Chain-of-Thought Spoofing Targets Reasoning AI Models

Researchers [Charles Ye], [Jasmine Cui], and [Dylan Hadfield-Menell] have shown that AI Large Language Models (LLMs) can fail to correctly distinguish between different instruction sources because they prioritize writing style over metadata tags, and this role confusion leads to a powerful attack called CoT (Chain of Thought) Forgery. We’ll explain exactly how it works after a bit of background review.

Prompt injection was where “getting an LLM to do something it shouldn’t” started by exploiting the fact that LLMs communicate like people, but are much more obedient. For a while, simply telling an LLM “ignore all previous instructions and <do something funny>” yielded results no matter how transparently dumb the instructions were, and the reason it worked at all was because LLMs do not have separate data and instruction streams; it’s all one big lump of input. It’s up to the model to sort legit instructions from untrusted, user-provided data. One step towards mitigating this was the addition of roles. Continue reading “Chain-of-Thought Spoofing Targets Reasoning AI Models”

scantron

Bubbles, Belts, And Bulbs: How The Scantron Works

Many of us remember back in our school days taking tests and filling out answers on a Scantron sheet, those long rows of A, B, C, D, and E that had to be filled in with a #2 pencil. Ever wonder why it needed a #2 pencil, or what the point of using a Scantron was at all? That question is answered in the latest video from [SimonRetro], where he takes a look at the Scantron and how it works.

One of the more interesting things about the Scantron is that it’s such a standalone device. No software needed, no keypad to mess with just two rocker switches. The on/off switch is also the way you tell it to forget the last answer sheet and allow you to program in a new test. Upon booting, you feed in a Scantron sheet with some specific boxes filled in, and then it’s programmed and ready to take in and grade all the students’ answers. Opening up the Scantron reveals it’s pretty interesting inside: one control board with early-’90s-era chips. There’s also a lightbulb (no LEDs) shining through the six reading sections of the card, as well as an arrangement of belts and motors to move the card through the machine. The printer is a seven-pin printer used in conjunction with a pair of ink rollers to print out the results on the cards.

[SimonRetro] also went ahead and tried different ways to mark the sheets including pens, Sharpies, colored pencils, and different thicknesses of pencils besides the #2 to see which would and wouldn’t work in the Scantron. Thanks [SimonRetro] for exploring this machine from many of our childhoods and sharing its inner workings. Be sure to check out some of our other reverse engineering articles that explore how classic devices work.

Continue reading “Bubbles, Belts, And Bulbs: How The Scantron Works”

DIY SI5351 Radio Tunes In SW, MW, And More

There are plenty of radios you can buy that pick up MW and SW bands if that’s what you’re into. Or, you can follow [mircemk]’s example, and whip one up yourself instead.

The build employs an ESP32 as the brains of the operation. It’s hooked up to a rotary encoder and a small colour TFT screen, which displays an old-school style tuning dial for choosing the desired frequency. This setup is paired with an Si5351—a capable clock generator chip that can deliver just about any frequency from <8KHz up to 150+ MHz on command. There’s naturally a bunch of supporting analog hardware for the radio end of things, plus a NE612 mixer IC and a PAM8403 class D audio amplifier board, hooked up to a small 0.25W speaker for audio output. [mircemk] has set up the rig to act as a simple radio set, or, with the flick of a switch, it can be configured for SDR use with an attached computer.

It’s a handsome build, and one that likely proves a pleasant way to browse the MW and SW bands on a rainy afternoon. We’ve looked at other hardware in this category before, too. Video after the break.

Continue reading “DIY SI5351 Radio Tunes In SW, MW, And More”

An EInk, ESP32-based Game Boy

This is one of those projects that was both inspired and made possible by the absolute embarrassment of dev boards available to the modern hacker. In this case, the dev board was the M5Stack PaperS3, which as the name implies combines an ESP32-S3 with an e-ink panel. [Wenting Zhang] picked one up and was immediately inspired to try and make an e-ink Game Boy.

The M5Stack PaperS3 made this project possible by exposing the display with row/column control — parallel, some would call it, as opposed to the usual serial interface of SPI. That allowed [Wenting] to work some of the same e-ink magic he perfected on his Modos monitors to allow partial refresh at up to 60 Hz. That the ESP32-S3 is capable of emulating a Game Boy while driving the screen should surprise no one, since it can emulate an MSX while outputting VGA or even Windows 95 on a 386. In this case, he’s basing the actual Game Boy emulation on Crank Boy.

Of course the e-ink screen on the M5Stack is far larger and has a much higher resolution than what the Game Boy shipped with, which lets him implement touch controls and scale the image up 3X so he can fake a couple of shades of grayscale while actually outputting black and white. Even better, if he was actually playing this thing on the regular, once the high-refresh portion of the screen starts to wear out, he can flip the orientation and keep gaming on the virtually-unrefreshed control portion of the screen — doubling the lifetime of the system, something many of you raised as a concern when we last looked at a his e-ink monitor project.

The only real shortcoming of this hack is the sound. With one-bit beeps coming out of the M5Stack buzzer, it’s got nothing on Nintendo’s hardware. Of course, that’s partially down to using the hardware as-is. With the addition of an I2S sound chip like the one used in the MOD player project we featured recently, you’d just need to squeeze out enough processor cycles to make this sound as good as it looks.

