ESP8266 UDP RX

UDP_RX.ino

#include <Arduino.h>

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>

uint8_t state = 0;

String SSID = "IOT";
String PSK = "mrfunkfunk";

// Initialize the wifi Udp library
WiFiUDP Udp;
const unsigned int localPort = 1337;    // local port to listen for UDP packets
const int UDP_PACKET_SIZE = 1; 		
byte packetBuffer[ UDP_PACKET_SIZE ]; //buffer to hold incoming and outgoing packets

void setup() {
  Serial.begin(115200);
  
  WiFi.hostname("UDPRX");
  WiFi.mode(WIFI_STA);
  WiFi.begin(SSID, PSK);
  
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }
  Serial.println();

  Serial.print("Connected, IP address: ");
  Serial.println(WiFi.localIP());
  
  Udp.begin(localPort);

}


void loop() {

if (Udp.parsePacket()) UDPrx();

yield();

if(state!=0){
  //do stuff with state
  state=0; //reset state
}

void UDPrx()
{
// We've received a packet, read the data from it
	Serial.println("udpRX!");
    memset(packetBuffer, 0, UDP_PACKET_SIZE); //reset packet buffer
    int read_bytes=Udp.read(packetBuffer,UDP_PACKET_SIZE);  // read the packet into the buffer

	state = packetBuffer[0];
}