ESP32 UDP Command Code Packet Sender Scheme

ESP32 control via Windows application by sending datagrams

Software designed for easy output control at the users request

The interface for sending commands is any UDP client that can send a UDP message - a datagram, such as Packet Sender on Windows.

Packet Sender requires configuration modification for valid sending of UDP datagrams. Select the option to add a 500ms pause (slow mode).

Setting up the Packet Sender is simple, it requires entering the IP address to which the data is sent, including the port. (ESP32 IP address - available in Serial Line List - UART)

UDP does not guarantee delivery of messages. For this reason, ESP32 will send a message to the sender on the success of the transmission upon receiving the message (ZAP / VYP). (However, the sender may discard or not receive the message)

As a result, it is possible to control the output on request, whether in the form of a diode or a relay with the switching of power consumers.

An interesting feature is the use of the asynchronous library for ESP32, where the functionality runs in the background without the need to program the transmission elements of the system.

Packet Sender can be downloaded at: https://packetsender.com/

ESP32 program - UDP CONTROL (via Packet Sender) Async

/*|-----------------------------------------------------------|*/
/*|SKETCH FOR ESP32 UDP DATAGRAMS CONTROL USING PACKET SENDER |*/
/*|Author: MARTIN CHLEBOVEC                                   |*/
/*|Web: http://arduino.clanweb.eu/udp-control-esp32.php       |*/
/*|Board: ESP32 DevkitC v4 / ESP32 Devkit v1                  |*/
/*|Buy me coffee: paypal.me/chlebovec                         |*/
/*|Send ON or OFF string from Packet Sender for change of pin |*/
/*|-----------------------------------------------------------|*/
 
#include "WiFi.h"
#include "AsyncUDP.h"
const char* ssid = "WIFI_NAME";
const char* pass = "WIFI_PASSWORD";
const int led = 2; //D pin (Build-in LED for Devkit V1)
AsyncUDP udp;
 
void setup()
{
  Serial.begin(115200);
  pinMode(led, OUTPUT);
  WiFi.disconnect(true);
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, pass);
 
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
 
  if (udp.listen(4444)) {
    Serial.print("UDP server na IP: ");
    Serial.print(WiFi.localIP());
    Serial.println(" port: 4444");
    udp.onPacket([](AsyncUDPPacket packet) {
      Serial.print("Type of UDP datagram: ");
      Serial.print(packet.isBroadcast() ? "Broadcast" : packet.isMulticast() ? "Multicast" : "Unicast");
      Serial.print(", Sender: ");
      Serial.print(packet.remoteIP());
      Serial.print(":");
      Serial.print(packet.remotePort());
      Serial.print(", Receiver: ");
      Serial.print(packet.localIP());
      Serial.print(":");
      Serial.print(packet.localPort());
      Serial.print(", Message length: ");
      Serial.print(packet.length()); //dlzka spravy
      Serial.print(", Payload: ");
      Serial.write(packet.data(), packet.length());
      Serial.println();
      String myString = (const char*)packet.data();
      if (myString.startsWith("ON")) {
        Serial.println("Action: Turning ON relay");
        digitalWrite(led, HIGH);
      } else if (myString.startsWith("OFF")) {
        Serial.println("Action: Turning OFF relay");
        digitalWrite(led, LOW);
      }
      packet.printf("ESP32 received %u bytes of data", packet.length()); //odpoved odosielatelovi
    });
  }
}
 
void loop()
{
  delay(1000);
}

Wiring diagram for ESP32 with UDP command control