Controlling Muscles With High Intensity Magnetic Pulses


We’re not quite sure what’s going on with our fellow hackers lately, but they all seem quite interested in finding inventive ways to scramble their brains. [Ben Krasnow] has put together a pair of videos detailing his experiments in transcranial magnetic stimulation, a process that looks like it would go quite nicely with the Brainwave Disruptor we showed you just yesterday.

Instead of building a coil gun with a set of supercapacitors he had on hand, [Ben] decided to build a magnetic coil that can be used to stimulate his brain through his skull. Once his capacitor bank is charged, a high current pulse is sent through the coil held against his head. This pulse generates a strong magnetic field in the coil, which in turn produces neuron stimulation in his primary motor cortex.

Be sure to watch both videos embedded below, as the first one mostly covers the theory behind his experiments, while the second video gives us the goods.

[Ben’s] day job involves working with professional grade TMS devices, so he has some experience with this technology. Before you try this on your own, be sure that you are doing this safely, because a misdirected pulse of 1700 volts to the head does not sound like a fun time at all.



67 thoughts on “Controlling Muscles With High Intensity Magnetic Pulses

    1. Barring the outright destruction of cells from to sharp a focus the worst case scenario is probably a grand mal seizure… I wish I had the electronics knowledge to build something like this so I could work on the coil configuration. May something similar to a Gamma Knife would allow a lower voltage to be used.

  1. What would it take to build a power source that could be discharged a a rate of 17Hz or higher? It could be synced to an EEG and with refinements to the coils focus could produce highly neat effects.

  2. Why not just stick a butter-knife into an electrical socket? I’m sure it stimulates the brain as well.

    If I have a kangaroo pouch orifice cut into me to smuggle food out of buffets, is that worthy of hackaday?

  3. Electro-shock therapy without insurance? You bet!

    j/k I think this is a wee bit dangerous for the average person to tinker with. Just my opinion. But if any of you end up curing disease or coming up with mind-control devices based upon this sort of apparatus, I didn’t warn you. :D

  4. Geez, what’s happening here in HAD ?

    More and more Darwin Award entries ?

    What next, an Arduino controlled .357 revolver
    with randomized solenoids to pull the trigger and
    play Russian Roulette with ?

    Oh wait, I better not give anyone any ideas…

  5. I am really disappointed with the comments so far. How does this warrant a Darwin award? This guy does things like this for a living, so I am sure he has a lot of knowledge on the dangers of focused magnetic fields on areas of the brain.

    It also seems that he has a large amount of proper electronic tools, such as a few oscilloscopes, a proper work bench with good lighting, it seems he insulated the wire that goes to the coil well, so I presume that he also has knowledge on high voltage safety.

    I am sure as hell going to try this out, specifically with the visual cortex.

    1. Good to hear someone not afraid to get their hands dirty. I was beginning to think that I came to the wrong site. I plan on trying it out on my prefrontal lobe. Irresponsible? Yes. Do I have the type of professional reputation that doing this would tarnish. Maybe but probably not.

    2. I really am tired of the safety Nazis. What’s worse are the ones who’s ignorance of electromagnetics drive their fear. People have been inducing currents in brain tissue for a while. Hell researchers have even planted electrodes in other peoples heads to stimulate the brain with electrical signals. Electricity is not magic. Of course you could seriously hurt yourself if you ground a circuit with high electrical potential through your body; there’s always an inherent risk if you don’t know what your doing. Just because you won’t let the dangerous magic sparky stuff anywhere near YOUR head doesn’t mean if someone experiments on their own head that they’re wacko.

    1. At first I was like WTF…
      But then(after I read your post) I was like OMG I need me some high energy magnetic fields!!

      In all seriousness though, I like body hacks(like with the current-sensing magnet under the skin one) and I would totally do some, but non-contact excitation of neurons scares me a bit though if I knew more about neuroscience I might not be so alarmed(on the other hand it could be far more alarming.

  6. I really like these crazy posts about messing with your brain and playing with radioactive material. The high risk stories can be the most interesting. But as intriguing as some of these things are I will not ever willfully partake in these experiments.

