XML Is A Quarter Century Old

February 11, 2023 by 58 Comments

For those of us who have spent entire careers working with structured data, it comes as something of a surprise to be reminded that XML is now 25 years old. You probably missed the XML standard on the 10th of February 1998, but it’s almost certain that XML has touched your life in many ways even if you remain unaware of it.

The idea of one strictly compliant universal markup language to rule them all was extremely interesting in an era when the Internet was becoming the standard means to interchange information and when the walled gardens dating back to the mini- and mainframe era were being replaced with open standards-based interchange. In the electronic publishing industry, it allowed encyclopedia and dictionary-sized data sets to be defined to a standard format and easily exchanged.  At a much smaller level, it promised a standard way to structure more mundane transactions. Acronyms and initialisms such as WAP, SOAP, and XHTML were designed to revolutionize the Web of the 21st century, but chances are that those are familiar only to the more grizzled developers.

In practice the one-size-fits-all approach of XML left it unwieldy, giving the likes of JSON and HTML4 the opening to be the standards we used. That’s not to say XML isn’t hiding in plain sight though, it’s the container for the SVG graphics format. Go on — tell us where else XML can be found, in the comments!

So, XML. When used to standardise large structured datasets it can sometimes be enough to bring the most hardened of developers to tears, but it remains far better than what went before. When hammered to fit into lightweight protocols though, it’s a pain in the backside and is best forgotten. It’s 25 years old, and here to stay!

Header: [Jh20], GFDL v1.2.

Pi Pico Breathes New Life Into Original PlayStation

February 10, 2023 by 22 Comments

Those gamers who were playing in the mid 1990s may retain a soft spot for Sony’s first PlayStation. The grey console was the thing to have a quarter century ago, but we’re guessing few who had one will have a soft spot for their CD mechanisms. These were seemingly manufactured from Sony’s finest chocolate, and would stop working at the slightest hint of getting warm.

With the hardware now long in the tooth, what is to be done with a dead CD drive? Perhaps [Xrider] has the answer, with a CD Drive emulator board which fits in the space left by the original (French language, translation link).

Doing the hard work is a Raspberry Pi Pico, building on the Picostation project. To that it brings a drive-shaped board, as well as a series of daughterboards for the various different revisions of the Sony motherboard. The games meanwhile are loaded from a micro-SD card.

As single board computers have become ever faster, it’s no surprise that one would be able to emulate a ’90s CD mechanism with ease. What this does raise though is the interesting prospect that the Picostation might be adapted for other less-popular CD-based platforms. For those of us for whom games consoles in the CD era were both work and play, we hope that other consoles will receive this benefit.

JFET Stands In For Triode In This Infinite Impedance Detector

February 10, 2023 by 6 Comments

An “Infinite Impedance Detector” might sound a little like something that [Zaphod Beeblebrox] would use to zip around the galaxy. It’s not, of course, but it is an interesting and useful demodulator for AM radio signals, as [Sebastian Westerhold] over at Baltic Labs explains in the brief but well-done video below.

If you’ve ever browsed through schematics of old vacuum tube radios, [Sebastian]’s JFET-based detector circuit might look strangely familiar. That’s because this demodulator is about as close to a direct translation between a vacuum tube circuit and a silicon circuit as possible. In fact, [Sebastian] even used literature from the triode version of this detector to figure out the values for some of the components. The only active component is a BF256B JFET; the rest are a small handful of resistors and caps. Construction is in the ever-popular ugly style.

The test setup is simple — a function generator set to 455 kHz and modulated with a 1,000 Hz sine wave. The detector demodulates the audio signal very cleanly, judging by the oscilloscope traces. Just for fun, [Sebastian] also tried a 10.7 MHz carrier with a 1,500 Hz audio modulation, and that worked fine too. He also tried a variation on the circuit with an IF transformer on the input. That circuit works just about the same as the transformerless version, although it does provide a little gain.

Earth-shattering stuff? Probably not. But it does show the fun you can have with a scrap of PCB and a few components, and seems like it could easily be the kind of project that would take you down the RF rabbit hole. Thanks to [Sebastian] for sharing this one with us.

