Arduino NFC Demo from Maker Faire Bay Area 2013 http://don.github.io/slides/2013-05-18-arduino-nfc

Arduino_NFC_LED_Demo

#include <Wire.h>
#include <Adafruit_NFCShield_I2C.h>
#include <NfcAdapter.h>

NfcAdapter nfc = NfcAdapter();

#include <Adafruit_NeoPixel.h>

// 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(60, 6, NEO_GRB + NEO_KHZ800);

void setup(void) {
    Serial.begin(115200);
    Serial.println("NFC Light Demo");
    nfc.begin();
    
    strip.begin();
    strip.show(); // Initialize all pixels to 'off'
}

void loop(void) {
    Serial.println("\nScan a NFC tag\n");
    if (nfc.tagPresent())
    {
        NfcTag tag = nfc.read();
        tag.print();
        
        NdefMessage message = tag.getNdefMessage();
        NdefRecord record = message[0];
        
        // Note we really should only handle TNF_MIME_MEDIA
        // and ensure that the mime type is "text/led"
        
        // payload is a byte array, could be binary
        String payload = getPayloadAsString(record);
        
        if (payload.startsWith("red")) 
        {
          setColor(255,0,0);
        } 
        else if (payload.startsWith("green")) 
        {
          setColor(0,255,0);
        } 
        else if (payload.startsWith("blue")) 
        {
          setColor(0,0,255);
        } 
        else if (payload.startsWith("bounce")) 
        {
          bounce();
        } 
        else if (payload.startsWith("rainbow")) 
        {
          rainbowCycle(5);
        } 
        else if (payload.startsWith("off")) 
        {
          setColor(0,0,0);
        } 
        else 
        {
          blink();
        }
                
    }
    delay(2000);
}

// set the whole strip to one color
void setColor(uint8_t red, uint8_t green, uint8_t blue) {
    uint8_t i;
    for (i = 0; i < strip.numPixels(); i++) {  
      strip.setPixelColor(i, red, green, blue);
    }
    strip.show();
}

// blink the strip on and off
void blink() {
  uint8_t i;
  uint8_t times = 3;
  for (i = 0; i < times; i++) {  
    setColor(255,255,255);
    delay(200);
    setColor(0,0,0);
    delay(200);
  }      
}

// make a light bounce up and down the strip
void bounce() {
  uint8_t i, x;
  uint8_t times = 3;
  uint8_t numPixels = strip.numPixels();
  uint8_t wait = 20;
  uint32_t color = strip.Color(255,0,255);
  uint32_t off = strip.Color(0,0,0);
 
  for (x = 0; x < times; x++) {
    for (i = 0; i < numPixels; i++) {
      strip.setPixelColor(i, color);
      if (i > 0) {
        strip.setPixelColor(i-1, off);
      }
      strip.show();
      delay(wait);
    }
    for (i = numPixels; i > 0; i--) { // note, this skips 0
      strip.setPixelColor(i, color);
      if (i < numPixels) {
        strip.setPixelColor(i+1, off);
      }
      strip.show();
      delay(wait);
    }
    // loop left light #1 on
    strip.setPixelColor(1, off);
    strip.show();
  }
}

// The payload is a byte array. We are expecting a string, but that is
// not always the case.  NdefRecord needs more helper methods
String getPayloadAsString(NdefRecord record) {

    int payloadLength = record.getPayloadLength();
    
    uint8_t* payloadBytes = (uint8_t*) malloc(payloadLength);

    // optionally zero out array
    memset(payloadBytes, 0, sizeof(payloadBytes));
   
    record.getPayload(payloadBytes);
    
    // cast because we *think* the payload is a String
    String payloadString = String((char*)payloadBytes);
    
    free(payloadBytes);
    
    return payloadString;
}

// rainbow methods are from Adafruit's strandtest sketch

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);
  }
}