CUstom header untuk menyembunyikan api key pada header

ArduinoCustomHeader

#include <SPI.h>
#include <Ethernet.h>
#include <PubSubClient.h>

// Update these with values suitable for your network.
byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
byte ip[]     = { 192, 168, 137, 2 };
byte dns2[]     = {8, 8, 8, 8};
byte gateway[]     = { 192, 168, 137, 1 };
String api_key = "API_KEY";

unsigned long time;


EthernetClient ethClient;

void setup()
{
  Serial.begin(9600);
  Ethernet.begin(mac, ip, dns2, gateway);
  Serial.print("My IP address: ");
  Serial.println(Ethernet.localIP());
}

void loop()
{
  // if there's a successful connection:
  if (ethClient.connect("api.geeknesia.com", 80)) {
    Serial.println("connecting...");
    // send the HTTP PUT request:
    ethClient.println("GET /api/data?attributes={\"motion\":\"1\"} HTTP/1.1");
    ethClient.println("Host: api.geeknesia.com");
    ethClient.println("User-Agent: arduino-ethernet");
    ethClient.println("api_key: " + api_key);
    ethClient.println("Connection: close");
    ethClient.println();
  }
  else {
    // if you couldn't make a connection:
    Serial.println("connection failed");
  }
  delay(30000);
}