21st Century Cheating: WiFi In A Calculator

Obviously, we would never endorse cheating on an exam, but sometimes a device is just too tempting to be left untouched. For [Neutrino], it was an old Casio calculator that happened to have a perfectly sized solar panel to fit a 128×32 OLED as replacement. But since the display won’t do much on its own, he decided to connect it to an ESP8266 and mount it all inside the calculator’s housing, turning it into a spy-worthy, internet-connected cheating device, including a stealthy user interface controlled by magnets instead of physical buttons. (Video, embedded below.)

Editor’s Update: Please read our follow-up coverage to the copyright claims made against this project. The video linked above and embedded below are unavailable due to these claims, despite widespread belief that this project does not violate copyright. For now, the original video is available via the Internet Archive.

To achieve the latter, [Neutrino] added two Hall effect sensors and a reed switch inside each end of the calculator. Placing a magnet — possibly hidden in a pen cap — near the reed switch will turn the display on, and placing another magnet near the Hall-effect sensors will navigate through the display’s interface, supporting two inputs with long, short, and multi-tap gestures each. To obtain information through WiFi, the ESP8266 connects to Firebase as backend, allowing to set up predefined content to fetch, as well as a possibility to communicate with your partner(s) in crime through a simple chat program.

As the main idea was to keep visible modifications to a minimum, one shortcoming is that charging the additional battery that powers the whole system would require an additional, external charging circuit. But [Neutrino] had a solution for that as well, and simply exposed two wires to the back, which could easily be mistaken for random solder splatters. And well, of course, requiring WiFi might also be tricky in some situations, so maybe you might want to consider a mobile network upgrade for yourself.

41 thoughts on “21st Century Cheating: WiFi In A Calculator

  1. I might have replaced that OLED display with something that didn’t light up. It’s not exactly inconspicuous.
    Shame he couldn’t have replaced the calculator display with something that could display text.

    1. If you get real clever with polarisers there’s probably a way to have a text screen visible under the calc screen as long as you’re wearing the special glasses with the right filter.

      1. You can just remove the polariser film from an LCD can’t you?

        Explaining why you’re sitting your exam wearing shades is left up to the motivated cheater.

  2. Nice! Maybe one day we will hack the damn high schools altogether and stop grading students by their ability to remember information. Information they will completely forget after the exam anyways. Kudos to this guy for doing real learning.

    1. Shh. We clearly only need to educate the masses to work in a traditional, 1950’s style business environment and screw any advice about changing things to try to better reflect changes brought on by all sorts of technology or time or new generations.

      Obviously the only way to measure the merit of a student is to ensure they memorize the most important things like formulas that don’t change and that you can just look up or their ability to calculate things by hand instead of with evil assistive technology like a calculator or memorizing the most important things like the exact date that a historic event happened rather than the contextual merits of the event itself.

    2. The hardest tests I ever took were open book tests in grad school. I think it’s fairly time consuming to write a challenging open book test that can feasibly be completed in an hour or so, but I noticed it really widened the distribution of scores and separated those who understood the material enough to find and apply the right equations and concepts quickly enough to complete the test from those who didn’t. I doubt most teachers are willing to sink that kind of time into test development, so it probably becomes easier to have closed book tests to try to separate those who understand the material from those who don’t.

      1. my best professors gave open-book exams that were impossible to finish in the allotted time. The goal is to measure performance and you can’t do that if people are finishing the exam because you don’t know how good they really are. Of course they are graded on a curve so that 57 you got just might be an A.

      2. I had the same experiences with my undergrad organic chemistry and biochemistry courses. FWIW, the hardest final exam I ever took was a take-home final in my undergrad organic chem course. I think it took close to a week including collaboration with other students (collaboration was encouraged by the professor – “What researcher would lock his or herself in a room with no resources?”).
        I gave my nursing students open-book exams where I could, which they generally hated… For some reason they also didn’t appreciate essay questions in pathophysiology – that they had to correctly explain fundamental physilogical processes gone wrong meant they needed to understand them.

