You get AUDIO FEEDBACK for VISUAL INPUT or
VISUAL FEEDBACK for AUDIO INPUT.
This App is an experimental approach on how handicapped people could use the iPhone for orientation.
It uses the light sensor to grab any change of the luminance and gives you prompt audio feedback.
Vice versa the ambient sound can be reflected by change of the color from green (silent) to red (noisy).
(if its quiet long enough youll experience the iPhone/iPad sleeping - it snores ...)