Secrets Of The Old Digital Design Titans

July 18, 2024 by Al Williams 46 Comments

Designing combinatorial digital circuits seems like it should be easy. After all, you can do everything you want with just AND, OR, and NOT gates. Bonus points if you have an XOR gate, but you can build everything you need for combinatorial logic with just those three components. If all you want to do is design something to turn on the light when the ignition is on AND door 1 is open OR door 2 is open, you won’t have any problems. However, for more complex scenarios, how we do things has changed several times.

In the old days, you’d just design the tubes or transistor circuits you needed to develop your logic. If you were wiring up everything by hand anyway, you might as well. But then came modules like printed circuit boards. There was a certain economy to having cards that had, say, two NOR gates on a card. Then, you needed to convert all your logic to use NOR gates (or NAND gates, if that’s what you had).

Small-scale ICs changed that. It was easy to put a mix of gates on a card, although there was still some slight advantage to having cards full of the same kind of gate. Then came logic devices, which would eventually become FPGAs. They tend to have many of one kind of “cell” with plenty of logic gates on board, but not necessarily the ones you need. However, by that time, you could just tell a computer program what you wanted, and it would do the heavy lifting. That was a luxury early designers didn’t have. Continue reading “Secrets Of The Old Digital Design Titans” →

FDM Filament Troubles: Keeping Hygroscopic Materials From Degrading

July 17, 2024 by Maya Posch 18 Comments

Despite the reputation of polymers used with FDM 3D printing like nylon, ABS, and PLA as being generally indestructible, they do come with a whole range of moisture-related issues that can affect both the printing process as well as the final result. While the concept of ‘baking’ such 3D printing filaments prior to printing to remove absorbed moisture is well-established and with many commercial solutions available, the exact extent to which these different polymers are affected, and what these changes look like on a molecular level are generally less well-known.

Another question with such hygroscopic materials is whether the same issues of embrittlement, swelling, and long-term damage inflicted by moisture exposure that affects filaments prior to printing affects these materials post-printing, and how this affects the lifespan of FDM-printed items. In a 2022 paper by Adedotun D. Banjo and colleagues much of what we know today is summarized in addition to an examination of the molecular effects of moisture exposure on polylactic acid (PLA) and nylon 6.

The scientific literature on FDM filaments makes clear that beyond the glossy marketing there is a wonderful world of materials science to explore, one which can teach us a lot about how to get good FDM prints and how durable they will be long-term.

Continue reading “FDM Filament Troubles: Keeping Hygroscopic Materials From Degrading” →

Smart Ball Technology Has Reached Football, But The Euros Show Us It’s Not Necessarily For The Better

July 16, 2024 by Lewin Day 56 Comments

*Adidas brought smart balls to Euro 2024, for better or worse. Credit: Adidas*

The good old fashioned game of football used to be a simple affair. Two teams of eleven, plus a few subs, who were all wrangled by a referee and a couple of helpful linesmen. Long ago, these disparate groups lived together in harmony. Then, everything changed when VAR attacked.

Suddenly, technology was being used to adjudicate all kinds of decisions, and fans were cheering or in uproar depending on how the hammer fell. That’s only become more prevalent in recent times, with smart balls the latest controversial addition to the world game. With their starring role in the Euro 2024 championship more than evident, let’s take a look at what’s going on with this new generation of intelligent footballs.

Continue reading “Smart Ball Technology Has Reached Football, But The Euros Show Us It’s Not Necessarily For The Better” →

The Mysterious Roman Dodecahedron Was Possibly Just For Knitting

July 14, 2024 by Maya Posch 41 Comments

Over the years archaeological digs of Roman sites have uncovered many of these strange dodecahedrons, usually made out of metal and with various holes in their faces. With no surviving records that describe how they were used, speculation has ranged from jewelry to a knitting aid. In a 2023 video by [Amy Gaines] it is this latter use which is explored, using a 3D printed dodecahedron and some wooden dowels to knit both gold wire and yarn into rather intricate patterns that are also referred to as ‘Viking Knitting’.

