This makes me think of of the Amazon Dash button which had a microphone [0] that would listen for ultrasound emitted from your phone to configure wifi credentia

This makes me think of of the Amazon Dash button which had a microphone [0] that would listen for ultrasound emitted from your phone to configure wifi credentials. [0] http://www.blog.jay-greco.com/wp/?p=116 http://www.blog.jay-greco.com/wp/?p=116