Add tone music example (#185)

libraries/rp2040/examples/ToneHappyBirthday/ToneHappyBirthday.ino

+// The speaker will play the tune to Happy Birthday continuously
+// Author: Tony DiCola
+// License: MIT (https://opensource.org/licenses/MIT)
+
+#include <Arduino.h>
+
+#ifdef USE_TINYUSB
+// For Serial when selecting TinyUSB.  Can't include in the core because Arduino IDE
+// will not link in libraries called from the core.  Instead, add the header to all
+// the standard libraries in the hope it will still catch some user cases where they
+// use these libraries.
+// See https://github.com/earlephilhower/arduino-pico/issues/167#issuecomment-848622174
+#include <Adafruit_TinyUSB.h>
+#endif
+
+// pin_buzzer should be defined by the supported variant e.g CPlay Bluefruit or CLUE.
+// Otherwise please define the pin you would like to use for tone output
+#ifndef PIN_BUZZER
+#define PIN_BUZZER    A0
+#endif
+
+uint8_t const pin_buzzer = PIN_BUZZER;
+
+// A few music note frequencies as defined in this tone example:
+//   https://www.arduino.cc/en/Tutorial/toneMelody
+#define NOTE_C4  262
+#define NOTE_CS4 277
+#define NOTE_D4  294
+#define NOTE_DS4 311
+#define NOTE_E4  330
+#define NOTE_F4  349
+#define NOTE_FS4 370
+#define NOTE_G4  392
+#define NOTE_GS4 415
+#define NOTE_A4  440
+#define NOTE_AS4 466
+#define NOTE_B4  494
+#define NOTE_C5  523
+#define NOTE_CS5 554
+#define NOTE_D5  587
+#define NOTE_DS5 622
+#define NOTE_E5  659
+#define NOTE_F5  698
+#define NOTE_FS5 740
+#define NOTE_G5  784
+#define NOTE_GS5 831
+#define NOTE_A5  880
+#define NOTE_AS5 932
+#define NOTE_B5  988
+
+// Define note durations.  You only need to adjust the whole note
+// time and other notes will be subdivided from it directly.
+#define WHOLE         2200       // Length of time in milliseconds of a whole note (i.e. a full bar).
+#define HALF          WHOLE/2
+#define QUARTER       HALF/2
+#define EIGHTH        QUARTER/2
+#define EIGHTH_TRIPLE QUARTER/3
+#define SIXTEENTH     EIGHTH/2
+
+// Play a note of the specified frequency and for the specified duration.
+// Hold is an optional bool that specifies if this note should be held a
+// little longer, i.e. for eighth notes that are tied together.
+// While waiting for a note to play the waitBreath delay function is used
+// so breath detection and pixel animation continues to run.  No tones
+// will play if the slide switch is in the -/off position or all the
+// candles have been blown out.
+void playNote(int frequency, int duration, bool hold = false, bool measure = true) {
+  (void) measure;
+
+  if (hold) {
+    // For a note that's held play it a little longer than the specified duration
+    // so it blends into the next tone (but there's still a small delay to
+    // hear the next note).
+    tone(pin_buzzer, frequency, duration + duration / 32);
+  } else {
+    // For a note that isn't held just play it for the specified duration.
+    tone(pin_buzzer, frequency, duration);
+  }
+
+  delay(duration + duration / 16);
+}
+
+// Song to play when the candles are blown out.
+void celebrateSong() {
+  // Play a little charge melody, from:
+  //  https://en.wikipedia.org/wiki/Charge_(fanfare)
+  // Note the explicit boolean parameters in particular the measure=false
+  // at the end.  This means the notes will play without any breath measurement
+  // logic.  Without this false value playNote will try to keep waiting for candles
+  // to blow out during the celebration song!
+  playNote(NOTE_G4, EIGHTH_TRIPLE, true, false);
+  playNote(NOTE_C5, EIGHTH_TRIPLE, true, false);
+  playNote(NOTE_E5, EIGHTH_TRIPLE, false, false);
+  playNote(NOTE_G5, EIGHTH, true, false);
+  playNote(NOTE_E5, SIXTEENTH, false);
+  playNote(NOTE_G5, HALF, false);
+}
+
+void setup() {
+  // Initialize serial output and Circuit Playground library.
+  Serial.begin(115200);
+
+  pinMode(pin_buzzer, OUTPUT);
+  digitalWrite(pin_buzzer, LOW);
+}
+
+void loop() {
+  // Play happy birthday tune, from:
+  //  http://www.irish-folk-songs.com/happy-birthday-tin-whistle-sheet-music.html#.WXFJMtPytBw
+  // Inside each playNote call it will play a note and drive the NeoPixel animation
+  // and check for a breath against the sound sensor.  Once all the candles are blown out
+  // the playNote calls will stop playing music.
+  playNote(NOTE_D4, EIGHTH, true);
+  playNote(NOTE_D4, EIGHTH);
+  playNote(NOTE_E4, QUARTER);       // Bar 1
+  playNote(NOTE_D4, QUARTER);
+  playNote(NOTE_G4, QUARTER);
+  playNote(NOTE_FS4, HALF);         // Bar 2
+  playNote(NOTE_D4, EIGHTH, true);
+  playNote(NOTE_D4, EIGHTH);
+  playNote(NOTE_E4, QUARTER);       // Bar 3
+  playNote(NOTE_D4, QUARTER);
+  playNote(NOTE_A4, QUARTER);
+  playNote(NOTE_G4, HALF);          // Bar 4
+  playNote(NOTE_D4, EIGHTH, true);
+  playNote(NOTE_D4, EIGHTH);
+  playNote(NOTE_D5, QUARTER);       // Bar 5
+  playNote(NOTE_B4, QUARTER);
+  playNote(NOTE_G4, QUARTER);
+  playNote(NOTE_FS4, QUARTER);      // Bar 6
+  playNote(NOTE_E4, QUARTER);
+  playNote(NOTE_C5, EIGHTH, true);
+  playNote(NOTE_C5, EIGHTH);
+  playNote(NOTE_B4, QUARTER);       // Bar 7
+  playNote(NOTE_G4, QUARTER);
+  playNote(NOTE_A4, QUARTER);
+  playNote(NOTE_G4, HALF);          // Bar 8
+
+  celebrateSong();
+
+  // One second pause before repeating the loop and playing
+  delay(1000);
+}