Autochrome For The 2020s

For all intents and purposes, photography here in 2024 is digital. Of course chemical photography still exists, and there are a bunch of us who love it for what it is, but even as we hang up our latest strip of negatives to dry we have to admit that it’s no longer mainstream. Among those enthusiasts who work with conventional black-and-white or dye-coupler colour film are a special breed whose chemistry takes them into more obscure pathways.

Wet-collodion plates for example, or in the case of [Jon Hilty], the Lumière autochrome process. This is a colour photography process from the early years of the twentieth century, employing a layer of red, green, and blue grains above a photosensitive emulsion. Its preparation is notoriously difficult, and he’s lightened the load somewhat with the clever use of CNC machinery to automate some of it.

Pressing the plates via CNC

His web site has the full details of how he prepares and exposes the plates, so perhaps it’s best here to recap how it works. Red, green, and blue dyed potato starch grains are laid uniformly on a glass plate, then dried and pressed to form a random array of tiny RGB filters. The photographic emulsion is laid on top of that, and once it is ready the exposure is made from the glass side do the light passes through the filters.

If the emulsion is then developed using a reversal process as for example a slide would be, the result is a black and white image bearing colour information in that random array, which when viewed has red, green, and blue light from those starch filters passing through it. To the viewer’s eye, this then appears as a colour image.

We can’t help being fascinated by the autochrome process, and while we know we’ll never do it ourselves it’s great to see someone else working with it and producing 21st century plates that look a hundred years old.

While this may be the first time we’ve featured such a deep dive into autochrome, it’s certainly not the first time we’ve looked at alternative photographic chemistries.

IRCB S73-7 Satellite Found After Going Untracked For 25 Years

When the United States launched the KH-9 Hexagon spy satellite into orbit atop a Titan IIID rocket in 1974, it brought a calibration target along for the ride: the Infra-Red Calibration Balloon (IRCB) S73-7. This 66 cm (26 inch) diameter inflatable satellite was ejected by the KH-9, but failed to inflate into its intended configuration and became yet another piece of space junk. Initially it was being tracked in the 1970s, but vanished until briefly reappearing in the 1990s. Now it’s popped up again, twenty-five years later.

As noted by [Jonathan McDowell] who tripped over S73-7 in recent debris tracking data, it’s quite possible that it had been tracked before, but hidden in the noise as it is not an easy target to track. Since it’s not a big metallic object with a large radar cross-section, it’s among the more difficult signals to reliably pick out of the noise. As can be seen in [Jonathan]’s debris tracking table, this is hardly a unique situation, with many lost (XO) entries. This always raises the exciting question of whether a piece of debris has had its orbit decayed to where it burned up, ended up colliding with other debris/working satellite or simply has gone dark.

For now we know where S73-7 is, and as long as its orbit remains stable we can predict where it’ll be, but it highlights the difficulty of keeping track of the around 20,000 objects in Earth orbit, with disastrous consequences if we get it wrong.

Pi with the PiFEX shield on the right, the SSD under test on the left with testpoints held by a jumper clip, jumper wires connecting the two together

JTAG Hacking An SSD With A Pi: A Primer

[Matthew “wrongbaud” Alt] is well known around these parts for his hardware hacking and reverse-engineering lessons, and today he’s bringing us a JTAG hacking primer that demoes some cool new hardware — the PiFEX (Pi Interface Explorer). Ever wondered about those testpoint arrays on mSATA and M.2 SSDs? This write-up lays bare the secrets of such an SSD, using a Pi 4, PiFEX, OpenOCD and a good few open-source tools for JTAG probing that you can easily use yourself.

The PiFEX hat gives you level-shifted bidirectional GPIO connectors for UART, SPI, I2C, JTAG, SWD and potentially way more, an OLED screen to show any debugging information you might need, and even a logic analyzer header so that you can check up on your reverse-engineering progress.

Continue reading “JTAG Hacking An SSD With A Pi: A Primer”

Tweeze Your Way To Soldering Success!

Soldering, for those of us who spend a lot of time at an electronics bench, is just one of those skills we have, in the way that a blacksmith can weld or a tailor can cut clothing. We have an uncommon skill with hot metal and can manipulate the tiniest of parts, and incidentally our chopstick skills aren’t that bad as a consequence, either.

But even the best with a soldering iron can find useful tips from an expert, and that’s where [Mr SolderFix] comes in. His channel is chock-full of soldering advice, and in his latest video he takes a look at tweezers. They’re a part of the solderer’s standard kit and we all have several pairs, but it’s fair to say that we don’t always have the right pair to hand.

