JWan Wiki

IPAddress local_IP(192, 168, 1, 2); // Replace with your desired static IP
IPAddress gateway(192, 168, 1, 1);    // Replace with your network gateway
IPAddress subnet(255, 255, 255, 0);   // Replace with your subnet mask
IPAddress primaryDNS(192,168,1,1);    // Optional: Replace with your primary DNS
IPAddress secondaryDNS(8, 8, 8, 8);   

void onwifidisconnect(const WiFiEventStationModeDisconnected& event) {
  debugln("reconnecting");
  WiFi.begin(ssid, password);
}

void setup(){
  WiFi.mode(WIFI_STA);
  WiFi.setAutoReconnect(true);
  WiFi.onStationModeDisconnected(onwifidisconnect);
  String hostname = "IoT";
  WiFi.hostname(hostname.c_str());
  // Configure static IP address  
  if (!WiFi.config(local_IP, gateway, subnet, primaryDNS, secondaryDNS)) {debugln("STA Failed to configure");}
  WiFi.begin(ssid, password);
  WiFi.setSleepMode(WIFI_LIGHT_SLEEP); // Reduces power while idle
  while (WiFi.status() != WL_CONNECTED) { delay(10); }
}