Python3 newbie

[Larz60+]

some additional PEP8 observations

Output:
1. Place all imports on separate lines
import serial
import time
# import random

2. def readData():
   def updateValue(...)

   should not contain capital letters, use under score:

3.
chamge: 
    '''
    use
    t_btn.config('text')[-1]
    to get the present state of the toggle button
    '''
to:
    """
    use
    t_btn.config('text')[-1]
    to get the present state of the toggle button
    """
4. import statement time not used

5. typo in 'meassages': GPIO.setwarnings(False)  # disable annoying warning meassages

these are not show stoppers, rather PEP8 conformance