TechyMagThings

Back in the early 1980s when 8-bit home computers became affordable educational toys for children, the traditional paper publishing industry did its best to keep up. For a few brief years, there were children’s books dedicated to the innards of a computer in meticulous detail, and courtesy of [Jason Jacques] we have a chance to look at one of the lesser-known ones.

The British publisher Ladybird made a series of four computer books, and while the first three had content for both the Sinclair Spectrum and the BBC Micro, the last in the series only featured the BBC. [Jason] took that book and re-imagined the missing Sinclair Spectrum version.

The surprise is how deep it dives into the architecture of an 8-bit computer, and it’s refreshing to see something that’s not unduly dumbed-down for kids. We’re guessing that this would have appealed to the 5% of kids who ran with their computers rather than just playing Jet Set Willy back then, and we’re sure a few grown-up 50-somethings may remember it or books like it.

If you think you may have seen Ladybird books here before, it may be because we reviewed another influential tech book of theirs for kids. Meanwhile you can take a look at the contemporary computer books from their arch-rival Usborne.

After getting his hands on a rope driver module from the Apollo project era that had a big ‘Scrapped Module’ stamped on it, [Mike Stewart] was naturally left curious as to what exactly had failed in this module. Originally destined for the Apollo Guidance Computer, these Raytheon-manufactured modules were the pinnacle of space-grade high-tech of the 1960s, with requisite acceptance testing so as to not endanger a very expensive space mission.

The cool part here is that the acceptance documents for the module in question (B16-B17) have been scanned in and can be found on the Internet Archive. With the part itself being potted and very much inaccessible, this document helpfully lays out the expected measurements on the module’s pins, as well as schematics and mechanical drawings. Unfortunately the reasons for the rejection were not recorded, so replicating the failing test results is required to understand the reason.

A slight complication here is that the testing procedure doesn’t just involve hooking up a multimeter for some voltage and capacitance measurements. There are also temperature and voltage extremes, and vibration tolerance involved, which would be somewhat complex to test, but most of all risk damaging a historical artefact. Thus a somewhat conservative testing procedure was chosen, even if this may not reveal the actual fault.

As noted in the video, sometimes modules were also rejected because someone simply dropped it on the floor along the way. However, generally if a module was found to be faulty they would open it to diagnose said fault, with a closer look at this module indeed revealing suspicious marks in the potting compound where it was apparently opened and conceivably repaired. This also might explain why they also put the ‘For engineering use only’ on it.

With multiple of such locations visible in the potting compound, these locations were mapped to the schematics for the module, to get some idea of what may have been accessed. After this, basic testing was performed on the module, as per the acceptance testing document.

Along the way an error was detected in said document, in the form of the wrong pin number. In table 4-2 the input pin 269 was mistakenly listed as having output pin number 169 when it should have been pin 168. Pin 169 is chassis ground, so this was presumably fixed in a later version of the document.

After all the testing with just stationary, room-temperature conditions, everything appeared to check out. This means that likely this was indeed a repaired module that got subsequently used for engineering purposes rather than installed in flight-ready hardware. The only issue found was that channels were out of calibration, but whether this was an original flaw or due to the module being half a century old is hard to tell in the absence of repair logs.

Overall it’s an exciting opportunity to document another part of history, since so many of the details pertaining to these original modules and related technologies got lost or muddled over the decades.

One of the disadvantages to collecting retro peripherals is that they’re not necessarily easy to use anymore. [eSPee77] changes that by retrofitting a Genius GM-6000 mouse with modern hardware, all while preserving the feel.

To make this mouse without compromising on the feel of the original, means replacing the PCB with a new one while retaining the same buttons and encoders. So [eSPee77] did exactly that. At the heart of the conversion lies an nRF52840 on a custom PCB. It uses new optical sensors to read the existing quadrature encoders, and uses the same type of switch for the mouse buttons as the original.

But from there, it diverges because–powered by the BLE capabilities of the nRF–this is actually a wireless mouse! And the modern features don’t end there, either. To support scrolling on a mouse which did not originally have it, you can press the middle mouse button while moving it forward/backward. Finally, as the cherry on the cake, it features an “air mouse” mode using an inertial measurement unit, handy for use in presentations.

