au BufRead,BufNewFile *.ino setlocal ft=arduino

au BufRead,BufNewFile *.ino setlocal ft=arduino
au BufRead,BufNewFile */Arduino/**/*.h setlocal ft=arduino
au BufRead,BufNewFile */Arduino/**/*.c setlocal ft=arduino
au BufRead,BufNewFile */Arduino/**/*.cpp setlocal ft=arduino

Load plugin for any c and c++ files in the Arduino folder
Load plugin for any c and c++ files in the Arduino folder

stevearc/vim-arduino