ESP8266 Community Forum

- Tue Mar 31, 2015 10:37 am #13114 Please find attached a working UDP Server Example.

The picture below shows (on the right) the use of a Mac as UDP client sending messages, and the serial output of the UDP Server sketch on the ESP (on the left).

Schermafbeelding 2015-03-31 om 17.27.50.png

UdpServer.ino.zip

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- Mon Apr 06, 2015 4:32 am #13618 Hi gerardwr, thanks for share your work. I'm starting with esp8266 and I need a UDP server than recives and send packets (sometimes server and sometimes client). I try it with lua in nodemcu and I can't do it.
Now I want to give a chance to ArduinoESP.

If in your example I want to send a response, Do you know how do it?

Regards,

jnogues

- Sat May 02, 2015 2:39 pm #16310 Hi,

I try to extend the example. If a Client send something to the ESP8266, the ESP8266 should answer with something. See the code... The ESP8266 answers onyl one time. Then the ESP8266 stop answering to the Client.

I'm sure, I miss something. But what? Any idea?

Thanks and greets, Bernd

Code: Select all/*
 * 31 mar 2015
 * This sketch display UDP packets coming from an UDP client.
 * On a Mac the NC command can be used to send UDP. (nc -u 192.168.1.101 2390).
 *
 * Configuration : Enter the ssid and password of your Wifi AP. Enter the port number your server is listening on.
 *
 */

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

extern "C" {  //required for read Vdd Voltage
#include "user_interface.h"
  // uint16 readvdd33(void);
}

int status = WL_IDLE_STATUS;
const char* ssid = "UPC0864334";  //  your network SSID (name)
const char* pass = "geheim990";       // your network password

unsigned int localPort = 12345;      // local port to listen for UDP packets

byte packetBuffer[512]; //buffer to hold incoming and outgoing packets

// A UDP instance to let us send and receive packets over UDP
WiFiUDP Udp;

void setup()
{
  // Open serial communications and wait for port to open:
  Serial.begin(115200);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  // setting up Station AP
  WiFi.begin(ssid, pass);
 
  // Wait for connect to AP
  Serial.print("[Connecting]");
  Serial.print(ssid);
  int tries=0;
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
    tries++;
    if (tries > 30){
      break;
    }
  }
  Serial.println();


printWifiStatus();

  Serial.println("Connected to wifi");
  Serial.print("Udp server started at port ");
  Serial.println(localPort);
  Udp.begin(localPort);
}

void loop()
{
  int noBytes = Udp.parsePacket();
  String received_command = "";
 
  if ( noBytes ) {
    Serial.print(millis() / 1000);
    Serial.print(":Packet of ");
    Serial.print(noBytes);
    Serial.print(" received from ");
    Serial.print(Udp.remoteIP());
    Serial.print(":");
    Serial.println(Udp.remotePort());
    // We've received a packet, read the data from it
    Udp.read(packetBuffer,noBytes); // read the packet into the buffer

    // display the packet contents in HEX
    for (int i=1;i<=noBytes;i++)
    {
      Serial.print(packetBuffer[i-1],HEX);
      received_command = received_command + char(packetBuffer[i - 1]);
      if (i % 32 == 0)
      {
        Serial.println();
      }
      else Serial.print(' ');
    } // end for
    Serial.println();
   
    Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
    Udp.write("Answer from ESP8266 ChipID#");
    Udp.print(system_get_chip_id());
    Udp.write("#IP of ESP8266#");
    Udp.println(WiFi.localIP());
    Udp.endPacket();
   
    Serial.println(received_command);
    Serial.println();
  } // end if


}

void printWifiStatus() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);
}


- Sun May 03, 2015 8:29 am #16348

Hi,

I try to extend the example. If a Client send something to the ESP8266, the ESP8266 should answer with something. See the code... The ESP8266 answers onyl one time. Then the ESP8266 stop answering to the Client.

I'm sure, I miss something. But what? Any idea?

Hi Bernd,

Have a look at my example here, that may help:
http://www.esp8266.com/viewtopic.php?f=29&t=2451