Musical Fairy Lights for Christmas

It's almost the festive season and numbers of shops have started putting out their festive decorations, I thought that it’s about the right time to build some musical fairy lights! 

What will happen

• Read the data from the song array,

• Play the note using the tone function then

• Light up the LED's, reading pattern array.

I'll be using the following:

• 12 x LED's

• 12 x Current limiting Resistors

• 1 x ULN2803 Darlington Transistor Array

• Some Jumper Wires

• 1 x piezo Speaker

• 1 x Breadboard and

• 1 x Arduino
• To make the string of fairy lights I used 5 wires from an Ethernet cable 
• 
  

 Code

/*
  Jingle Bell Lights
  Fairy Lights with Jingle Bells as a tune.
  By Asiri H.  H/W: 4(or more) x LED's, 4(or more) x 220OHM resistors, ULN2803A, Piezo Speaker, Arduino UNO. 
*/

//GLOBAL VARS
 int barTime = 1200;                                     // 8/8 = 1000ms
byte nrLEDS = 4;                                         // 4 Base LEDs, You can add many in parallel
byte leds[] = { 3, 4, 5, 6};
byte speaker = 11;

byte patternLength = 64;                                 // pattern Length
byte songLength = 51;

const byte song[] = {                                    // Jingle Bells Data
  29, 2,29, 2,29, 4,29, 2,29, 2,29, 4,29, 2,32, 2,25, 3,27, 1,29, 8,30, 2,30, 2,
  30, 3,30, 1,30, 2,29, 2,29, 2,29, 1,29, 1,29, 2,27, 2,27, 2,29, 2,27, 4,32, 4,
  29, 2,29, 2,29, 4,29, 2,29, 2,29, 4,29, 2,32, 2,25, 3,27, 1,29, 8,30, 2,30, 2,
  30, 2,30, 2,30, 2,29, 2,29, 2,29, 1,29, 1,32, 2,32, 2,30, 2,27, 2,25, 8
}
;                                                        // The Structure is Note Number then 
                                                         // NoteLength in 8th's 
const byte pattern[] = {                                 //Pattern Data 
  0b0001,0b0010,0b0100,0b1000,                           //Bits corrispond to Leds in Array
  0b0001,0b0010,0b0100,0b1000,
  0b0001,0b0010,0b0100,0b1000,
  0b0001,0b0010,0b0100,0b1000,

  0b1000,0b1100,0b0100,0b0110,
  0b0010,0b0011,0b0001,0b1001,
  0b1000,0b1100,0b0100,0b0110,
  0b0010,0b0011,0b0001,0b1001,

  0b1010,0b0101,0b1010,0b0101,
  0b1010,0b0101,0b1010,0b0101,
  0b1010,0b0101,0b1010,0b0101,
  0b1010,0b0101,0b1010,0b0101,
  
  0b1100,0b0011,0b1100,0b0011,
  0b1100,0b0011,0b1100,0b0011,
  0b1100,0b0011,0b1100,0b0011,
  0b1100,0b0011,0b1100,0b0011,
  };

//FUNCTIONS 
 int noteToHz(int note) {                                 // Convert a Note Nr. to Frequency
  float freq = 440 * (pow(1.059463094359,note-21));       // -21 gives you note 1 at C3 (I Think)
  return int(freq);                                       // Results are accurate to 1hz
}

void lightLEDs(byte PORT_X) {                             // Control LED's State
  for (int q = 0;q<nrLEDS;q++) {
    digitalWrite(leds[q],bitRead(PORT_X,q));
  }
}


void setup() { //setup OUTPUT pins
  pinMode(speaker,OUTPUT);
  for(int t = 0; t < nrLEDS; t++){
    pinMode(leds[t],OUTPUT);
  }
}

void loop() {
  // Music Loop
  for (int t = 0; t < songLength; t++) {
    // Notes, Length and play the melody
    int note = noteToHz(song[t * 2]);
    int length = ((song[(t * 2)+1] * barTime) / 8);
    tone(speaker, note,  length - 50);
    
    // Flashing Lights!
    lightLEDs(pattern[t % patternLength]);
    delay(length);
  }
  
  // Silence Loop
  int randomSilence = random(1000,5000);
  for (int t = 0;t<randomSilence;t++){
    lightLEDs(pattern[t % patternLength]);  
    delay(barTime/4);
  }
}