If the room is dark all the 5 LEDs will light up with a moving pattern. If the room is well lit all the LEDs will go off. In the video below there wasn't enough light in the room to turn all the LEDs off! probably on direct sunlight they will all go off.
There is not only full bright and complete dark, light level has been measured and shown on scale of 0-5. No LEDs(0) for full bright light and 5 LEDs for complete darknessnesssssssss!!!
See the video below.
I am working on the schematic of this. Will update soon once i finish drawing this up.