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.

Step 1: What You Need?

1 x Arduino Board ( Arduino UNO used in this tutorial) 
1 x Arduino Ethernet Shield

Don't have components? Don't worry. Just click the component's name. 

Step 2: Build Your Circuit.

The Ethernet shield allows you to connect a WizNet Ethernet controller to the Arduino boards 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.

In the above image, the Arduino or Genuino board would be stacked below the Ethernet shield.

Step 3: Upload The Code.

1. Select the Arduino board type: Select Tools >> Board >> Select your correct Arduino board used.

2. Find the port number by accessing device manager on Windows. See the section Port (COM&LPT) and look for an open port named "Arduino Uno (COMxx)". If you are using a different board, you will find a name accordingly. What matters is the xx in COMxx part. In my case, it's COM3. So my port number is 3.

Select the right port: Tools >> Port >> Select the port number.

3. You can find this code in the example of Arduino IDE.

Select File >> Examples >> Ethernet >> ChatServer

Click press the "upload" button (see the button with right arrow mark).

/*
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 created 18 Dec 2009
by David A. Mellis
modified 9 Apr 2012
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 myDns(192,168,1, 1);
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 0, 0); // telnet defaults to port 23
EthernetServer server(23);
boolean alreadyConnected = false; // whether or not the client was connected previously void setup() {
// initialize the ethernet device
Ethernet.begin(mac, ip, myDns, gateway, subnet);
// start listening for clients
server.begin();
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
} Serial.print("Chat server address:");
Serial.println(Ethernet.localIP());
} void loop() {
// wait for a new client:
EthernetClient client = server.available(); // when the client sends the first byte, say hello:
if (client) {
if (!alreadyConnected) {
// clear out the input buffer:
client.flush();
Serial.println("We have a new client");
client.println("Hello, client!");
alreadyConnected = true;
} if (client.available() > 0) {
// 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.write(thisChar);
}
}
} 

Download:

Arduino IDE

Sources:https://www.arduino.cc/en/Tutorial/ChatServer  

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Author & Editor

My Robot Education Sdn. Bhd. (Robotedu.my) was founded in 2015 as the first robotics education centre in Malaysia to provide Arduino-based robotics courses for youths. Our vision is to be able to provide robotics education to every youth in Malaysia.