back
93 comments
Or, "How to kill people with pacemakers". Seriously, there are a lot of bad uses for this which have nothing to do with phones.
This is being operated at distances where you could just as easily hit the device directly with a hammer. To scale the distance up to just a couple of meters (say about 50 times the distance), you'd need to scale up the power by about 50*50 = 2500 times.

I suppose it is conceivable that a suitcase-sized device could disrupt the actions of pacemakers of people walking within a meter or two. But it could just as well cause trouble with much more conventional means.

There's probably a fairly large set of people who would never consider hitting someone in the chest with a hammer, but would fire up a device like this for the lulz, not knowing that someone with a pacemaker was within range.
Actually even more since some near-field components fall off at 1/r^3.
Would those means leave a more obvious forensic trace? I mean... a hammer is going to leave a mark.
Dick Cheney has several vulnerabilities, besides disabled telemetry.
Or one of those going off on a plane. Horrible consequences.
You'd need a lot more current in order to cause horrible consequences for an airplane. Lots of redundant systems, lots of testing for electromagnetic tolerance.
Oh, please. An induction coil charger probably emits more power.

In addition, this emits a VERY wide bandwidth noise pulse (look at the frequency output of a spark gap transmitter) which of necessity puts very little power in any specific band.

You would not be able to take this into a plane, but good thought.
Oh damn it... that's a good point. What would the effect be if you got one into a critical part of a power or transmission station too? Not good I bet.
This won't destroy your phone. Phones are extensively tested when it comes to both creating and withstanding EM interference. Best it could do - maybe - is crash one that is on the edge of its spec and you would probably have to get pretty close for that (fall off as the square (edited) of the distance).
There's a very big difference between EM interference and an EM pulse. One is the by-product of all digital electronics and one is a device specifically designed to induce enough current on a circuit board/IC/etc to damage it.

That said, based on the size of that thing in the photo I suspect it wouldn't damage anything!

The biggest difference is the fieldstrength of the primary field used to induce a voltage in the target, the same basic principles apply.

It takes a (much) higher fieldstrength to induce voltages that will destroy electronics than what's required to flip the occasional bit without damage.

Lightning can cause EMP like effects by inducing voltage in conductors not directly hit by the lightning.

Shouldn't the signal fall off with the square of the distance (inverse-square law)?
Yes, apologies.
aiui.

its not linear.

either it induces a voltage high enough to cause disruption or it doesnt.

the limiting factor is the voltage not the power (power is tiny)

Yes.
Would it disable an annoying car alarm?
Yes, or the entire car: https://www.youtube.com/watch?v=cuus8OtPY0w

Vehicle disabling EMPs are of great interest to the likes of CHP, and such.

Or stereo or subwoofer? I find that an interesting concept.
How about something like an Explosively pumped flux compression generator, I'm thinking there must be bits of EEPROM or equivalent in the phone that hold important info like the imei number, that if damaged, would render it unusable?
I'll upvote the article if you build and test it :) (On your phone, in your lab).

That has a chance of working due the very fast rise time you might be able to induce a sufficiently large voltage to cause some actual damage, it will be a 'one shot' affair though. But anything involving regular coils and some push button arrangement will likely cause it's own insulation to break down long before it will do damage to a phone.

That's one of the reasons the spark gap is there in the first place, without it you'd hit the limits of the coil insulation very quickly.

Spark gaps are a pretty nasty way to generate EM interference so there is some truth to the story.

But even with my plasma cutter (12.5 KW, so not the smallest in the catalog) and stick welder I never managed to crash a cell phone.

The plasmacutter did have the habit of resetting the controller until I properly decoupled all the lines into it.

"People will say it's a booooomb..." to the tune of People Will Say We're in Love

Seriously though... can you imagine how many laws you'd break using that? The FBI would hang you up by your pubic hair, tar, and feather you.

Just to clarify after seeing several posts below. The magnetic and electric near fields fall off from 1/r^3 to 1/r^2, depending on component. The far fields fall off at 1/r, hence the familiar 1/r^2 for power (not amplitude).

http://www.rfcafe.com/references/electrical/near-far-field.h...

This thing operates in the near field, so it is pretty much useless past a distance of a coil diameter.

If you wanted to do this right, you'd match the impedance to the antennae impedance of a typical phone antennae.

This gets around the square rule, sort of, and you won't need a suitcase full of batteries to power the thing.

Things like that were used to cheat slot machines http://empjammer.com/how-a-emp-jammer-working
Much cheaper to use an electric gas lighter.

That's what we used to test on stuff that was supposed to be reliable and it is amazing how hard it is to defend against it. If you could survive 10 seconds or more without a latch losing state or some other bitflip then it was usually a pretty good job. Even so, this required physical contact to something made of metal on the machine (even if most of it is properly grounded there always is some exposed metal that isn't).

I hope the engineering on that product is better than the English, it is barely understandable.

Heh - showing my age here, but I remember using gas lighters (stolen from school heaters) to zap free game credits into Asteroids machines...
Here's the Nevada Gaming Commission's answer to that.[1] More stuff should have security standards like this.

[1] http://gaming.nv.gov/modules/showdocument.aspx?documentid=29...

ESD is not EMP.
I've often thought about using a wok as a dish and putting a magnetron at the focus. High power directed microwaves would probably damage a lot of things. And made from kitchen hardware...
Probably safer to let somebody else try this... ;) A couple of Ukrainians made a cool YouTube video recently where they built something similar and used it to blow up some cell phones. https://www.youtube.com/watch?v=FIU8WZR9DNA
The video is lovely (and now I absolutely want to try it at home!). That said, the ending disturbed me. As I understood, it basically said - "don't worry, none of our neighbours suffered, because they all moved out when the war started".

EDIT:

Holy shit, they have a video of what's left of their town after shelling stopped: https://www.youtube.com/watch?v=v4mc5mHksl8.

You really don't want to microwave a Lithium-Ion battery.
I think they've been using it on Samsung Note 7s more recently.
This seems like a device that is possible to cause a lithium battery fire because of the discharge rate.
What component is failing in order to cause that iphone's screen to fade out in that way?
Why a second external coil? It isn't aligned with the first coil and so the induced EMF is minimized (usually such coils are co-axial).
It doesn't destroy phones, though. It resets them at max according to the video and tests.
Funny he can build an EMP generator but can't properly bias an LED.
this reminds me of a coworker who tried to create a tiny DC motor with a battery, a magnet, and _non-enameled_ wire. yeah, that didn't work out too well for him. I tried to explain why the wire needed to be enameled, but the cargo-cult science was strong with him.
How would the design need to be changed to make it possible to zap a phone from a distance of 1-10 meters?
You need 1.21 Gigawatts for that.

(Seriously, though, you'll need to square the power source as you double the distance.)

Sweet! ... My EMP generator only works on Samsung Galaxy Note 7s!
"18650 lithium battery cell"

Or, possibly, explode into flaming death.

Ok, so let me put it another way: how much resistance does that circuit have?