Need help with sending continuous data from PC to Arduino via UDP

Projects Interfacing w/ Software on the Computer
1

I need to be able to send data to the Arduino via the UDP. I searched for guides and I came across this Arduino Ethernet Board UDP communication between C# and Arduino - Interfacing w/ Software on the Computer - Arduino Forum. I tested it out and as I've understood based on the code it was supposed to run continuously but when I tried it, it sort of gets stuck after the first send and receive.

Here's the arduino sketch

#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>

//MAC on board: 90-A2-DA-0E-D9-91
byte mac[] = {
  0x90, 0xA2, 0xDA, 0x0E, 0xD9, 0x91 };
IPAddress ip(172, 29, 38, 80);

int led = 9;

unsigned int localPort = 8888;

char packetBuffer[UDP_TX_PACKET_MAX_SIZE];

//Initialize EthernetUDP
EthernetUDP Udp;

char replyMsg[] = "Value Received";
char errMsg[] = "Problem";

void setup()
{
  //Start Ethernet and UDP
  pinMode(led, OUTPUT);
  Ethernet.begin(mac,ip);
  Udp.begin(localPort);

  Serial.begin(9600);
}

void loop()
{
  int packetSize = Udp.parsePacket();
  char noNo[] = "Hello";

  if(packetSize)
  {
    for(int i=0;i<UDP_TX_PACKET_MAX_SIZE;i++) packetBuffer[i] = 0;

    Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);

    char valIn[packetSize]; // = packetBuffer;
    
    for(int i = 0; i < packetSize; i++)
    {
      valIn[i] = packetBuffer[i];
    }
    String theVal = valIn;

    int strIndex = theVal.length();

    if(theVal.substring(0,1) == "1")
    {
      digitalWrite(led, HIGH);
      Udp.beginPacket(Udp.remoteIP(), 8888);
      Udp.write("Flame On!");
      Udp.endPacket();
    }
    else if(theVal.substring(0,1) == "0")
    {
      digitalWrite(led, LOW);
      Udp.beginPacket(Udp.remoteIP(), 8888);
      Udp.write("Flame off.");
      Udp.endPacket();      
    }
    else if(theVal.substring(0,1) == "3")
    //Blinks the LED - off, on; ending off
    {
      digitalWrite(led, LOW);
      Udp.beginPacket(Udp.remoteIP(), 8888);
      Udp.write("Fade in...");
      Udp.endPacket();
      int i = 1;
      for(int x = 0; x > -1; x = x + i)
      {
        analogWrite(led, x);
        if(x == 255) i = -1;
        delay(20);
      }
            Udp.beginPacket(Udp.remoteIP(), 8888);
      Udp.write("Fade out...");
      Udp.endPacket();
      digitalWrite(led, LOW);
    }
    else
    {
      Udp.beginPacket(Udp.remoteIP(), 8888);
      Udp.write(errMsg);
      Udp.endPacket();
    }
  }
  delay(10);
}

and this is the c# code:

using System;
using System.Text;
using System.Net;
using System.Net.Sockets;

namespace SendReceiveUDP
{
    class Program
    {
        static void Main(string[] args)
        {
            //Port and IP Data for Socket Client
            var IP = IPAddress.Parse("172.29.38.80");

            int port = 8888;

            string inputVal = "1";
            while (inputVal != string.Empty)
            {
                var udpClient = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                var sendEndPoint = new IPEndPoint(IP, port);
                var receiveEndPoint = new IPEndPoint(IP, port);

                var clientReturn = new UdpClient(port);
                inputVal = string.Empty;
                inputVal = Console.ReadLine();

                if (inputVal == string.Empty) break;
                try
                {
                    int inputInt;
                    int.TryParse(inputVal, out inputInt);

                    // Sends a message to the host to which you have connected.
                    Byte[] sendBytes = Encoding.ASCII.GetBytes(inputInt.ToString());

                    udpClient.SendTo(sendBytes, sendEndPoint);
                    string returnData = string.Empty;
                    // Blocks until a message returns on this socket from a remote host.

                    Byte[] receiveBytes;

                    receiveBytes = clientReturn.Receive(ref receiveEndPoint);
                    returnData = Encoding.ASCII.GetString(receiveBytes);

                    // Uses the IPEndPoint object to determine which of these two hosts responded.
                    Console.WriteLine("Message Received: " +
                                      returnData.ToString());

                    if (inputInt == 3)
                    {
                        receiveBytes = clientReturn.Receive(ref receiveEndPoint);
                        returnData = Encoding.ASCII.GetString(receiveBytes);

                        // Uses the IPEndPoint object to determine which of these two hosts responded.
                        Console.WriteLine("Message Received: " +
                                          returnData.ToString());
                    }

                    udpClient.Close();
                    clientReturn.Close();
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                }
            }
        }
    }
}

Can anyone tell me what's wrong and what I need to do to get this to work?
and by the way can I receive UDP packets and then send stuff via the serial port at the same time?

2

by the way can I receive UDP packets and then send stuff via the serial port at the same time?

with same time what you mean?

The arduino operates a trasitional loop() in whicht he code snippet is processed one by one so. it goes one by one ,so if you are reading from the serial port then after it will do your udp thing when offcourse the code statements for udp handing comes.

if you want to do things at the same time then I think you should use RTOS to get the functionality of threads ,google RTOS for arduino ,there are many out there that I have used succesfully.