  7. Not a week ago I actually took part in a medical study using TMS, it was damned interesting:
    Given the correct location on the brain and correct frequency of pulses, it’s possible to totally flip a person’s sense of right and wrong.

    As for the hack sense of this article, this most definitely counts in my book!

    1. Wow, that sounds really interesting :D, you know what its called or anything else I could read up on this? Coincidentally I watched a documentary a few weeks ago (cant remember what its called) were they were experimenting with low frequency magnetic pulses in a specific configuration near the brain and they produced what the called the ‘god experience’ were the test subjects all produced similar ‘spiritual’ happenings (all rather interestingly very similar to those apparently experienced by the ancient prophets in the bible according to the program). All in all bloody interesting and very crazy XD.

      1. Agreed, I did it at the University of Birmingham for a Phd researcher; even without the financial recompense it was worth a few hours of my time!

        A quick Google of ‘TMS morality’ brings up a few news articles, apparently the US Military plan to use it to keep soldiers fighting…

      1. The things about that though is that TMS is not permanent and the effects only work as long as the brain is being stimulated so you would have to have tons of people running around with the required equipment to do so.

        I also believe that it only changes peoples perceptions of other peoples moral actions.

        So if you normally considered that Robin Hood is doing bad, you would then think he’s doing good under stimulation.

        It doesn’t change your inherent sense of morality in that you would still consider what you’re doing to be no different than before.

      2. It seems that the stimulation “overworks” some parts of the brain that are responsible for moral judgement, so the brain falls back to more infantile modes of reasoning.

        The specific question asked in the study was, if I remember it correctly, to evaluate a man who tries to throw his wife off a bridge but fails in the attempt and the wife is left unharmed.

        The people recieving the TMS were more inclined to believe that whatever ends well is all well, but in the case he actually did manage to toss his wife, they too figured that the man is doing a wrong.

        The effect is a bit subtle. It’s not like you suddenly become a sociopath.

    2. Ah… no.

      TMS uses more than one magnetic field to produce a localized effect. Two waves properly timed will constructively interfere in one spot, allowing researchers to “stimulate” specific areas of the brain.

      The spot so generated is necessarily large and diffuse (using current techniques) relative to the size of a neuron. You can’t stimulate individual neurons, or even individual cortical columns with current technology.

      The brain has a damping mechanism that prevents feedback resonance in the neural circuits. At any one time several brainwave frequencies are passed around the system with positive feedback. Without the damping mechanism the positive feedback would amplify the frequencies resulting in an epileptic seizure.

      Like gently pushing a playground swing in tempo with the swinging: eventually the cycles get so large…

      The damping mechanism is apparently easy to damage – that’s why the result of cranial damage is sometimes epilepsy. The brain swells, a small part is “bruised” and scars form, and the survivor has periodic seizures for the rest of their life.

      So if you want to believe that the effects are temporary because the induced electric field cannot possibly damage a thin gelatinous wire, feel free.

      And if you think that you can’t lock yourself into a seizure state such that you can’t turn the device off, or that your friends in the room will be able to handle it if you do, then by all means go for it.

      Oh, and for the record, TMS is relatively new. When you perform experiments on yourself you will be almost completely in the dark for expected results.

    3. Assuming you’re referring to the Young et. al. study at MIT recently, in this experiment TMS didn’t exactly ‘flip a person’s sense of right and wrong’ (though the majority of media coverage seemed to go out of it’s way to push this interpretation for a nice sensational story), rather it impaired the ability of participants to use their knowledge of other people’s intentions to make moral judgements.

      I think if you have a search around, the paper (‘Disruption of the right temporoparietal junction with transcranial magnetic stimulation reduces the role of beliefs in moral judgments’ published in PNAS) should be obtainable without a journal subscription – interesting read.

