ESP8266 UDP Server Example

Hello everyone,

In this tutorial, i will show you how to receive UDP Packets via ESP8266.

I assume that you know something about UDP and i will not show you to how udp is working.

In this tutorial, will sent an UDP packet via pc that connected to same network with esp8266 and we show the UDP packets on Serial Port Screen.

This tutorial contains 3 simple steps. 2 of steps are main and final step is for testing.

We need :

Hardware :
1 x Esp8266 Board (I am using ESP8266 -07)
1 x USB to RS232 Chip for programming (FTDI)


Software :
Packet Sender ( for sending UDP Packets) Download

Step 1 : Connecting Wi-Fi Network

#include <ESP8266WiFi.h>

const char* ssid     = "KeyTech-1";
const char* password = "TOBB_Muhendis";


void setup() {
  Serial.begin(115200);
  delay(10);

  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
 
  WiFi.begin(ssid, password);
  WiFi.config(IPAddress(192, 168, 1, 60), IPAddress(192, 168, 1, 1), IPAddress(255, 255, 255, 0));
 
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected"); 
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

int value = 0;

void loop() {

}

 
I dont explain this step because this is very common part for esp8266.

Note: I set my ip address static 192.168.1.60
WiFi.config(IPAddress(192, 168, 1, 60), IPAddress(192, 168, 1, 1), IPAddress(255, 255, 255, 0)); //This line is optional... 

Step 2 : Starting UDP Server

We use WifiUDP library for setting an UDP Server.

Firstly, we create a WiFiUDP Object and i have selected udp server port 2807. You can change your port number whatever you want or which port yo need to listen. Also i created a packet buffer and i selected its size as 2. You can change it to how many bytes you need in your project.

//Creating UDP Listener Object.
WiFiUDP UDPTestServer;
unsigned int UDPPort = 2807;

//Packet Buffer
const int packetSize = 2;
byte packetBuffer[packetSize];


Secondly, in void setup() , starting udp listener ...

 UDPTestServer.begin(UDPPort); 



Thirdly, creating a udp message handle. You Can access your data in myData variable. I selected to it as string. You can change it what you need or what you are sending. I will sent String type packets for testing ...

void handleUDPServer() {
  int cb = UDPTestServer.parsePacket();

  if (cb) {
    UDPTestServer.read(packetBuffer, packetSize);

    String myData = "";
   
    for(int i = 0; i < packetSize; i++) {
      myData += (char)packetBuffer[i];
    }

    Serial.println(myData);

  }
}

 Complete Project Code : 

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

const char* ssid     = "XXX";
const char* password = "XXX";

WiFiUDP UDPTestServer;
unsigned int UDPPort = 2807;

const int packetSize = 2;
byte packetBuffer[packetSize];

void setup() {
  Serial.begin(115200);
  delay(10);

  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
 
  WiFi.begin(ssid, password);
  WiFi.config(IPAddress(192, 168, 1, 60), IPAddress(192, 168, 1, 1), IPAddress(255, 255, 255, 0));
 
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected"); 
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());

  UDPTestServer.begin(UDPPort);
 
}

int value = 0;

void loop() {
   handleUDPServer();
   delay(1);
}

void handleUDPServer() {
  int cb = UDPTestServer.parsePacket();
  if (cb) {
    UDPTestServer.read(packetBuffer, packetSize);
    String myData = "";
    for(int i = 0; i < packetSize; i++) {
      myData += (char)packetBuffer[i];
    }
    Serial.println(myData);
  }
}

 Download Complete Project

 Step 3 : Testing UDP Server ...

In this step we will test our esp8266 udp listener ... Run the packetsender program that you downloaded before.  On below picture, i explain how you can use the program. Program will send UDP Packets when press the Send button.

Here is the final result ...

 
 
You can see your UDP Packets on Serial Port Screen.

I hope it will helps you on your projects.  You download complete project on below link. 

Download Complete Project