How to Create a Countdown Timer in Python 

A countdown timer is an ideal way to set targets to complete tasks eg keep a reminder for the oven etc. For large-scale applications such as industries, complex timers are used, which are custom-designed for various purposes such as triggering or flipping a switch after a delay of set time. We might have noticed a screensaver appearing on the desktop when left idle for sometime. This happens because of the timer which calculates our idle time. Similarly, automatic logging out of websites, OTP expiration, captcha expiration are all based on a timer which nullifies these password after the time period expires.

Python Countdown Timer Project:

We will create a simple countdown timer using python and display 2 notifications, one with the app created and another on the desktop to remind the user of the time elapsed. A good understanding of functions and Tkinter widgets to understand the code flow is ideal.

Project Prerequisites:

The python countdown timer project makes use of tkinter for GUI development, time module for creating a delay, and plyer to create desktop notifications. We make use of Tkinter, a built-in GUI library in python. To check its availability, import it:

python <<< import tkinter

On Windows systems, reinstalling python will fix the issue. Time module is a built-in library and hence does not require any installation.

Now, to install plyer please run below command using pip:

pip install plyer

Project File Structure:

There are many GUI libraries supported by python such as PyQT5, Kivy, Pyside2 etc. Tkinter is widely used by many developers and is easy for beginners to practice.

Let’s have a look at the steps to python countdown timer project:

1. Importing modules: time, tkinter, and plyer
2. Initializing the window and declaring the dimensions
3. Defining functions for timer and placeholders
4. Creating the user input interface
5. Addition of a button to activate the timer

Now let’s discuss the complete implementation in detail.

Feel free to play with the values and change your input methods.

Below is the implementation of the above python code:

# The Coder Space 
#Countdown Clock and Timer
#Import necessary modules
from plyer import notification 
from tkinter import messagebox
from tkinter import *
import time

#Assign class and set dimensions of the interface
window = Tk()
window.geometry("300x200")
window.title("The Coder Space- Countdown and notification")

#Function to activate timer and show notifications once timer is up
def timer(): 

    #Since we use placeholders, we check if the user entered an integer
    try:
        timer_time = int(hour_entry.get())*3600 + int(min_entry.get())*60 + int(sec_entry.get())
        
    except:
        messagebox.showerror(message="Enter Valid Time")
    #The user cannot activate a timer with no time set
    #To update the timer with every decreasing second and display a notification    
    if timer_time >0:
        hour = 0
        min = 0 
        sec = 0    
        #If minutes is more than 60, it has to be set to the next hour
        while timer_time >= 0:
            min, sec = divmod(timer_time,60)
            if min > 60:
                hour, min = divmod(min,60) 
            #Set the declared variables with the new values to display                
            hours.set(hour)
            mins.set(min)
            secs.set(sec)
            #Sleep for 1 creates a delay of 1 second
            time.sleep(1)   
            #Update the changes on the window for every second
            window.update()
            #Decrement the timer value by 1
            timer_time -= 1
        #Create a desktop notification
        notification.notify(
            #Title of the notification,
            title = "TIMER ALERT",
            #Body of the notification
            message = "Hey amigo!\nDid you do what you wanted to achieve? \nIf not, try again with a new timer",
            app_icon = "/home/deepika/Downloads/internship/countdown_timer/pictures/bell.ico",
            #Notification stays for 30 seconds
            timeout  = 30,
        )
        #This notification is provided by tkinter with the created app
        messagebox.showinfo(message="Timer Complete!")         
        
#Remove the placeholders for every entry field based on click    
def h_click(event):
        hour_entry.delete(0,'end')         
def m_click(event):
        min_entry.delete(0,'end')
def s_click(event):    
        sec_entry.delete(0,'end')
        
#Label for displaying the title of the app
#position of the label or widget is set using pack().
#pack defaults to centered alignment on a x row and y column coordinate
title_label_1 = Label(window, text="DataFlair Countdown timer with notification",font=("Gayathri", 11)).pack()
title_label_2 = Label(window, text="Put 0 in fields not of use",font=("Gayathri", 10)).pack()
#Variables using which the timer is updated in the function
hours = IntVar()
mins = IntVar()
secs = IntVar()

#To read user input for hours, minutes and seconds
hour_entry = Entry(window, width=3,textvariable=hours,font=("Ubuntu Mono",18))
min_entry = Entry(window, width=3,textvariable=mins,font=("Ubuntu Mono",18))
sec_entry = Entry(window, width=3,textvariable=secs,font=("Ubuntu Mono",18))

#Placeholder for the entry widgets
hour_entry.insert(0,00)
min_entry.insert(0,00)
sec_entry.insert(0,00)

#Positioning the entry widgets.
#place() takes an x(from the left) and y(from the top) coordinate
hour_entry.place(x=80,y=40)
min_entry.place(x=130,y=40)
sec_entry.place(x=180,y=40)

#To link the defined placeholder removal functions on mouse click
hour_entry.bind("<1>", h_click)
min_entry.bind("<1>", m_click)
sec_entry.bind("<1>", s_click)

#button to activate the timer function
button = Button(window,text='Activate Timer', bg = 'Red',command=timer).pack(pady=40)

#Close the window and exit the app
window.mainloop()

-- The Coder Space

Output:

--The Coder Space

Thankyou Guys!

!! Jai Hind !!