Arduino Function:


This function opens a file on the SD card or create it if doesn't exist.

Syntax, mode)


  • filename: the name the file to open, which can include directories (delimited by forward slashes, /) - char *
  • mode (optional): the mode in which to open the file, defaults to FILE_READ - byte. one of:

FILE_READ: open the file for reading, starting at the beginning of the file. 
FILE_WRITE: open the file for reading and writing, starting at the end of the file.


 a File object referring to the opened file; if the file couldn't be opened, this object will evaluate to false in a boolean context, i.e. you can test the return value with "if (f)".

Based on the reference originally written by Arduino Community, and