serial_and_leds.ino

// Using adafruit's LED library: https://github.com/adafruit/LPD8806
#include <LPD8806.h>
#include <SPI.h>

int dataPin  = 2;
int clockPin = 3;

// First parameter is the number of LEDs in the strand.  The LED strips
// are 32 LEDs per meter but you can extend or cut the strip.  Next two
// parameters are SPI data and clock pins:
LPD8806 strip = LPD8806(32, dataPin, clockPin);

int incomingByte = 0;   // for incoming serial data

void colorChase(uint32_t c, uint8_t wait);

void setup() {
  // Start up the LED strip
  strip.begin();

  // Update the strip, to start they are all 'off'
  strip.show();
  
  Serial.begin(9600);     // opens serial port, sets data rate to 9600 bps
}

void loop() {
        // send data only when you receive data:
        if (Serial.available() > 0) {
                // read the incoming byte:
                incomingByte = Serial.read();

                // say what you got:
                Serial.print("I received: ");
                Serial.println(incomingByte, DEC);
        }
        else {
          incomingByte = 2;
        }
        
        Serial.println("Looping the lights");
        
        // Send a simple pixel chase based on the sent time    
        colorChase(strip.Color(127,127,127), incomingByte - '0'); // white
        colorChase(strip.Color(127,0,0)    , incomingByte - '0'); // red
        colorChase(strip.Color(127,127,0)  , incomingByte - '0'); // yellow
        colorChase(strip.Color(0,127,0)    , incomingByte - '0'); // green
        colorChase(strip.Color(0,127,127)  , incomingByte - '0'); // cyan
        colorChase(strip.Color(0,0,127)    , incomingByte - '0'); // blue
        colorChase(strip.Color(127,0,127)  , incomingByte - '0'); // magenta
}

// Chase a dot down the strip
// good for testing purposes
void colorChase(uint32_t c, uint8_t wait) {
  int i;

  Serial.print("Wait time is: ");
  Serial.println(wait, DEC);
  
  for (i=0; i < strip.numPixels(); i++) {
    strip.setPixelColor(i, 0);  // turn all pixels off
  }

  for (i=0; i < strip.numPixels(); i++) {
      strip.setPixelColor(i, c); // set one pixel
      strip.show();              // refresh strip display
      delay(wait);               // hold image for a moment
      strip.setPixelColor(i, 0); // erase pixel (but don't refresh yet)
  }
  strip.show(); // for last erased pixel
}