You Can Get A Precision Instrument-Guided Landing Even In Antarctica

August 23, 2024 by Lewin Day 8 Comments

Traditional airports spend big money to install instrument landing systems (ILS) to guide planes in safely. In places like Antarctica, though, it’s simply not possible to permanently install a massive antenna array for localization, particularly with all the ice shifting about on the regular. As covered by Flightradar24, the solution to this is to use a transponder landing system (TLS) instead.

A TLS tracks planes by using multilateration—basically, transponder signals are picked up by multiple antennas and the time delays are used to figure out the position of the aircraft. It then sends the guidance signals a plane would normally expect to receive from an ILS transmitter array, for horizontal and vertical guidance. These signals appear to the plane to be coming from antennas located as per a typical ILS array, with the TLS able to generate signals from ‘virtual emanation points” as needed. This allows the TLS to generate different landing approaches to suit different planes and conditions. From the pilot and aircraft side, it’s all perfectly transparent.

In Antarctica’s McMurdo station, landings are handled by a TLS system that barely takes up more space than a single shipping crate. The system can be set up in just a few hours, unlike a traditional ILS which takes significant installation work spanning weeks or months at best. At the moment, though, the landing strip at McMurdo is stable enough that the system only needs periodic realignment every three years or so.

You might assume that if you’re approaching Antarctica by plane, everything would be on manual. However, the creature comforts of modern airports are available even at one of the the most southerly airports on Earth!

Creating Customized Diffraction Lenses For Lasers

August 23, 2024 by Bryan Cockfield 3 Comments

[The Thought Emporium] has been fascinated by holograms for a long time, and in all sorts of different ways. His ultimate goal right now is to work up to creating holograms using chocolate, but along the way he’s found another interesting way to manipulate light. Using specialized diffraction gratings, a laser, and a few lines of code, he explores a unique way of projecting hologram-like images on his path to the chocolate hologram.

There’s a lot of background that [The Thought Emporium] has to go through before explaining how this project actually works. Briefly, this is a type of “transmission hologram” that doesn’t use a physical object as a model. Instead, it uses diffraction gratings, which are materials which are shaped to light apart in specific ways. After some discussion he demonstrates creating diffraction gratings using film. Certain diffraction patterns, including blocking all of the light source, can actually be used as a lens as the light bends around the blockage into the center of the shadow where there can be focal points. From there, a special diffraction lens can be built.

The diffraction lens can be shaped into any pattern with a small amount of computer code to compute the diffraction pattern for a given image. Then it’s transferred to film and when a laser is pointed at it, the image appears on the projected surface. Diffraction gratings like these have a number of other uses as well; the video also shows a specific pattern being used to focus a telescope for astrophotography, and a few others in the past have used them to create the illusive holographic chocolate that [The Thought Emporium] is working towards.

Continue reading “Creating Customized Diffraction Lenses For Lasers” →

A very tiny keyboard with RGB backlighting.

Tiny Custom Keyboard Gets RGB

August 23, 2024 by Lewin Day 12 Comments

Full-size keyboards are great for actually typing on and using for day-to-day interfacing duties. They’re less good for impressing the Internet. If you really want to show off, you gotta go really big — or really small. [juskim] went the latter route, and added RGB to boot!

This was [juskim]’s attempt to produce the world’s smallest keyboard. We can’t guarantee that, but it’s certainly very small. You could readily clasp it within a closed fist. It uses a cut down 60% key layout, but it’s still well-featured, including numbers, letters, function keys, and even +,-, and =. The build uses tiny tactile switches that are SMD mounted on a custom PCB. An ATmega32U4 is used as the microcontroller running the show, which speaks USB to act as a standard human interface device (HID). The keycaps and case are tiny 3D printed items, with six RGB LEDs installed inside for the proper gamer aesthetic. The total keyboard measures 66 mm x 21 mm.

Don’t expect to type fast on this thing. [juskim] only managed 14 words per minute. If you want to be productive, consider a more traditional design.

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Hackaday Podcast Episode 285: Learning Laser Tricks, Rocket Science, And A Laptop That’s Not A Laptop

August 23, 2024 by Kristina Panos 1 Comment

This week on the Podcast, we have something a little different for you. Elliot is on vacation, so Tom was in charge of running the show and he had Kristina in the hot seat.

First up in the news: the 2024 Tiny Games Challenge is still underway and has drawn an impressive 44 entries as of this writing. You have until 9AM PDT on September 10th to show us your best tiny game, whether that means tiny hardware, tiny code, or a tiny BOM.

Then it’s on to What’s That Sound, which Tom and Kristina came up with together, so there will be no pageantry about guessing. But can you get it? Can you figure it out? Can you guess what’s making that sound? If you can, and your number comes up, you get a special Hackaday Podcast t-shirt.

Now it’s on to the hacks, beginning with an open-source liquid-fueled rocket and a really cool retro trackball laptop. Then we’ll discuss screwdriver mange, the Wow! signal, and whether you’re using you’re calipers incorrectly. Finally, we look at a laptop that that isn’t really a laptop, and one simple trick to keep things aligned on your laser engraver.

