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Examples > Ethernet Library
Chat Server
A simple server that distributes any incoming messages to all connected clients. To use, open a terminal window, telnet to your devices IP address, and type away. Any incoming text will be sent to all connected clients (including the one typing). Additionally, you will be able to see the client's input in your serial monitor as well.
Hardware Required
- Arduino Ethernet Shield
- Shield-compatible Arduino board
Circuit
The Ethernet shield allows you to connect a WizNet Ethernet controller to the Arduino via the SPI bus. It uses pins 10, 11, 12, and 13 for the SPI connection to the WizNet. Later models of the Ethernet shield also have an SD Card on board. Digital pin 4 is used to control the slave select pin on the SD card.
The shield should be connected to a network with an ethernet cable. You will need to change the network settings in the program to correspond to your network.
image developed using Fritzing. For more circuit examples, see the Fritzing project page
In the above image, the Arduino would be stacked below the Ethernet shield.
Schematic
Code:
Chat Server
A simple server that distributes any incoming messages to all
connected clients. To use telnet to your device's IP address and type.
You can see the client's input in the serial monitor as well.
Using an Arduino Wiznet Ethernet shield.
Circuit:
* Ethernet shield attached to pins 10, 11, 12, 13
* Analog inputs attached to pins A0 through A5 (optional)
created 18 Dec 2009
by David A. Mellis
modified 10 August 2010
by Tom Igoe
*/
#include <SPI.h>
#include <Ethernet.h>
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network.
// gateway and subnet are optional:
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(192,168,1, 177);
IPAddress gateway(192,168,1, 1);
IPAddress subnet(255, 255, 0, 0);
// telnet defaults to port 23
EthernetServer server(23);
boolean gotAMessage = false; // whether or not you got a message from the client yet
void setup() {
// initialize the ethernet device
Ethernet.begin(mac, ip, gateway, subnet);
// start listening for clients
server.begin();
// open the serial port
Serial.begin(9600);
}
void loop() {
// wait for a new client:
EthernetClient client = server.available();
// when the client sends the first byte, say hello:
if (client) {
if (!gotAMessage) {
Serial.println("We have a new client");
client.println("Hello, client!");
gotAMessage = true;
}
// read the bytes incoming from the client:
char thisChar = client.read();
// echo the bytes back to the client:
server.write(thisChar);
// echo the bytes to the server as well:
Serial.print(thisChar);
}
}