  8. Sorry,
    I am really all about making and hacking.
    However, I have my doubts about this one. Sure he is a pro and he might now what he is doing. However, there are certain rules and certain ethic guidance in the scientific community and he might brake with most of them within the video.
    1. Guess the device should be designed according to medical device standards BEFORE attaching it to your head
    2. He could/should mention that he tested it before by e.g., detecting the magnetic impulse by some measurement device, confirming about the “hot-spot” location and strength
    3. There should be studies, he should mention studies confirming the effect of these impulses on neurons and brain tissue.
    4. Monitoring of the vital functions during the experiment to stop in case of an emergency.
    etc. etc. etc.

    The way he is presenting it, as a quick dirty hack without any measures of safety and testing, does misguide people. Somehow remembers me of the good old times where scientist was used to keep there high radioactive materials in there desk drawers.

    1. “However, there are certain rules and certain ethic guidance in the scientific community and he might brake with most of them within the video.”

      Good thing this isn’t the scientific community, then!

    2. I am also concerned about the safety of this. Reading his blog comments and responses, he seems to think that somehow his job and prior TMS experience makes him immune to accidents.
      As far as I can tell there is small but real risk of seizure and fainting. Holding a charged coil in your hand during this might end badly. In the least he should have had another person nearby to render help in case something goes wrong.

    3. There are certain guidelines to writing English too, but that didn’t stop you pissing all over them.

      Why should he follow any kind of guidelines? He’s presenting something that’s a bit fun to the world, it’s not a thesis, or paper. It’s not subject to any of the guidelines that you say.

      Sure, I *MUCH* prefer it when I read a really detailed write up, that mentions or at least links all prior research etc, but not everyone is going to do that.

      1. nice…
        take out the grammar and spelling gun if you have nothing else to say… I know there are mistakes. Sorry for that, typed on Android device with automatic spell check does often make things worse rather then better.
        My point was just he can do what he want, he can toast his brain or do all kind of wonderful stuff with it. He should just mention that this is not something you should try without precaution and knowledge about the topic.
        I did not disagree with the project just with the form of presentation. That’s all

  9. As has been mentioned, people are using a very similar technology to replace electroconvulsive therapy (formerly, electroshock therapy). The benefits of this approach are that the effects can be much more localized. There’s a psychologist in Canada who has been using this approach in a very specific area of the brain to induce feelings of contact with god (seriously, google the god helmet). Given the scope of the potential effects, I’d be concerned about not knowing either the precise location or effects upon the affected area.

  10. So…could something like this be used to simulate the effects of marijuana or something? Just think…get high as a kite, and be 100% sober within a minute of removing the helmet…then go down to the clinic and pass a drug test. Something like that could really hurt the cartels.

    1. maybe but its probably just safer to smoke some KBspice or some low grade salvia XD
      its probably safer to just do meth than shoot pulses of electricity randomly in to the brain XD

  11. Very nice! As a neuroscientist engaged in TMS-research I highly appreciate the boldness of building your own stimulation coils =). As to the dangers: This guy has some obvious experience and knows what he’s doing. Delivering single pulses holds virtually no danger and multiple pulses are somewhat out of reach of your average coil due to heat.
    As for ethics: Experimenting on yourself is never unethical in my opinion :), I’m guessing that he won’t be using it for treatment and or scientific research.

    Again, Nice job sir!

  12. What exactly does “working with” mean?

    I’m pretty sure a doctor has little to no clue as to how a CAT scan is built and I’m pretty sure a CAT scan engineer doesn’t know much about how the human body works.

    I just seems like this guy is someone who services the machines and I wouldn’t exactly trust his knowledge of the brain as much as I would a neurosurgeon.

    Still, it’s his brain to do so with and I’m impressed with his abilities.

    1. Not sure why a few commenters seem think TMS might provide a high (doesn’t seem to be anything that suggests this anywhere?), might be due to the recent post on the brain machine.

      Afraid to say this isn’t going to happen.

  13. talking about cardiac muscles (Dj NurSpek) this could be a viable replacement for de-fibrillation unit now, recent reports show they damage areas of an and around the heart, thoughts?

