Switch and LED on and off using the internet

This requires an ethernet shield and an LED connected to pin 6.

Copy the code into a new sketch and upload it to your arduino and then open your web browser to



//simple button GET server code to control servo and arduino pin 6
//for use with IDE 1.0
//open serial monitor to see what the arduino receives
//use the \ slash to escape the ” in the html
//for use with W5100 based ethernet shields
//Powering a servo from the arduino usually DOES NOT WORK.
//note that the below bug fix may be required
// http://code.google.com/p/arduino/issues/detail?id=605

#include <SPI.h>
#include <Ethernet.h>

#include <Servo.h>
Servo myservo;  // create servo object to control a servo

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
byte ip[] = { 192, 168, 1, 177 }; // ip in lan
byte gateway[] = { 192, 168, 1, 1 }; // internet access via router
byte subnet[] = { 255, 255, 255, 0 }; //subnet mask
EthernetServer server(80); //server port

String readString;


void setup(){

pinMode(6, OUTPUT); //pin selected to control
//start Ethernet
Ethernet.begin(mac, ip, gateway, subnet);
//the pin for the servo co
//enable serial data print
Serial.println(“server LED test 1.0”); // so I can keep track of what is loaded

void loop(){
// Create a client connection
EthernetClient client = server.available();
if (client) {
while (client.connected()) {
if (client.available()) {
char c = client.read();

//read char by char HTTP request
if (readString.length() < 100) {

//store characters to string
readString += c;

//if HTTP request has ended
if (c == ‘\n’) {

Serial.println(readString); //print to serial monitor for debuging

client.println(“HTTP/1.1 200 OK”); //send new page
client.println(“Content-Type: text/html”);

client.println(“<TITLE>LED on/off</TITLE>”);
client.println(“<H1>LED On/Off</H1>”);
client.println(“<hr />”);
client.println(“<br />”);

client.println(“<a href=\”/?lighton\”\”>Turn On Light</a>”);
client.println(“<a href=\”/?lightoff\”\”>Turn Off Light</a><br />”);


//stopping client

///////////////////// control arduino pin
if(readString.indexOf(“?lighton”) >0)//checks for on
digitalWrite(6, HIGH);    // set pin 4 high
Serial.println(“Led On”);
if(readString.indexOf(“?lightoff”) >0)//checks for off
digitalWrite(6, LOW);    // set pin 4 low
Serial.println(“Led Off”);
//clearing string for next read