Cockroaches In Space: Waste Processing And A Healthy Protein Source Combined

October 12, 2024 by Maya Posch 51 Comments

As the current frontier of humanity in space, the International Space Station is heavily reliant on Earth not only for fresh supplies but also as a garbage disposal service for the various types of waste produced on the ISS by its human occupants. As future manned missions take humans further away from Earth, finding ways to reprocess this waste rather than chucking it out of the nearest airlock becomes a priority. One suggested solution comes from a Polish company, Astronika, with their insect bioreactor that can process organic material into useful biomass.

Interestingly, the cockroach species picked was the Madagascar hissing cockroach, one of the largest (5 – 7.5 cm) species. This is also a cockroach species which is often kept as a pet. In this closed-loop bioreactor that Astronika has developed, these cockroaches would chew their way through up to 3.6 kg of waste per week in the large version, with the adult cockroaches presumably getting turned into fresh chow and various materials at some point. Beyond the irrational ‘yuck’ factor that comes with eating insect protein, one of the biggest issues we can see with this system is that the long-duration mission crew may get attached to the cockroaches, as they are rather cute.

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Approximating An ADC With Successive Approximation

October 12, 2024 by Al Williams 17 Comments

[Igor] made a VU meter with LEDs using 8 LEDs and 8 comparators. This is a fast way to get one of 8 bits to indicate an input voltage, but that’s only the equivalent of a 3-bit analog to digital converter (ADC). To get more bits, you have to use a smarter technique, such as successive approximation. He shows a chip that uses that technique internally and then shows how you can make one without using the chip.

The idea is simple. You essentially build a specialized counter and use it to generate a voltage that will perform a binary search on an unknown input signal. For example, assuming a 5 V reference, you will guess 2.5 V first. If the voltage is lower, your next guess will be 1.25 V. If 2.5 was the low voltage, your next guess will be 3.75 V.

The process repeats until you get all the bits. You can do this with a microcontroller or, as [Igor] shows, with a shift register quite simply. Of course, you can also buy the whole function on a chip like the one he shows at the start of the video. The downside, of course, is the converter is relatively slow, requiring some amount of time for each bit. The input voltage also needs to stay stable over the conversion period. That’s not always a problem, of course.

If that explanation didn’t make sense, watch the video. An oscilloscope trace is often worth at least 1,000 words.

There are, of course, many ways to do such a conversion. Of course, when you start trying to really figure out how many bits of resolution you have or need, it gets tricky pretty fast.

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If You Can’t Say Anything Nice

October 12, 2024 by Elliot Williams 398 Comments

[Editor’s Note: After we posted this, we got hit by a comment-report attack, and about 1,000 (!) comments across the whole site got sent back into the moderation queue on Saturday. We’ve since re-instated them all, but that took a lot of work.

About halfway down the comments in this article, the majority of comments are “hey, why did you delete this?” We didn’t, and they should be all good now. We debated removing the “try deleting this!” comments, but since we didn’t delete them in the first place, we thought we should just leave them. It makes a royal mess of any discussion, and created a lot more heat than light, which is unfortunate.]

You know what your mom would say, right? This week, we got an above average number of useless negative comments. A project was described as looking like a “turd” – for the record I love the hacker’s angular and futuristic designs, but it doesn’t have to be to your taste. Then someone else is like “you don’t even need a computer case.” Another commenter informed us that he doesn’t like to watch videos for the thirtieth time. (Yawn!)

What all of these comments have in common is that they’re negative, low value, non-constructive, and frankly have no place on Hackaday. The vast majority are just kind of Eeyorey complaining about how someone else is enjoying a chocolate ice cream, and the commenter prefers strawberry. But then some of them turn nasty. Why? If someone makes a project that you don’t like, they didn’t do it to offend you. Just move on quietly to one you do like. We publish a hack every three hours like a rubidium clockwork, with a couple of original content pieces scattered in-between on weekdays.

And don’t get us wrong: we love comments that help improve a project. There’s a not-so-fine line between “why didn’t you design it with trusses to better hold the load?” and “why did you paint it black, because blue is the superior color”. You know what we mean. Constructive criticism, good. Pointless criticism, bad.

It was to the point that we were discussing just shutting down the comments entirely. But then we got gems! [Maya Posch]’s fantastic explainer about the Lagrange points had an error: one of the satellites that Wikipedia said was at an earth-moon Lagrange point is actually in normal orbit around the moon. It only used the Lagrange point as a temporary transit orbit. Says who? One of the science instrument leads on the space vehicle in question. Now that is a high-value comment, both because it corrects a mistake and enlightens us all, but also because it shows who is reading Hackaday!

Or take [Al Williams]’s article on mold-making a cement “paper” airplane. It was a cool technique, but the commenters latched onto his assertion that you couldn’t fly a cement plane, and the discussions that ensued are awesome. Part of me wanted to remind folks about the nice mold-making technique on display, but it was such a joy to go down that odd rabbit hole, I forgive you all!

We have an official “be nice” policy about the comments, and that extends fairly broadly. We really don’t want to hear what you don’t like about someone’s project or the way they presented it, because it brings down the people out there who are doing the hard work of posting their hacks. And hackers have the highest priority on Hackaday.

Have You Heard Of The Liquid Powder Display?

