This example is for Wiring version 1.0 build 0100+. If you have a previous version, use the examples included with your software. If you see any errors or have comments, please let us know.
Photoresistor by BARRAGAN http://barraganstudio.com
Reads values from a photoresistor connected to analog input pin 0 (or A0) and prints the result to the serial monitor The value read from the sensor is proportional to the amount of light that hits the sensor's surface.
Serial.begin(9600); // starts the serial port at 9600
sensorValue = analogRead(0); // read analog input pin 0Serial.print(sensorValue, DEC); // prints the value readSerial.print(" "); // prints a space between the numbersdelay(100); // wait 100ms for next reading