Kill a loop with Button Jupyter Notebook?

Question

I want to:

• Read from serial port (infinite loop)
• when "STOP" button pressed --> Stop reading and plot data

From How to kill a while loop with a keystroke? I have taken the example to interrupt using Keyboard Interrupt, This works, but i would like to use a button.

EXAMPLE WITH KEYBOARD INTERRUPT

weights = []
times = [] 
#open port 
ser = serial.Serial('COM3', 9600)
try:
   while True: # read infinite loop
       #DO STUFF
       line = ser.readline()   # read a byte string
       if line:
           weight_ = float(line.decode())  # convert the byte string to a unicode string
           time_ = time.time()
           weights.append(weight_)
           times.append(time_)
           print (weight_)
#STOP it by keyboard interup and continue with program 
except KeyboardInterrupt:
   pass
#Continue with plotting

However I would like to do it with a displayed button (easier for people to use). I have tried making a button (in Jupiter Notebook) that when pressed break_cicle=False, but the loop doesn't break when button pressed:

 #make a button for stopping the while loop 
button = widgets.Button(description="STOP!") #STOP WHEN THIS BUTTON IS PRESSED
output = widgets.Output()
display(button, output)
break_cicle=True


def on_button_clicked(b):
    with output:
        break_cicle = False # Change break_cicle to False
        print(break_cicle)
        
ser.close()   
button.on_click(on_button_clicked)
ser = serial.Serial('COM3', 9600)
try:
    while break_cicle:

        print (break_cicle)
        line = ser.readline()   # read a byte string
        if line:
            weight_ = float(line.decode())  # convert the byte string to a unicode string
            time_ = time.time()
            weights.append(weight_)
            times.append(time_)
            print (weight_)
except :
    pass

ser.close()    

EXAMPLE WITH GLOBAL NOT WORKING

from IPython.display import display
import ipywidgets as widgets

button = widgets.Button(description="STOP!") #STOP WHEN THIS BUTTON IS PRESSED
output = widgets.Output()
display(button, output)
break_cicle=True

def on_button_clicked():
    global break_cicle #added global
    with output:
        
        break_cicle = False # Change break_cicle to False
        print ("Button pressed inside break_cicle", break_cicle)
    
    
button.on_click(on_button_clicked)
try:
    while break_cicle:
        print ("While loop break_cicle:", break_cicle)
        time.sleep(1)
except :
    pass
print ("done")

Despite me pressing the button a few times,from the following image you can see that it never prints "Button pressed inside break_cicle".