For how useful USB thumb drives are for quickly toting around and copying files from one computer to another, they can be a bit of a security headache. Programs can be loaded on them with all kinds of malware; they can be obscured in some ways that are difficult to detect, and they can be set up to execute certain programs when they’re plugged in. The general wisdom is to simply avoid untrusted USB devices completely, but that sort of abstinence-only policy rarely works in the real world. If, for some reason, an untrusted USB device absolutely needs to be used, many of these security issues can be mitigated with this tool.

Built by [Novamostra], the device is simple on the surface: it’s a Raspberry Pi Pico mated to a 2-in-1 USB splitter cable. But with the USB Neutralizer software they have written loaded onto the Pico, it automatically destroys the ability of any connected USB thumb drive to load files. The program works by deleting the first and last 34 Logical Block Addressing (LBA) sectors on the drive immediately when it’s plugged in, without doing anything else. This effectively corrupts the drive bad enough to prevent malicious software in the partitions from doing anything, allowing the user to (relatively) safely put the USB drive into their computer and format it for re-use. The code for this tool is also open-source and reviewable on the project’s GitHub page.

Of course, this isn’t a perfect security solution for all USB attacks. It doesn’t erase or replace the firmware on the drive itself, and although firmware-level attacks are rare they’re not out of the question for all users, all the time. It also won’t prevent a malicious physical attack like this high-voltage one, and it may also not stop hidden or obscured partitions or devices programmed for storage and some other nefarious purpose simultaneously, like a USB HID. But still, this solves a great many of the problems associated with getting new drives from semi-untrustworthy sources, like retailers or friends whose computer skills we don’t fully trust.

When you hear the word TV, you probably think of a big LED screen, maybe even the old CRT TVs, but in either case it’s something large and fairly complicated. However, thanks to the persistence of vision, it doesn’t have to be. In this handheld-sized project from [Ancient], the Scanwheel is born, a miniature mechanical TV that uses a spinning disk and some LEDs to produce an image.

The electronics of the Scanwheel are pretty straightforward. The smarts come from a Raspberry Pi Pico, an A4988 motor driver, a couple of LEDs, and a small 21-02485 stepper motor. The Raspberry Pi Pico is used to command the motor speed as well as coordinate the LEDs to turn on at the right time. The case is 3D printed; the base includes space for the various support electronics as well as some small light baffles to ensure the LEDs don’t bleed over outside their intended area. The top of the case is a disk that includes 20 small holes spaced evenly around the perimeter at varying heights, allowing light to only leave the disk when one of these holes is in front of the LEDs.

When you put all these pieces together, spin the motor up to roughly 900 RPM, and turn the LEDs on in a precise order, you end up with a really cool result: a miniature TV. And due to the five different LEDs in this build, you actually have a color 20×20 pixel display in the center and, on either side of that, two more 20×20 black-and-white displays capable of showing different images. Thanks [Ancient] for sharing this awesome build that takes advantage of the persistence of vision effect to create a unique display. Be sure to check out the video below as well as the instructions on how to build your own. And if you enjoy this sort of thing, check out some of our other persistence-of-vision projects as well.

Optical cavities – two mirrors arranged to reflect light multiple times between them – form the basis of lasers and certain optical filters. Since any angle between the two mirrors results in light being scattered away, parallel alignment is essential, yet difficult to maintain. Nevertheless, [Timothy Giles] managed to 3D-print and align such an optical cavity, and used it to detect minute shifts in space and wavelength.

The cavity has two semi-transparent mirrors facing towards each other. One mirror is held in a 3D-printed mount, and the other is attached to the diaphragm of a speaker with a hole drilled through the center. The hole avoids the speaker coil, and allows light exiting the optical cavity through the semi-transparent mirror to appear on a paper target, which is monitored by a webcam. On the other side of the optical cavity, a laser diode coupled to a single-mode fiber shines in through the other mirror. Alignment is challenging, but the webcam makes it easier; as the mirrors tilt relative to each other, the pattern seen on the paper target changes, providing feedback for more precise adjustment.

