Robin-no, opening and closing isnt a problem.
Have you done any tests to prove that?
the problem is accessing the values of the variables- like "positionLeft" that is on the arduino code.
If I take your statement literally it cannot be done. The Arduino is the only thing that can acces Arduino variables.
Your Arduino program can send the value of a variable using Serial.println(myVariable) - but you have already been told that in an earlier Reply.
This YouTube video seems to be doing what you want