#include <SD.h>

String data_string = "Hello";
int CS_pin = 10;
float refresh_rate = 5000.0;
void setup() 
{
  Serial.begin(9600);
  Serial.println("Initialising card");
  pinMode(CS_pin, OUTPUT);
  // put your setup code here, to run once:
  if (!SD.begin(CS_pin))
  {
    Serial.println("Card failure");
    return;
  }
  Serial.println("Card ready");
}

void loop() 
{
  File log_file = SD.open("LOG.txt", FILE_WRITE);
  if (log_file){
    log_file.println(data_string);
    log_file.close();
    Serial.println(data_string);
  } else {
    Serial.println("Couldn't open the file");
  }
  delay(refresh_rate);
  // put your main code here, to run repeatedly:

}