While too much of our information streams have become infected with endless discussion of the current White House, this week there’s a direct connection to Leon Theremin. So – let’s dive in, shall we?

In case you’ve managed to avoid US news, you might not know that the Counselor to the President of the United States recently speculated to an interviewer that a microwave oven could be used as a spying device, and specifically, as a camera.

And that led to stories like this one:
No, Microwave Ovens Cannot Spy on Youโ€”for Lots of Reasons [Wired]

The problem is, what these article claims miss some of the actual mechanics of how espionage occur.

Irrespective of any discussion of the usefulness of this observation, some of the fact checking from the tech press has asked the wrong questions. (This really is a CDM story – just bear with me.)

First, can a microwave oven be used as a spying device? Answer: well, do you mean microwave ovens or microwaves? In fact, not only can you use a microwaves to eavesdrop on people, anyone with some basic electronic skills could build the system themselves. A 2005 article from EE Times shows you how (thanks, Jan Klug):

Eavesdropping using microwaves

Here, the idea is to use low-power microwaves to “illuminate” an area and amplify sound in that area.

This is literally (and now unintentionally hilariously) in the Design How-To section of the magazine. Apologies to any EE Times readers I’ve just gotten on a watch list. Hey, more time indoors to work on electronics projects, right? No?

Spying with microwaves is actually reasonably easy, because electromagnetic frequencies reflect physical vibrations – they become a carrier for sound. So even without a microphone, EMF signals can under the right circumstances contain the traces of sound waves as amplitude modulation. s

Now, this won’t come as news to anyone who’s a fan of the history of Leon Theremin, because the inventor of the instrument of the same name also pioneered the technique. I’ve actually shown his invention (The Bug) in lectures, because the story is just too good.

And anyone who’s met Theremin history expert Andrey Smirnov has surely heard the story, as he tells it frequently.

EE Times also credits Lev. But let’s just copy-paste from our friends as the United States NSA:

On August 4, 1945, Soviet school children gave a carving of the Great Seal of the United States to U.S. Ambassador Averell Harriman. It hung in the ambassador’s Moscow residential office until 1952 when the State Department discovered that it was ‘bugged.’

The microphone hidden inside was passive and only activated when the Soviets wanted it to be. They shot radio waves from a van parked outside into the ambassador’s office and could then detect the changes of the microphone’s diaphragm inside the resonant cavity. When Soviets turned off the radio waves it was virtually impossible to detect the hidden ‘bug.’ The Soviets were able to eavesdrop on the U.S. ambassador’s conversations for six years.

From a declassified 2007 NSA report

Beware of Soviets bearing gifts, apparently. This is doubly ironic, as I’d pondered before constructing one of these in a workshop or hacklab.

See also:
Eavesdropping using microwaves – addendum

The key is the resonant cavity. It doesn’t require a power source, and it’s hard to detect, but you still have to plant the device. Using RF signal as in the example above is advantageous because you don’t have to do that. The EE Times story is a great read, because it gives some history into patent applications around the concept – some of them unrelated to sound detection, looking instead to distance. (I’m told the AutoTune algorithm was first developed for seismic exploration, so remember that imaging and sound are connected.)

Proximity mattered, as far as the original bug. The US Embassy at the time was situated on a busy roadway, close to the sidewalk, in the middle of Moscow. (I’ve been to the location.) Receiving the signal must have been stupidly easy. Theremin’s technique also has the advantage of more successfully penetrating walls.

Here’s the problem: the microwave oven isn’t terribly useful. Theoretically, any large EMF source could have the impact of the illuminating beam above. But I think you might have to try this to see if it works effectively. It could be either that the microwave oven when on created enough EMF disturbance to accidentally recreate the conditions in the EE article, thus amplifying sound signal. The obvious problem there is: it’d only work while the microwave was in use, making this a haphazard intelligence gathering device.

Or, alternatively, every time the microwave oven was on, it’d screw up your existing EMF-based espionage. I’ll be honest, I’m not sure – maybe some expert in our readership can speculate.

Either way, this isn’t a desirable device for the job.

Addendum: Steve Hillman notes on Facebook that the statement “there’s no microphone in a microwave” is itself false. The piezo speaker that produces the beeps is also a mic. Now, you’re scoring points only for pedantry here, because you would have to then get signal from that piezo… at which point you’re hacking into an appliance and you might as well just add your own bug (also originally a Leon Theremin invention). But what the whole episode reveals is that a lot of people actually don’t understand basic electronics and old-fashioned analog-style espionage.