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An Instant Camera Using E-Paper As Film

February 10, 2023 by 16 Comments

The original Polaroid cameras were a huge hit not just for their instant delivery, but for the convenient size of the permanent images they delivered. It’s something that digital cameras haven’t been able to replicate, which drew [Cameron] to produce a modern alternative. In the place of the chemical film of the original, it uses a removable e-paper display in a frame. The image is stored in the pixels of the e-paper, which can be kept as a digital version of the photograph until reattached and replaced with another freshly taken picture.

At its heart is an ESP32 with a camera, and the “film” is a Waveshare NFC e-paper module. The device is 3D printed, and manages a very creditable early-1970s aesthetic redolent of the more upmarket Polaroids of the day. Using it is as simple as pressing the button and deciding whether you like what’s on the screen. You can see it in action in the video below the break.

We like his project for its aesthetics, as well as for the very idea of using e-paper as a medium. There’s also something to be said for not having to put a Polaroid print in a clip under your armpit while it develops. Meanwhile if you do hanker for the real thing, it’s a subject we’ve looked at in the past.

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3D Printing Support Gets Down To Tacks

February 10, 2023 by 9 Comments

If you use supports for FDM 3D printing, you might find that some designs are more amenable than others to automatically-generated supports. [Slant 3D] , for example, shows a cool-looking eagle with a downward-curved beak that comes to a point. Using traditional supports would allow the print to succeed, but didn’t allow the beak to form correctly. To combat this, he uses something called a “thumbtack” in the design. There are several flavors, as you can see in the video below, and it widens out the small part yet has a tiny contact with the actual part so you can easily remove it.

One of the thumbtacks looks more like a Hersey’s kiss to us. It makes sense. The point can touch the part to support and the fat base gives a nice target for the automatic support feature in your slicer to grab. There’s also a spherical base so you can rotate to odd angles. The final thumbtack looks like an alien spacecraft and provides multiple contact points.

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Bridging The Gap Between Dissimilar Road Types With Foam

February 10, 2023 by 27 Comments

When you think of driving up or down an embankment, do you ever wonder how much foam you’re currently driving on? Probably not, because it hardly seems like a suitable building material. But as explained by [Practical Engineering] in the video below the break, using an expanded material to backfill an embankment isn’t as dense as it sounds.

In many different disciplines, mating dissimilar materials can be difficult: Stretchy to Firm; Soft to Hard; Light to Heavy. It’s that last one, Light to Heavy, that is a difficult match for roadways. A bridge may be set down in bedrock, but the embankments approaching it won’t be. The result? Over time, embankment settles lower than the bridge does, causing distress for cars and motorists alike. What’s the solution?

To mitigate this, engineers have started to employ less dirty materials to build their otherwise soil based embankments. Lightweight concrete is one solution, but another is Expanded Polystyrene (EPS) foam. Its light weight makes installation simple in anything but a strong breeze, and it’s inexpensive and durable. When used properly, it can last many years and provide a stable embankment that won’t settle as far or as quickly as one made of dirt. Because as it turns out, dirt is heavy. Who knew?

Aside from roadways and bespoke aircraft, EPS foam has also been used for making home insulation. What’s your favorite use for EPS foam? Let us know in the comments below.

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Hackaday Podcast 205: Hackaday Berlin, So Many Sundials, And Ovens Pinging Google

February 10, 2023 by 9 Comments

Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi start this week’s episode off with the announcement of Hackaday Berlin on March 25th. It’s been quite some time since we’ve been on the other side of the pond, because we had to cancel 2020’s Hackaday Belgrade due to COVID-19, so excitement is high for all three days of this “one-day” event.

After a new What’s that Sound, discussion moves on to an impressive collection of DIY sundials, the impact filament color has on the strength of 3D printed parts, the incredible retrocomputer replicas of Michael Gardi, and the Arduino FPGA that you’ve probably never heard of. We’ll wrap things up with the unexpected difficulties of mixing multiple cheap audio sources in Linux, and try to figure out why our kitchen appliances need to be connected to the Internet.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in  the comments!

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