Wenn-Programm

void setup()
{
  pinMode(13,OUTPUT);
  pinMode(7,INPUT);
}
void loop()
{
  if(digitalRead(7)==HIGH)
  {
    digitalWrite(13,HIGH);
  }
  if(digitalRead(7)==LOW)
  {
    digitalWrite(13,LOW);
  }
}

anderes: void setup() {

 pinMode(7,OUTPUT);    //LED
 pinMode(8,OUTPUT);    //Lautsprecher

} void loop() {

 digitalWrite(7,HIGH);  //LED an
 delay(2000);           // 2sec verz.
 digitalWrite(7,LOW);   //Led aus
 tone(8,20000,1000);      // Ton an
 delay(2000);           // 2sec verz.

}

Mit Schalter:

void setup() {

 pinMode(9,INPUT);
 pinMode(2,OUTPUT);

} void loop() {

 if(digitalRead(9)==HIGH)
 {
   digitalWrite(2,HIGH);
 }
 else
 {
   digitalWrite(2,LOW);
 }

}