And that brings us to the next question:

Could a microwave be used as an imaging device? Here, the likely answer is – possibly, sort of, but here again it wouldn’t be your first choice.

Now, the couple of tech articles I read on this target may have asked too narrow a question. Given recent revelations that camera-equipped computers and smart TVs used the actual in-built cameras as hacking targets, they asked whether microwaves could be hacked in the same way. There, the answer is pretty definitively no, because there aren’t many microwaves with optical cameras facing outward.

But strictly speaking, can you definitively rule out the possibility of using a microwave as an imaging device? Probably not.

First, yes, there are ways of using electromagnetic radiation to produce an image. See the above technique, and think radar: if you can make a sound, you can make a picture, too. The trick is, you might wind up with a precise image of what someone had put in their microwave, at least using whatever conventional approaches I’ve been able to find. If some lumpen picture of last night’s Chinese take-out is your idea of vital surveillance, then you’ll be happy with this solution. But uh… yeah, that’s unlikely.

Of course, if your objective is spying, getting quality data is important.

But there could be other techniques. One friend pointed me to this:

Rosenthal Sensor [Eric Rosenthal, GitHub]

Conspiracy theorists, that involves DARPA (US defense funding) and New York City, not far from Trump Tower. But… okay, it’s actually not directly applicable to the microwave oven example. But it does prove that there are unique ways of making sensors, which means there are all sorts of unknowns here – and just talking about webcams and the Internet of Things isn’t sufficient.

In other words, while laughing off the question of whether a microwave oven could be used, the respondents were overly focused on the idea of a literal webcam as necessary for producing an image.

That said, back to reality.

The thing is, clever methods of surveillance become less appealing once you have loads of Internet-connected devices with sensors on them and poor security. And that’s to say nothing of the fact that it’s easy to compromise someone’s existing data simply by guessing their password, or waiting for them to make something public that was intended as private, or any other number of techniques.

But I think what’s more interesting than any of this is the fact that spying is all about doing something that the other person doesn’t expect. That’s what made Theremin a genius. He took a technique that was technologically simple and applied it to a new context, in such a way that no one had thought to look.

They didn’t ask the right questions. And they didn’t precisely state the right answer.

And that’s fundamentally what science is about – asking questions, rather than assuming you have the answers already, and being precise in how you state what answers you find.

By that measure, these articles failed, as did I with my initial kneejerk reaction. Thanks to Tessa Lena via Facebook for calling us out on that.

And I’d say culture is often about finding answers from entirely different questions – which is how the person who is the father of the modern electronic musical instrument is also the father of the modern surveillance state. I just hope, frankly, his weird-sounding music outlives all these other institutions.

With that in mind:

Meanwhile, if you want to learn electronics with the help of the NSA (your tax dollars at work, Americans!), here you go:

Homebrew NSA bugs

And… I’m not helping any of us get our DIY electronic instruments across national borders, am I? Sorry. (Maybe just wink knowingly at border crossing people and tell them they shouldn’t ask more questions, or some people higher up will be displeased. Actually, no, maybe definitely don’t do that.)

  • PK Doing the real work!

  • Christopher Rose

    True that! You might also check out the idea of small fiber optics cameras in your t v

  • Max

    Does this matter in a world where people are installing always on listening devices in their homes to order toilet paper online and post a continuous stream of information about themselves on Facebook and twitter?

    • It probably doesn’t, no. ๐Ÿ˜‰

      And I suspect that’s actually why these stories overlooked obvious uses of passive analog microphone systems.

      On the other hand, the fact that people are overlooking those techniques mean that they’re vulnerable to them all over again. ๐Ÿ™‚

  • Timothy53

    So pretty much the answer to the question “Can the microwave (understood by about 99.9% of the population to mean a household appliance) be turned into camera or even a microphone?” is a one word answer. “No”

    And the accompanying question “Is Kellyanne Conway a big dummy?” another one word answer “Yes.”

    And the third question: “Should Conway just shut the firetruck up before she looks even sillier than she does now?” another one word answer: “Yes.”

    But as in high school when you were assigned a 500 word essay you padded this assignment.

    • pcmediahost

      Lol. Yes it can be. Just tape your cell phone on the microwave and hit record. Then while you are at it, stop taking bias liberal media hook line and sinker. This is common sence… You should feel stupid just for trusting this nonsense.

      • Timothy53

        I saw the interview. Her own mouth moving. She really is that stupid.

        Never Remember the Bowling Green Massacre.

      • mikieb

        well that left in January!

      • Veronica Velasquez Walter

        Wouldn’t Dump be stupid for not noticing a cell phone taped to the side of his microwave? “Common sense”, mm hmm…

    • BigKahuna


      • Timothy53

        I did read the article. You didn’t. The writer used 500 words where one would have sufficed.

