Wearable Cone Of Silence Protects You From Prying Ears

Careful,  the walls have ears. Or more specifically, the smart speaker on the table has ears, as does the phone in your pocket, the fitness band on your wrist, possibly the TV, the fridge, the toaster, and maybe even the toilet. Oh, and your car is listening to you too. Probably.

How does one fight this profusion of listening devices? Perhaps this wearable smart device audio jammer will do the trick. The idea is that the MEMS microphones that surround us are all vulnerable to jamming by ultrasonic waves, due to the fact that they have a non-linear response to ultrasonic signals. The upshot of that is when a MEMS hears ultrasound, it creates a broadband signal in the audible part of the spectrum. That creates a staticky noise that effectively drowns out any other sounds the microphone might be picking up.

By why a wearable? Granted, [Yuxin Chin] and colleagues from the University of Chicago have perhaps stretched the definition of that term a tad with their prototype, but it turns out that moving the jammer around does a better job of blocking sounds than a static jammer does. The bracelet jammer is studded with ultrasonic transducers that emit overlapping fields and result in zones of constructive and destructive interference; the wearer’s movements vary the location of the dead spots that result, improving jamming efficacy. Their paper (PDF link) goes into deeper detail, and a GitHub repository has everything you need to roll your own.

We saw something a bit like this before, but that build used white noise for masking, and was affixed to the smart speaker. We’re intrigued by a wearable, especially since they’ve shown it to be effective under clothing. And the effect of ultrasound on MEMS microphones is really interesting.

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Building A Smart Speaker From Scratch

Smart speakers have proliferated since their initial launch earlier this decade. The devices combine voice recognition and assistant functionality with a foreboding sense that paying corporations for the privilege of having your conversations eavesdropped upon could come back to bite one day. For this reason, [Yihui] is attempting to build an open-source smart speaker from scratch.

The initial prototype uses a Raspberry Pi 3B and a ReSpeaker microphone array. In order to try and bring costs down, development plans include replacing these components with a custom microphone array PCB and a NanoPi board, then implementing basic touch controls to help interface with the device.

There’s already been great progress, with the build showing off some nifty features. Particularly impressive is the ability to send WiFi settings to the device using sound, along with the implementation of both online and offline speech recognition capabilities. This is useful if your internet goes down but you still want your digital pal to turn out the lights at bed time.

It’s not the first time we’ve seen a privacy-focused virtual assistant, and we hope it’s not the last. Video after the break.

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Win Back Some Privacy With A Cone Of Silence For Your Smart Speaker

To quote the greatest philosopher of the 20th century: “The future ain’t what it used to be.” Take personal assistants such as Amazon Echo and Google Home. When first predicted by sci-fi writers, the idea of instant access to the sum total of human knowledge with a few utterances seemed like a no-brainer; who wouldn’t want that? But now that such things are a reality, having something listening to you all the time and potentially reporting everything it hears back to some faceless corporate monolith is unnerving, to say the least.

There’s a fix for that, though, with this cone of silence for your smart speaker. Dubbed “Project Alias” by [BjørnKarmann], the device consists of a Raspberry Pi with a couple of microphones and speakers inside a 3D-printed case. The Pi is programmed to emit white noise from its speakers directly into the microphones of the Echo or Home over which it sits, masking out the sounds in the room while simultaneously listening for a hot-word. It then mutes the white noise, plays a clip of either “Hey Google” or “Alexa” to wake the device up, and then business proceeds as usual. The bonus here is that the hot-word is customizable, so that in addition to winning back a measure of privacy, all the [Alexas] in your life can get their names back too. The video below shows people interacting with devices named [Doris], [Marvin], [Petey], and for some reason, [Milkshake].

We really like this idea, and the fact that no modifications are needed to the smart speaker is pretty slick, as is the fact that with a few simple changes to the code and the print files it can be used with any smart speaker. And some degree of privacy from the AI that we know is always listening through these things is no small comfort either.

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