Automated Green House Blog:18.2 - Data Logging: SD Card

/*

This script measures the enviroment withing a greenhouse

Sends data to SD Card with Time Stamp

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/>.

    >Arduino

    >Ethernet shield Arduino Ethernet shield R3 with micro SD connector

Much of this code is largely based on Jeremy Blum's Tutorials Thanks for the great work!

*/

#include <SPI.h>

#include <SD.h>

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

const int Spacing=10; //how long in sconds to wait between logging data

// what we will print at the top of log [collums]

String header = "Seconds, Analog_Average, Ram,";

//******** Change Value Below For Board Of Choice *********//

/* ATMega168 ATMega328P ATmega1280 ATmega2560

SRAM 1024 bytes 2048 bytes 8192 Bytes 8192 Bytes

*/

const int Total_Ram = 8192 ; //change this value for the correct one from above data

//******************** End of Recomended Changes ****************************//

int Ram=0;

float  max_Ram=0;

#define SS_SD_CARD   4

#define SS_ETHERNET 10

float Analog_Value=0;

//Some stuff for making second readings

unsigned  long Second=0;

unsigned long Last_Send= 0;

//Some stuff for making second readings

long Last_Second=0;

int Reading=0;

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

int freeRam () {

extern int __heap_start, *__brkval;

int v;

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

};

//******************************************************************//

//*****************************Setup Loop *************************************//

void setup() {

  // Open serial communications

  Serial.begin(9600);

digitalWrite(SS_ETHERNET, HIGH); // Ethernet not active

digitalWrite(SS_SD_CARD, LOW);  // SD Card ACTIVE

  Serial.print("Initializing SD card...");

  // see if the card is present and can be initialized:

  if (!SD.begin(SS_SD_CARD)) {

    Serial.println("Card failed, or not present");

    // don't do anything more:

  }

   else Serial.println("card initialized.");

//Printing the file header

  File dataFile = SD.open("datalog.txt", FILE_WRITE);

  // if the file is available, write a header to it:

  if (dataFile) {

    dataFile.println("  ");

    dataFile.println(header);

    dataFile.close();

  }

  // if the file isn't open, pop up an error:

  else {

    Serial.println("error opening datalog.txt");

  }

}

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

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

void loop() {

Second=millis()/1000;

//Taking one reading every second

if(Second!=Last_Second){

   Analog_Value=(analogRead(A0)+ Analog_Value);

   Last_Second=Second;

   Reading++ ;

   }

//Checking how much ram we are using

if(freeRam()>=Ram){

             Ram=(freeRam());

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

};

//Averaging Readings and calling the logging functions [see below code]

if(Second%Spacing==0 && Second!=Last_Send){

   Last_Send= Second;

     Analog_Value=Analog_Value/Reading;

     Reading=0; //setting things back ready for more readigs

     Second=millis()/1000;

     Activate_SD();

     Log_SD();

     Activate_Eth();

     Analog_Value=0;

}

};

//********************************* End Of Main **********************************//

//*************** Activating Sd Card **************************//

void Activate_SD(){

  digitalWrite(SS_ETHERNET, HIGH); // Ethernet not active

  digitalWrite(SS_SD_CARD, LOW);  // SD Card ACTIVE

delay(10);

if (!SD.begin(SS_SD_CARD)) {

    Serial.println("Card failed, or not present");

    // don't do anything more:

  }

   else Serial.println("card initialized.");

};

//**************** Function To activate ethernet *************//

void Activate_Eth(){

  digitalWrite(SS_ETHERNET, LOW); // Ethernet not active

  digitalWrite(SS_SD_CARD, HIGH);  // SD Card ACTIVE

};

//**************** Function to Log SD **********************//

void Log_SD(){

  File dataFile = SD.open("datalog.txt", FILE_WRITE);

  // if the file is available, write to it one variable at a time

  if (dataFile) {

    dataFile.print("");

    dataFile.print(Second);

    dataFile.print(",  ");

    dataFile.print(Analog_Value);

    dataFile.print(",  ");

    dataFile.println(max_Ram);

    dataFile.close();

    // print to the serial port too:

    Serial.println("Posting!");

    Serial.print("Analog_Average: ");

    Serial.println(Analog_Value);

    Serial.print("Max_Ram: ");

    Serial.println(max_Ram);

    Serial.print("Seconds: ");

    Serial.println(Second);

    Serial.println("Data Logged");

  }

  // if the file isn't open, pop up an error:

  else {

    Serial.println("error opening datalog.txt");

  }

};