How send data via wifi in Arduino

Official Hardware Classic UNO R4 WiFi
1

Hello all, many day can not figure out, how I can send data from UNO R4 to python script via UDP. I created the next script for Arduino to send data via UDP, but without any result. My python script can not establish connect. Can you help where is problem?

char ssid[] = "";        // your network SSID (name)
char pass[] = "";   // your network password (use for WPA, or use as key for WEP)
int test = 123;
#include <WiFiS3.h>
int status = WL_IDLE_STATUS;
#include "arduino_secrets.h" 
unsigned int localPort = 2390;      // local port to listen on
WiFiUDP Udp;

void setup() {
  if (WiFi.status() == WL_NO_MODULE) {
    while (true);
  }

  while (status != WL_CONNECTED) {
    status = WiFi.begin(ssid, pass);
    delay(10000);
  }
  Udp.begin(localPort);
}

void loop() {
    IPAddress remoteIp = Udp.remoteIP();
    test = test + 1;
    Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
    Udp.write(test);
    Udp.endPacket();
}

and python script

import socket
s = socket.socket(family = socket.AF_INET, type = socket.SOCK_DGRAM)
s.bind (("192.168.1.115", 2390))  
while True:
 data = str(s.recv(1024),encoding='utf-8')
 print(data)
2

Not being an expert by any means, it seems you may be looking for a server-client arrangement (?) --
Python with Arduino LESSON 16: Simple Client Server Configuration over Ethernet | Technology Tutorials (toptechboy.com)

There's a pretty good server-client for ESP8266, in C/Arduino, at randomnerdtutorials.com.
I haven't looked, a Python version may be available there.

3

IPAddress remoteIp = Udp.remoteIP();

it doesn't have that IP. you can only read the remote IP for incoming messages (of course)

4

thank, actually I wanted to use a script from the documentation
for Wi-Fi® UDP Send Receive String

/*
  WiFi UDP Send and Receive String

  This sketch waits for a UDP packet on localPort using the WiFi module.
  When a packet is received an Acknowledge packet is sent to the client on port remotePort

  created 30 December 2012
  by dlf (Metodo2 srl)

  Find the full UNO R4 WiFi Network documentation here:
  https://docs.arduino.cc/tutorials/uno-r4-wifi/wifi-examples#wi-fi-udp-send-receive-string
 */


#include <WiFiS3.h>

int status = WL_IDLE_STATUS;
#include "arduino_secrets.h" 
///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID;        // your network SSID (name)
char pass[] = SECRET_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)

unsigned int localPort = 2390;      // local port to listen on

char packetBuffer[256]; //buffer to hold incoming packet
char  ReplyBuffer[] = "acknowledged\n";       // a string to send back

WiFiUDP Udp;

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  // 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(10000);
  }
  Serial.println("Connected to WiFi");
  printWifiStatus();

  Serial.println("\nStarting connection to server...");
  // if you get a connection, report back via serial:
  Udp.begin(localPort);
}

void loop() {

  // if there's data available, read a packet
  int packetSize = Udp.parsePacket();
  if (packetSize) {
    Serial.print("Received packet of size ");
    Serial.println(packetSize);
    Serial.print("From ");
    IPAddress remoteIp = Udp.remoteIP();
    Serial.print(remoteIp);
    Serial.print(", port ");
    Serial.println(Udp.remotePort());

    // read the packet into packetBuffer
    int len = Udp.read(packetBuffer, 255);
    if (len > 0) {
      packetBuffer[len] = 0;
    }
    Serial.println("Contents:");
    Serial.println(packetBuffer);

    // send a reply, to the IP address and port that sent us the packet we received
    Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
    Udp.write(ReplyBuffer);
    Udp.endPacket();
  }
}


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");
}
5

yes, but for send message from python I need in advance have connection between python and Arduino. But I don't have

6

with UDP there is no connection. only single messages. use in the sketch the IP address of the computer with the python script

7

thank you very much, but what would the script command for this look like?
Actually, I can send slowly data via an HTML web server, I need exactly very quickly

8

This script is works, but slowly

#include "WiFiS3.h"

char ssid[] = "";
char pass[] = "";
int status = WL_IDLE_STATUS;
WiFiServer server(80);

void setup() {
  Serial.begin(9600);
  while (status != WL_CONNECTED) 
    {
    status = WiFi.begin(ssid, pass);
    }
  server.begin();
}
  int a = 0;
void loop() {

  WiFiClient client = server.available();
    client.println("HTTP/1.1 200 OK");
    client.println("Content-type:text/html");
  //  int c = 8;
  //  client.print(c);

    String currentLine = "";
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        if (c == '\n') {
          if (currentLine.length() == 0) {
            client.println();
            a += 1;
            client.print(a);
            break;
          } else {
            currentLine = "";
          }
        } else if (c != '\r') {
          currentLine += c;
        }
      }
    }
    client.stop();
    Serial.println("Client disconnected.");
}
9

that is a server running on the Arduino so a client can connect to it. in case of the UDP sketch you want to send a message to an UDP listener on a different device, so you have to specify where do you want to send it. don't you see the difference between the sender and the receiver? that the sender must specify where it wants to send the message?

10

thank you, I implemented via UDP, but works slowly anyway, about 50 transfer for one sec with the next code. Do you know how I can speed up this script ?

#include <WiFi.h>
#include <WiFiUdp.h>

char ssid[] = "mywifi";
char pass[] = "mypassword";

WiFiUDP udp;
WiFiServer server(139);

void setup() {
  Serial.begin(9600);
  WiFi.begin(ssid, pass);
  Serial.println("WiFi connected.");
  
  udp.begin(139);
  Serial.println("UDP initialized.");
  server.begin();
  Serial.println("Server started.");
}

WiFiClient client = server.available();
int a = 30;
void loop() 
{    
    udp.beginPacket("192.168.1.241", 139);
    udp.print(a);
    udp.endPacket();
}

and read with python


import socket
UDP_IP = "my_ip"  
UDP_PORT = 139   

sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.bind((UDP_IP, UDP_PORT))
while True:
    data, addr = sock.recvfrom(2)  
    print(data)
11

port 139 is a no,no..
it's registered SMB, Netbios..
try a different port, like add 2 0's to it.. port 13900..
I search the port number just to make sure I'm clear..
a packet every 20ms, not sure if you are going to get much faster than that..
Don't need the server in the sketch not using it..

good luck.. ~q

12

slow down the sending. you are flooding the network

1 Like
13

thank you so much, will try!