- Yes, there are several ways to approach the 'end of project' phase. You can either just dedicate the Arduino board to the dedicated application and buy another. You can purchase a mini version of the board that includes a USB connection and load your application code and needed external components and mount it into a small enclosure. Here is but just one example:
http://store.fundamentallogic.com/ecom/index.php?main_page=product_info&cPath=2&products_id=28
- The Arduino USB serial interface and Arduino serial software commands are a very simple basic character based interface, one character at a time, in either direction. How you send send and receive data, assemble messages and commands, and act on it is all under your own program control both on the PC side and the Arduino side, you are free (and must) develop the protocol yourself. The fact that it is such a low level interface means if can be programmed to do just about anything but puts the burden on your software skills.
Good luck with your project and wish you success.
Lefty