    3. History is mostly about memorization. The trend toward not memorizing parallels the worsening knowledge of American and world history, which in turn leads to today’s horrid political beliefs.

      1. do you remember (!??!) the guy in the movie “The Graduate” who could memorize everything instantly but he had no analytical skills? He made it all the way to Harvard Law before he washed out.

  3. He could have wired the recharge pins to the screw holes. It would require more skill than I have, but would be invisible. Or let the charger wires inside the calculator. To recharge you open the case, and charge. No need to charge it at school…

    1. It’s a clever piece of engineering, but when I was in school, I had no time or resources for that sort of thing. It was easier to just study for the test. Managed to get my EE degree without cheating.

        1. If I’d been any good at cheating, I probably could have gotten better grades.
          I know my limits…and I’m a terrible criminal. It’s easier for all concerned if I’m honest :-)

          (I wish I could be an evil politician, I’d be a lot richer by now…I just don’t have it in me)

      1. “easier to just study”
        Yeah, that’s always the funny thing: the real cheat is to just program all the answers into your own brain. The teacher will never catch that kind of cheating!

        Although I’ve found that most of the time, cheats and hacks are not about saving effort. Paradoxically they require quite a bit more ingenuity and motivation than just cramming and taking one’s education seriously. Haven’t you ever wasted an hour to save five minutes before? Or spent way more on building your own thing instead of buying it ready-made? In a way, that isn’t the point.

  4. I made a very similar device in 2018. It also had an SSD1306 based OLED display, with an ESP8266 – 01 bitbanging I2C, and handling a button. I created everything, from the I2C bitbang driver, OLED driver, custom memory optimised font map, everything. I created it to resemble a smart watch. I then wrote a custom protocol and its server application on my android smartphone to serve the text on my cheating “smart watch”, using a hotspot. Turns out an ESP consumes a LOT of power, so with everything done, the project was stopped right in the tracks by the unavailability of a suitable battery. I used ESP_NONOS_SDK.

    After watching this project’s video, I really think I had no reason to reinvent the wheel by creating my own font map, or drivers. I often forget how easy it is these days to create anything with Arduino and all the libraries it offers.

  5. The Adeptus Mechanius would NOT ONLY approve they would ENCOURAGE him to install it into a limb.

    Ancient B.C. Accountants going to their exam with Counting Trays and BEANS.

    Guy shows up with an ABBACUS!


    Anyone have a Casio Nspire without the CAS? I have GREAT news for you.

    Sorry, there is no MATLAB or Wolfram Alpha clients for you though.

    Doesn’t matter if you “show your work these days” the ingant masses sitting next to you will say you are writing some sort of manifesto.

    And his Mod with Magnets to his Calc will get him blasted by the Air Marshall. (Aka it’s a “remote det”)

    Never underestimate the envy or stupidity of the masses.

  6. My suggestions :
    1. Add a camera from aside.
    2. Use some big but darker display which replace the main display.
    3. Replace the keyboard board with some navigation scheme, which trigger on specific key, else simulate normal calculator.

  7. Could have easily had both devices share the calc display and the buttons. Have the ESP8266 power the calculator too. Secret combo press has the ESP8266 take over the display via powering down the calculator, just run the lines in parallel.

  8. Ah, good old original Timex Datalink, got me through some examinations at the time, especially physics and hydraulics. Probably still have it a drawer.

    I had a single teacher at college that had an exam with text book consultation. I was the only one with the 3 volumes duly annotated and got a small appraisal from him for it. Can’t remember how the score went though 🤣

  9. Ah!! I remember a very similar project i had like… 13 years ago, where i scraped all of the inside of the calculator leaving nothing but the case and keypad, replaced the screen for the typical 2row green display, and tried to fit an arduino mini. The input used a (resistive?) touchscreen from some chinese site, that would catch the keypresses against it and decode based on coordinates, allowing to use the original keypad of the calc. Of course, any real capability of calculation was removed lol

    Never got to real have it working thou, my electronics & soldering skills were not at their best, but i did procrastinate a lot of time, and isn’t it what we want when aproaching finals? :P

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