//  do ,  re ,  mi ,  fa , sol , la ,  si ,  do 
int freqs[] = { 
  1915, 1700, 1519, 1432, 1275, 1136, 1014, 956};
void setup(){
  pinMode(11,OUTPUT);
  Serial.begin(9600); //open the serial to print
}
void loop(){
  int val = Serial.read(); //read the serial to see
  if(val>’0’ && val <= ‘9’){ //which key was pressed
    val = val - ‘0’; //convert the character to an integer
    Serial.print(val,DEC);
    Serial.println();
    for(int i=0; i<500; i++){ //duration of the tone (.5 seconds)
      digitalWrite(11,HIGH);
      delayMicroseconds(freqs[val]); //the tone’s frequency
      digitalWrite(11,LOW);
      delayMicroseconds(freqs[val]);
    }
  }
}