gistfile1.c

#include <math.h>
#include "oh_tannenbaum.h"

/* This melody is defined in the header above. */
int const melody[] = MELODY;

/********************************************************/
/* 3.) Define a constant LOUDSPEAKER_PIN containing the 
   number of the digital pin you just connected the 
   "+" pin of your loudspeaker to.
 */
 
 int const LOUDSPEAKER_PIN = 8;

/********************************************************/

/********************************************************/
/* 7.) Define a new function waitForTap,
   that does nothing until the analog port A0 has
   some value greater than 10.
   
   Call that function just before you call play(int, long).
 */
 
 void waitForTap() {
   if(analogRead(0) > 10) {
     // Do something
   }
 }
 

/********************************************************/

void play(int note, long duration) {
  pinMode(LOUDSPEAKER_PIN, OUTPUT);
  /********************************************************/
  /* The variable note gives you a frequency in Hz.
     The variable duration is given in milliseconds.

     5.) Generate a rectangular wave with the given 
     frequency and duration.
     To do so, change the value at the loudspeaker pin
     to HIGH and to LOW for a sufficient number of
     times and wait an appropriate time after you set
     each value.

     Hint: Think about the resolutions you need!
     You may want to use more percise functions than the
     ones from the LEDFlash example
   */
   
   /*
     1.000.000mikrosekunden = 1sec
     Hz = Schwingung pro Sekunde
   
   */
   
   int i;
   
   for(i = 0; i < duration; i++) {
      digitalWrite(LOUDSPEAKER_PIN, HIGH);
      delayMicroseconds(1000000/note);
      digitalWrite(LOUDSPEAKER_PIN, LOW);
      delayMicroseconds(1000000/note);
    }
   
   

  /********************************************************/
  pinMode(LOUDSPEAKER_PIN, INPUT);
}


/* the setup routine runs once when you press reset: */
void setup() {
  pinMode(LOUDSPEAKER_PIN, INPUT);
}

/* the loop routine runs over and over again forever: */
void loop() {
  /********************************************************/
  /* 4.) Look at the included melody.
     How can you determine how long it is?
     
     Call play(int, long) with each note in the melody.
     Play each note for 125ms.
  */
  
  int arraySize, i;
  
  arraySize = sizeof(melody)/sizeof(int);
  
  
  for(i = 0; i < arraySize; i++) {
    waitForTap();
    play(melody[i], 125);
    delay(20);
  }

  /********************************************************/
 
  delay(500);
}