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

Extending the Raspberry Pi GPIO with an I/O expander


As we have seen, making use of the higher-level bus protocols allows us to connect to more complex hardware quickly and easily. The I2C can be put to great use by using it to expand the available I/O on the Raspberry Pi as well as providing additional circuit protection (and, in some cases, additional power to drive more hardware).

There are lots of devices available that provide I/O expansion over the I2C bus (and also SPI), but the most commonly used is a 28-pin device, MCP23017, which provides 16 additional digital input/output pins. Being an I2C device, it only requires the two signals (SCL and SDA connections plus ground and power) and will happily function with other I2C devices on the same bus.

We shall see how the Adafruit I2C 16x2 RGB LCD Pi Plate makes use of one of these chips to control an LCD alphanumeric display and keypad over the I2C bus (without the I/O expander, this would normally require up to 15 GPIO pins).

Getting ready...