buzzer with notes

gistfile1.c

// Buzzer example function for the CEM-1203 buzzer (Sparkfun's part #COM-07950).
// by Rob Faludi
// http://www.faludi.com
// Matehacked by Lucas and Jerônimo

int noteToFreq(int note)
{
  return (int) pow(2, (double)note/12) * 440; 
}

void setup() {
  pinMode(4, OUTPUT); // set a pin for buzzer output
  pinMode(2, OUTPUT);
}


void loop() {
  buzz(2, noteToFreq(39), 50);
  buzz(4, noteToFreq(36), 50);
  delay(25);
  buzz(2, noteToFreq(42), 100);
  buzz(4, noteToFreq(39), 200);
  delay(25);
  buzz(2, noteToFreq(45), 150);
  buzz(4, noteToFreq(41), 100);
  delay(25);
  buzz(2, noteToFreq(42), 100);
  buzz(4, noteToFreq(39), 150);
  delay(25);
}

void buzz(int targetPin, long frequency, long length) {
  long delayValue = 1000000/frequency/2; // calculate the delay value between transitions
  //// 1 second's worth of microseconds, divided by the frequency, then split in half since
  //// there are two phases to each cycle
  long numCycles = frequency * length/ 1000; // calculate the number of cycles for proper timing
  //// multiply frequency, which is really cycles per second, by the number of seconds to 
  //// get the total number of cycles to produce
 for (long i=0; i < numCycles; i++){ // for the calculated length of time...
    digitalWrite(targetPin,HIGH); // write the buzzer pin high to push out the diaphram
    delayMicroseconds(delayValue); // wait for the calculated delay value
    digitalWrite(targetPin,LOW); // write the buzzer pin low to pull back the diaphram
    delayMicroseconds(delayValue); // wait againf or the calculated delay value
  }
}