Hackers Transform a Smartphone Gyroscope Into an Always-on Microphone

Apps that use your smartphone’s microphone need to ask permission, but the motion sensors? No say-so needed. That might not sound like a big deal, but security researchers from Stanford University and defense firm Rafael have discovered a way to turn Android phone gyroscopes into crude microphones.

http://www.engadget.com/2014/08/15/gyrophone-eavesdropping-hack/