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Arduino Server for JSON-P pin values
/*
Web Server returning data as JSON-P, adapted from http://arduino.cc/en/Tutorial/WebServer
A simple web server that returns the value of the analog input pins as
a JSON-P object, using an Arduino Wiznet Ethernet shield.
Circuit:
* Ethernet shield attached to pins 10, 11, 12, 13 (standard configuration)
* Analog inputs attached to pins A0 through A5 (optional)
* Example of reading LM35 on pin A0:
LM35 pins: {1: 5V, 2: A0, 3: gnd}
created 18 Dec 2009
by David A. Mellis
modified 19 Mar 2012
by Sam Fentress
*/
#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:
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(169,254,1,1);
char callback[27] = "arduinoEthernetComCallback";
// 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()
{
// start the Ethernet connection and the server:
Ethernet.begin(mac, ip);
server.begin();
}
void loop()
{
// listen for incoming clients
EthernetClient client = server.available();
if (client) {
// an http request ends with a blank line
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) {
char c = client.read();
// 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: application/json");
client.println();
// output the value of each analog input pin as a json-p object
client.print(callback);
client.print("('{");
for (int analogChannel = 0; analogChannel < 6; analogChannel++) {
client.print("\"A");
client.print(analogChannel);
client.print("\": ");
client.print(analogRead(analogChannel));
if (analogChannel != 5) {
client.print(",");
}
}
client.println("}')");
break;
}
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
delay(1);
// close the connection:
client.stop();
}
}
@scspaeth
scspaeth commented Sep 5, 2012

Sam:
Thank you for sharing this simple way to interface Arduino inputs to access by browsers. Some small modifications will help me to use it in a new context.
Steve

@brains1960

Is it possible to modify this and use it without an Ethernet Shield? I have a Bluetooth shield but I doubt that would be helpful

@gachet
gachet commented Feb 9, 2017

great example. It is possible some help for doing the same with YUN?

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