Raspberry Pi Projects!

480 Pages·2013·30.143 MB·English

by  Andrew Robinson (Author), Mike Cook (Author)

Raspberry Pi®
Projects
Dr. Andrew Robinson
Mike Cook
Jonathan Evans
Sean McManus
This edition first published 2014
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To the kitchen table inventors, and their long-suffering families that have to live with them.
–Andrew Robinson
To Mike Bibby, who was the first editor to give me the opportunity to write regularly about
computers and hardware. His unfailing enthusiasm about all things and his inability to take
anything just on trust are an example to us all. A continuing and valued friend.
–Mike Cook
Publisher’s Acknowledgements
Some of the people who helped bring this book to market include the following:
Editorial and Production Marketing
VP Consumer and Technology Publishing Associate Marketing Director
Director Louise Breinholt
Michelle Leete
Marketing Manager
Associate Director–Book Content Lorna Mein
Management
Martin Tribe Senior Marketing Executive
Kate Parrett
Associate Publisher
Chris Webb Marketing Assistant
Polly Thomas
Executive Commissioning Editor
Craig Smith
Project Editor
Dana Lesh
Copy Editors
Dana Lesh, Kathryn Duggan
Technical Editor
Genevieve Smith-Nunes
Editorial Manager
Jodi Jensen
Senior Project Editor
Sara Shlaer
Editorial Assistant
Annie Sullivan
About the Authors
Andrew Robinson is the founder of a successful embedded computing design consultancy
firm based in Manchester. Passionate about education, he runs workshops and training
sessions for all levels of experience, from design engineers to teachers and school children.
His projects with the Raspberry Pi have appeared in the national press and on ITV, Channel
5 and BBC television. He is an Honorary Research Fellow of the University of Manchester,
where previously he completed his Ph.D. in low power-embedded processors.
Andrew can trace his enthusiasm for electronics and computers back to building a working
model lighthouse at the age of five.
Mike Cook, veteran technical author and electronics maker from the U.K., was born in Manchester
and still lives close by. He is best known to the public for a series of over 300 articles which
appeared in The Micro User, Acorn Computing and Acorn User from 1983 to 2000. These were called
the “Body Building Course” and “Run the Risc” and covered the design and build of new gadgets,
interfaces and peripherals for the old (vintage) BBC computer and the RISC PC. He also wrote
numerous reviews, software articles and the readers’ problem page in these magazines.
Mike started work in the late sixties at an industrial electronics company in Oldham. He
went on to take a degree in physical electronics at Newcastle, including a year spent working
at the Admiralty Underwater Weapons establishment at Portland. His post-graduate research
was in sound compression at the University of Salford. He spent over 20 years at Manchester
Metropolitan University (initially Manchester Polytechnic) lecturing in physics, specialising
in computer instrumentation, astronomy and image processing. Later he moved back into
industry where he headed the hardware design team for the pioneering digital terrestrial set
top box, and has been a development manager for security and RFID products.
He now works freelance as an embedded electronics consultant and author. His last book
was The Raspberry Pi For Dummies published by Wiley.
Recently he has been designing even more things in the arena of physical computing, exhibiting
at the U.K. Maker Fairs, Mini Maker Fairs and the prestigious New York World Maker fair.
Mike was the recipient of a Maker of Merit Blue Ribbon at the 2013 Rome Maker Faire.
Jonathan Evans has had a life-long interest in computers and electronics. At the tender
age of 10, he taught himself how to program a computer, and he quickly learned how
computers and electronics could be married for a functionality to keep his siblings out of his
room. He has gone on to become a distinguished IT professional with over 20 years of
experience. His passion for creation and innovation combines perfectly with the Raspberry
Pi phenomenon, and in his spare time he enjoys exploring projects to make the Raspberry Pi
relevant to everyday life. He enjoys sharing his ideas at www.projects.privateeyepi.
com where he continues to explore the endless possibilities of this computing platform.
Sean McManus writes inspiring books and articles about computing. He contributed the chapter
on Minecraft to Raspberry Pi Projects, and his previous books include Raspberry Pi For Dummies
(written with Mike Cook), Scratch Programming in Easy Steps, iPad for the Older and Wiser, Microsoft
Office for the Older and Wiser, and Web Design in Easy Steps. Visit his website at www.sean.co.uk.
Contents
Introduction ..................................................................................1
A History of Making ..........................................................1
Consumer Computing ........................................................2
Why Everyone Should Learn About Computing ..................................2
Enter the Raspberry Pi ........................................................3
About This Book .............................................................4
How to Use This Book ........................................................4
The Future ..................................................................6
Part I: Getting Started with the Raspberry Pi
CHAPTER 1
Getting Your Raspberry Pi Up and Running.......................................9
The Operating System .......................................................10
Connecting Your Raspberry Pi ................................................16
The Boot Process ............................................................25
Starting the Graphical Desktop ................................................26
Starting a Terminal under X ..................................................26
Troubleshooting ............................................................26
Let the Fun Begin! ...........................................................28
CHAPTER 2
Introductory Software Project: The Insult Generator ........................29
Running Your First Python Program ...........................................30
Saving Your Program ........................................................33
Generating an Insult .........................................................36
Insult Your Friends by Name! .................................................39
Create a Stream of Insults! ...................................................41
Putting It All Together .......................................................45
Part II: Software Projects
CHAPTER 3
Tic-Tac-Toe ................................................................................49
Errors .....................................................................50
Making a Start ..............................................................51
A Two-Player Game .........................................................55
Getting the Computer to Play .................................................59
Over to You ................................................................70
CHAPTER 4
Here’s the News...........................................................................71
Early Teleprompters .........................................................72
The Pi Prompter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
What You Need to Do .......................................................73
A Step Closer to a Usable Program .............................................78
Your Final Pi Prompter Code. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84
The Physical Setup for Your Prompter ..........................................89
Over to You ................................................................92
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RASPBERRY PI PROJECTS
CHAPTER 5
Ping...........................................................................................93
Early Commercial Products ...................................................94
The Ping Game ..............................................................94
Improving the Ping Game ....................................................99
A Single-Player Game .......................................................104
A Two-Player Game ........................................................111
Over to You ...............................................................118
CHAPTER 6
Pie Man ....................................................................................121
