MIDI Color Organ Testing

MIDI to PWM LED Array using World Semiconductor WS2803

Two 18 Channel PWM Constant Current LED Drivers
Three Octave MIDI Driven LED ARRAY
Info on connecting WS2803, LEDs, Arduino, RasPI

Arduino code MIDI_WS803 MIDI_WS2803.ino // MIDI_WS2803 // By Thomas Olson // teo20130301.01 // MIDI IN to WS2803 LED Array // WS2803 pin4 CKI -> ws2803_clockPin (digital pin 5) // WS2803 pin5 SDI -> ws2803_dataPin (digital pin 6) // WS2803 pin2 IREF = Rext to GND // WS2803 pin6-23 = OUT0-17 // MIDI IN - digital pin 7 // MIDI OUT - digital pin 8 // This program takes MIDI Note Velocitys from Channel 0 // and applies them to a linear LED array where Velocity values are PWM values. // This test uses two WS2803 in series to represent three octaves. #include <SoftwareSerial.h> SoftwareSerial midiSerial(7,8); // instantiate MIDI serial port uint8_t midiCommand; uint8_t midiNote; uint8_t midiVelocity; //uint8_t midiChannel = 0; // MIDI channel 1 to 16 are actually 0 to 15; // define which pins are the WS2803 control signals const int ws2803_clockPin = 5; const int ws2803_dataPin = 6; #define nLEDs 36 // Three Octaves #define LOWEST_NOTE 48 // What MIDI note starts the 3 octaves. #define nNOTES 128 // MIDI has 127 notes per MIDI channel uint8_t notes[nNOTES]; // Array of note velocities/LED PWM levels void setup(){ pinMode(ws2803_clockPin, OUTPUT); pinMode(ws2803_dataPin, OUTPUT); // Initialize WS2803 - Clock needs to be low at least 600us to prepare itself. digitalWrite(ws2803_clockPin, LOW); delayMicroseconds(600); // Initialize the note array velocities / ledBar PWM levels to all OFF. for(int note = 0; note < nNOTES; note++){ notes[note] = 0x00; } loadWS2803(); midiSerial.begin(31250); // MIDI devices baud rate are 31,250 } void loop(){ do{ if (midiSerial.available()){ midiCommand = midiSerial.read(); //1st byte is MIDI command midiNote = midiSerial.read(); //2nd byte is MIDI note midiVelocity = midiSerial.read(); //3rd byte is note Velocity switch (midiCommand) { case 128: // Only interested in MIDI Channel 0. notes[midiNote] = 0; break; case 144: // Only interested in MIDI Channel 0. switch(midiVelocity) { case 0: // Alternative to turn off a note notes[midiNote] = 0; break; default: // Turn on note. notes[midiNote] = midiVelocity; break; } break; default: // Ignore all other MIDI commands. break; } loadWS2803(); } } while (midiSerial.available() > 24); } //loop // MIDI note velocities are 0-127. WS2803 PWM levels are 0-255. So double // velocities to scale to PWM levels. void loadWS2803(){ for (int wsOut = LOWEST_NOTE; wsOut < LOWEST_NOTE + nLEDs; wsOut++){ shiftOut(ws2803_dataPin, ws2803_clockPin, MSBFIRST, 0xFF & (2 * notes[wsOut])); } delayMicroseconds(600); // 600us needed to latch and reset WS2803s }