int inpin = 8;
int val = 0;
char ch;

void setup() {
  pinMode(WLED, OUTPUT);
  pinMode(inpin, INPUT); 
  Serial.begin(9600);
}

void loop() {
  // since the pin has the internal
  // pullup resistor enabled 
  // reading the pin with nothing attach to it will
  // return HIGH
  if (Serial.available() > 0) {
    ch = Serial.read();
    if (ch == 'p') {
      // since the pin has the internal
      // pullup resistor enabled 
      // reading the pin when disconnected will
      // return HIGH
      pullup(inpin);
    } 
    else {
      // since the pin has the internal
      // pullup resistor enabled 
      // reading the pin when disconnected will
      // return LOW or unstable readings
      noPullup(inpin);
    }
  }

  val = digitalRead(inpin);
  if (val == HIGH) 
  {
    digitalWrite(WLED, HIGH);
  } 
  else {
    digitalWrite(WLED, LOW);
  }
}