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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.

Pitch follower by Tom Igoe
Plays a pitch that changes based on a changing analog input circuit: 8-ohm speaker on digital pin 8 photoresistor on analog 0 to 5V 4.7K resistor on analog 0 to ground

    void setup()
    {
      // initialize serial communications (for debugging only):
      Serial.begin(9600);
    }

    void loop()
    {
      // read the sensor:
      int sensorReading = analogRead(A0);
      // print the sensor reading so you know its range
      Serial.println(sensorReading);
      // map the pitch to the range of the analog input.
      // change the minimum and maximum input numbers below
      // depending on the range your sensor's giving:
      int thisPitch = map(sensorReading, 400, 1000, 100, 1000);

      // play the pitch:
      tone(8, thisPitch, 10);
    }