Author: Qianyue Zhou

For Halloween, I designed a glowing butterfly headpiece, inspired by the elegance and vibrance of blue butterflies. The headpiece is adorned with artificial butterflies and small LED lights woven through blue, glittery fabric to create a whimsical, ethereal effect. I chose this concept because butterflies symbolize transformation and beauty—perfect for a night of costumes and creativity.

Throughout the process, I learned a lot about wiring and working with LEDs to achieve the right brightness. One thing I’d do differently is adjust the wiring to make it less visible, perhaps by hiding it within thicker fabric or creating a dedicated channel for the wires.

Materials Used:

• Artificial butterflies
• Blue glitter fabric
• LED string lights
• Battery pack
• Wire

#include <Adafruit_NeoPixel.h>

#define PIN 1

#define NUM_LEDS 8

#define BRIGHTNESS 50

// Parameter 1 = number of pixels in strip
// Parameter 2 = pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
//   NEO_RGB     Pixels are wired for RGB bitstream
//   NEO_GRB     Pixels are wired for GRB bitstream, correct if colors are swapped upon testing
//   NEO_RGBW    Pixels are wired for RGBW bitstream
//   NEO_KHZ400  400 KHz bitstream (e.g. FLORA pixels)
//   NEO_KHZ800  800 KHz bitstream (e.g. High Density LED strip), correct for neopixel stick
Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, PIN, NEO_GRBW + NEO_KHZ800);

void setup() {

  strip.setBrightness(BRIGHTNESS);
  strip.begin();
  strip.show(); // Initialize all pixels to 'off'
}

void loop() {
  // Alternate fading between blue and purple
  fadeColor(strip.Color(0, 0, 255));   // Blue
  fadeColor(strip.Color(128, 0, 128)); // Purple
}

// Function to fade in and out a specified color
void fadeColor(uint32_t color) {
  // Gradually increase brightness
  for (int brightness = 0; brightness <= 255; brightness += 5) {
    setStripColor(color, brightness);
    delay(30); // Adjust delay for slower or faster fade
  }
  
  // Gradually decrease brightness
  for (int brightness = 255; brightness >= 0; brightness -= 5) {
    setStripColor(color, brightness);
    delay(30); // Adjust delay for slower or faster fade
  }
}

// Function to set all LEDs to a specific color with specified brightness
void setStripColor(uint32_t color, int brightness) {
  uint8_t r = (color >> 16) & 0xFF;
  uint8_t g = (color >>  8) & 0xFF;
  uint8_t b =  color        & 0xFF;

  // Apply brightness scaling
  r = (r * brightness) / 255;
  g = (g * brightness) / 255;
  b = (b * brightness) / 255;

  // Set color for all LEDs
  for (int i = 0; i < strip.numPixels(); i++) {
    strip.setPixelColor(i, strip.Color(r, g, b));
  }
  strip.show();
}

}

// Fill the dots one after the other with a color
void colorWipe(uint32_t c, uint8_t wait) {
  for(uint16_t i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c);
    strip.show();
    delay(wait);
  }
}

void pulseWhite(uint8_t wait) {
  for(int j = 0; j < 256 ; j++){
      for(uint16_t i=0; i<strip.numPixels(); i++) {
          strip.setPixelColor(i, strip.Color(0,0,0, j ) );
        }
        delay(wait);
        strip.show();
      }

  for(int j = 255; j >= 0 ; j--){
      for(uint16_t i=0; i<strip.numPixels(); i++) {
          strip.setPixelColor(i, strip.Color(0,0,0, j ) );
        }
        delay(wait);
        strip.show();
      }
}


void rainbowFade2White(uint8_t wait, int rainbowLoops, int whiteLoops) {
  float fadeMax = 100.0;
  int fadeVal = 0;
  uint32_t wheelVal;
  int redVal, greenVal, blueVal;

  for(int k = 0 ; k < rainbowLoops ; k ++){
    
    for(int j=0; j<256; j++) { // 5 cycles of all colors on wheel

      for(int i=0; i< strip.numPixels(); i++) {

        wheelVal = Wheel(((i * 256 / strip.numPixels()) + j) & 255);

        redVal = red(wheelVal) * float(fadeVal/fadeMax);
        greenVal = green(wheelVal) * float(fadeVal/fadeMax);
        blueVal = blue(wheelVal) * float(fadeVal/fadeMax);

        strip.setPixelColor( i, strip.Color( redVal, greenVal, blueVal ) );

      }

      //First loop, fade in!
      if(k == 0 && fadeVal < fadeMax-1) {
          fadeVal++;
      }

      //Last loop, fade out!
      else if(k == rainbowLoops - 1 && j > 255 - fadeMax ){
          fadeVal--;
      }

        strip.show();
        delay(wait);
    }
  
  }



  delay(500);


  for(int k = 0 ; k < whiteLoops ; k ++){

    for(int j = 0; j < 256 ; j++){

        for(uint16_t i=0; i < strip.numPixels(); i++) {
            strip.setPixelColor(i, strip.Color(0,0,0, j ) );
          }
          strip.show();
        }

        delay(2000);
    for(int j = 255; j >= 0 ; j--){

        for(uint16_t i=0; i < strip.numPixels(); i++) {
            strip.setPixelColor(i, strip.Color(0,0,0, j ) );
          }
          strip.show();
        }
  }

  delay(500);


}

void whiteOverRainbow(uint8_t wait, uint8_t whiteSpeed, uint8_t whiteLength ) {
  
  if(whiteLength >= strip.numPixels()) whiteLength = strip.numPixels() - 1;

  int head = whiteLength - 1;
  int tail = 0;

  int loops = 3;
  int loopNum = 0;

  static unsigned long lastTime = 0;


  while(true){
    for(int j=0; j<256; j++) {
      for(uint16_t i=0; i<strip.numPixels(); i++) {
        if((i >= tail && i <= head) || (tail > head && i >= tail) || (tail > head && i <= head) ){
          strip.setPixelColor(i, strip.Color(0,0,0, 255 ) );
        }
        else{
          strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
        }
        
      }

      if(millis() - lastTime > whiteSpeed) {
        head++;
        tail++;
        if(head == strip.numPixels()){
          loopNum++;
        }
        lastTime = millis();
      }

      if(loopNum == loops) return;
    
      head%=strip.numPixels();
      tail%=strip.numPixels();
        strip.show();
        delay(wait);
    }
  }
  
}
void fullWhite() {
  
    for(uint16_t i=0; i<strip.numPixels(); i++) {
        strip.setPixelColor(i, strip.Color(0,0,0, 255 ) );
    }
      strip.show();
}


// Slightly different, this makes the rainbow equally distributed throughout
void rainbowCycle(uint8_t wait) {
  uint16_t i, j;

  for(j=0; j<256 * 5; j++) { // 5 cycles of all colors on wheel
    for(i=0; i< strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
    }
    strip.show();
    delay(wait);
  }
}

void rainbow(uint8_t wait) {
  uint16_t i, j;

  for(j=0; j<256; j++) {
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel((i+j) & 255));
    }
    strip.show();
    delay(wait);
  }
}

// Input a value 0 to 255 to get a color value.
// The colours are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
  WheelPos = 255 - WheelPos;
  if(WheelPos < 85) {
    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3,0);
  }
  if(WheelPos < 170) {
    WheelPos -= 85;
    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3,0);
  }
  WheelPos -= 170;
  return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0,0);
}

uint8_t red(uint32_t c) {
  return (c >> 8);
}
uint8_t green(uint32_t c) {
  return (c >> 16);
}
uint8_t blue(uint32_t c) {
  return (c);
}