now, running the Apple Diagnostics program is not yet achievable. Plenty of functionality still isn’t implemented, either, like USB communication or even audio, which was the iPod’s whole raison d’être. Still, you can play some Brick Breaker like it’s 2006 if you’ve been missing it badly.

We see all kinds of emulators around these parts; this 60 FPS NES emulator running on a microcontroller was a particularly impressive recent effort. If you’re cooking up your own emulators for unique platforms, or unique emulators for non-unique platforms, let us know on the tipsline!

This week Jonathan chats with Nathan Freitas of the Guardian Project! What is going on at the forefront of Open Source and privacy advocacy? Where are we on a true Tor browser on iOS? And what’s the ideal solution to the Android Lockdown issue? Watch to find out!

• https://cyber.harvard.edu/people/nfreitas
• https://guardianproject.info
• https://proofmode.org

Did you know you can watch the live recording of the show right on our YouTube Channel? Have someone you’d like us to interview? Let us know, or have the guest contact us! Take a look at the schedule here.

Direct Download in DRM-free MP3.

If you’d rather read along, here’s the transcript for this week’s episode.

Theme music: “Newer Wave” Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 4.0 License

A pyrotechnic charge is set off by passing a high voltage through a filament within it, melting the filament and igniting the charge. We could think of a variety of circuits that could do this, but perhaps we wouldn’t have come up with [Michał Słomkowski]’s solution. He’s used the ringer crank generator from an old military field telephone. It’s an old project he’s shared with us due to its recent republishing on his website.

The basic principle is simple enough, winding the generator charges a capacitor bank through a bridge rectifier. Then a thyristor is used as the trigger device, dumping the contents of the capacitor into the filament. But the full circuit has a couple of refinements. There’s a charge indicator circuit using a couple of Zener diodes and an LED, and a filament tester which passes a non-triggering current through the filament from a 9 volt battery. We like the use of an over-the-top high-current thyristor, no doubt what he had in his junk box.

Perhaps it’s a symbol of how far technology has moved, that today it’s surprisingly rare to find a bridge rectifier or a thyristor, and building this device today would involve a microcontroller and probably an AliExpress inverter module as a matter of course.

Meanwhile, should field telephones interest you, we’ve been there before.

[Matt Lenhard] has an interesting writeup explaining exactly how fraudsters offer access to cutting-edge AI models at a tenth of the price. Perhaps unsurprisingly, the secret is to get tokens for free from anywhere they can and by any means necessary. Then wrap them in a pretty relay API, and sell access to it.

Relaying tokens is not by itself a shady practice. That distinction belongs to services that obtain tokens fraudulently, opening the door to selling them at rates far below market value. This practice is widespread and profitable, in part because the abuse is so hard to pin down and stop.

One source of tokens is free credits on new accounts. New accounts are spooled up as fast as possible, hammered until they’re empty, then it’s done all over again. Another method is to sign up as pay-after, possibly with a stolen card, and simply ensure the account has no valid payment method once the bill comes due. Or set up a temporary card, pay some minimum up front and consume as much as possible, then initiate a chargeback. It doesn’t matter if individually each of these doesn’t amount to much before they get flagged, because it’s being leveraged relentlessly on a massive scale by automated systems.

There are the shadier methods, too. Fraudsters don’t just target providers directly. Consumer software products with AI features get reverse-engineered, then the back ends hammered for all they are worth. Poorly-coded support chatbots can be highjacked into serving fraudsters’ traffic instead of just their own. It doesn’t actually matter where the tokens come from, after all. As long as the fraudsters are obtaining them for free (or at least below their costs) then it’s profit.

That last point is one [Matt] zeroes in on with advice on how to mitigate this abuse. He goes into detail in his writeup but what it comes down to is recognizing that it’s a numbers game. Fraudsters depend entirely on obtaining tokens for free, or nearly free. So just like using an AI to keep phone scammers tied up, anything that raises friction increases the fraudster’s costs, in turn encouraging them to find an easier target.

Fluid simulations are one of the “killer apps” of high-performance computing, but if you can’t afford the performance, they can take a depressingly long time to run. Depending on your use case, as long as you keep the Reynold’s number in mind– or are just looking for a qualitative look at pretty flows–you might be able to get away with purely-practical simulations using rheoscopic fluid, as [Visual Thinker] demonstrates in a recent video.

The fluid, as you can guess from the name, lets you scope out rheos— that’s flow, for those of you didn’t take Greek. Making it is as simple as you could ask for: get some mica flakes, which are readily available to add ‘sparkle’ to cosmetics, and mix with water and a drop of soap. The soap isn’t always necessary, but depending on your mica it helps keep it in suspension and avoid clumping– [Visual Thinker] found it helped him a good deal. Being flat plates of reflective material, the mica flakes catch the light and sparkle beautifully– and since they align with the fluid shear, they show you exactly what’s going on in your ‘simulation’.

[Visual Thinker] isn’t starting with serious simulations; the first thing he tries is essentially a toy that lets him see fluid flow around a Benchy by sticking magnets in it and using it to move a cross-section of its hull though a thin layer of fluid sandwitched betwixt pieces of laser-cut acrylic. We don’t call it a toy to disparage it, though– we totally want one. [Visual] mentions the idea of a coffee table combining the concept with the kind of underslung mechanism we see in sand drawing tables, which sounds dangerously hypnotic. If any of you build one, please try and tear your eyes away long enough to let us know.

He has another beautiful piece that make the video worth watching: a wind-tunnel, again made of laser-cut acrylic and printed parts. With careful consideration of the scale and flow speeds, that one might actually prove useful– and even if it doesn’t, it’s pretty enough that it doesn’t really matter. Beauty has its own utility sometimes.

Most wind tunnels we see around here use actual wind, but rheoscopic fluid was invented for this sort of thing, even if it does make for pretty baubles.