The Pie Man Game .........................................................122
Gather Your Resources ......................................................123
Setting the Stage ...........................................................127
The Game Action ...........................................................133
Drawing the Screen .........................................................141
The Final Function .........................................................144
Over to You ...............................................................150
CHAPTER 7
Minecraft Maze Maker ................................................................151
Installing Minecraft ........................................................152
Starting Minecraft. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153
Playing Minecraft ..........................................................154
Preparing for Python .......................................................156
Using the Minecraft Module .................................................156
Over to You ...............................................................174
Part III: Hardware Projects
CHAPTER 8
Colour Snap ..............................................................................177
Implementing the Game ....................................................178
The Software for Testing the Game ...........................................193
The Software for the Game ..................................................196
Over to You ...............................................................202
CHAPTER 9
Test Your Reactions...................................................................203
Welcome to the Embedded World!. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .204
Obtaining Components .....................................................205
Setting up PiFace Digital ....................................................206
Connecting PiFace Digital ...................................................210
Using the Emulator .........................................................210
Interfacing with Python .....................................................211
The Reaction Timer .........................................................214
What Will You Interface? ....................................................226
vii
TABLE OF CONTENTS
CHAPTER 10
The Twittering Toy.....................................................................227
Hacking the Toy ...........................................................228
Making It Talk .............................................................232
Making It Move ............................................................235
Connecting to Twitter ......................................................239
Putting It All Together ......................................................245
Wrapping Up ..............................................................248
CHAPTER 11
Disco Lights ..............................................................................251
Defining Your Sequence .....................................................252
Getting the Code to Do More ................................................254
A Small Detour into Theory ..................................................256
Designing the Sequencer ....................................................257
Implementing the Sequencer ................................................258
The Lights .................................................................265
Using Longer Strip Lights ...................................................268
Making the Lights Move ....................................................269
Designing the Circuit .......................................................270
Building the Circuit .........................................................273
Running the Circuit ........................................................273
Over to You ...............................................................274
CHAPTER 12
Door Lock ................................................................................275
The System Overview .......................................................276
Safety-Critical Systems ......................................................276
The Door Lock Hardware ....................................................277
The Initial High-Level Software Simulation ....................................278
The Output Block ..........................................................281
The Input Block ............................................................283
The Authentication Block ....................................................284
Unlocking Doors Without Touching ..........................................286
Testing the Program and Fitting the Lock .....................................292
Networking Multiple Doors .................................................293
Over to You ...............................................................294
The Art of Programming ....................................................295
CHAPTER 13
Home Automation ......................................................................297
The Internet Of Things ......................................................298
Project 1: How to Create a Motion Sensor and Door Switch ......................298
Project 2: How to Monitor Your Home with a Webcam ..........................305
Project 3: How to Make a Temperature Gauge ..................................312
Project 4: How to Send an E-mail Alert ........................................317
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RASPBERRY PI PROJECTS
Project 5: How to Send an E-mail Using a Wireless Remote ......................324
Over to You ...............................................................331
CHAPTER 14
Computer-Controlled Slot Car Racing...........................................333
Obtaining a Slot Car Racer ...................................................334
Hacking Your Slot Car Racer .................................................334
Getting the Player Input ....................................................336
The Software ..............................................................346
The Game .................................................................348
Over to You ...............................................................354
CHAPTER 15
Facebook-Enabled Roto-Sketch ...................................................355
The Concept ...............................................................356
Rotary Encoder Types ......................................................356
The Encoder Output ........................................................357
Posting to Facebook ........................................................366
The Final Roto-Sketch Program ..............................................369
Creating a Symmetrical Pattern ..............................................375
Over to You ...............................................................381
CHAPTER 16
The Pendulum Pi, a Harmonograph .............................................383
The Concept ...............................................................385
The Hall Effect .............................................................385
Enter the Arduino ..........................................................387
Putting It Together .........................................................388
Programming the Arduino ...................................................399
Programming the Pi ........................................................412
Using the Pendulum Pi ......................................................418
Over to You ...............................................................419
CHAPTER 17
The Techno–Bird Box, a Wildlife Monitor.....................................421
Building Invisible Light Beam Sensors .........................................423
Mounting the Sensors ......................................................427
Recording Activity to a File ..................................................431
Processing the Data ........................................................442
Dealing with Sensor Noise ...................................................448
Drawing a Graph ...........................................................454
Putting the Nest Box into Service .............................................458
Over to You ...............................................................458
The Possibilities Are Endless .................................................460
Index........................................................................................461