This demo uses an array of LEDs and two sets of speakers. As there are 12 different steps in an octave, I used 4 LEDs to represent the steps, leaving 4 undefined light combinations. Different songs can be programmed in to the code.
Video Player
Sources: Tech Excercise music Sequencer
</pre>// MusicSequenceDemo.ino : demonstrate generation of two simultaneous tones at different rates and patterns// The example program generates audio-frequency square waves at different// pitches and patterns on pins 4 and 5 to demonstrate an event-loop control// structure allowing parallel execution of multiple timed tasks with pattern// generation.// Define the pin numbers on which the outputs are generated.constintoutputPin1 = 4;constintoutputPin2 = 5;//Define LED outputsconstintoutputPin3 = 7;constintoutputPin4 = 8;constintoutputPin5 = 9;constintoutputPin6 = 10;intoutputPins[4] = {outputPin3, outputPin4, outputPin5, outputPin6};/****************************************************************/// Define the rhythm patterns for the two outputs using a simple pattern language.// Note values:// G = high pitch// C = low pitch// R = rest// Note durations:// q = quarter note// e = eighth note// s = sixteenth note// A note value symbol affects the pitch generated by the successive note duration symbols.// Any unknown symbol (including spaces) are ignored.constchar*rhythm1 ="fs Rs fs Rs Es Rs fs Rs As Rs Es Rs fs Rs fs Rs";constchar*rhythm2 ="Cs Rs Cs Rs Cs Rs Cs Rs Ge Re Ge Re";constchar*rhythm3 ="fq Rq fq Rq Ee Re fe Re Ae Re Ee Re fq Rq fe Rq";// Define the timing constants for the rhythmic elements.constlongquarter_duration = 500000;// 120 bpm/****************************************************************/// Define the timing constants for the audio output.//A3 is 1e6/(440)=2273constlongA3_half_period = 2273;boola_Lights [4] = {false,false,false,true};//A#3 is 1 step down from A3= 233.08, half period isconstlongAS3_half_period = 2145;boolaS_Lights [4] = {false,false,true,false};//B3 is 2 steps down from A3= 246.94constlongB3_half_period = 2025;boolb_Lights [4] = {false,false,true,true};// The low pitch is middle-C, the high pitch is the G a fifth above it. Given// A3 of 220 Hz and equal temperament, middle C4 has a frequency// 220*pow(2, 3.0/12) = 261.626 Hz.// The half-period in microseconds is 1e6/(2*261.626), rounded to an integer:constlongC4_half_period = 1911;boolc_Lights [4] = {false,true,false,false};constlongCS4_half_period = 1804;boolcS_Lights [4] = {false,true,false,true};constlongD4_half_period = 1703;boold_Lights [4] = {false,true,true,false};constlongDS4_half_period = 1607;booldS_Lights [4] = {false,true,true,true};constlongE4_half_period = 1517;boole_Lights [4] = {true,false,false,false};constlongF4_half_period = 1432;boolf_Lights [4] = {true,false,false,true};constlongFS4_half_period = 1351;boolfS_Lights [4] = {true,false,true,false};// The just intonation ratio for a musical fifth is 3/2, so// G4 = 1.5*261.626 = 392.438 Hz, and the half period duration in// microseconds is 1e6/(2*392.438): G4_half_periodconstlongG4_half_period = 1274;boolg_Lights [4] = {true,false,true,true};constlongGS4_half_period = 1204;boolgS_Lights [4] = {true,true,false,false}; voidLEDflip(boollights[4]){for(inti=0; i<4; i++) {if(lights[i]==true) {digitalWrite(outputPins[i], HIGH);}else{digitalWrite(outputPins[i], LOW);}}}/****************************************************************/// C++ class to generate a rhythmic sound pattern on a single output.classMelodyGenerator {private:// number of the pin to use for outputintoutput_pin;// current output stateintoutput_value;/// the time elapsed in microseconds since the last waveform update occurredunsignedlongtone_elapsed;/// the time elapsed in microseconds since the last pattern update occurredunsignedlongpattern_elapsed;// interval between output waveform transitions in microsecondslongtone_interval;// flag which indicates that no tone is generatedboolresting;// interval between pattern transitions in microsecondslongpattern_interval;// current pattern stringconstchar*pattern_string;// current position within the pattern stringintpattern_pos;public:// Constructor to initialize an instance of the class. This does not// configure the hardware, only the internal state.MelodyGenerator(intpin,constchar*pattern );// Update function to be called as frequently as possible to generate the// output. It requires the number of microseconds elapsed since the last// update.voidupdate(longinterval);};// Constructor for an instance of the class.MelodyGenerator::MelodyGenerator(intpin,constchar*pattern){// initialize the state variablesoutput_pin = pin;output_value = LOW;tone_elapsed = 0;pattern_elapsed = 0;tone_interval = C4_half_period;resting =false;pattern_interval = quarter_duration;pattern_string = pattern;pattern_pos = 0;} // Update polling function for an instance of the class.voidMelodyGenerator::update(longinterval){// Check whether the next transition time has been reached, and if so, update// the state and hardware output.tone_elapsed += interval;if(tone_elapsed >= tone_interval) {// Reset the timer according to the desired interval to produce a correct// average rate even if extra time has passed.tone_elapsed -= tone_interval;// Update the output pin to generate the audio waveform.output_value = !output_value;if(!resting) {digitalWrite( output_pin, output_value);}else{digitalWrite( output_pin, LOW);}}//-----------------------------------------------// Check whether the pattern interval has expired.pattern_elapsed += interval;if(pattern_elapsed >= pattern_interval) {pattern_elapsed -= pattern_interval;// Process one or more symbols from the rhythm pattern. This will process// any note value symbols until a note duration symbol is reached.for(;;) {charnext_symbol = pattern_string[pattern_pos];// Advance counter to next pattern string position.pattern_pos++;// if the next symbol is the end of the string, recycle to the beginning.if(next_symbol == 0) {pattern_pos = 0;continue;}elseif(next_symbol =='G') {tone_interval = G4_half_period;LEDflip(g_Lights);resting =false;continue;}elseif(next_symbol =='A') {tone_interval = A3_half_period;LEDflip(a_Lights);resting =false;continue;}elseif(next_symbol =='B') {tone_interval = B3_half_period;LEDflip(b_Lights);resting =false;continue; }elseif(next_symbol =='C') {tone_interval = C4_half_period;LEDflip(c_Lights);resting =false;continue;}elseif(next_symbol =='D') {tone_interval = D4_half_period;LEDflip(d_Lights);resting =false;continue;}elseif(next_symbol =='E') {tone_interval = E4_half_period;LEDflip(e_Lights);resting =false;continue;}elseif(next_symbol =='F') {tone_interval = F4_half_period;LEDflip(f_Lights);resting =false;continue;}elseif(next_symbol =='a') {tone_interval = AS3_half_period;LEDflip(aS_Lights);resting =false;continue;}elseif(next_symbol =='c') {tone_interval = CS4_half_period;LEDflip(cS_Lights);resting =false;continue;}elseif(next_symbol =='d') {tone_interval = DS4_half_period;LEDflip(dS_Lights);resting =false;continue;}elseif(next_symbol =='f') {tone_interval = FS4_half_period;LEDflip(fS_Lights);resting =false;continue;}elseif(next_symbol =='g') {tone_interval = GS4_half_period;LEDflip(gS_Lights);resting =false;continue;}elseif(next_symbol =='R') {resting =true;continue;}elseif(next_symbol =='q') {pattern_interval = quarter_duration;break;// leave the symbol-reading loop}elseif(next_symbol =='e') {pattern_interval = quarter_duration / 2;break;// leave the symbol-reading loop}elseif(next_symbol =='s') {pattern_interval = quarter_duration / 4;break;// leave the symbol-reading loop}else{// all other symbols are ignoredcontinue;}}}}/****************************************************************/// Global variables.// Declare two instances of the pattern generator.MelodyGenerator generator1( outputPin1, rhythm1 );MelodyGenerator generator2( outputPin2, rhythm3 );// The timestamp in microseconds for the last polling cycle, used to compute// the exact interval between output updates.unsignedlonglast_update_clock = 0;/****************************************************************//****************************************************************/// This function is called once after reset to initialize the program.voidsetup(){// Initialize two digital output pins, one for each pattern generator.pinMode( outputPin1, OUTPUT );pinMode( outputPin2, OUTPUT );pinMode(outputPin3, OUTPUT);pinMode(outputPin4, OUTPUT);pinMode(outputPin5, OUTPUT);pinMode(outputPin6, OUTPUT);}/****************************************************************/// This function is called repeatedly as fast as possible from within the// built-in library to poll program events.voidloop(){// The timestamp in microseconds for the last polling cycle, used to compute// the exact interval between output updates.staticunsignedlonglast_update_clock = 0;// Read the microsecond clock.unsignedlongnow = micros();// Compute the time elapsed since the last poll. This will correctly handle wrapround of// the 32-bit long time value given the properties of twos-complement arithmetic.unsignedlonginterval = now - last_update_clock;last_update_clock = now;// update the pattern generatorsgenerator1.update(interval);generator2.update(interval);}/****************************************************************/<pre>
Leave a Reply
You must be logged in to post a comment.