US Patent 7587602 Methods and devices responsive to ambient audio

A portable device uses a microphone to listen to ambient audio, derives data from captured audio signals, and uses the derived data to request delivery of the audio or related information to the user's home or other location. The device is desirably pocket-sized, or suitable for carrying on a key-ring. The device may also detect a watermark signal that is present in the user's environment (e.g., played through a public address speaker system) to aid the user in recalling the context from which the audio was requested.