Monitor your sensors with a Web server

Web server

This example shows you how to create a Web server to answer a HTTP request and to display on an HTML page the values of the sensors connected on the Shield.


  • Arduino board
  • Arduino Ethernet Shield 2


Arduino Ethernet 2 Shield 
Mount your Ethenet shield 2 on an Arduino board and connect it to the network using the Ethernet cable. 
Attach some sensors or analog inputs to pins A0, A1, A2, A3, A4, A5.


To using this sketch you must include the"SPI" and "Ethernet2" libraries, and you must indicate the Mac address of your Shield and IP address of your network. 
After you upload this example in your Arduino board and you wait that the loading is completed. Finally you open a browser and you connect to the IP address shown on your 
Serial monitor so you can display the values of the sensors connected to six analogic pins between A0 and A5.

The complete code and its detailed description are shown down.

Web Server
A simple web server that shows the value of the analog input pins.
using an Arduino Wiznet Ethernet shield.
* 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 9 Apr 2012
by Tom Igoe
#include <SPI.h>
#include <Ethernet2.h>
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
IPAddress ip(192, 168, 1, 177);
// Initialize the Ethernet server library
// with the IP address and port you want to use
// (port 80 is default for HTTP):
EthernetServer server(80);
void setup() {
// Open serial communications and wait for port to open:
while (!Serial) {
  ; // wait for serial port to connect. Needed for Leonardo only
// start the Ethernet connection and the server:
Ethernet.begin(mac, ip);
Serial.print("server is at ");
void loop() {
// listen for incoming clients
EthernetClient client = server.available();
if (client) {
  Serial.println("new client");
  // an http request ends with a blank line
  boolean currentLineIsBlank = true;
  while (client.connected()) {
    if (client.available()) {
      char c =;
      // if you've gotten to the end of the line (received a newline
      // character) and the line is blank, the http request has ended,
      // so you can send a reply
      if (c == '\n' && currentLineIsBlank) {
        // send a standard http response header
        client.println("HTTP/1.1 200 OK");
        client.println("Content-Type: text/html");
        client.println("Connection: close"); // the connection will be closed after completion of the response
        client.println("Refresh: 5"); // refresh the page automatically every 5 sec
        client.println("<!DOCTYPE HTML>");
        // output the value of each analog input pin
        for (int analogChannel = 0; analogChannel < 6; analogChannel++) {
          int sensorReading = analogRead(analogChannel);
          client.print("analog input ");
          client.print(" is ");
          client.println("<br />");
      if (c == '\n') {
        // you're starting a new line
        currentLineIsBlank = true;
      else if (c != '\r') {
        // you've gotten a character on the current line
        currentLineIsBlank = false;
  // give the web browser time to receive the data
  // close the connection:
  Serial.println("client disconnected");