This excellent content from the Hackaday writing crew highlights recurring topics and popular series like Linux-Fu, 3D-Printering, Hackaday Links, This Week in Security, Inputs of Interest, Profiles in Science, Retrotechtacular, Ask Hackaday, Teardowns, Reviews, and many more.
We’ve now spent several months in this series journeying through the world of audio, and along the way we’ve looked at the various parts of a Hi-Fi system from the speaker backwards to the source. It’s been an enjoyable ride full of technical detail and examining Hi-Fi myths in equal measure, but now it’s time to descend into one of the simplest yet most controversial areas of audio reproduction. Every audio component, whether digital or analogue, must be connected into whatever system it is part of, and this is the job of audio cables, sometimes referred to as interconnects. They are probably the single component most susceptible to tenuous claims about their performance, with audiophiles prepared to spend vast sums on cables claimed to deliver that extra bit of listening performance. Is there something in it, or are they all the same bits of wire with the expensive ones being a scam? Time to take a look.
What Makes A Nearly Good Cable
In a typical domestic audio system with digital and analogue signals you might expect to find two types of cable, electrical interconnects that could carry either analogue or digital signals, and optical ones for digital signals. We’re here to talk about the electrical cables here as they’re the ones used for analogue signals, so lets start with a little transmission line theory. Continue reading “Know Audio: A Mess Of Cables”→
We’ve gotten used to the GPIO-available functions of Raspberry Pi computers remaining largely the same over the years, which is why it might have flown a little bit under the radar: the Raspberry Pi 4 has six SPI controllers, six I2C controllers, and six UARTs – all on its 40-pin header. You can’t make use of all of these at once, but with up to four different connections wired to a single pin you can carve out a pretty powerful combination of peripherals for your next robotics, automation or cat herding project.
The datasheet for these peripherals is pleasant to go through, with all the register maps nicely laid out – even if you don’t plan to work with the register mappings yourself, the maintainers of your preferred hardware enablement libraries will have an easier time! And, of course, these peripherals are present on the Compute Module 4, too. It might feel like such a deluge of interfaces is excessive, however, it lets you achieve some pretty cool stuff that wouldn’t be possible otherwise.
Having multiple I2C interfaces helps deal with various I2C-specific problems, such as address conflicts, throughput issues, and mixing devices that support different maximum speeds, which means you no longer need fancy mux chips to run five low-resolution Melexis thermal camera sensors at once. (Oh, and the I2C clock stretching bug has been fixed!) SPI interfaces are used for devices with high bandwidth, and with a few separate SPI ports, you could run multiple relatively high-resolution displays at once, No-Nixie Nixie clock style.
As for UARTs, the Raspberry Pi’s one-and-a-half UART interface has long been an issue in robotics and home automation applications. With a slew of devices like radio receivers/transmitters, LIDARs and resilient RS485 multi-drop interfaces available in UART form, it’s nice that you no longer have to sacrifice Bluetooth or a debug console to get some fancy sensors wired up to your robot’s brain. You can enable up to six UARTs. Continue reading “Did You Know That The Raspberry Pi 4 Has More SPI, I2C, UART Ports?”→
There’s an old joke about the Thermos bottle that keeps things hot and cold, so someone loaded it with soup and ice cream. That joke is a little close to home when it comes to FDM 3D printers.
You want to melt plastic, of course, or things won’t print, so you need heat. But if the plastic filament gets hot too early, it will get soft, expand, and jam. Heat crawling up the hot end like this is known as heat creep and there are a variety of ways that hot ends try to cope with the need to be hot and cold at the same time. Most hotends today are air-cooled with a small fan. But water-cooled hotends have been around for a while and are showing up more and more. Is it a gimmick? Are you using, planning to use, or have used (and abandoned) water cooling on your hot end?
Heat Break
The most common method is to use a heat-break between the heating block and the rest of the filament path. The heat-break is designed to transfer as little heat as necessary, and it usually screws into a large heat sink that has a fan running over it. What heat makes it across the break should blow away with the fan cooling.
High tech solutions include making heat-breaks out of titanium or even two dissimilar metals, all with the aim of transferring less heat into the cooler part of the hot end. More modern hot ends use support structures so the heatbreak doesn’t need mechanical rigidity, and they can make very thin-walled heatbreaks that don’t transmit much heat. Surely, then, this is case closed, right? Maybe not.
While it is true that a standard heat-break and a fan can do the job for common 3D printing tasks, there can be problems. First, if you want to print fast — time is money, after all — you need more power to melt more filament per second. If a heatbreak transfers 10% of the heat, this increases demands on the upstream cooling. Some engineering materials want to print at higher temperatures, so you can have the same problem there as well. If you want to heat the entire print chamber, which can help with certain printing materials, that can also cause problems since the ambient air is now hotter. Blowing hot air around isn’t going to cool as effectively. Not to mention, fans that can operate at high temperatures are notoriously expensive.
