Book Image

Raspberry Pi 3 Cookbook for Python Programmers - Third Edition

By : Steven Lawrence Fernandes, Tim Cox
Book Image

Raspberry Pi 3 Cookbook for Python Programmers - Third Edition

By: Steven Lawrence Fernandes, Tim Cox

Overview of this book

Raspberry Pi 3 Cookbook for Python Programmers – Third Edition begins by guiding you through setting up Raspberry Pi 3, performing tasks using Python 3.6, and introducing the first steps to interface with electronics. As you work through each chapter, you will build your skills and apply them as you progress. You will learn how to build text classifiers, predict sentiments in words, develop applications using the popular Tkinter library, and create games by controlling graphics on your screen. You will harness the power of a built in graphics processor using Pi3D to generate your own high-quality 3D graphics and environments. You will understand how to connect Raspberry Pi’s hardware pins directly to control electronics, from switching on LEDs and responding to push buttons to driving motors and servos. Get to grips with monitoring sensors to gather real-life data, using it to control other devices, and viewing the results over the internet. You will apply what you have learned by creating your own Pi-Rover or Pi-Hexipod robots. You will also learn about sentiment analysis, face recognition techniques, and building neural network modules for optical character recognition. Finally, you will learn to build movie recommendations system on Raspberry Pi 3.
Table of Contents (23 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
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...