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1. Overview

In  lesson 1 ,  we have learned how to use Arduino to make simple web server and display “Hello World” in your remote browser.  In this lesson we will make a little more complicated project. We ’ll learn how to use remote browser to   to send signal to Arduino through Internet and  turn on/off an LED .

2.Parts and Devices List

Parts quantity
Arduino UNO 1
Ethernet Shield W5100 1
USB cable 1
200 ohm resistor 1

3)Circuit Graph:

First, please insert the W5100 Ethernet Shield into your UNO board, then use an RJ45 ethernet cable to connect your W5100 shield to your Router.

Then  connect the LED long pin  to D4 in W5100 shield through a 200 ohm resistor, LED short pin to GND , circuit is as below:

4)Software Installation:

Download the sketch file from :

Unzip the download file and enter the folder W5100-lesson2, double click the w5100-lesson2.ino file, upload the sketch to your Arduino. Open your Serial Monitor, you can see your router will assign an IP address to your Arduino   as following:

In above example, is the IP address of my Arduino.
Now use another computer or your cell phone’s  browser to visit url :
Your browser will show following result:

5)Make a Test:

Click Turn On LED link, your LED will be turn on , then click Turn Off LED link, your LED will be turn off.