EmpfangenUDP

/* Create a WiFi access point and provide a web server on it. */

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <WiFiUDP.h>

/* Set these to your desired credentials. */
const char *ssid = "ESPap";
const char *password = "thereisnospoon";

// UDP variables
unsigned int localPort = 8888;
WiFiUDP UDP;
boolean udpConnected = false;
char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to hold incoming packet,
char ReplyBuffer[] = "acknowledged"; // a string to send back

ESP8266WebServer server(80);

/* Just a little test message.  Go to http://192.168.4.1 in a web browser
 * connected to this access point to see it.
 */
void handleRoot() {
    server.send(200, "text/html", "<h1>You are connected</h1>");
}

void setup() {
    delay(1000);
    Serial.begin(115200);
    Serial.println();
    Serial.print("Configuring access point...");
    /* You can remove the password parameter if you want the AP to be open. */
    WiFi.softAP(ssid, password);

    IPAddress myIP = WiFi.softAPIP();
    Serial.print("AP IP address: ");
    Serial.println(myIP);
    server.on("/", handleRoot);
    server.begin();
    Serial.println("HTTP server started");

  udpConnected = connectUDP();
  if (udpConnected)
  {
    // initialise pins
    pinMode(D5,OUTPUT);
    pinMode(D0,OUTPUT);
    digitalWrite(D0,HIGH);
  }

}

void loop()
{
  server.handleClient();
  if(udpConnected)
    {

      // if there’s data available, read a packet
      int packetSize = UDP.parsePacket();
      if(packetSize)
        {
          // turn LED on
          digitalWrite(D5,HIGH);
          delay(50);
          digitalWrite(D5,LOW);
        }
     delay(10);
    }
}

boolean connectUDP()
{
  boolean state = false;

  Serial.println("");
  Serial.println("Connecting to UDP");

  if(UDP.begin(localPort) == 1)
  {
    Serial.println("Connection successful");
    state = true;
  }
  else
  {
     Serial.println("Connection failed");
  }
  return state;
}