Hello all 
I am struggling to find reasons for this and asking for help for a problem.
I am using an Arduino Nano IoT 33 Board with ESP32(NINA-W102) Wifi chip for this communication.
The problem is I can smoothly communicate this device for both read/write WIFI UDP communication both in my different c++ console program and a serial port monitor program (You can find it here: https://blog.daum.net/pg365/276).
Even I can communicate with the c++ console program and Unity via LAN UDP communication.
So the code for all Arduino code, c++ console program code, and even the c# code in Unity have NO PROBLEM…
I also gave permission to ports I am using on Windows Firewall.
The Error message I got here is "System.Net.Sockets.SocketException (0x80004005): " Failing to connect the device…
Similar issues in forums said just restarting solved the problem,
but in my case, the communication was never successful and restart didn’t help.
I will really appreciate any comments from you.
Thanks so much in advance.
I am attaching my c# code and Arduino code for you just for references
Arduino code:
#include <WiFiClient.h>
#include <WiFiServer.h>
#include <WiFiUdp.h>
#include <WiFiNINA.h>
#include <Arduino_LSM6DS3.h>
#include <SPI.h>
#include <WiFiUDP.h>
//#include "arduino_secrets.h"
///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = "----"; // your network SSID (name)
char pass[] = "----"; // your network password (use for WPA, or use as key for WEP)
int keyIndex = 0; // your network key Index number (needed only for WEP)
int status = WL_IDLE_STATUS;
// if you don't want to use DNS (and reduce your sketch size)
// use the numeric IP instead of the name for the server:
IPAddress server(192, 168, 1, 31); // name address for Google (using DNS)
WiFiUDP Udp;
unsigned int localUdpPort = 58432;
const int analogInPin = A0; // Analog input pin that the potentiometer is attached to
int sensorValue = 0;
float aX, aY, aZ;
float gX, gY, gZ;
char tmpAx[7]; char tmpAy[7]; char tmpAz[7];
char tmpGx[7]; char tmpGy[7]; char tmpGz[7];
//String tmpAx; String tmpAy; String tmpAz;
//String tmpGx; String tmpGy; String tmpGz;
char cBuf[128];
const char * spacer = ", ";
unsigned long lastConnectionTime = 0; // last time you connected to the server, in milliseconds
const unsigned long postingInterval = 20L; // delay between updates, in milliseconds
void setup() {
//Initialize serial and wait for port to open:
Serial.begin(9600);
if (!IMU.begin()) {
Serial.println("Failed to initialize IMU!");
while (true); // halt program
}
Serial.println("IMU initialized!");
// check for the WiFi module:
if (WiFi.status() == WL_NO_MODULE) {
Serial.println("Communication with WiFi module failed!");
// don't continue
while (true);
}
String fv = WiFi.firmwareVersion();
if (fv < WIFI_FIRMWARE_LATEST_VERSION) {
Serial.println("Please upgrade the firmware");
}
// attempt to connect to Wifi network:
while (status != WL_CONNECTED) {
Serial.print("Attempting to connect to SSID: ");
Serial.println(ssid);
// Connect to WPA/WPA2 network. Change this line if using open or WEP network:
status = WiFi.begin(ssid, pass);
// wait 10 seconds for connection:
delay(3000);
}
Serial.println("Connected to wifi");
if (Udp.begin(localUdpPort)){
Serial.println("UDP connected");
}
printWifiStatus();
}
void loop() {
// if there are incoming bytes available
// from the server, read them and print them:
Serial.println("\nStarting connection to server...");
// if you get a connection, report back via serial:
int packetSize = Udp.parsePacket();
if (packetSize) { //packetSize
Serial.println("Recieved packet UDP");
//client.println("Connection from Arduino");
//client.write("Connection from Arduino 2\n", 30);
sensorValue = analogRead(analogInPin);
// Read IMU
if (IMU.accelerationAvailable() && IMU.gyroscopeAvailable()) {
IMU.readAcceleration(aX, aY, aZ);
IMU.readGyroscope(gX, gY, gZ);
}
dtostrf(aX, 7, 3, tmpAx);
dtostrf(aY, 7, 3, tmpAy); dtostrf(aZ, 7, 3, tmpAz);
dtostrf(gX, 7, 3, tmpGx); dtostrf(gY, 7, 3, tmpGy); dtostrf(gZ, 7, 3, tmpGz);
//tmpAx = String(aX); tmpAy = String(aY); tmpAz = String(aZ);
//tmpGx = String(gX); tmpGy = String(gY); tmpGz = String(gZ);
sprintf(cBuf, "Arduino Out: %d, %s, ", sensorValue, tmpAx, tmpAz); //?????? I don't know....
