Hackers can eavesdrop on conversations near a smartphone by measuring sound vibrations with the smartphone's built-in motion sensor.
Experiments have previously shown that smartphone gyroscopes and accelerometers, known collectively as inertial measurement units (IMUs), can detect sound vibrations in the air and eavesdrop on conversations. This means that apps that don't have permission to use the microphone can work around this issue by using the IMU as a makeshift sound sensor.
To combat this, Google has set limits…
Source: www.newscientist.com