Is That An EMP Generator In Your Pocket Or Is My Calculator Just Broken?

Ah, what fond memories we have of our misspent youth, walking around with a 9,000-volt electromagnetic pulse generator in our Levi’s 501s and zapping all the electronic devices nobody yet carried with them everywhere they went. Crazy days indeed.

We’re sure that’s not at all what [Rostislav Persion] had in mind when designing his portable EMP generator; given the different topologies and the careful measurement of results, we suspect his interest is strictly academic. There are three different designs presented, all centering around a battery-powered high-voltage power module, the Amazon listing of which optimistically lists as capable of a 400,000- to 700,000-volt output. Sadly, [Rostislav]’s unit was capable of a mere 9,000 volts, which luckily was enough to get some results.

Coupled to a spark gap, one of seven different coils — from one to 40 turns — and plus or minus some high-voltage capacitors in series or parallel, he tested each configuration’s ability to interfere with a simple pocket calculator. The best range for a reset and scramble of the calculator was only about 3″ (7.6 cm), although an LED hooked to a second coil could detect the EMP up to 16″ (41 cm) away. [Rostislav]’s finished EMP generators were housed in a number of different enclosures, one of which totally doesn’t resemble a pipe bomb and whose “RF Hazard” labels are sure not to arouse suspicions when brandished in public.

We suppose these experiments lay to rest the Hollywood hype about EMP generators, but then again, their range is pretty limited. You might want to rethink your bank heist plans if they center around one of these designs.

39 thoughts on “Is That An EMP Generator In Your Pocket Or Is My Calculator Just Broken?

    1. (@Kilian)
      There have been videos around demonstrating (Chinese) locks can be glitched with EMP. The most notable issue is the locks first do a self test, opening and closing the lock after each power up. So crashing these locks will open the door. Electronic locks (cost < €250) are usually quite poorly designed.

      There are other examples that show glitching 'request to enter' intercom systems but I've yet to see the attack verified. It's quite easy to fake but quite hard to test.

      1. I should imagine many of the request to enter locks would be almost impossible to open with a low power emp of this sort. Mainly due to the deign of the locking mechanism itself being an electromagnetic catch.
        Something that could output a large static magnetic field and being properly positioned, might be better suited, essentially causing flux redirection and weakening the holding force such that the lock could be forced open.
        Not something I’ve ever bothered to try but theoretically possible.

        1. > I should imagine many of the request to enter locks would be almost impossible to open with a low power emp of this sort.

          High power to open lock is meaningless when lock unlocks itself temporaryly during reset. I had such problem with one iot device which could be misappropriated for using with garage doors and gates, but occasionally it would lost connectivity and reset, causing gate to open. Good thing we discovered it during beta tests and those dogs which were released by accident didn’t bite anyone. We had to exchange several emails with manufacturer before they admitted that their module indeed drives output for 100ms after reset. It’s enough to send “open” signal to gate.

          1. Man I want to hear the rest of this story, I hope you mean actual dogs and not that you worked for a kindly old man named John Hammond who had a bad day with some locking systems ;)

    2. EMP as demonstrated are not that hard to build. I find it a bit sad that the designs are still build with 90’s technology with very little control over the output. I would appreciate if someone could add more modern, better controlled designs. What ideas and tools can we use from the solid state Telsa coils for example? Surely there must be a better way.

      1. The lucid science disaggregator is a good example. On the site, he mentions that his system can *kill* laptops and digital cameras from a fair distance, and he had to move his lab to a distant storage unit to avoid killing the neighbors’ electronics and record his sessions from a makeshift bunker. And still killed his laptop and camera.

        My hackerspace got a donation of a couple dozen old portable defibrillators, which they didn’t want and were going to throw away, and which I grabbed. This gives me about 2 dozen really high quality pulse capacitors of 2,000 volt rating at 100uF. High quality capacitors use special construction and silvered wire/electrodes for fast discharge, and are rated for fast discharge without damage. Or so I’ve read.

        I’ve often daydreamed about using the capacitors to build a Marx generator like the disaggregator in the link, and I’m pretty sure it would kill electronics in a fair range and be dangerous as hell, and probably could be charged up with lithium batteries for “back of a van” portable.

        I haven’t done that because I don’t have a use for it and I’m not a James Bond villain.


        (I’d be happy to trade or sell the lot. I need some power electronics in the 100 watt 10 MHz range which I’m struggling to design, so would be happy to do trade-in-kind. Contact me on .IO if interested. Note that what I need is not any type of standard ham power amp or other kit, so actual design would be needed.)

      1. WIsh people stop using the term ” taser ” !
        An actual ” taser ” (now Axon) is a carefully calibrated and very precise waveform – NOT – a random voltage pulse !

    3. Electronic door locks are “Energize coil to open” so.. with the electronics fried the door would stay locked,

      Fire exits are energized to stay locked but are only able to be opened from the inside. So with the electronics fried you couldn’t get in but in an emergency the occupants could get out. There is an opportunity for an inside job breach however the security system would probably be unaffected so get ready for the security guards.


      1. The sad thing is, sometimes you don’t need to fry the electronic lock, you just to crash it causing it to power cycle and do a self test, which *hopefully* performs a self test (i.e. lock/unlock sequence during boot).

  1. My guess is, that the keypad of the doorlock or the electric components of the locking/unlocking mechanism might be disabled and the door would stay in whichever state it was before? (locked / unlocked)

    1. lol

      my first job out of high school was in a game arcade

      little snot bags used to “zap” the coin door with piezio lighter guts or stove igniter mechanisms

      I put a small ceramic capacitor between the metal of the coin door and the slam switch

      I was not popular

      which is why god invented 12″ shifting spanners…

  2. Next on the agenda, pocket sized coil compression emp. Imagine what will happen if someone creates a mechanically stable superconductor that can operate at the temperature of liquid nitrogen or dry ice.

      1. Yes that depends on the specific scenario. At the involved wavelength, a distance gain in the ballpark of two-digits needs a physical huge or complex antenna system. A directivity as found in lasers would increase the range remarkable. It’s a pity that something the size of an ordinary laserpointer won’t work here.

  3. I’d love to know if static generators would work similarly to EMP. I remember how my computer/monitor just flips itself off during those cool and dry winter days.

  4. This: “Explosively Pumped Flux Compression Generator.”[1] Excerpting: “An explosively pumped flux compression generator (EPFCG) is a device used to generate a high-power electromagnetic pulse by compressing magnetic flux using high explosive. An EPFCG only ever generates a single pulse as the device is physically destroyed during operation. An EPFCG package that could be easily carried by a person can produce pulses in the millions of amperes and tens of terawatts.”

    The rest of the article goes into a lot more detail. These chemical EMP generators can be made into bombs, put onto missiles, even fired by artillery. A bomb or missile sized device can take out the grid of a large city – no nukes needed.

    1. Explosively Pumped Flux Compression Generator

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