October 12, 2024 by Jenny List 10 Comments

Over the decades the technology behind flat panel displays has continuously evolved, and we’ve seen many of them come and go. Among the popular ones there are a few that never quite made the big time, usually because a contemporary competitor took their market. An example is in a recent [Wenting Zhang] video, a mystery liquid powder display. We’d never heard of it, so we were intrigued.

The first segment of the video is an examination of the device, and a comparison with similar-looking ones such as a conventional LCD, or a Sharp Memory LCD. It’s clearly neither of those, and the answer finally came after a lot of research. A paper described a “Quick response liquid powder” as a mechanism for a novel display, and thus it was identified. It works by moving black and white electrically charged powder to flip a pixel from black to white, and its operation is not dissimilar to the liquid-based e-ink displays which evidently won that particular commercial battle.

The process of identifying the driver chip and pinout should be an essential watch for anyone with an interest in display reverse engineering. After a lot of adjusting timing and threshold voltages the dead pixels and weird effects fall away, and then it’s possible to display a not-too-high-quality image on this unusual display, through a custom PCB with an RP2040. Take a look at the video below the break.

We’ve seen [Wenting Zhang]’s work here a few times before, most recently in a very impressive mirror-less camera project.

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What’s Your SWR? Are You Sure?

October 12, 2024 by Al Williams 11 Comments

If you are involved in any sort of radio transmission, you probably have at least heard of SWR or standing wave ratio. Most transmitters can measure it these days and most ham radio operators have tuners that measure it, also. But what are you measuring? [KI8R] points out that if your coax has loss — and what coax doesn’t? — you are probably getting an artificially low reading by measuring at the transmitter.

The reason is that most common SWR-measuring instruments pick up voltage. If you measure, for example, 10V going out and 1V going back, you’d assume some SWR from that. But suppose your coax loses half the voltage (just to make an obvious example; if your coax loses half the voltage, you need new coax).

Now, you really have 5V getting to your antenna, and it returns 2V. The loss will affect the return voltage just like the forward voltage. Reflecting 2V from 5 is a very different proposition from reflecting 1V out of 10!

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Are CRT TVs Important For Retro Gaming?

October 11, 2024 by Dave Rowntree 51 Comments

We always thought the older console games looked way better back in the day on old CRTs than now on a modern digital display. [Stephen Walters] thinks so too, and goes into extensive detail in a lengthy YouTube video about the pros and cons of CRT vs digital, which was totally worth an hour of our time. But are CRTs necessary for retro gaming?

The story starts with [Stephen] trying to score a decent CRT from the usual avenue and failing to find anything worth looking at. The first taste of a CRT display came for free. Left looking lonely at the roadside, [Stephen] spotted it whilst driving home. This was a tiny 13″ Sanyo DS13320, which, when tested, looked disappointing, with a blurry image and missing edges. Later, they acquired a few more displays: a Pansonic PV-C2060, an Emerson EWF2004A and a splendid-looking Sony KV24FS120. Some were inadequate in various ways, lacking stereo sound and component input options.

A poor analog cable coupled with rendering inaccuracy gives a nice filtering effect

A large video section discusses the reasons for the early TV standards. US displays (and many others using NTSC) were designed for 525 scan lines, of which 480 were generally visible. These displays were interlaced, drawing alternating fields of odd and even line numbers, and early TV programs and NTSC DVDs were formatted in this fashion. Early gaming consoles such as the NES and SNES, however, were intended for 240p (‘p’ for progressive) content, which means they do not interlace and send out a blank line every other scan line. [Stephen] goes into extensive detail about how 240p content was never intended to be viewed on a modern, sharp display but was intended to be filtered by the analogue nature of the CRT, or at least its less-than-ideal connectivity. Specific titles even used dithering to create the illusion of smooth gradients, which honestly look terrible on a pixel-sharp digital display. We know the differences in signal bandwidth and distortion of the various analog connection standards affect the visuals. Though RGB and component video may be the top two standards for quality, games were likely intended to be viewed via the cheaper and more common composite cable route.

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PC Floppy Copy Protection: Vault Corporation Prolok

October 11, 2024 by Jenny List 7 Comments

In the 2020s we’re used to software being readily accessible, and often free, whether as-in-beer or as-in-speech. This situation is a surprisingly new one, and in an earlier era of consumer software it was most often an expensive purchase. An anti-piracy industry sprang up as manufacturers tried to protect their products, and it’s one of those companies that [GloriousCow] examines in detail, following their trajectory from an initial success through to an ignominious failure driven by an anti-piracy tech too extreme even for the software industry.

Vault Corporation made a splash in the marketplace with Prolok, a copy protection system for floppies that worked by creating a physically damaged area of the disc which wouldn’t be present on a regular floppy. The write-up goes into detail about the workings of the system, including how to circumvent a Prolok protected title if you find one. This last procedure resulted in a lawsuit between Prolok and Quaid Software, one of the developers of circumvention tools, which established the right of Americans to make backup copies of their owned software.

The downfall of Vault Corporation came with their disastrously misjudged Prolok Plus product, which promised to implant a worm on the hard disks of pirates and delete all their files in an act of punishment. Sensing the huge reputational damage of being tied to such a product the customers stayed away, and the company drifted into obscurity.

For those interested further in the world of copy protection from this era, we’ve previously covered the similar deep dives that [GloriousCow] has done on Softguard’s Superlok as well as the Interlock system from Electronic Arts.