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Topic: OpenLog questions and sample code (Read 1 time) previous topic - next topic


First let me start by saying "long time listener, first time caller"  I am trying to learn C and write good Code, easily understood and modular. With modular testing in mind I am trying to build a simple function I can use in a larger program to log time and temperature to a SD card.   So with that in mind I want create a file, and then write to that file logging time and temperature every minute.  At this point I have updated the firmware of OpenLog and have it doing the test sketch, I have written a simple sketch myself to write data to the card.  I have not been able to create a file or add to it.  Here is my code, I have tried to keep it really simple you can see what didn't work commented out.

Thank you in advance for looking at this.
Code: [Select]

Arduino TX to OpenLog RXI
Arduino 5V to OpenLog VCC
Arduino GND to OpenLog GND

A simple test sketch to show writing to a file

#include <SoftwareSerial.h>
#include <SdFat.h>
SdFile file;

int ledPin =  13; //Status LED connected to digital pin 13
int i =0;         // declare i an integer
SdFat sd;
SdFile myFile;

void setup()
{ //beginning void setup
  pinMode(ledPin, OUTPUT);   // set the Pin to output 
  Serial.begin(9600);        //Serial.begin(9600); //9600bps is default for OpenLog
  delay(1000);               //Wait a second for OpenLog to init

//Works with Arduino v1.0              This section does not work at all
// Serial.print(26);
// Serial.print(26);
// Serial.print(26);
// new myFile;
// myFile.open("AAAATEST.TXT");
  for(int i = 1 ; i < 10 ; i++){          // beginning for loop
  Serial.print(i);                        // prints the number of the loop
  Serial.println("Excellent First Test"); // junk line for something to print and test
  }                                       // end for loop
}// end void setup
void loop()
{// beginning void loop
}// end void loop


Where have you initialized the SD device? Nothing happens automatically just because the hardware is connected.


Well actually the code does work, it prints the 1-9 for loop, so sorry for my ignorance but I didn't see any ititilization in the OpenLog setup sketch and so didn't include any.  Suggestions for code I will happily work in, compile and test. 



Mar 22, 2013, 06:41 pm Last Edit: Mar 22, 2013, 07:00 pm by xazirhs Reason: 1
Hi, I am having the same problem, I bought the openlog and I haven't been able to use it. First how do we connect it to arduino Uno so that I can make it to create a csv file and then every 3 or 4 minutes add the data from some sensors to the file? I have searched the web but I haven't found a solution. I have an example from http://www.jeremyblum.com/2011/04/05/tutorial-11-for-arduino-sd-cards-and-datalogging/ but he is using SPI connection.
Code: [Select]
//Program by Jeremy Blum
//SD Card Demonstration
//Some code from public domain work by Tom Igoe

#include <SD.h>         //SD Card Library
#include <Wire.h>       //I2C Library

//SPI SD Card Pins
  //MOSI = Pin 11
  //MISO = Pin 12
  //SCLK = PIN 13
  int CS_pin = 10;
  int pow_pin = 8;
//I2C Temperature Pins
  //SDA = Analog Pin 4
  //SCL = Analog Pin 5
//IR Distance Sensor Pins
  int IR1_pin = 2;
  int IR2_pin = 3;
//Light Sensor Pins
  int light_pin = 1;

float refresh_rate = 0.0;  //Dataloger Refresh Rate
int temp_address = 72;     //Address of the I2C Temp Sensor
long id = 1;                //Use this to store the id # of our reading.

void setup()
  Serial.println("Initializing Card");
  //CS Pin is an output
  pinMode(CS_pin, OUTPUT);
  //SD Card will Draw Power from Pin 8, so set it high
  pinMode(pow_pin, OUTPUT); 
  digitalWrite(pow_pin, HIGH);
  //Initialize Card
  if (!SD.begin(CS_pin))
      Serial.println("Card Failure");
  Serial.println("Card Ready");
  //Read the Configuration information (COMMANDS.txt)
  File commandFile = SD.open("COMMANDS.txt");
  if (commandFile)
    Serial.println("Reading Command File");
    float decade = pow(10, (commandFile.available() - 1));
      float temp = (commandFile.read() - '0');
      refresh_rate = temp*decade+refresh_rate;
      decade = decade/10;
    Serial.print("Refresh Rate = ");
    Serial.println("Could not read command file.");
  //Write Log File Header
  File logFile = SD.open("LOG.csv", FILE_WRITE);
  if (logFile)
    logFile.println(", , , ,"); //Just a leading blank line, incase there was previous data
    String header = "ID, Light, Temp, IR1, IR2";
    Serial.println("Couldn't open log file");

void loop()
  //Check Light Level
  int light_level = analogRead(light_pin);
  //Read Temperature
  Wire.beginTransmission(temp_address); //Start talking
  Wire.send(0); //Ask for Register zero
  Wire.endTransmission(); //Complete Transmission
  Wire.requestFrom(temp_address, 1); //Request 1 Byte
  while(Wire.available() == 0); //wait for response
  int temp_c = Wire.receive(); // Get the temp
  int temp_f = round(temp_c*9.0/5.0 +32.0);  //Convert to stupid American units
  //Read Distances
  int IR1_val = analogRead(IR1_pin);
  int IR2_val = analogRead(IR2_pin);
  //Create Data string for storing to SD card
  //We will use CSV Format 
  String dataString = String(id) + ", " + String(light_level) + ", " + String(temp_f) + ", " + String(IR1_val) + ", " + String(IR2_val);
  //Open a file to write to
  //Only one file can be open at a time
  File logFile = SD.open("LOG.csv", FILE_WRITE);
  if (logFile)
    Serial.println("Couldn't open log file");
  //Increment ID number

can you help me please or point me something to read about it?

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