//sprintf(cBuf,"%s, %s, %s\n", cBuf, tmpAy, tmpAz);
Serial.print("Connected to server : ");
Serial.print(cBuf);
Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
Serial.println(Udp.remoteIP()); Serial.println(Udp.remotePort());
Udp.write(cBuf);
Udp.endPacket();
delay(100);
}
else {
// if you couldn't make a connection:
Serial.println("connection failed");
}
}
void printWifiStatus() {
// print the SSID of the network you're attached to:
Serial.print("SSID: ");
Serial.println(WiFi.SSID());
// print your board's IP address:
IPAddress ip = WiFi.localIP();
Serial.print("IP Address: ");
Serial.println(ip);
// print the received signal strength:
long rssi = WiFi.RSSI();
Serial.print("signal strength (RSSI):");
Serial.print(rssi);
Serial.println(" dBm");
}
char *dtostrf(double val, signed char width, unsigned char prec, char *sout) {
char fmt[20];
sprintf(fmt, "%%%d.%df", width, prec);
sprintf(sout, fmt, val);
return sout;
}
Unity c# code:
using UnityEngine;
using UnityEngine.Networking;
using System;
using System.Collections;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Collections.Generic;
using System.Linq;
public class UDPReciever : MonoBehaviour
{
Thread udpListeningThread;
public int portNumberReceive;
UdpClient receivingUdpClient;
string[] delimiters = { ", ", "," };
string[] data;
void Start()
{
initListenerThread();
}
void initListenerThread()
{
Debug.Log("Started on : " + portNumberReceive.ToString());
udpListeningThread = new Thread(new ThreadStart(UdpListener));
// Run in background
udpListeningThread.IsBackground = true;
udpListeningThread.Start();
Debug.Log("Start");
}
public void UdpListener()
{
if (receivingUdpClient == null)
{
receivingUdpClient = new UdpClient(portNumberReceive);
}
while (true)
{
//Listening
try
{
IPEndPoint RemoteIpEndPoint = new IPEndPoint(IPAddress.Parse("192.168.1.27"),58432);
receivingUdpClient.Client.ReceiveTimeout = 150;
Debug.Log(RemoteIpEndPoint);
// Blocks until a message returns on this socket from a remote host.
byte[] receiveBytes = receivingUdpClient.Receive(ref RemoteIpEndPoint);
Debug.Log("Recieve");
if (receiveBytes != null)
{
string returnData = Encoding.UTF8.GetString(receiveBytes);
Debug.Log("Message Received" + returnData.ToString());
Debug.Log("Address IP Sender" + RemoteIpEndPoint.Address.ToString());
Debug.Log("Port Number Sender" + RemoteIpEndPoint.Port.ToString());
data = returnData.Split(delimiters, StringSplitOptions.None);
Debug.Log(data);
}
}
catch (Exception e)
{
Debug.Log("Error");
Debug.Log(e.ToString());
}
}
Debug.Log("Loop");
}
void OnDisable()
{
Debug.Log("UDPDisable");
if (udpListeningThread != null && udpListeningThread.IsAlive)
{
udpListeningThread.Abort();
}
receivingUdpClient.Close();
}
}