#include <SoftwareSerial.h>

SoftwareSerial SSerial(8, 7); // Arduino RX, Arduino TX

const int ledPin = 9;      // the pin that the LED is attached to

void setup()
{
  // initialize the serial communication:
  SSerial.begin(9600);

  // initialize the ledPin as an output:
  pinMode(ledPin, OUTPUT);
}

void loop()
{
  byte brightness;

  // check if data has been sent from the computer:
  if (SSerial.available()) {
    // read the most recent byte (which will be from 0 to 255):
    brightness = SSerial.read();
    // set the brightness of the LED:
    analogWrite(ledPin, brightness);
  }
}