How do I send UDP messages via Wi-Fi?

Projects Programming
1

Hello,
My task is to send UDP messages from my pc to the arduino uno (connected to the wifi shield) and back. I'm not sure how I'm suppose to do this. I connected my arduino board to wifi using the shield, but I don't know what to do next. Please help me find a solution.

Thank you.

2

connected to the wifi shield

The WiFi shield? There are lots of WiFi shields.

Using which version of the IDE?

3

Arduino Uno Wifi Shield R3... Arduino 1.0.5 software

4

Here is what my code looks like so far:

/*
WiFi UDP Send and Receive String

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

Circuit:

  • WiFi shield attached

created 30 December 2012
by dlf (Metodo2 srl)

*/

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

int status = WL_IDLE_STATUS;
char ssid[] = "GTvisitor"; // your network SSID (name)
int keyIndex = 0; // your network key Index number (needed only for WEP)

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

char packetBuffer[255]; //buffer to hold incoming packet

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 Leonardo only
}

// check for the presence of the shield:
if (WiFi.status() == WL_NO_SHIELD) {
Serial.println("WiFi shield not present");
// don't continue:
while(true);
}

// 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);

// 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);
}

5

Hello,
My task is to send UDP messages from my pc to the arduino uno (connected to the wifi shield) and back. I'm not sure how I'm suppose to do this. I connected my arduino board to wifi using the shield, but I don't know what to do next. Please help me find a solution.

Thank you.

6

HELP PLEASE

7

Help please!

8

It should go something like this if the UDP listener is 192.168.0.2 on port 8888.

IPAddress remoteIP(192,168,0,2);
int remotePort = 8888;

strcpy(packetBuffer,"This is a test");

Udp.beginPacket(remoteIP,remotePort);
Udp.write(packetBuffer,strlen(packetBuffer));
Udp.endPacket();
9

Where am I suppose to put that in the code?

10

You did not include a loop() function, so there was really nowhere in your code to put it. But for a test, this should do. It sends a udp packet once a second. It does not listen for a response.

void loop() {
  IPAddress remoteIP(192,168,0,2);
  int remotePort = 8888;

  strcpy(packetBuffer,"This is a test");

  Udp.beginPacket(remoteIP,remotePort);
  Udp.write(packetBuffer,strlen(packetBuffer));
  Udp.endPacket();

  delay(1000);
}
11

Ok. It's saying these errors:

WiFiUdpSendReceiveString.ino: In function 'void loop()':
WiFiUdpSendReceiveString:71: error: invalid conversion from 'char*' to 'const uint8_t*'
WiFiUdpSendReceiveString:71: error: initializing argument 1 of 'virtual size_t WiFiUDP::write(const uint8_t*, size_t)'

and it won't let me upload

12

Ok. It's saying these errors:

So, line 71 needs a cast. What is line 71?

13

I forgot about the uint_8t*. That is a byte type, not char. This usually fixes it.

// change this
char packetBuffer[255]; //buffer to hold incoming packet
// to this
byte packetBuffer[255]; //buffer to hold incoming packet

Or you can cast it as a (byte*).