It was refreshing to hear him confirm that a good pair of tweezers, once a certain quality threshold has been met, need not necessarily be the most expensive set. We’ve certainly seen expensive tweezers with suspiciously bendy ends, and have found random AliExpress purchases which have stood the test of time. He also makes the point about which situations a set of tweezers with serrated heads might be more useful, and he demonstrates with a crystal oscillator.

As with photography though, we’d observe that sometimes the best set of tweezers to rectify a mishap are the ones in your hand. If you’re interested in more from [Mr SolderFix], we’ve featured his work more than once in the past. When he showed us how to lift SMD pins, for example.

Two pictures of the same black dog, wearing two separate pairs of the AR glasses reviewed in these two articles

A Master-Class On Reverse-Engineering Six AR Glasses

Augmented reality (AR) tech is getting more and more powerful, the glasses themselves are getting sleeker and prettier, and at some point, hackers have to conquer this frontier and extract as much as possible. [Void Computing] is writing an open source SDK for making use of AR glasses, and, along the way, they’ve brought us two wonderful blog posts filled with technical information laid out in a fun to read way. The first article is titled “AR glasses USB protocols: the Good, the Bad and the Ugly”, and the second one follows as “the Worse, the Better and the Prettier”.

Have you ever wanted to learn how AR glasses and similar devices work, what’s their internal structure, which ones are designed well and which ones maybe not so much? These two posts have concise explanations, more than plenty of diagrams, six case studies of different pairs of AR glasses on the market, each pair demonstrated by our hacker’s canine assistant.

[Void Computing] goes in-depth on this tech — you will witness MCU firmware reverse-engineering, HID packet captures, a quick refresher on the USB-C DisplayPort altmode, hexdumps aplenty, and a reminder on often forgotten tools of the trade like Cunningham’s law.

If reverse-engineering lights your fire, these high-level retrospectives will teach you viable ways to reverse-engineer devices in your own life, and they certainly set a high bar for posts as far as write-ups go. Having read through these posts, one can’t help but think that some sort of AR glasses protocol standard is called for here, but fortunately, it appears like [Void Computing]’s SDK is the next best thing, and their mission to seize the good aspects of a tentative cyberpunk future is looking to be a success. We’ve started talking about AR glasses over a decade ago, and it’s reassuring to see hackers catching up on this technology’s advancements.

We thank [adistuder] for sharing this with us on the Hackaday Discord server!

No Solder! Squeeze Your Parts To The PCB

What’s solder for, anyway? It’s just the stuff that sticks the parts to the PCB. If you’re rapid prototyping, possibly with expensive components, and want to be able to remove chips from the board easily when you spin up the next iteration, it would be great if you didn’t have to de-solder them to move on. If only you could hold the parts without the solder…

That’s exactly the goal behind [Zeyu Yan] et al’s SolderlessPCB, which uses custom 3D printed plastic covers to do the holding. And it has the knock-on benefit of serving as a simple case.

In their paper, they document some clever topologies to make sure that the parts are held down firmly to the board, with the majority of the force coming from screws. We especially like the little hold-down wings for use with SMD capacitors or resistors, although we could absolutely see saving the technique exclusively for the more high value components to simplify design work on the 3DP frame. Still, with the ability to automatically generate 3D models of the board, parts included, this should be something that can be automated away.

The group is doing this with SLA 3D printing, and we imagine that the resolution is important. You could try it with an FDM printer, though. Let us know if you do!

This is the same research group that is responsible for the laser-cut sheet-PCB origami. There’s clearly some creative thinking going on over there.

The Minimalistic Dillo Web Browser Is Back

Over the decades web browsers have changed from the fairly lightweight and nimble HTML document viewers of the 1990s to today’s top-heavy browsers that struggle to run on a system with less than a quad-core, multi-GHz CPU and gigabytes of RAM. All but a few, that is.

Dillo is one of a small number of browsers that requires only a minimum of system resources and will happily run on an Intel 486 or thereabouts. Sadly, the project more or less ended back in 2016 when the rendering engine’s developer passed away, but with the recent 3.10 release the project seems to be back on track, courtesy of efforts by [Rodrigo Arias Mallo].

Although a number of forks were started after the Dillo project ground to a halt, of these only Dillo+ appears to be active at this point in time, making this project revival a welcome boost, as is its porting to Atari systems. As for Dillo’s feature set, it boasts support for a range of protocols, including Gopher, HTTP(S), Gemini, and FTP via extensions. It supports HTML 4.01 and some HTML 5, along with CSS 2.1 and some CSS 3 features, and of course no JavaScript.

On today’s JS-crazed web this means access can be somewhat limited, but maybe it will promote websites to have a no-JS fallback for the Dillo users. The source code and releases can be obtained from the GitHub project page, with contributions to the project gracefully accepted.

Thanks to [Prof. Dr. Feinfinger] for the tip.