THX, Chris. GOT IT!

In this RaspberryVersion on Git you only must change the Line in AR2.py where the BAUDRATE is defined. Actual it is at 9600baud but Arduino Communicates with 115200baud.

If i changed it, my Arduino talks to the Raspberry else you got no Communication.

def setCom():
  global ser
  port = "/dev/ttyACM0" #+ comPortEntryField.get()
  baud = 115200
  ser = serial.Serial(port, baud)

Okay, lets build some Touchscreen Handheld Device :-D.

My plan is it to downsize your Main Softwarevisualisation for a Touchscreen with buttons like Orientation changes from Base to Tool to SingleAxis.

Greetings Daniel

@Wampo I confirm your def setCom() settings work even in case of running the python AR2 script on Ubuntu 16.04. Another thing to do when running on Ubuntu is to run the script with "sudo". For example sudo python3 AR2.py. Else this error will appear: serial.serialutil.SerialException: [Errno 13] could not open port /dev/ttyACM0: [Errno 13] Permission denied: '/dev/ttyACM0'.