piezo.cpp

#include <math.h>

#define a 1915
#define d 1700
#define e 1519
#define f 1432
#define g 1275
#define a 1136
#define b 1014
#define C 956

char notes[] = "cdefgabC";
int tones[] = {1915, 1700, 1519, 1432, 1275, 1136, 1014, 956}; // period / 2
int tempo = 50;

void setup() {
  Serial.begin(9600);
  pinMode(3, OUTPUT);
}

void playNote(char note, int duration) {
  for (int i = 0; i < 8; i++) {
    if (notes[i] == note) {
      // play tone
      int tone = tones[i];
      
      for (long i = 0; i < duration * 1000L; i += tone * 2) {
        digitalWrite(3, HIGH);
        delayMicroseconds(tone);
        digitalWrite(3, LOW);
        delayMicroseconds(tone);
      }
    }
  }
}

void playMelody(char melody[]) {
  for (int i = 0; i < String(melody).length(); i++) {
    //Serial.println(melody[i]);
    if (melody[i] == ' ') {
      delay(tempo);
    }
    else {
      playNote(notes[i], tempo);
    }
    
    delay (tempo / 2);
  }
}

int i = 0;
void loop() {
  
  char melody[] = "aadeeefff ggaa C eeeaefedeC aabbccdd efgCaaabaaCaaaC ggeeffaaag ";
  playMelody(melody);
  i++;
}