Continue reading “An EInk, ESP32-based Game Boy”

Jenny’s Daily Drivers: KolibriOS 0.7.7

It’s a fact of life when starting a computer, that booting into whatever operating system you use will take a while. Mine takes somewhere around 30 seconds, and yours probably does too. There has always been the promise of something faster just around the corner, but somehow the OS just keeps getting a little bigger. Perhaps the only computer with a disk based operating system I have ever owned which bucked this trend was a Commodore Amiga, and that machine’s booting speed was achieved by keeping most of its OS in a ROM. The subject of today’s Daily Drivers takes the idea of a long boot time and shreds it, leaving an experience more akin to that Amiga of old. It’s called KolibriOS, it’s small enough to run from a floppy disk if you want it to, it’s lightweight, and fast as lightning. It achieves this feat by being written entirely in assembly language, and it exists as a free fork of the earlier MenuetOS which moved to a proprietary licence in its 64 bit version. I downloaded the ISO file, and gave it a spin.

The KolibriOS GUI with the Netsurf browser showing the KolibriOS wiki.
You can surf the web with NetSurf, but not the encrypted web.

The minimum system requirements for KolibriOS are meagre, 1Mb of disk space, 8Mb of RAM, and a 586-class 32-bit processor. On a 2020s ThinkPad it boots in the proverbial blink of an eye, and drops immediately into a GUI desktop. It has the slightly pixelated look of a 1990s machine, there’s none of the anti-aliasing we’re used to today going on there. Installed software ranges from a set of games, emulators, graphics editors and viewers, internet software including the Webview and Netsurf web browsers, and assembly software development.

The immediate impression is of a mature and useful operating system, without any crashes or blue screens, and with applications that load on a dime. Unfortunately though, despite all the competence I can’t call it a Daily Driver by my definition of being able to write for Hackaday, because the web browser doesn’t support https. Immediately the majority of the modern Internet is off-limits, including this site. This changes the parameters of my review and I can no longer proceed as I normally would, but it doesn’t end it. Something this polished deserves a while to play around. Continue reading “Jenny’s Daily Drivers: KolibriOS 0.7.7”

A Light-Up Map Of Monaco

If you want to get around Monaco, a map — digital or otherwise — is probably the best way to navigate. But if you just want to appreciate the city’s form in a more artistic way, you might enjoy [Terence Grover’s] latest project—a backlit topographic map of the unique principality.

The touch mode allows one to draw patterns across the map.

The project started with a QGIS mesh of Monaco, with the data fed through the Open-Meteo elevation API, which takes into account building heights. This was used as the basis for the heights of 179 pieces of 20 mm x 20 mm acrylic. These were assembled into a laser cut steel base, and were sanded on all sides but the base in order to allow them to diffuse light more effectively.

Strips of CS8812 LEDs are used to light the plastic towers, driven by a pair of Adafruit Feather RP2040 Scorpio boards. They’re fed pixel data from a Raspberry Pi 5, which runs a Flask panel accessed over an iPad. This allows control over the LED map display, showing things like civic data, highlighted events, and weather. There’s even a touch-sensitive mode that lets one paint fun patterns across the representation of the city.

We love a good artistic map, particularly when they’re full of LEDs and represent useful information.

Continue reading “A Light-Up Map Of Monaco”

Know Your Food: Organic Production

A few weeks ago we published the first in a new series of articles, Know Your Food. It was born out of the realisation that most people know surprisingly little about what they eat, and to apply a bit of Hackaday curiosity to received opinion on the subject. As we put it then: “To know both how common foodstuffs should be made, as well as how they are made industrially, should be an essential for everyone” We’ll continue in that vein, with a look at organic food.

If you buy your food in a supermarket it’s likely that in the vegetable aisle you’ll be presented with a choice. On one hand you will have the normal vegetable, and on the other and usually for a slightly higher price, the organic version of the same vegetable. What’s going on?

So What Is This Organic Stuff All About?

A watercolour picture of a bucolic scene with a farmhouse surrounded by trees, and some cows in the foreground.
It is unlikely that a typical organic farm in the 2020s will resemble this John Constable painting. John Constable, Public domain.

Organic production is a system of agriculture that emphasises natural fertilisers, pesticides, and farming methods over synthetic or intensive ones. It has its roots in the first half of the 20th century, and as the decades progressed it has become an important sector of agricultural industry. I grew up steeped in organic agriculture because my grandfather was an early adherent in the years following the war, so I’ve seen it from the sharpest end. There is a lot to commend organic production for and plenty of reasons to embrace it, but with that come some problematic aspects, and even dubious claims. Here I’ll try to unpick some of that.

It’s tempting to believe that all organic production is somehow a return to a 19th century rural idyl, complete with the obligatory chickens in the farmyard. Some organic producers do take a slice of this back-to-the-land approach to their craft, but the reality of organic farming is a very modern approach to managing the ecosystem. Organic farmers are not wary of progress, and neither are they reluctant to use pesticides or other chemicals. Instead they do so according to the principles of organic agriculture, so any techniques they use are designed to be beneficial to the ecosystem, and any chemicals have a natural origin. Continue reading “Know Your Food: Organic Production”