String error

[Kurta]

have you checked what kind of data you get on the serial port?

    arduinoString = arduinoData.readline()
    print(arduinoString) # check the output

About the same thing,, i was down this path to begin with your correct this is a good place to start

this is what i got:
b'63,71\r\n'
i had a hunch it was a mismatch of data