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?

Go to menu sketch -> Add File... This will open up filer box. Locate your header file and click on it. It will then appear in a tab on the IDE window you are working in.