arduino.ini

/*
Project Name: SmartBoiler
Project Website: http://gcool.info/2013/10/20/smartboiler/
Description: Script to control arduino Yun
Version: 0.0
Author: George Koulouris
Author URI: http://gcool.info/
*/

#include <Process.h>

/* Include library to control the servo motor */
#include <Servo.h>

/* Define a variable for our servo motor */
Servo servoMain;

/* In my configuration, taking into account the length of the arm, the switch is turned off when the servo is at 160 deg */
int down = 160;

/* In my configuration, taking into account the length of the arm, the switch is turned on when the servo is at 10 deg */
int up = 10;

/* Define a variable to store the status of the switch (on or off) */
int pos;

void setup()
{
  /* Initialize Bridge */
  Bridge.begin();
  
  /* Initialize Serial Port */
  Serial.begin(9600);
  
  /* The yellow cable of the servo is connected to pin 9. Red = 5V, Brown = GND */
  servoMain.attach(9);

  /* Switch off the heater */
  pos = down;
  servoMain.write(pos); 
}

void loop()
{
    /* Check whether the heater is turned on */
    if (runCurl() == true) {
      pos = up;
    } else {
      pos = down;
    }
    
    /* Update the position of the servo */
    servoMain.write(pos);
    
    /* Wait for 1s */
    delay(1000);
}

bool runCurl() {
  /* Launch "curl" command to check whether the heater is turned on
     curl is command line program for transferring data using different internet protocols */
  /* Create a process and call it "p" */   
  Process p;  

  /* Process that launch the "curl" command */  
  p.begin("curl"); 
  
  /* Add the URL parameter to "curl". It actually checks a .txt file on my server. If it is 0, then the heater is switched off. Else it is switched on. */
  p.addParameter("http://gcool.info/smartboiler/boiler_status.txt"); 
  
  /* Run the process and wait for its termination */
  p.run();

  /* A process output can be read with the stream methods */
  while (p.available()>0) {
    char c = p.read();
    
    /* Check whether the heater is turned on */ 
    if (c=='0') {
      /* If it is 0, then the heater is switched off... */
      return false;
    } else {
      /* ...else it is switched on. */
      return true; 
    }
  }
}