Researchers create ultrasonic wearable bracelet that jams all nearby microphones
From smartphones, smart speakers to other microphone-equipped gadgets, all such devices might be snooping on you without even your knowledge. But if you aren't willing to take any chances, there is a solution for you. As part of an experiment, researchers at the University of Chicago have created a bracelet that uses ultrasonic signals to jam all the microphones near the wearer.
About the experimental microphone jamming bracelet
Design-wise, the bracelet is not really ergonomic but it does the job (at least that's the claim). You simply wear the "privacy bracelet" around your wrist and turn it on with a single tap to block out surrounding microphones. The device packs 24 transducers, a micro-controller, a signal generator, a 3W amplifier, and a lithium battery to ensure hands-free operation.
How does the bracelet work?
When you turn on the bracelet, it starts to emit 24k-26kHz white noise. Notably, this ultrasonic frequency is inaudible to human ears. However, due to non-linearities in the microphone's amplifier (of your gadget), the ultrasonic signals "leak into the audible spectrum after being captured by the microphones, producing a jamming signal inside the microphone circuit that jams (disrupts) voice recordings", according to the researchers.
The wearable bracelet design has some specific advantages
Having multiple transducers in a stationary jammer will cancel out white noise from each other, and thus result in blind spots or simply lower coverage. However, the wearable design leverages natural hand gestures to minimize blind spots. Furthermore, by arranging the transducers in a ring layout, the bracelet jams microphones present in multiple directions, even if the mics are hidden or covered by materials.
When will we see a device like this?
Since this privacy bracelet is an experiment, we may not see it anytime soon. The researchers have told The New York Times that they could manufacture the device for as little as $20 (nearly Rs. 1,400), and some investors have already shown preliminary interest. But imagine the havoc it would play with phone calls if people start wearing such devices in public.
