Increment file name

Development Boards Arduino
6

I’m sorry, I couldn’t be more descriptive because I didn’t really know what was wrong.

I’ve found the “solution” and this is the code:

/*
  SD card datalogger
 
 This example shows how to log data from three analog sensors 
 to an SD card using the SD library.
 	
 The circuit:
 * analog sensors on analog ins 0, 1, and 2
 * SD card attached to SPI bus as follows:
 ** MOSI - pin 11
 ** MISO - pin 12
 ** CLK - pin 13
 ** CS - pin 4
 
 created  24 Nov 2010
 modified 9 Apr 2012
 by Tom Igoe
 
 This example code is in the public domain.
 	 
 */

#include <SD.h>

// On the Ethernet Shield, CS is pin 4. Note that even if it's not
// used as the CS pin, the hardware CS pin (10 on most Arduino boards,
// 53 on the Mega) must be left as an output or the SD library
// functions will not work.
const int chipSelect = 10;

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
  }


  Serial.print("Initializing SD card...");
  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
  pinMode(10, OUTPUT);
  
  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present");
    // don't do anything more:
    return;
  }
  Serial.println("card initialized.");
  char filename[16]; // make it long enough to hold your longest file name, plus a null terminator
  int n = 0;
  snprintf(filename, sizeof(filename), "data%03d.csv", n); // includes a three-digit sequence number in the file name
  while(SD.exists(filename)) {
    n++;
    snprintf(filename, sizeof(filename), "data%03d.csv", n);
  }
  Serial.println(n);
  Serial.println(filename);
  //now filename[] contains the name of a file that doesn't exist
  
  File dataFile = SD.open(filename, FILE_WRITE);
  

  }
void loop()
  {
 }

The files are being created as I wanted. The problem is:

  1. Since I’m using the function setup() to create them, I can’t use the “filename” to write in the loop();

  2. If I use my logic inside of the function loop(), it creates a lot of files because it’s a loop and that’s not what I want.

Can I use a variable defined inside of setup(), to manage files inside of the function loop()?