const int ledPin = 13; // pin the LED is connected to
int blinkRate=0; // blink rate stored in this variable
void setup()
{
  Serial.begin(9600); // Initialize serial port to send and receive at 9600 baud
  pinMode(ledPin, OUTPUT); // set this pin as output
}
void loop()
{
 if ( Serial.available()) // Check to see if at least one character is available
 {
 char ch = Serial.read();
  if(ch >= '0' && ch <= '9') // is this an ascii digit between 0 and 9?
  {
    blinkRate = (ch - '0'); // ASCII value converted to numeric value
    blinkRate = blinkRate * 100; // actual blinkrate is 100 mS times received
  }
 }
 blink();
}
// blink the LED with the on and off times determined by blinkRate
void blink()
{
  digitalWrite(ledPin,HIGH);
  delay(blinkRate); // delay depends on blinkrate value
  digitalWrite(ledPin,LOW);
  delay(blinkRate);
}