Read Variable value from SDcard

Hi guys, I need help with this question, How can I make for read one value from SDcard and pass to a variable? I already recorded the value of a variable on SDcard, on the following example, recorded the pin value of exit from led, now supposing that I want read the value for the exit pin from SDcard, how can I do this ?

Thanks for any help. :slight_smile:

Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain.

// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
#include <SD.h>
File myFile;
int led = 10;
// the setup routine runs once when you press reset:
void setup() {
// Open serial communications and wait for port to open:
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only

Serial.print("Initializing SD card...");
// On the Ethernet Shield, CS is pin 4. It's set as an output by default.
// Note that even if it's not used as the CS pin, the hardware SS pin 
// (10 on most Arduino boards, 53 on the Mega) must be left as an output 
// or the SD library functions will not work. 
pinMode(10, OUTPUT);

if (!SD.begin(4)) {
Serial.println("initialization failed!");
Serial.println("initialization done.");

// open the file. note that only one file can be open at a time,
// so you have to close this one before opening another.
if (SD.exists("test.txt")) {
SD.remove("test.txt"); //We don't want to use the same file THIS IS THE BUG?
myFile ="test.txt", FILE_WRITE);

// if the file opened okay, write to it:
if (myFile) {
Serial.print("Writing to test.txt...");
// close the file:
} else {
// if the file didn't open, print an error:
Serial.println("error opening test.txt");

// re-open the file for reading:
myFile ="test.txt");
if (myFile) {

// read from the file until there's nothing else in it:
while (myFile.available()) {
// close the file:
} else {
// if the file didn't open, print an error:
Serial.println("error opening test.txt");

// initialize the digital pin as an output.
pinMode(led, OUTPUT); 
// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(5000); // wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(5000); // wait for a second

Maybe if you add a few more useless curly braces yo your code and don't bother with proper formatting, things will get better.

Using code tags doesn't apply to you, either. Or does it?

Check #7 below,148850.0.html