As we mentioned previously when yet another one of these dodecahedrons was uncovered, their use was unlikely to be of supreme relevance in military or scientific circles on account of a lack of evidence. What is quite possible is that these were both attractive shapes for jewelry (beads), and useful knitting aids for both jewelry makers (for e.g. gold wire braiding) and quite possibly yarn-related uses. The results which [Amy] demonstrates in the video for the gold wire in particular bear a striking resemblance to ancient braided gold chains on display at the Met and other museums, which leads credence to this theory.

If these items were effectively just common knitting tools, that would explain why the historical record is mum on them, as they would have been as notable as a hammer or a precision lathe used by the ancient Greeks.

Thanks to [john] for the tip.

Continue reading “The Mysterious Roman Dodecahedron Was Possibly Just For Knitting” →

The NSA Is Defeated By A 1950s Tape Recorder. Can You Help Them?

July 13, 2024 by Jenny List 59 Comments

One of the towering figures in the evolution of computer science was Grace Hopper, an American mathematician, academic, and Naval reservist, whose work gave us the first programming languages, compilers, and much more. Sadly she passed away in 1992, so her wisdom hasn’t directly informed the Internet Age in the manner of some of her surviving contemporaries.

During her life she gave many lectures though, and as [Michael Ravnitzky] discovered, one of them was recorded on video tape and resides in the archives of America’s National Security Agency. With the title “Future Possibilities: Data, Hardware, Software, and People”, it was the subject of a Freedom Of Information request. This in turn was denied, on the grounds that “Without being able to view the tapes, NSA has no way to verify their responsiveness”. In short, the recording lies on Ampex 1″ reel-to-reel video tape, which the NSA claims no longer to be able to read.

It’s fairly obvious from that response that the agency has no desire to oblige, and we’d be very surprised to find that they keep a working Ampex video system to hand on the off-chance that a passing researcher might ask for an archive tape. But at the same time it’s also obvious that a lecture from Rear Admiral Hopper is an artifact of international importance that should be preserved and available for study. It’s an interesting thought exercise to guess how many phone calls Hackaday would have to make to secure access to a working Ampex video recorder, and since we think for us that number would be surprisingly low it’s likely the NSA know exactly who to call if they needed that tape viewed in a hurry. We don’t have influence over secretive government agencies, but if we did we’d be calling shame on them at this point.

If you’re curious about Grace Hopper, we’ve talked about her work here in the past.

Thanks [F4GRX] for the tip.

Ampex image: Telecineguy., Public domain.

Rulers Of The Ancient World — Literally!

July 13, 2024 by Al Williams 29 Comments

If you were expecting a post about ancient kings and queens, you are probably at the wrong website. [Burn Heart] has a fascination with ancient measuring devices and set out to recreate period-correct rules, although using decidedly modern techniques.

The first example is a French rule for measuring the “pied du Roi” or king’s foot. Apparently, his royal highness had large feet as a the French variant is nearly 13 inches long. The next rulers hail from Egypt and measure cubits and spans. Turns out the pyramid builders left a lot of information about measurements and their understanding of math and tools like dividers.

Other rules from Rome, Japan, and the Indus Valley are also included. According to the post, one set of these rulers used locally sourced wood, but a second “limited” edition used wood that the originals might have. Most of the rulers were etched via CNC, although the French ruler was hand-etched.

The Romans, apparently, had smaller feet than French royalty, as their Pes or foot was about 11.65 inches. There are plenty of little tidbits in the post ranging from the origin of the word inch to why the black wood used for piano keys is called ebony.

We’ll stipulate this isn’t exactly a hack, although it is fine workmanship and part of hacker culture is obsessing over measuring things, so we thought it was fair game. These days, rulers are often electronic. Which makes it natural to put them on a PC board.

Embedded Python: MicroPython Is Amazing

July 11, 2024 by Arya Voronova 105 Comments

In case you haven’t heard, about a month ago MicroPython has celebrated its 11th birthday. I was lucky that I was able to start hacking with it soon after pyboards have shipped – the first tech talk I remember giving was about MicroPython, and that talk was how I got into the hackerspace I subsequently spent years in. Since then, MicroPython been a staple in my projects, workshops, and hacking forays.

If you’re friends with Python or you’re willing to learn, you might just enjoy it a lot too. What’s more, MicroPython is an invaluable addition to a hacker’s toolkit, and I’d like to show you why. Continue reading “Embedded Python: MicroPython Is Amazing” →