Including my own header files

It seems I must have a “libraries/” folder in the “Arduino/libraries” folder in order to include my own header file for my own sketch, the source code of which is in an “Arduino/” folder. Is there way to have my own header file in the same folder as my own source code? Or is this an oddity of the IDE?

Is there way to have my own header file in the same folder as my own source code? Or is this an oddity of the IDE?

Of course there is.

#include <someFile.h>
and
#include “someFile.h”
will both include someFile.h. The difference is WHERE the file is included from (the libraries folder or the current folder).

The intention is that the #include “…” syntax include files in the same directory only
(local includes), whereas #include <…> syntax goes and looks for the file in the standard
places for libraries in your system.

In practice its implemented by having two path-lists for the two syntaxes, quite
how they are configered on the Arduino I can’t recall exactly, but I think it all
works as intended, but be aware it might look in several places for your file and
if there is a name-clash between files this sometimes causes confusion (especially
if you use the wrong syntax).