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!

Download in DRM-free MP3 and savor at your leisure.

Continue reading “Hackaday Podcast Episode 285: Learning Laser Tricks, Rocket Science, And A Laptop That’s Not A Laptop” →

Ethernet History: Why Do We Have Different Frame Types?

August 23, 2024 by Maya Posch 9 Comments

Although Ethernet is generally considered to be a settled matter, its history was anything but peaceful, with its standardization process (under Project 802) leaving its traces to this very day. This is very clear when looking at the different Ethernet frame types in use today, and with many more historical types. While Ethernet II is the most common frame type, 802.2 LLC (Logical Link Control) and 802 SNAP (Subnetwork Access Protocol) are the two major remnants of this struggle that raged throughout the 1980s, even before IEEE Project 802 was created. An in-depth look at this history with all the gory details is covered in this article by [Daniel].

The originally proposed IEEE 802 layout, with the logical link control (LLC) providing an abstraction layer.

We covered the history of Ethernet’s original development by [Robert Metcalfe] and [David Boggs] while they worked at Xerox, leading to its commercial introduction in 1980, and eventual IEEE standardization as 802.3. As [Daniel]’s article makes clear, much of the problem was that it wasn’t just about Ethernet, but also about competing networking technologies, including Token Ring and a host of other technologies, each with its own gaggle of supporting companies backing them.

Over time this condensed into three subcommittees:

802.3: CSMA/CD (Ethernet).
802.4: Token bus.
802.5: Token ring.

An abstraction layer (the LLC, or 802.2) would smooth over the differences for the protocols trying to use the active MAC. Obviously, the group behind the Ethernet and Ethernet II framing push (DIX) wasn’t enamored with this and pushed through Ethernet II framing via alternate means, but with LLC surviving as well, yet its technical limitations caused LLC to mutate into SNAP. These days network engineers and administrators can still enjoy the fallout of this process, but it was far from the only threat to Ethernet.

Ethernet’s transition from a bus to a star topology was enabled by the LANBridge 100 as an early Ethernet switch, allowing it to scale beyond the limits of a shared medium. Advances in copper wiring (and fiber) have further enabled Ethernet to scale from thin- and thicknet coax to today’s range of network cable categories, taking Ethernet truly beyond the limits of token passing, CSMA/CD and kin, even if their legacy will probably always remain with us.

This Week In Security: Crash Your IPhone, Hack Your Site, And Bluetooth Woes

August 23, 2024 by Jonathan Bennett 6 Comments

There have been some hilarious issues on mobile devices over the years. The HTC Dream had a hidden shell that was discovered when a phone rebooted after sending a text containing just the word “reboot”. iOS has gotten in on the fun from time to time, and this time it’s ""::. Type the double quotes, a colon, and any other character, and Apple’s Springboard service crashes.

Another hacker dug in a bit, and realized that Springboard is trying to jump execution to a null pointer, leading to a crash. It’s very odd that user input breaks the query parser badly enough to jump to null like that. There are a couple interesting questions that we have to ask. Given that the crash trigger is quite flexible, "anything goes":x, is it possible to manipulate that function pointer to be something other than null? And perhaps more importantly, why is the code crashing, instead of an invalid address error as one would expect from a Pointer Authentication Code (PAC) violation? Regardless, the bug seems to be fixed in the latest iOS 18 builds.

Continue reading “This Week In Security: Crash Your IPhone, Hack Your Site, And Bluetooth Woes” →

The Famous Computer Cafe Has Now Been Archived Online

August 23, 2024 by Lewin Day 4 Comments

You might think that TV stations or production houses would be great at archiving, but it’s not always the case. Particularly from the public access perspective. However, if you’re a fan of The Famous Computer Cafe, you’re in luck! The beloved series has now been preserved on The Internet Archive!

If you’re not familiar with the show, it was a radio program broadcast from 1983 to 1986. It was pumped out of a variety of radio stations in southern and central California in the period. The creators making sure to keep a copy of each episode in reel-to-reel tape format. For years, these tapes were tragically lost, until archivist [Kay Savetz] was able to recover some of them from a recent property sale. From there, a GoFundMe paid for digitization, and the show has been placed on The Internet Archive with the blessings of the original creators.

This is quite the cultural victory, particularly when you observe the list of guests on the show. Timothy Leary, Bill Gates, Jack Tramiel, and even Douglas Adams made appearances in the recovered recordings. Sadly, though, not all the tapes have been recovered. Episodes with Gene Roddenberry, Robert Moog, and Ray Bradbury are still lost to time.

If you fancy a listen, 53 episodes presently exist on the archive. Take a trip back in time and hear from some technological visionaries—and futurists—speaking their minds at the very beginning of the microcomputer era! If you find any particularly salient gems, don’t hesitate to drop them on the tip line.