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.


48 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.

      1. I worked in Public School K-12 IT for a handful of years, I watched laptops, iPads, and chrome books enter the classrooms during my tenure – none made any significant impact on teaching methods – all were used to let kids watch videos (after getting their devices and headphones sorted out) instead of watching a filmstrip or video on a classroom screen w/o headphones…progress!

        Anything with a browser in the classroom is more a distraction than a tool for learning.

        My favorite example was one time I was talking to the head librarian in a HS library, behind her was an assistant librarian using a screen view tool to scan the screens on the library computers to enforce usage guidelines. While talking to the librarian, the assistant called up a screen and a student was flipping through screens of women in underwear bras and pantries), the librarian skipped on to the next screen. I asked the assistant librarian to go back, and she put up the screen with the women in underwear, and I asked her if that was OK? She asked “what do you mean?” I said, I presume the school usage policy says something about calling up such images on a public computer in the library, she replied “I have no idea.” I asked, then why are you doing that, looking at everyone’s screens? She replied she was looking for broken computers.

        Turns out the librarians were reluctant to enforce school district usage policy, they opted to only enforce those rules that made their jobs easier.

        The limiting factor in education reform is the teacher – they Generally don’t want to adopt anything that will make their jobs harder.

    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.

        1. The problem with grading on a curve was that everyone’s score is relative To the best score in the room. I’ve taken those ball-buster ‘graded on a curve’ exam in college, I didn’t like it, the OCD in me couldn’t handle not being able to finish the exam.

      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.

        1. When I was a student in college, the most annoying students were pre-nursing school students. It seemed like every time a professor would introduce a new topic their hands would go up and they’d ask “Will this be on the test?”

          My college didn’t offer nursing degrees, so students struggled to get the best possible grades, to help them transfer to one of the better nursing programs.

          The frustrated professors typically just said the same thing each time – “Anything we discuss in class can be on the exam”.

    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.

    1. TI85 had a bug that allowed upload of Z80 code via a backup restore cable. Small program to emulate the factory reset screen and trap the hard reset button sequence, et voila!

  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

  10. My college calculator hack was swapping the guts of a ti-83 with a ti-89(the old squared off versions). My college wouldn’t let you take exams with anything but a ti-83 or ti-83 plus. The 89’s can solve algebraic formulas, do derivatives and integrals, basically everything you need to double check answers, and find small mistakes in a large problem.

    It was a little difficult to get everything in the case, and while the keypad spacing is the same, different keys are in different places. At first I moved the correct keycaps to the correct positions, but it looked obviously different next to a real ti-83. So instead I used a little printout of the ti-89 key positions to help me memorize which keys were out of position.

    I still did the work and learned the material, but my stress levels during exams went way down. When you’re doing an 18 step problem that covers several pages, it’s nice to be able to quickly check that you didn’t mess up one little bit that will throw the answer off and make you lose 20 points.

    The better hack using today’s tech would be to replace the screen with something you can drive with a Pi Zero W, then run a modified TI emulator that can pull step by step solves from Wolfram alpha.

    I knew people who did all of their class assignments by copying the Wolfram ‘step by step” solutions. Some of these idiots got caught when my professor designed some problems that Wolfram solves using linear algebra, and these dopes still copied the answers, despite having no way to explain how or why they solved the problem using methods they haven’t learned yet.

  11. No cheating discussed here, but I thought you all might be interested in the effects of a technology change.

    When I was in college working on my Aerospace engineering degree, scientific calculators were just coming on the scene. Since our tests were designed with a slide rule in mind, I could usually complete them using my trusty Dietzgen Log-Log (which I still have). Where I was getting hammered was that the students with calculators were able to finish faster and had time to go back and check their work to eliminate stupid mistakes.

    As a poor GI-bill student, I couldn’t afford the then new HP-35 at almost $400 (about $2400 in today’s dollars). Even when Texas Instruments brought out the SR-50 at $170 (over $1K equivalent) it was still beyond my reach. Finally, I found an SR-50 on sale for $115 and grabbed it. My GPA improved considerably because of it and I eventually managed to graduate.

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