Arduino deurbel

wi wil mij helpen deze sketch aan te passen voor mijn deurbel programma mij is niet helemaal duidelijk waar ik op moet letten en waar je wat in moet voeren api key ??? waar vind ik die

#include
#include

#define switchPin 7 // Snap action switch which closes when the mailbox door is opened.
#define ledPin 9

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192,168,1,2 }; // local Arduino IP
byte server[] = { 192,168,1,1 }; // IP of your web server

Client client(server, 80);

void setup() {
Ethernet.begin(mac, ip);
Serial.begin(9600);
delay(1000);
pinMode(switchPin, INPUT);
pinMode(ledPin, OUTPUT);
//delay(20000);
}

void loop() {
if (digitalRead(switchPin) == HIGH) // if button is pressed: {
digitalWrite(ledPin, HIGH);
Serial.println("Button pressed");
if (client.connect()) { //connect to server
Serial.println("connected to server");
// Make a HTTP request:
client.println("GET /~silas/example.php"); //location of ProwlPHP script
client.println();
}
else {
Serial.println("connection failed");
}
delay(1000);
Serial.print("Response from server: ");
while (client.available()) {
char c = client.read();
Serial.print(c);
}
Serial.println();
// if the server's disconnected, stop the client:
if (!client.connected()) {
Serial.println("disconnecting from server");
client.stop();
}
while (digitalRead(switchPin) == HIGH) {
// hold here while button is pressed
}
Serial.println("Button released");
digitalWrite(ledPin, LOW);
delay(500);
}
}