Quickly moving through the book and the next project is a creating a light sensitive tone generator.
Simple to create, the circuit has one photo resistor (as used for the RGB LED), connected by a power wire, resistor to ground and an Analog (A0) cable from the Arduino.
the first 5 seconds the time to set the range between 0 -1023 by placing you hand over the photo-resistor.
Now when you move your hand over it again your notice a tone which changes on light allowance. (No video for this one as it is an annoying noise).