World War I Coded Message Appears Cracked, Finally

When you think of wartime cryptography, you probably think of World War II and Enigma, although there were other famous codes used during that war. But in fact, there have been codes used through wars and in peacetime for much longer. Even the Romans used codes. Of course, World War I, or The Great War, as it would have been known, had its share of codes and, as you might expect, most of these have been broken long ago. Most of them. But apparently an AI model, GPT-6 Astra, recently cracked one that was previously undeciphered.

If you aren’t up on century-old cryptography, the ADFGVX cipher appeared in 1918. It began as ADFGX, but after a few months grew an extra letter — and a larger grid. The letters were chosen because their Morse-code patterns were relatively easy to distinguish: A, D, F, G, V, and X.

The original ADFGX version used a 5×5 grid containing the alphabet, usually merging I and J. The later ADFGVX version expanded this to 6×6, making room for all the letters and the digits as well.

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Reverse Engineering A Sony Car Stereo LCD

For his own reasons, [Jose Luis Monteiro] (aka [emsyscode]) decided he needed to drive the LCD on a Sony CDX-A250 car stereo’s front panel using an Arduino. There’s probably a sweet project in the works, or perhaps he just wanted to see if it could be done. Either way, more power to [Jose], because he totally pulled it off and put the results up on GitHub for all to enjoy. There’s also a project video showing how he did the reverse-engineering, which you can see below.

The driver for this diminutive LCD is a chip obviously labeled LC75826W, and that’s what the Arduino ends up talking to. Thankfully, there was a datasheet available for that part, which gave [Jose] a great starting point for figuring out how to use it. While [Jose] is working with the LC75826W driver, he’s quite explicit in his GitHub repo that this repository is not a driver library for that chip. The code only targets the specific LCD on the CDX-A250 head unit. Still, if you’ve got a different oddball LCD that uses this driver, [Jose]’s code is a great place to start, and since it’s under an MIT license, you can fork to your heart’s content.

Kudos to Sony for not obfuscating the part or using a chip-on-board black blob — you can reverse-engineer an LCD driven by one of those, but it’s a lot more work. If you’re wondering how and why those black blobs come to be, we’ve got you covered.

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A Bandpass Filter Pulls In The Signals

It’s an unfortunate side effect of proximity to a large transmitter that the received signal can overload a receiver’s front end even when tuned to other frequencies. [Rfrht]’s had this problem with nearby FM broadcast transmissions overloading the 2 metre and 70 centimetre amateur bands. The solution?  Design and build a bandpass filter. This allows the signals you want to pass through while rejecting or attenuating out-of-band frequencies. The resulting PCB is very nice indeed.

On board, aside from the filters themselves, are a low-noise preamplifier and relays to switch between receive and transmit. Everything is controlled by logic-level signals. All components are surface-mount, and the PCB layout clearly takes special care with RF routing.

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The guts of the server, with lots of sticks of DDR3, and not a single GPU in sight.

No GPU, No Problem: Flagship LLMs On A GPU-less Teenaged Server

There are lots of reasons to run LLMs locally, from privacy concerns to just wanting to futz about with the technology, but if you want to run the big models, the standard logic is that you need big money for lots and lots of VRAM. [MattMo] is calling that into question with his recent video — embedded below, naturally — in which he gets GLM 5.3 Flash, Qwen 3.8 Flash and Qwen 3.8 27B all running on a 14-year-old server without a single GPU.

The secret, if you can call it that, is that they aren’t running very fast: four tokens per second was about the max. Those four tokens are excreted from the twin Xeon processors of the vintage Dell PowerEdge R720 server, with the models living in its 348 GB of DDR3 system memory. That’s enough even for the largest flagship models, but as you can see by the speed, things are a bit bottlenecked by having only 20 threads available between the two processors. Said processors are also old enough to lack certain instructions that might have helped speed things up. Still, [MattMo] argues in the video that this is more than just a dancing bear: there are workloads where batch-processing at 4tps might make sense, and there are people who already have servers of this class laying around in their homelabs. The intersection of that Venn diagram is probably pretty lonely, but if that’s you — hey! [MattMo] says it’ll work, so give it a shot.

If you had to buy the hardware, well, it’s also quite reasonable on the second-hand market, with [MattMo] estimating about $600 given prevailing prices. He also points out that the newer models may still get some optimization to improve speeds, but don’t expect real-time conversations with Hal 9000.  Still, in terms of local LLMs, it certainly beats the pants off toy models running via Llama on the PSP or the C64.

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Teardown And Repair Of An Insoma Water Timer

Water timers are nifty devices that can water the lawn at set times or keep that vegetable garden from turning into a dustbowl. When [electronupdate] timer refused to output water on any of its three outlets, he did the right thing. Instead of angrily checking the warranty on the sodding thing, he tore it apart to attempt a repair.

As expected, the design of these devices is quite straightforward. Three solenoids control whether an outlet is open or closed. A control board also handles the user controls and display.

There was no obvious sign of damage, and the PCB was potted in a white substance that should have kept out any moisture. A quick check with a battery revealed that the three solenoids also worked just fine, so the cause likely was somewhere on the — potted — PCB.

These solenoids are rated for 6VDC and take about 20 ms to act, but on an oscilloscope capture it was plain to see that the board was only putting out around 2V. This wasn’t enough to drive the solenoid, raising the question of what had gone wrong on the controller board and setting the stage for some fun epoxy potting compound scraping.

A good bit of elbow grease revealed the control ICs, the H-bridges that drive the solenoids, and the rest of the circuitry, including a power boost circuit with a big electrolytic capacitor. The latter had a bit of suspicious liquid near its base, which turned out to be the culprit. Perhaps the most annoying thing here is that this electrolytic capacitor had the temerity to fail after only four months of use, but at least it was an easy enough fix.

If we had been in there, we might have been tempted to avoid many future battery changes. Impractical, but we wonder if anyone ever built a water timer with a water clock?

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Laser Your Way Into Debug Mode On The RP2350

The RP2350 is actually a pretty secure chip, all things considered. It has secure boot, ARMv8’s TrustZone to split secure and non-secure execution, and you can permanently disable debug — the Pi Foundation even included glitch detection, meaning the traditional ‘zap the chip until it obeys’ technique is blocked. That’s why the [Ledger Donjon] security team went full Bond Villain and strapped everyone’s favourite fruit-flavoured microcontroller to a table with a slowly-approaching laser beam.

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A Hotspot Becomes A Handheld

A Linux handheld computer is, in theory, easy and inexpensive given the availability of single-board computers, but in practice the budget invariably edges well into three figures. There’s an interesting alternative from [bkovac] that won’t break the bank as much, using a cheap 4G wireless hotspot, an iPhone USB keyboard case accessory, and, though a cheaper display could suffice, a fancy Adafruit Sharp memory display.

The hotspot is available from AliExpress for around 20 dollars/Euros/pounds, and it’s referred to by its model number, MF800. It’s powered by a Qualcomm MSM8916, also known as the Snapdragon 410, which you might have found in a budget cellphone early in the last decade. Importantly, though, it’s supported by mainstream Linux, and while it’s by no means the fastest on the block, it can be a poor man’s alternative to a Raspberry Pi. It comes with a small SPI display, but this project replaces it with a much bigger Sharp SPI memory display.

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