Book Image

Raspberry Pi for Python Programmers Cookbook - Second Edition

Book Image

Raspberry Pi for Python Programmers Cookbook - Second Edition

Overview of this book

Raspberry Pi cookbook for Python Programmers is a practical guide for getting the most out of this little computer. This book begins by guiding you through setting up the Raspberry Pi, performing tasks using Python 3 and introduces the first steps to interface with electronics. As you work through each chapter you will build up your skills and knowledge and apply them as you progress throughout the book, delving further and further into the unique abilities and features of the Raspberry Pi. Later, you will learn how to automate tasks by accessing files, build applications using the popular Tkinter library and create games by controlling graphics on screen. You will harness the power of the built-in graphics processor by using Pi3D to generate your own high quality 3D graphics and environments. Connect directly to the Raspberry Pi’s hardware pins to control electronics from switching on LEDs and responding to push buttons right through to driving motors and servos. Learn how to monitor sensors to gather real life data and to use it to control other devices, and view the results over the Internet. Apply what you have learnt by creating your own Pi-Rover or Pi-Hexipod robots. Finally, we will explore using many of the purpose built add-ons available for the Raspberry Pi, as well as interfacing with common household devices in new ways.
Table of Contents (18 chapters)
Raspberry Pi for Python Programmers Cookbook - Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Hardware and Software List
Index

A controlled shutdown button


The Raspberry Pi should always be shut down correctly to avoid the SD card being corrupted (by losing power while performing a write operation to the card). This can pose a problem if you don't have a keyboard or screen connected (if you are running an automated program or controlling it remotely over a network and forget to turn it off) as you can't type the command or see what you are doing. By adding our own buttons and LED indicator, we can easily command a shutdown, reset, and startup again to indicate when the system is active.

Getting ready

You will need the following equipment:

  • 3 x Dupont female to male patch wires

  • Mini breadboard (170 tie points) or a larger one

  • Push button switch (momentary close)

  • General purpose LED

  • 2 x 470-ohm resistors

  • Breadboarding wire (solid core)

The entire layout of the shutdown circuit will look as shown in the following figure:

The controlled shutdown circuit layout

How to do it…

Create the shtdwn.py script as follows:

#!/usr/bin/python3...