Arduino/build/shared/examples/10.StarterKit/p07_Keyboard/p07_Keyboard.ino

/*
  Arduino Starter Kit example
 Project 7  - Keyboard
 
 This sketch is written to accompany Project 7 in the
 Arduino Starter Kit
 
 Parts required:
 two 10 kilohm resistors
 1 Megohm resistor 
 220 ohm resistor
 4 pushbuttons
 piezo
 
 Created 13 September 2012
 by Scott Fitzgerald
 
 http://arduino.cc/starterKit
 
 This example code is part of the public domain 
*/

// create an array of notes
// the numbers below correspond to 
// the frequencies of middle C, D, E, and F
int notes[] = {262, 294, 330, 349};

void setup() {
    //start serial communication
  Serial.begin(9600);
}

void loop() {
  // create a local variable to hold the input on pin A0
  int keyVal = analogRead(A0);
  // send the value from A0 to the Serial Monitor
  Serial.println(keyVal);
  
  // play the note corresponding to each value on A0
  if(keyVal == 1023){
    // play the first frequency in the array on pin 8
    tone(8, notes[0]);
  }
  else if(keyVal >= 990 && keyVal <= 1010){
    // play the second frequency in the array on pin 8
    tone(8, notes[1]);
  }
  else if(keyVal >= 505 && keyVal <= 515){
    // play the third frequency in the array on pin 8
    tone(8, notes[2]);
  }
  else if(keyVal >= 5 && keyVal <= 10){
    // play the fourth frequency in the array on pin 8
    tone(8, notes[3]);
  }
  else{
    // if the value is out of range, play no tone
    noTone(8);
  }
}