+/- to turn on/off the LED

int led =13;

char ch;

void setup()

{

  // put your setup code here, to run once:

  pinMode(led,OUTPUT);

  Serial.begin(9600);

  Serial.println("+/- to turn on/off the LED");

}

void loop()

{

  // put your main code here, to run repeatedly:

  if(Serial.available())

  {

    ch =Serial.read();

  }

  if (ch=='+')

  {

    delay(1000);//delay 1秒中才不會一直出現ON字

    Serial.println("ON");

    digitalWrite(led,HIGH); 

  }

  else if(ch=='-')

  {

    delay(1000);//delay 1秒中才不會一直出現OFF字

    Serial.println("Off");

    digitalWrite(led,LOW); 

  }

}