I am working on my senior project "Computer Engineering Student". The project has a register, entrance gate and server on the same pc, and an exit gate. I need the register to be an android application. The entrance and exit gates have an interface for the pc, both of them are connected with Arduino with LED. The project is on Java. My problems are: each program is in a different device, so they need to be connected with the server. As I mentioned above the entrance gate and the server on the same pc, the android application, and the connection with Arduino in entrance gate to light the LED same as the exit. The registered program is checking is the user already registered or not. the entrance and the exit will do the same if the user enters the parking or not. For the Arduino, need to use [login to view URL] . Thank you in advance.