Scrambling Pocket Calculators Made Easy With EMP Box V2

[Rostislav Persion] has for some time been interested in making small, portable EMP devices capable of interfering with nearby electronics. In these EMP devices, high voltage is used to create a portable spark gap generator, whose operation in turn creates electromagnetic pulses capable of resetting or scrambling nearby electronics such as pocket calculators.

Bridging adjacent holes narrows the spark gap, resulting in more frequent pulses.

His original EMP box designs relied on spark gaps constructed from metal screws threaded into a clear plastic insulator, but this newest design ditches fussy screw adjustments and relies on perfboard. By cutting out a single row of plated perfboard holes and soldering the high voltage terminals to each end, the empty holes in between form the essential parts of a spark gap.

It’s even adjustable: one simply bridges adjacent holes with solder to effectively decrease the gap. As for generating the high voltage itself, a DC voltage multiplier from Amazon takes care of that. Watch the device reset some calculators in the short video below.

Looking for high-voltage experiments that aren’t so sketchy? Get yourself a Van de Graff generator, some metal balls, and a little bit of oil, and make some art.

47 thoughts on “Scrambling Pocket Calculators Made Easy With EMP Box V2

      1. It is a broad spectrum signal. So the power is low. But GPS signals are weak yes, but I think the emp would not reach far.

        A jammer made for making noise on the right frequency will reach further. Some just adds more to the background noise, but I think if you got a jammer that actually sends out pseudo random data with the right modulation on the frequency will reach even more devices.

  1. I would love to see more DIY jammers and EMP. They’re critical in modern conflict, but the technology available to civilians is lacking. I wonder how this basic design could be improved, some kind of antenna or reflector? Adjustable capacitor for frequency tuning?

    1. > I would love to see more DIY jammers and EMP. They’re critical in modern conflict

      Military/industrial appliances are well protected against EMP devices, at least the ones not involving the use of nuclear power. If you build one of these toys, you have zero chances to use them effectively in any conflict against even the crappiest military, including the police, but can severely harm people carrying medical devices that for size and weight reasons cannot be properly screened. Please stay away from these “projects”.

        1. As a millwright I can say with absolute certainty that this project is dangerous around pacemakers.

          Solid state magnetic motor couplings are dangerous enough, an EMP…

          Might wanna do your homework before you dismiss safety precautions out of hand.

          1. What about being a millwright qualifies you to say ‘boo’ about this?

            Similar statement: As an Electrical Engineer I can say with absolute certainty that pushup bras are dangerous when cup size is above F. You should never be under a dangerous load on a lifting device.
            It’s not wrong, but the qualifying phrase is irrelevant.

            I remember building a spark gap generator with my 100 in 1 electronics kit in middle school. Used it to annoy my big sister. Worked like a charm.

  2. if some clown sets off my implanted defibrillator with this or a similar device then if I cause them to cease to exist it will be justifiable homicide. Things like this can be very dangerous.

    1. Lets expand this by listing commonly types of functional electrical stimulation technologies: cardiac pacemaker, implantable cardioverter-defibrillator, cochlear implant, urinary bladder control, diaphragm pacing, fecal incontinence control and myoelectric prosthesis. And insulin pumps. (Did I miss something?)

      So chance to meet a human that might react to EMP are quite high.


    2. Shouldn’t all those implanted medical devices be well shielded and protected from electromagnetic fields? Considering this is a lot a stuff wireless connected to the internet. RC toys. It’s not just a stay away from microwave ovens thing anymore. Rules on paper, don’t make it safe.

      Most of these EMP devices only have a range of a few inches. Just knowing that, and why, will be a dream-killer for most. Discussing these sort of things, point out undesired consequences, and limitations. The potential, and the vast variety of electronic devices to mess with. Wouldn’t you think that a portable EMP would have been done to death by now? Who hasn’t had a loud neighbor?

  3. I can see why people would want to do this, but I really hope they don’t make a habit of it.

    1. It’s a radio transmitter.

    2. I do know several people who have implanted pacemaker and defibrillators, to whom devices like this are potentially dangerous.

    3. Properly shielded and suppressed devices probably aren’t bothered, but these have become more the exception than the rule.

    4. If you want to see a proper ESD testing gun:

  4. I’m typically against not covering stories because they’re dangerous, but this crossed a line. These are ready-made portable units explicitly for interfering with devices, and as far as I know this isn’t for any research purposes. It is of course a fool’s errand to try to hide information about spark gap transmitters, but this is as accessible as a how-to article, including what you need to buy and where. I’m almost certain that the author and HaD are criminally liable for people following this design, at least in the US.

    1. Eh, don’t be such a baby. Dabbling in dark arts responsibly is part of being a hacker. Devices like this have lots of uses, like bypassing electronic locks, and interfering with MCU security features. It only has a range of a few inches, so its hardly a weapon of mass destruction. He even put warning labels on them.

      1. Popular Science had a diagram on how to theoretically build a large emp in the 90’s.
        Had a large coil charged by caps and an explosive charge to rupture the coil to release the emp.

  5. Surely this would be a lot more effective with a tesla-coil style resonant circuit ?
    On the spark gap side, a spark plug is probably a longer-lived device than a bit of perf board. For EMC testing of engine controllers we used to put them in a pressurised but not rf-proof cylinder (a very thick glass wall).

  6. This seems quite interesting for noise immunity testing of self built electronics. Having a built-in distance measurement would be a nice addition for this. Maybe a time-of-flight sensor works (as long as it does not get destroyed by the pulses themself), or maybe just a simple plastic slide out ruler

  7. I think I remember reading making an actual EMP device is highly illegal as they are baffingly classified as weapons of mass destruction, in the us and Canada at least, nothing to stop people in more sensible countries experimenting

    But let’s face it, regarding armong the civilian population, we are pretty much hopelessly outgunned and out equipped at this point. An armed uprising would be a bloodbath no matter how you work it

    It could be argues there is a sort of equilibrium, and the government will engage in as much oppression as they can get away with. On that case more armaments of various kinds, preferably of a non lethal character of course, could make sense, merely helping to hold back the tide of disaster slightly, but that has benefit.

  8. As a ham radio operator, i have questions. I can hear the FCC compliant transformer at the end of the street, and a lighting strike a thousand miles away. I’m not sure how dangerous this is, but it is certainly harmful to the rf spectrum. Sure, the FCC doesn’t actually enforce its rules, but that doesn’t mean this sort of thing isn’t harmful.

    You aren’t only disrupting hard to disrupt things near by with the EMP, you are also disrupting easy to disrupt things far away with the RF. Utility monitors, medical pagers, etc. That will be easy to find using radio direction finding, if not used incredibly sparingly.

  9. The Calculator turns back on and still displays 0 which makes me believe that this EMP is not really all that effective because a truly damaging EMP would erase the devices firmware that’s imbeeded inside the device and with it all functionality of the device.

    In simple terms. The EMP didn’t brick the calculator it only interupted its power supply so I wouldn’t say it scrambled anything.

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