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

Controlling USB devices


The Universal Serial Bus (USB) is used extensively by computers to provide additional peripherals and expansion through a common standard connection. We will use thepyusb Python library to send custom commands to connected devices over USB.

The following example controls a USB toy missile launcher, which in turn allows it to be controlled by our Python control panel. We can see that the same principle can be applied to other USB devices, such as a robotic arm, using similar techniques, and the controls can be activated using a sensor connected to the Raspberry Pi GPIO:

The USB Tenx Technology SAM missile launcher

Getting ready

We will need to install pyusb for Python 3 using pip-3.2 as follows:

sudo pip-3.2 install pyusb

You can test whether pyusb has installed correctly by running the following:

python3> import usb> help (usb)> exit()

This should allow you to view the package information, if it was installed correctly.

How to do it...

We will create the following...