Book Image

Python Programming with Raspberry Pi

By : Sai Yamanoor, Srihari Yamanoor
Book Image

Python Programming with Raspberry Pi

By: Sai Yamanoor, Srihari Yamanoor

Overview of this book

Raspberry Pi Zero is a super-small and super-affordable product from Raspberry Pi that is packed with a plethora of features and has grabbed the notice of programmers, especially those who use Python. This step-by-step guide will get you developing practical applications in Python using a Raspberry Pi Zero. It will become a valuable resource as you learn the essential details of interfacing sensors and actuators to a Raspberry Pi, as well as acquiring and displaying data. You will get started by writing a Python program that blinks an LED at 1-second intervals. Then you will learn to write simple logic to execute tasks based upon sensor data (for example, to control a motor) and retrieve data from the web (such as to check e-mails to provide a visual alert). Finally, you will learn to build a home automation system with Python where different appliances are controlled using the Raspberry Pi. The examples discussed in each chapter of this book culminate in a project that help improve the quality of people’s lives.
Table of Contents (17 chapters)
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Connecting to the Internet – web requests


Now that we discussed the try/except keywords, let's make use of it to build a simple application that connects to the Internet. We will write a simple application that retrieves the current time from the Internet. We will be making use of the requests library for Python (http://requests.readthedocs.io/en/master/#).

The requests module enables connecting to the Web and retrieving information. In order to do so, we need to make use of the get() method from the requests module to make a request:

import requests
response = requests.get('http://nist.time.gov/actualtime.cgi')

In the preceding code snippet, we are passing a URL as an argument to the get() method. In this case, it is the URL that returns the current time in the Unix format (https://en.wikipedia.org/wiki/Unix_time).

Let's make use of the try/except keywords to make a request to get the current time:

#!/usr/bin/python3

import requests

if __name__ == "__main__":
  # Source for link: http://stackoverflow...