  14. I’m disappointed at all the FUD coming out of the community here. This is a legitimately cool hack. If we all hide in our holes from the dangers of the world, we will never come up with world changing innovations.

    Do you know what happened in the early days of x-ray experimentation? One of Edison’s glass workers tested the tubes on his hands regularly. It ended with cancer, amputations, and death. Given what x-ray does for us today, I think it was worth it.

    Being at the forefront of innovation is dangerous, hard work. The innovators know this, and don’t need cowardly, ignorant haters casting them in a bad light with false claims and exaggerations.

    More personally, I know there are some bright people around the site here and would love to see some intellectually stimulating (no pun intended) conversation, rather than a pile of “This dude is crazy! That’s stupid and dangerous! [Electricity|Chemistry|Radiation] is scary!” comments. If you want safe, established science, I’m sure there’s a site out there for you that shows how to mix baking soda and vinegar.

    1. Maybe comments would be more positive if he presented it in a way that showed he cares about his brain.
      A little introduction about safety and health effects would demonstrate that he knows about it and is able to judge about the possible risks.
      The infamous “Don’t try this at home” might be worse to mention in any medical self-testing hack.

      Your example for xrays is not comparable. The poor buddy you mentioned had simply no idea about the danger. Curie and many other scientist died because of the same reasons. You really think they just ignored the safety issues for the sake of discovery?

      1. Agreed. Point taken.

        I’m out of rants right now, but warning labels are a slippery slope that lead to “Caution: Hot” on coffee. A pointer to known, subtle, invisible dangers is wholly warranted in this case, though.

        That said, I don’t think a maker should be chastised here for not including warnings, ever. We’re grown-ups, we can do some google and find the documented dangers of our seizure-inducing epileptic death coil before we build it. Perhaps others don’t feel like I do that it goes without saying that science can be dangerous and that you should look before you leap and be prepared for the consequences.

  15. I was looking into using PCB coils with multiple concentric wires (aka Litz wire) driven from an array of smaller capacitors.
    This would get around the heat problem methinks.

    Stack the coils with bismuth layers (a diamagnetic metal) to somewhat shield adjacent coils.
    Monitor the resultant fields using magnetic viewing film double layered then laminated in clear plastic for 3-D like effect.

    Ought to generate a more finely tuned vertically addressable field, which could be enough to generate phosphenes.

    Just a thought…

  16. Pyrolytic graphite film would also work, you can get this as large sheets intended for use on power transistor arrays.
    Its crazy expensive though, but for this purpose graphite sheets and bismuth in thin layers might combine the effects of both.
    Essentially, the PG/Bi sheets act a bit like a superconductor but without the requirements for cryogenic temperatures, as attenuating the field in the undesired direction should be enough on its own.

    Think video full erase head here.

    Another idea, use Bi foil and then put Epoxy mixed with iron powder over the coil(s) on the PCB side with Superglue insulator to focus the field even further.

    I tried the Superglue technique on a homemade PCB N2 laser with silver paint as the capacitor plate, worked well with a good 10nF capacitance for about 2 in2 of plate area!!!

  17. There is nice online book available online on bioelectromagnetism:

    I have not followed the progress on inductor development (and multichannel arrays) for some years but single point TMS is reachable for dedicated amateur and quite cheaply. I would say, that even some area mapping is possible using CNC.

    The main goal is to have smallest possible volume of excitation (depending on coil design) – the smaller you get the higher is the resolution.

    Considering safety – single pulse can be considered relatively safe. Repetitive fast TMS or experiments with deeper excitation starts to be the nono territory…

    If anyone knows more about the rumor of permanent VC damage (one comment of the original site) by TMS – please link.

  18. I wanted to let you know that detailed design considerations and an actual, working circuit for a TMS is available in my book:

    D. Prutchi, M. Norris, “Design and Development of Medical Electronic Instrumentation”, Wiley Interscience, 2005.

    The TMS stimulator is described in pages 346 to 356. There is also a discussion of the energy levels required for magnetic-pulse stimulation of other tissues and organs (e.g. cardiac pacing, phrenic nerve stimulation, etc.)

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