Plot Real Time Serial Data in Python - user-interface

Question

I couldn't plot the real time serial data come from arduino.
I working on a project this project details are like that :
I have pressure sensor that detects the pressure on them probs.I transfer the pressure measured on the probes to the computer via serial port communication with the help of arduino uno.
ı can read the data come from arduino on the Spyder Editor(python)
Using this data ( 2 pressure value coming from arduino) ı have to plot real time serial data on the GUI.
I create the GUI.
But I couldn't plot the data.
I would really appreciate any help or comments , thanks for every effort !
`
# -*- coding: utf-8 -*-
"""
Created on Thu Dec 29 03:57:27 2022
#author: Berk
"""
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure
import tkinter as tk
import numpy as np
import serial
import time
import datetime
xs=[]
ys=[]
serialPort=serial.Serial(port="COM5", baudrate=9600,
bytesize=8,timeout=2,stopbits=serial.STOPBITS_ONE)
cond=False
date=str(datetime.datetime.now())
date=date.replace(" ",",")
date=date.replace(":",".")
while (True):
try:
if (serialPort.in_waiting > 0):
serialString=serialPort.readline()
data=serialString.decode("utf8", errors="replace")
replaced_data=data.replace("\r","")
replaced_data=replaced_data.replace("\n","")
# replaced_data=replaced_data.replace(":","-")
print(replaced_data)
###---plot data---###
def plot_data():
global cond,data
data=np.append()
print(data)
if(cond==True):
a=serialPort.readline()
a.decode()
if(len(data<100)):
data=np.append(data,float(a[0:4]))
else:
data[0:99]=data[1:100]
data[99]=float(a[0:4])
print(a)
lines.set_xdata(np.arange(0,len(data)))
lines.set_ydata(data)
canvas.draw()
def plot_start():
global cond
cond=True
serialPort.reset_input_buffer()
def plot_stop():
global cond
cond=False
#######GUI########
root=tk.Tk()
root.title('Pressure Value From Sensor')
root.configure(background='light blue')
root.geometry("700x500")
#####PLOTTİN ON GUI##########
fig=Figure();
ax=fig.add_subplot(111)
ax.set_title('Pressure By Time')
ax.set_xlabel('By Time')
ax.set_ylabel('Pressure')
ax.set_xlim(0,500)
ax.set_ylim(0,500)
lines=ax.plot([],[],0)
canvas=FigureCanvasTkAgg(fig,master=root)
canvas.get_tk_widget().place(x=10,y=10,width=500,height=400)
canvas.draw()
root.after(1,plot_data)
##button##
root.update();
start=tk.Button(root,text='Stop',font=('calibri',12),command=lambda:plot_start())
start.place(x=100,y=450)
root.update();
start=tk.Button(root,text='Start',font=('calibri',12),command=lambda:plot_stop())
start.place(x=start.winfo_x()+start.winfo_reqwidth()+20,y=450)
##startint serial port###
serialPort=serial.Serial(port="COM5", baudrate=9600,
bytesize=8,timeout=2,stopbits=serial.STOPBITS_ONE)
serialPort.reset_input_buffer()
root.after(1,plot_data)
root.mainloop()
`