Imagine wearing a wearable, such as a bracelet or necklace, that was capable of knocking out the microphones around us. A mic jammer, we might say. That would prevent someone from being able to secretly record a conversation or the voice assistants from being able to pick up what we say. Well, that device exists and, although it is not exactly disguised, it works.
Its name is somewhat bombastic: Cyberpunk Ultrasonic Microphone Jammer. It has been created (now we will clarify) Naomi Wu, one of the best-known Chinese YouTubers in the maker and 3D printing world. It is a necklace full of ultrasonic microphones that take advantage of a vulnerability in the microphones of mobile phones and portable devices to block the capture of our voice.
A wearable that blocks the microphones
The device of Naomi Wu, known on YouTube by her alias Naomi ‘SexyCyborg’ Wu, is a 3D printed necklace, but it is based on a device developed by the University of Chicago that last year won a few awards to the innovation. This was not a necklace, but a bracelet filled with ultrasonic transducers.
How does it work? How do you get to inhibit the microphones of mobiles, smart speakers and watches? Well, this wearable is based on an exploit that takes advantage of the fact that when the microphones of portable devices are exposed to ultrasonic noise (inaudible to the human ear), it filters into the audible spectrum of the microphone and produces an interference signal. within its circuit. In short, people can hear us, but microphones cannot.
The original model, which is shaped like a bracelet, also uses hand gestures to improve interference coverage. As you move your hand, the transducers emit sound in different directions and increase the effectiveness of the device. The idea of putting it on a necklace, as Naomi Wu has done, also has its raison d’être: getting the microphones to point in the same direction in which you speak.
In the video on these lines we can see the process of construction of the necklace and the result, which is most interesting. When the microphones on the collar are activated, the microphones are unable to capture the voice of the YouTubers well. Instead, we hear the typical white noise of interference. An easy-to-see sample is at minute 20:58.
The necklace is a bit bulky and quite large, but the YouTubers assures that its size could be reduced to make it more compact. The project is open source and all the code can be found on GitHub. The original paper can also be accessed at this link.