There are other downsides to fans. Over a long print, a marginal system might eventually let enough heat creep up. Then there’s the noise of a fan blowing during operation. True, you probably have other fans and noisy parts, but it is still one more noise source. With water cooling, you can move the radiator outside a heated enclosure and use larger, slower, and quieter fans while getting more cooling right where you want it. Continue reading “3D Printering: Water-Cooled Hotends”→
When a tiny fleck of plastic-covered silicon can provide enough capacity to store a fair percentage of humanity’s collected knowledge, it may seem like a waste of time to be fooling around with archaic storage technology like floppy disks. With several orders of magnitude less storage capacity than something like even the cheapest SD card or thumb drive, and access speeds that clock in somewhere between cold molasses and horse and buggy, floppy drives really don’t seem like they have any place on the modern hacker’s bench.
Or do they? Learning the ins and out of interfacing floppy drives with modern microcontrollers is at least an exercise in hardware hacking that can pay dividends in other projects. A floppy drive is, after all, a pretty complex little device, filled with electromechanical goodies that need to be controlled in a microcontroller environment. And teasing data from a stream of magnetic flux changes ends up needing some neat hacks that might just serve you well down the line.
So don’t dismiss the humble floppy drive as a source for hacking possibilities. The folks at Adafruit sure haven’t, as they’ve been working diligently to get native floppy disk support built right into CircuitPython. To walk us through how they got where they are now, Ladyada and PT will drop by the Hack Chat. Be sure to come with your burning questions on flux transitions, MFM decoding, interface timing issues, and other arcana of spinning rust drives.
After all the fuss and bother along the way, it seems a bit anticlimactic now that the James Webb Space Telescope has arrived at its forever home orbiting around L2. The observatory finished its trip on schedule, arriving on January 24 in its fully deployed state, after a one-month journey and a couple of hundred single-point failure deployments. The next phase of the mission is commissioning, and is a somewhat more sedate and far less perilous process of tweaking and trimming the optical systems, and getting the telescope and its sensors down to operating temperature. The commissioning phase will take five or six months, so don’t count on any new desktop photos until summer at the earliest. Until then, enjoy the video below which answers some of the questions we had about what Webb can actually see — here’s hoping there’s not much interesting to see approximately in the plane of the ecliptic.
The really nice thing about doing something the “wrong” way is that there’s just so much variety! If you’re doing something the right way, the fastest way, or the optimal way, well, there’s just one way. But if you’re going to do it wrong, you’ve got a lot more design room.
Case in point: esoteric programming languages. The variety is stunning. There are languages intended to be unreadable, or to sound like Shakespearean sonnets, or cooking recipes, or hair-rock ballads. Some of the earliest esoteric languages were just jokes: compilations of all of the hassles of “real” programming languages of the time, but yet made to function. Some represent instructions as a grid of colored pixels. Some represent the code in a fashion that’s tantamount to encryption, and the only way to program them is by brute forcing the code space. Others, including the notorious Brainf*ck are actually not half as bad as their rap — it’s a very direct implementation of a Turing machine.
So you have a set of languages that are designed to be maximally unlike each other, or traditional programming languages, and yet still be able to do the work of instructing a computer to do what you want. And if you squint your eyes just right, and look at as many of them all together as you can, what emerges out of this blobby intersection of oddball languages is the essence of computing. Each language tries to be as wrong as possible, so what they have in common can only be the unavoidable core of coding.
While it might be interesting to compare an contrast Java and C++, or Python, nearly every serious programming language has so much in common that it’s just not as instructive. They are all doing it mostly right, and that means that they’re mostly about the human factors. Yawn. To really figure out what’s fundamental to computing, you have to get it wrong.
This article is part of the Hackaday.com newsletter, delivered every seven days for each of the last 200+ weeks. It also includes our favorite articles from the last seven days that you can see on the web version of the newsletter.
Want this type of article to hit your inbox every Friday morning? You should sign up!
Join Hackaday Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi on another whirlwind tour of the week’s top stories, hacks, and projects. We start off with some breaking Linux security news, and then marvel over impeccably designed pieces of hardware ranging from a thrifty Z table for the K40 laser cutter to a powerful homebrew injection molding rig. The finer technical points of a USB device that only stores 4 bytes at a time will be discussed, and after taking an interactive tour through the internals of the 555 timer, we come away even more impressed by the iconic 50 year old chip. We’ll wrap things up by speculating wildly about all the bad things that can happen to floating solar panels, and then recite some poetry that you can compile into a functional computer program should you feel so inclined.
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
