Arduino Roomba Blink Challenge 2

/*  Roomba Blink - Challenge 2

        by Justin Modra, follow my on Twitter @JustinModra
        May 30, 2015

    Sends an active low pulse to the DD (Device Detect) Pin of the Roomba 4000
    for 500msec to wake the Roomba up from the default power on sleep state

    Puts the Roomba in Full Command Mode, turn off safety features
    ignore wheel drops, cliff detectors and connected charger

        Initializes a software defined serial port
        on pins 5 and 6 of the Arduino Uno

    Illuminates the Roomba Power LED
        Color fades through the possible color values from 0 to 255

    Roomba Serial Command Interface Specification at the following location:
    http://www.ecsl.cs.sunysb.edu/mint/Roomba_SCI_Spec_Manual.pdf

    ArduinoUno Digital IO 5 RX to Roomba pin 4 TXD (yellow wire)
    ArduinoUno Digital IO 6 TX to Roomba pin 3 RXD (orange wire)
    ArduinoUno Digital IO 7 DD to Roomba pin 5 DD  (black wire)

        See the project description at the following website:
        https://nightskylife.wordpress.com/2015/05/26/interfacing-roomba-model-4000-with-arduino-uno/

*/

#include <SoftwareSerial.h>
SoftwareSerial mySerial(5, 6); //rx,tx
int ddPin = 7;


// the setup function runs once when you press reset or power the board
void setup() {
  pinMode(ddPin,  OUTPUT);
  pinMode(13, OUTPUT);
  mySerial.begin(57600);
  //Use Device Detect to wake Roomba
  digitalWrite(ddPin, HIGH);
  delay(100);
  digitalWrite(ddPin, LOW);
  delay(500);
  digitalWrite(ddPin, HIGH);
  delay(2000);
  //Initialize Roomba SCI
  // Start SCI
  mySerial.write(128);
  delay(100);
  // Enable control
  mySerial.write(130);
  delay(100);
  // Enable full control, no safety, all commands
  mySerial.write(132);
  delay(100);
}

// the loop function runs over and over again forever
void loop() {

  for (int fadecount=0; fadecount < 256; fadecount++) {
      mySerial.write(139);                   // control LEDs opcode
      mySerial.write((byte)0);               // Status LED off
      mySerial.write((byte)fadecount);       // Power Color
      mySerial.write(255);               // Intensity set to full

      delay(100);
  }
}