    • For what it’s worth I actually agree with this criticism, and I’m the author.

      The interesting question is, where did Timothy53 get my high school essays?

      I’m guessing by spying on me through a microwave.

    • Veronica Velasquez Walter

      You read my mind about the big dummy part!

  • Fungi2bewith

    6 Comments! I feel privileged
    Could she have been speaking of Microwaves themselves? Yaknow, the beams transmitted from point to point?
    The other thing that came to mind was , Was she reveling something she was briefed on and is generally NOT known as spycraft? ‘Til now?

    • Timothy53

      When one says “the microwave” they are talking about the household appliance. And Conway is not smart enough to understand how one would use microwaves to to intercept conversation.

      No, she meant the microwave oven.

      • BigKahuna

        …which have the possibilty to be mic’ed, but not likely.

      • foljs

        Well, with the IoT and the tendency to put communication devices and wifi in all kind of previously dumb appliances (TVs and fridges being the most famous examples) it’s not unthinkable that a microwave oven could be used for that thing (and not through it’s microwave abilities).

        But it’s also possible that she had heard/read somewhere of using microwaves (the actual waves) for spying, but understood it as using the ovens. Which is wrong, but then again it was just used as an example of how seemingly innocuous things can be used for spying nowadays. Which is true, even if the example given is wrong.

  • tracyhaynes

    Well, I think this was a terrific article, and gives Conway the MODICUM of credit she deserves. In other words, yeah, Microwaves ( the directed energy itself ) can be used to listen in and even create a type of image. My guess is that Conway was exposed to a conversation about this in some way or other, but didn’t completely understand what she heard. But that’s a guess, of course. Again, a terrific article about some of the possibilities which exist. TH

    • Veronica Velasquez Walter

      The article says it would give you an image of the food in the microwave. Useful.

      • tracyhaynes

        An oven would give you an image of the food. A microwave transmitter ( essentially a microwave gun ) is something different, and could give you images of a sort, or audio, depending on how your receiver is tuned. And no, I don’t think Conway really gets this, at all.

  • Gary Jones

    Just because one thinks a microwave can’t be used to spy with don’t make it so. It has broad band waves and can be sent or received and with billions of $$$$ in their budget the govt can get their information like Burger King anyway you want it, Leave Conway alone. She may not be sharpest knife in the drawer but she’s not the TARGET. osama obama mohammerhead is the SPY.

    • Veronica Velasquez Walter

      Bhahahahaha, that’s so dumb!

  • ZooTooK

    If you can clear sight, filming material that easily resonates can be turned into sound: https://www.youtube.com/watch?v=FKXOucXB4a8

  • Mikebark

    Kellyanne did NOT say “microwave OVENS”! She said “MICROWAVES”! which can indeed be used for eavesdropping!

    Secondly, I’ve heard that exaggeration many times before in one form or another, such as “Our 100K watt radio transmitter is so powerful, if we turn it up, you’ll hear our broadcast coming from your toaster!” A funny exaggeration, of course, and if you believe they actually meant it, does that make THEM stupid…..or YOU?

  • Veronica Velasquez Walter

    She said microwaves can be turned into cameras. Cameras, not bugs.

  • Michael Johnsen

    But make sure you protect yourself! https://www.youtube.com/watch?v=srXapLVmvJ8&t=40s

  • Dad911

    It is common knowledge that microwaves can be used to listen in to
    people in a room. It was pioneered by the Russians during the cold war.
    Google it

    โ€œOn August 4, 1945, Soviet school children gave a carving of the Great Seal of the United States to U.S. Ambassador Averell Harriman. It hung in the ambassador’s Moscow residential office until 1952 when the State Department discovered that it was ‘bugged.’

    The microphone hidden inside was passive and only activated when the Soviets wanted it to be. They shot radio waves from a van parked outside into the ambassador’s office and could then detect the changes of the microphone’s diaphragm inside the resonant cavity. When Soviets turned off the radio waves it was virtually impossible to detect the hidden ‘bug.’ The Soviets were able to eavesdrop on the U.S. ambassador’s conversations for six years.โ€

  • ron

    Check out the work of Dina Katabi’s lab at MIT, her group has been using WiFi to track people, and listen to heartbeats, and monitor babies through walls. Doing imaging through walls using WiFi seems like a real possibility.

  • Sam Smiles-Oftn

    has no one else noticed something odd about the Github link..? a glitch in the Matrix. have anohter peek, esp the last paragraph.