Light reflected within the cavity can interfere constructively or destructively with incoming light, changing the brightness of the emitted beam. [Tim] used the speaker as a linear actuator to vary the cavity’s length, which, by counting the peaks in brightness, allowed him to measure the diaphragm’s displacement. This also demonstrated a laser diode’s wavelength instability: when the cavity was set to a constant length and the laser started up, the output brightness would cycle a few times. As the diode was warming up, its output wavelength was shifting, creating the same changing interference pattern.

To get a Gaussian beam distribution, [Tim] used a fiber-coupled laser; if you’d like to build one, we’ve seen a coupling mechanism built before. Most lasers are built around an internal optical cavity, but some instead use an external cavity.

At a time when so-called “artificial intelligence” seems inescapable, we were encouraged to see news that Amazon will be cracking down on third-party sellers that use AI-generated images for their product listings. They won’t be prevented from using the images, but they will need to clearly indicate that they don’t represent reality and were produced via artificial means. This comes in response to a recently enacted New York law that requires the disclosure of AI in advertisements.

But it’s not quite a clear cut as it might seem on the surface, as the New York law is actually about AI-generated people rather than products. Specifically, it’s designed to make it clear when a “synthetic performer” has been used in place of a human actor. As such, it would appear that the easiest way for Amazon sellers to dodge the new rule is to simply not include any humans in their AI slop images and videos. In other words, they can continue to post fake pictures of products without having to inform the consumer so long as they don’t show a fake person holding it.

Under normal circumstances we’d leave something like this next one for our weekly security column, but the utter lack of security in the Pope’s official “Click To Pray” mobile application revealed by researcher BobDaHacker on Friday is just too good a story to pass up. For one thing, who knew that there was an “official” prayer app? We don’t dabble in theology around these parts, but we’re fairly sure the good book didn’t mention anything about requiring a smartphone to give praise.

In any event, the service was so poorly constructed that you could simply step through the sequentially assigned numerical user IDs via the endpoint at api.clicktopray.org — because of course there’s a prayer API — and download any user’s personal information such as their full name, email address, and date of birth. There wasn’t even any rate limiting, so BobDaHacker was able to write simple script to quickly suck up the account details for each one of the service’s 700,000+ faithful users.

After waiting six months for a response from anyone at the Pope’s Worldwide Prayer Network, BobDaHacker took the story to the press. That seemed to get the pontiff’s attention, as the issue has now been addressed. Amen.

We know many readers appreciate a more minimalist approach to software, and still others are operating older devices that struggle with the admittedly ponderous bulk of the modern web. Both groups will likely appreciate brolly.sh, which provides a plain-text weather forecast for anywhere on Earth using data from Open-Meteo. It doesn’t just look the part either — we’re happy to report that if you pull down the forecast page for your location using something like wget, the resulting file is plain HTML which could be further parsed with grep and friends if you’re on a machine that doesn’t have a browser.

Speaking of older devices, Android Authority is reporting that Google has finally phased out support for Android 6.0 Marshmallow in Play services. This means that while devices running the older version of the mobile operating system will still be usable, they won’t be able to download software from the Play Store. Given that Marshmallow was released in October of 2015, this probably shouldn’t come as much of a shock. Any device out there that’s still running such an old release of the OS obviously hasn’t received any security updates in years, so the inability to download the latest mobile game should be the least of your worries if you are actually still using such a device as a daily driver.

Finally, given the impact Neuromancer has had on the hacker and maker communities over the decades, we felt obligated to point out that Apple has finally released a trailer for their upcoming adaptation. The ten episode series kicks off in January, and until now we haven’t had a good look at the aesthetic they were going for. Part of what made the novel so influential was how it described the world and the technology within it, but bringing those concepts to life on screen in a way that impresses modern audiences is going to be a unique challenge.

With how many hackers have put together their own real-world versions these last several years, we’re especially interested in the show’s depiction of cyberdecks. The novel itself doesn’t actually go into much detail about what they supposedly looked like, but contemporary illustrations were heavily influenced by 8-bit computers of the era from the likes of Amstrad and Atari. As much as we’d like to see something along those lines, we imagine a big-budget prestige television series probably demands something a bit sexier.

See something interesting that you think would be a good fit for our weekly Links column? Drop us a line; we’d love to hear about it.