/*

  Web Server

A simple web server that shows the value of the analog input pins. A uptime counter and a ram checker.

using an Arduino Wiznet Ethernet shield.

Michael Ratcliffe  Mike@MichaelRatcliffe.com

    This program is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.

    This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License

    along with this program.  If not, see <http://www.gnu.org/licenses/>.

    heavily based ont he work of David A. Mellis and the later work  by Tom Igoe

*/

//**************** All Defualt Libraries ************************************//

#include <SPI.h>

#include <Ethernet.h>

//****************** User Defined Variables *********************************//

// 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(192, 168, 9, 10);

// Initialize the Ethernet server library

EthernetServer server(80);

//************ Ram Checker Variable  ***********************//

/*  ATMega168 ATMega328P  ATmega1280  ATmega2560

SRAM  1024 bytes  2048 bytes  8192 Bytes  8192 Bytes

*/

const int Total_Ram = 2048; //change this value for the correct one from above data

//********************************************* End OF Recomended Changes ********************//

//*************Seting up the Ram check********************//

int freeRam () {

extern int __heap_start, *__brkval;

int v;

return (int) &v - (__brkval == 0 ? (int) &__heap_start : (int) __brkval);

};  

//********Just Some variables we use to convert to % ************//

float Ram=3;

float Ram_Ussage=0;

int Ram_error=0;

//************************** Just Some basic Definitions used for the Up Time LOgger ************//

long Day=0;

int Hour =0;

int Minute=0;

int Second=0;

int HighMillis=0;

int Rollover=0;

//************************** Setutp ********************************************************//

void setup() {

  // Open serial communications and wait for port to open:

  Serial.begin(9600);

  while (!Serial) {

    ; // wait for serial port to connect. Needed for Leonardo only

  }

  // start the Ethernet connection and the server:

  Ethernet.begin(mac, ip);

  server.begin();

  Serial.print("server is at ");

  Serial.println(Ethernet.localIP());

}

//********************* End Of Setup ************************************************//

//******************************* Main Loop ****************************************//

void loop() {

uptime(); //Runs the uptime script located below the main loop and reenters the main loop

print_Uptime(); // prints to serial

Max_Ram();  // updates ram ussage

//**** This is the bit that hosts your "webpage"  

  EthernetClient client = server.available();

  if (client) {

    Serial.println("new client");

    // an http request ends with a blank line

    boolean currentLineIsBlank = true;

    while (client.connected()) {

      if (client.available()) {

        char c = client.read();

        Serial.write(c);

        // 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: text/html");

          client.println("Connection: close");  // the connection will be closed after completion of the response

          client.println("Refresh: 5");  // refresh the page automatically every 5 sec

          client.println();

          client.println("<!DOCTYPE HTML>");

          client.println("<html>");

          //********** Printing the uptime at the top

          client.print("Uptime Counter:   ");

          client.print(Day);

          client.print("  Days   ");

          client.print(Hour);

          client.print("  Hours  ");

          client.print(Minute);

          client.print("  mins  ");

          client.print(Second);

          client.print("  seconds ");

          client.println("<br />");

          //********** Printing how much ram we used

          client.print("Max_Ram:   ");

          client.println(Ram_Ussage);

          //Creating a new line

          client.println("<br />");

          // output the value of each analog input pin

          for (int analogChannel = 0; analogChannel < 6; analogChannel++) {

            int sensorReading = analogRead(analogChannel);

            client.print("analog input ");

            client.print(analogChannel);

            client.print(" is ");

            client.print(sensorReading);

            client.println("<br />");

          }

          client.println("</html>");

          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();

    Serial.println("client disconnected");

  }

}

//************************ Uptime Code - Makes a count of the total up time since last start ****************//

void uptime(){

//** Making Note of an expected rollover *****//  

if(millis()>=3000000000){

HighMillis=1;

}

//** Making note of actual rollover **//

if(millis()<=100000&&HighMillis==1){

Rollover++;

HighMillis=0;

}

long secsUp = millis()/1000;

Second = secsUp%60;

Minute = (secsUp/60)%60;

Hour = (secsUp/(60*60))%24;

Day = (Rollover*50)+(secsUp/(60*60*24));  //First portion takes care of a rollover [around 50 days]

};

//******************* Prints the uptime to serial window **********************//

void print_Uptime(){

  Serial.print(F("Uptime: ")); // The "F" Portion saves your SRam Space

  Serial.print(Day);

  Serial.print(F("  Days  "));

  Serial.print(Hour);

  Serial.print(F("  Hours  "));

  Serial.print(Minute);

  Serial.print(F("  Minutes  "));

  Serial.print(Second);

  Serial.println(F("  Seconds"));

  Serial.print(Ram_Ussage);

  Serial.println(F("% Ram Used "));

};

//************* Loop for calculating Ram Ussage, called from main loop***//  

    void Max_Ram(){

            if(freeRam()>=Ram){

             Ram=(freeRam());

             Ram_Ussage=(((Total_Ram-Ram)/Total_Ram)*100);

                              };

             if(Ram_Ussage>=70){

              Ram_error=1; // Use this set flag to warn the user of a potential Ram ussage problem, or reset the arduino if it becomes true

                              };

};