/* Play Melody * ----------- * * Program to play a simple melody * * Tones are created by quickly pulsing a speaker on and off * using PWM, to create signature frequencies. * * Each note has a frequency, created by varying the period of * vibration, measured in microseconds. We'll use pulse-width * modulation (PWM) to create that vibration. * We calculate the pulse-width to be half the period; we pulse * the speaker HIGH for 'pulse-width' microseconds, then LOW * for 'pulse-width' microseconds. * This pulsing creates a vibration of the desired frequency. * * (cleft) 2005 D. Cuartielles for K3 * Refactoring and comments 2006 clay.shirky@nyu.edu * See NOTES in comments at end for possible improvements */ // TONES ========================================== // Start by defining the relationship between // note, period, & frequency. #define c 3830 // 261 Hz #define d 3400 // 294 Hz #define e 3038 // 329 Hz #define f 2864 // 349 Hz #define g 2550 // 392 Hz #define a 2272 // 440 Hz #define b 2028 // 493 Hz #define C 1912 // 523 Hz // Define a special note, 'R', to represent a rest #define R 0 // SETUP ============================================ // Set up speaker on a PWM pin (digital 9, 10 or 11) int speakerOut = 9; // Do we want debugging on serial out? 1 for yes, 0 for no int DEBUG = 1; void setup() { pinMode(speakerOut, OUTPUT); if (DEBUG) { Serial.begin(9600); // Set serial out if we want debugging } } // MELODY and TIMING ======================================= // melody[] is an array of notes, accompanied by beats[], // which sets each note's relative length (higher #, longer note) int melody[] = { C, b, g, C, b, e, R, C, c, g, a, C }; int beats[] = { 16, 16, 16, 8, 8, 16, 32, 16, 16, 16, 8, 8 }; int MAX_COUNT = sizeof(melody) / 2; // Melody length, for looping. // Set overall tempo long tempo = 10000; // Set length of pause between notes int pause = 1000; // Loop variable to increase Rest length int rest_count = 100; //<-BLETCHEROUS HACK; See NOTES // Initialize core variables int tone_ = 0; int beat = 0; long duration = 0; // PLAY TONE ============================================== // Pulse the speaker to play a tone for a particular duration void playTone() { long elapsed_time = 0; if (tone_ > 0) { // if this isn't a Rest beat, while the tone has // played less long than 'duration', pulse speaker HIGH and LOW while (elapsed_time < duration) { digitalWrite(speakerOut,HIGH); delayMicroseconds(tone_ / 2); // DOWN digitalWrite(speakerOut, LOW); delayMicroseconds(tone_ / 2); // Keep track of how long we pulsed elapsed_time += (tone_); } } else { // Rest beat; loop times delay for (int j = 0; j < rest_count; j++) { // See NOTE on rest_count delayMicroseconds(duration); } } } // LET THE WILD RUMPUS BEGIN ============================= void loop() { // Set up a counter to pull from melody[] and beats[] for (int i=0; i