Arduino: Ethernet Web Server Control LED
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Code
/*--------------------------------------------------------------
Program: eth_websrv_LED
Description: Arduino web server that serves up a web page
allowing the user to control an LED
Hardware: - Arduino Uno and official Arduino Ethernet
shield. Should work with other Arduinos and
compatible Ethernet shields.
- LED and resistor in series connected between
Arduino pin 2 and GND
Software: Developed using Arduino 1.0.3 software
Should be compatible with Arduino 1.0 +
References: - WebServer example by David A. Mellis and
modified by Tom Igoe
- Ethernet library documentation:
http://arduino.cc/en/Reference/Ethernet
Date: 11 January 2013
Author: W.A. Smith, http://startingelectronics.org
--------------------------------------------------------------*/
#include <SPI.h>
#include <Ethernet.h>
// MAC address from Ethernet shield sticker under board
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(10, 0, 0, 20); // IP address, may need to change depending on network
EthernetServer server(80); // create a server at port 80
String HTTP_req; // stores the HTTP request
boolean LED_status = 0; // state of LED, off by default
void setup()
{
Ethernet.begin(mac, ip); // initialize Ethernet device
server.begin(); // start to listen for clients
Serial.begin(9600); // for diagnostics
pinMode(2, OUTPUT); // LED on pin 2
}
void loop()
{
EthernetClient client = server.available(); // try to get client
if (client) { // got client?
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) { // client data available to read
char c = client.read(); // read 1 byte (character) from client
HTTP_req += c; // save the HTTP request 1 char at a time
// last line of client request is blank and ends with \n
// respond to client only after last line received
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");
client.println();
// send web page
client.println("<!DOCTYPE html>");
client.println("<html>");
client.println("<head>");
client.println("<title>Arduino LED Control</title>");
client.println("</head>");
client.println("<body>");
client.println("
LED
"); client.println("
Click to switch LED on and off.
");
client.println("<form method=\"get\">");
ProcessCheckbox(client);
client.println("</form>");
client.println("</body>");
client.println("</html>");
Serial.print(HTTP_req);
HTTP_req = ""; // finished with request, empty string
break;
}
// every line of text received from the client ends with \r\n
if (c == '\n') {
// last character on line of received text
// starting new line with next character read
currentLineIsBlank = true;
}
else if (c != '\r') {
// a text character was received from client
currentLineIsBlank = false;
}
} // end if (client.available())
} // end while (client.connected())
delay(1); // give the web browser time to receive the data
client.stop(); // close the connection
} // end if (client)
}
// switch LED and send back HTML for LED checkbox
void ProcessCheckbox(EthernetClient cl)
{
if (HTTP_req.indexOf("LED2=2") > -1) { // see if checkbox was clicked
// the checkbox was clicked, toggle the LED
if (LED_status) {
LED_status = 0;
}
else {
LED_status = 1;
}
}
if (LED_status) { // switch LED on
digitalWrite(2, HIGH);
// checkbox is checked
cl.println("<input type=\"checkbox\" name=\"LED2\" value=\"2\" \
onclick=\"submit();\" checked>LED2");
}
else { // switch LED off
digitalWrite(2, LOW);
// checkbox is unchecked
cl.println("<input type=\"checkbox\" name=\"LED2\" value=\"2\" \
onclick=\"submit();\">LED2");
}