Teachers Beware: This Calculator Mod Makes Cheating Ridiculously Easy

When I was in high school, all students were required to own a Texas Instruments TI-83 graphing calculator. That wasn’t an arbitrary decision, it was a deliberate choice to ensure that students could follow along with lessons and to help teachers prevent cheating. Of course, we were mostly just happy that we could share games with our friends via the link cable feature. But that same functionality is exactly what gave ChromaLock the ability to design this mod for TI-84 calculators that makes cheating ridiculously easy.

This mod works with TI-84 Plus Silver Edition and TI-84 Plus C Silver Edition graphing calculators. It gives the calculator access to the internet and a handful of tools that would be useful for cheating during exams. For example, there is an applet for talking to ChatGPT, another for displaying stored images (such as formulas), and another for chatting with smarter and more studious friends. And best of all (or worst of all, depending on your perspective), it is very difficult for teachers to detect or disable. Suffice it to say that ChromaLock just gave the cheaters of the world a valuable gift.

The mod hardware is actually very simple and consists of a small PCB with a handful of resistors, a level shifter, and a Seeed Studio XIAO ESP32-C3 development board. That fits inside the calculator’s enclosure and connects to the same link cable jack that we used to transfer games. When one of the aforementioned applets needs something from the internet, it sends a request to the ESP32 through that jack. The ESP32 then connects to the internet (through a hotspot or Wi-Fi network), finds the information, and returns a response.

But to prevent cheating, teachers often clear students’ calculator storage or put those calculators in test mode to prevent the use of unauthorized applets. That’s why ChromaLock’s mod is particularly clever: it bypasses those anti-cheating techniques entirely.

The modded calculator doesn’t have to start the test with any applets installed. It can also be in test mode. The unscrupulous student just has to remember a short passcode. When they send that passcode over the link, the ESP32 will automatically respond by transferring all of the necessary applets—just like if you were receiving a game from a friend. So, the student can start an exam with a “clean” calculator, then retrieve all of the applets they need to cheat to their heart’s content.

I honestly feel bad for today’s teachers, because I have no idea how they can fight this kind of ingenuity. The only answer is probably to stop students from using their own calculators.