Get MAC-Adress of Particle Device - From https://community.particle.io/t/how-to-get-mac-address/1411/5
byte mac[6];
void setup()
{
Serial.begin(9600);
WiFi.macAddress(mac);
}
void loop () {
Serial.print("MAC: ");
for( int i=0; i<6; i++) {
Serial.printf("%02x%s", mac[i], i != 5 ? ":" : "");
}
}