rgb_led_matrix/arduino/rgb_led_matrix.ino

#include "Adafruit_NeoPixel.h"

#define PIN 6
enum {
  WIDTH=16,
  HEIGHT=16,
  N=WIDTH*HEIGHT*3
};
// 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
//   NEO_KHZ400  400 KHz bitstream (e.g. FLORA pixels)
//   NEO_KHZ800  800 KHz bitstream (e.g. High Density LED strip)
Adafruit_NeoPixel strip = Adafruit_NeoPixel(WIDTH * HEIGHT, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  strip.begin();
  strip.show(); // Initialize all pixels to 'off'
  Serial.begin(115200);
}

int j = 0;
int counter = 0;
char buf[3*WIDTH*HEIGHT];

void loop() {
  int incomingByte = 0;  
  while((Serial.available() > 0) && (incomingByte != -1)) {
    incomingByte = Serial.read();
    if (incomingByte != -1) {
      if(incomingByte == 254)
        counter = 0;
      else{
        buf[counter] = incomingByte;
        counter++;
        if (counter >= N)
          counter = 0;
      }
    }
  }
  if (counter >= N-1) {
    for (int i = 0; i < WIDTH*HEIGHT; i++) {
      strip.setPixelColor(i, strip.Color(buf[3*i], buf[3*i+1], buf[3*i+2]));
    }
    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 colorFill(uint32_t c) {
  for(uint16_t i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, c);
  }
  strip.show();
//  delay(50);
}

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);
  }
}

// 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);
  }
}

// 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) {
  if(WheelPos < 85) {
   return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
  } else if(WheelPos < 170) {
   WheelPos -= 85;
   return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else {
   WheelPos -= 170;
   return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
}