Python Forum

With the help of some earlier coding suggestion, I was trying to select the serial port with which I have connected the wireless modem.

I am using serial.tools.list_ports to list down all the com ports available in the laptop but after selecting the com port I am not able to open that

I am using mentioned below python code

import serial
import json
import tkinter
from tkinter import messagebox
from tkinter import *
import tkinter as ttk
import serial.tools.list_ports

ard = serial.Serial();
root = ttk.Tk()
root.title("Read Sensor")

B = None
C = None 

# Add a grid
mainframe = Frame(root)
mainframe.grid(column=0,row=0, sticky=(N,W,E,S) )
mainframe.columnconfigure(0, weight = 1)
mainframe.rowconfigure(0, weight = 1)
mainframe.pack(pady = 100, padx = 100)
 
# Create a Tkinter variable
tkvar1 = StringVar(root)
tkvar = StringVar(root)

#Serial Port
a=serial.tools.list_ports.comports()
for w in a:
    print(w.device)
    k = [w.device]
    print(k)
ser_dict = { i for i in k }
print (ser_dict)
val1 = tkvar1.get()
if val1 in ser_dict:
    ard.port = str (ser_dict[val1])
    ard.open()
    if C:
        C.destroy()
        C = ttk.Button(root, text =val1, command = dropCall)
        C.pack()

 
# Dictionary with options
baud = { '9600','119200','34800'}

#Pop Up desciption
popupMenu1 = OptionMenu(mainframe, tkvar1, *ser_dict)
Label(mainframe, text="Serial Port").grid(row = 1, column = 1)
popupMenu1.grid(row = 2, column =1)

popupMenu2 = OptionMenu(mainframe, tkvar, *baud)
Label(mainframe, text="Baudrate").grid(row = 3, column = 1)
popupMenu2.grid(row = 4, column =1)


#Serial Callback Functions
def helloCallBack():
    k = ard.readline().decode('ascii');
    if(len(k)>0):
        print (k);
        size = len(k);
        #print (k[0:size-2]);
        print (size);
        messagebox.showinfo('Message From Arduino',k[0:size-2]+'\n'+str(size))     

#baudrate functions
def dropCall(*args):
   global B
   value = tkvar.get()
   ## using a dictionary instead of if statements
   ## to show how dictionaries are used
   baud_dict={'9600':value, '34800':value, '119200':value}
   if value in baud_dict:
      ard.baudrate = int(baud_dict[value])
      if B:
         B.destroy()
      B = ttk.Button(root, text =value, command = helloCallBack)
      B.pack()

#Link Function
tkvar.trace('w', dropCall)

Due to mentioned below error I am not able to access that port

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\Misha\AppData\Local\Programs\Python\Python36\lib\tkinter\__init__.py", line 1702, in __call__
    return self.func(*args)
  File "C:\Users\Misha\Desktop\test\GUItest.py", line 60, in helloCallBack
    k = ard.readline().decode('ascii');
  File "C:\Users\Misha\AppData\Local\Programs\Python\Python36\lib\site-packages\serial\serialwin32.py", line 267, in read
    raise portNotOpenError
serial.serialutil.SerialException: Attempting to use a port that is not open

Will looking forward for your suggestions

Read the error traceback, it's quite clear, on line 60:

Quote:serial.serialutil.SerialException: Attempting to use a port that is not open

(Jan-07-2019, 03:26 PM)Larz60+ Wrote: [ -> ]ard.open()

I already mentioned for opening the port as well as code is reading the port but still facing this issue can you suggest what will be useful here?

Perhaps if val1 in ser_dict is never true and ard.open() is never reached.