DIY Passive Radar System Verifies ADS-B Transmissions

April 29, 2024 by Bryan Cockfield 5 Comments

Like most waves in the electromagnetic spectrum, radio waves tend to bounce off of various objects. This can be frustrating to anyone trying to use something like a GMRS or LoRa radio in a dense city, for example, but these reflections can also be exploited for productive use as well, most famously by radar. Radar has plenty of applications such as weather forecasting and various military uses. With some software-defined radio tools, it’s also possible to use radar for tracking aircraft in real-time at home like this DIY radar system.

Unlike active radar systems which use a specific radio source to look for reflections, this system is a passive radar system that uses radio waves already present in the environment to track objects. A reference antenna is used to listen to the target frequency, and in this installation, a nine-element Yagi antenna is configured to listen for reflections. The radio waves that each antenna hears are sent through a computer program that compares the two to identify the reflections of the reference radio signal heard by the Yagi.

Even though a system like this doesn’t include any high-powered active elements, it still takes a considerable chunk of computing resources and some skill to identify the data presented by the software. [Nathan] aka [30hours] gives a fairly thorough overview of the system which can even recognize helicopters from other types of aircraft, and also uses the ADS-B monitoring system as a sanity check. Radar can be used to monitor other vehicles as well, like this 24 GHz radar module found in some modern passenger vehicles.

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AI Can Now Compress Text

April 28, 2024 by Jenny List 42 Comments

There are many claims in the air about the capabilities of AI systems, as the technology continues to ascend the dizzy heights of the hype cycle. Some of them are true, others stretch definitions a little, while yet more cross the line into the definitely bogus. [J] has one that is backed up by real code though, a compression scheme for text using an AI, and while there may be limitations in its approach, it demonstrates an interesting feature of large language models.

The compression works by assuming that for a sufficiently large model, it’s likely that many source texts will exist somewhere in the training. Using llama.cpp it’s possible to extract the tokenization information of a piece of text contained in its training data and store that as the compressed output. The decompressor can then use that tokenization data as a series of keys to reassemble the original from its training. We’re not AI experts but we are guessing that a source text which has little in common with any training text would fare badly, and we expect that the same model would have to be used on both compression and decompression. It remains a worthy technique though, and no doubt because it has AI pixie dust, somewhere there’s a hype-blinded venture capitalist who would pay millions for it. What a world we live in!

Oddly this isn’t the first time we’ve looked at AI text compression.

Hack In Style With This Fallout Cyberdeck

April 28, 2024 by Julian Scheffers 15 Comments

There’s always an appeal to a cool-looking computer case or cyberdeck – and with authentic-looking Vault-Tec style, [Eric B] and [kc9psw]’s fallout-themed cyberdeck is no exception.

The case looks like it came straight out of one of the Fallout games and acts the part: while (obviously) not capable of withstanding a direct nuclear bomb impact, it can protect the sensitive electronics inside from the electromagnetic pulse and shockwave that follows – if you keep it closed.

And it’s not just the case that’s cool: This cyberdeck is packed full of goodies like long-range radios, SDRs, ADSB receivers, a Teensy 4.1, and dual Raspberry Pis. But that’s just the hardware! It also comes with gigabytes upon gigabytes of Wikipedia, Wikihow, TED talks, and other information/entertainment, for the less eventful days in the wastelands.

If you, too, would like to have one, fret not! The parts list and design files are public, even though some assembly is required.

Hackaday Links: April 28, 2024

April 28, 2024 by Dan Maloney 24 Comments

Well, it’s official — AI is ruining everything. That’s not exactly news, but learning that LLMs are apparently being used to write scientific papers is a bit alarming, and Andrew Gray, a librarian at University College London, has the receipts. He looked at a cross-section of scholarly papers from 2023 in search of certain words known to show up more often in LLM-generated text, like “commendable”, “intricate”, or “meticulous”. Most of the words seem to have a generally positive tone and feel a little fancier than everyday speech; one rarely uses “lucidly” or “noteworthy” unless you’re trying to sound smart, after all. He found increases in the frequency of appearance of these and other keywords in 2023 compared to 2022, when ChatGPT wasn’t widely available.

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You Can Run BASIC On An Old HP 4592 Protocol Analyzer

April 28, 2024 by Lewin Day 10 Comments

What do you do when you find an ancient piece of test gear and want to have fun? Well, you can always try getting BASIC running on it, and that’s precisely what [David Kuder] did.

The HP4952A Protocol Analyzer actually looks a lot like an old computer, even if it was never meant for general-purpose use. The heart of the machine is a Zilog Z80 CPU, though, so it shares a lot in common with microcomputers of its era.

Among other hacks, [David] worked to get Microsoft Basic-80 running on the machine. Initially, he was only able to get it up and running on the display, with no way to read the keyboard, disk, or access the serial port. Eventually, by diving into the nitty-gritty of the machine, he was able to at least get the keyboard working along with some basic BASIC programs. Usable memory is just 8KB, but you can do a fair bit with that when you’ve only got a 32×16 display for output anyway!

It’s a neat hack and one that was extendable to the HP4957A as well. We’ve seen similar machines on these pages before, too! If you’ve got your own neat retro hacks on the boil, don’t hesitate to drop us a line!

[Thanks to Christopher Zell for the tip!]

Corral Some Zippy Blue Flames Into 3D Printed Troughs

April 28, 2024 by Donald Papp 20 Comments

[Steve Mould] came across an interesting little phenomenon of blue flames zipping around a circular track. This led to diving down a bit of a rabbit hole about excitable mediums, ultimately leading him to optimize the shapes and come up with some pretty wild variations which he shows off in a video (also embedded below.)

After figuring out that the moving flame depended on combustion of fuel vapor in an environment that didn’t allow for the whole surface to stay lit at once, [Steve] tried to optimize the design of 3d-printed channels and raceways to encourage this effect, and he came up with some pretty novel ones. The 3D models are here if you’d like to try them for yourself (we especially like the “figure eight” and “rays” models.)

The video is an excellent show & tell of everything [Steve] dove into, complete with plenty of demonstrations of harnessing this effect to create some nifty running flames. Check it out in the video below, and if unintuitive physical effects are your thing, don’t miss [Steve]’s peeling apart of the turntable paradox.

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Boneblocker Is A Big LED Wall That Rocks

April 28, 2024 by Lewin Day 3 Comments

[Nick Lombardy] took on a job almost every maker imagines themselves doing at some point. He built a giant LED wall and he did a damn fine job of it, too. Introducing BoneBlocker.

BoneBlocker is an 8 x 14 wall of glass blocks that lives at a bar called The Boneyard. Each block was given a length of WS2812B LED strip. 30 LED/meter strips were chosen, as initial maths on the 60 LED/meter strips indicated the whole wall would end up drawing 1.5 kW. Discretion, and all that.

The whole display is run from a WT32-ETH01 board, which is a fast ESP32-based module that has onboard Ethernet to boot. [Nick] used the WLED library as he’d seen others doing great things with it, performance-wise. He ended up using one board per column to keep things fast, but he reckons this was also probably a little bit of overkill.

His article steps through the construction of the wall, the electronics, and the software required to get some games working on the display. The final result is quite something. Perhaps the best bit is his explanation of the custom controller he built for the game. Dig into it, you won’t be disappointed.

In particular, we love how the glass blocks elevate this display to a higher aesthetic level. We’ve seen other great projects tread this same route, too. Video after the break.

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