A team of University of Michigan researchers has developed a system that can inform a smart home ‘ or listen for the signal that would turn on a smart speaker ‘ without eavesdropping on audible sound. The key to the device, called PrivacyMic, is ultrasonic sound at frequencies above the range of human hearing. The system pieces together ultrasonic information that’s all around us to identify when its services are needed, and sense what’s going on around it. Researchers have demonstrated that it can identify household and office activities with greater than 95% accuracy. The team has applied a patent protection through the U-M Office of Technology Transfer.
Source: https://www.helpnetsecurity.com/2021/06/14/privacymic-smart-home-system/