Activate this bracelet with 24 speakers — developed by married University of Chicago professors — and Alexa can’t eavesdrop
Zheng characterized her reaction differently. First she objected to having the device in their house, she said. Then, when Zhao put the Echo in a workspace they shared, she made her position perfectly clear: “I said, ‘I don’t want that in the office. Please unplug it. I know the microphone is constantly on.’”
Last year, Ben Zhao decided to buy an Alexa-enabled Echo speaker for his Chicago home. Zhao just wanted a digital assistant to play music, but his wife, Heather Zheng, was not enthused. “She freaked out,” he said.
Zhao and Zheng are computer science professors at the University of Chicago, and they decided to channel their disagreement into something productive. With the help of an assistant professor, Pedro Lopes, they designed a piece of digital armor: a “bracelet of silence” that will jam the Echo or any other microphones in the vicinity from listening in on the wearer’s conversations.
The bracelet is like an anti-smartwatch, both in its cyberpunk aesthetic and in its purpose of defeating technology. A large, somewhat ungainly white cuff with spiky transducers, the bracelet has 24 speakers that emit ultrasonic signals when the wearer turns it on. The sound is imperceptible to most ears, with the possible exception of young people and dogs, but nearby microphones will detect the high-frequency sound instead of other noises.