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

Getting a sense of direction


In order to navigate your robot around the environment, you will need to keep track of which way your robot is facing. You can estimate the angle that your robot turns at by measuring the angle that it turned at in a fixed time period. For wheeled robots, you can also measure the rotation of each wheel using a rotary encoder (a device that provides a count of the wheel's rotations). However, as you make the robot take multiple turns, the direction the robot is facing becomes more and more uncertain as differences in the surfaces and the grip of the wheels or legs cause differences in the angles that the robot is turning at.

Fortunately, we can use an electronic version of a compass; it allows us to determine the direction that the robot is facing by providing an angle from magnetic North. If we know which direction the robot is facing, we can receive commands requesting a particular angle and ensure that the robot moves towards it. This allows the robot to perform...