Table Of ContentAndroid Things Quick
Start Guide
Build your own smart devices using the Android
Things platform
Raul Portales
BIRMINGHAM - MUMBAI
Android Things Quick Start Guide
Copyright © 2018 Packt Publishing
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First published: August 2018
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Published by Packt Publishing Ltd.
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ISBN 978-1-78934-179-9
www.packtpub.com
Sometimes, hammers glow for a reason
-Iridessa, about Tinkerbell
To my parents, who always supported me on my endeavours; such as when they gave me my
first electronics kit -even if it did not made sense to them as a toy- which planted the seeds for
this book.
– Raul Portales
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Contributors
About the author
Raul Portales is a software engineer who has had a love for computers, electronics, and
gadgets in general for as long as he remembers.
He jumped into Android as soon as it was released. Raul has worked on social networks,
education, healthcare, and even founded a gaming studio and a consultancy company.
Specializing in mobile and UX, he speaks frequently at conferences and meetups.
Raul's love for electronics reignited when Google announced Android Things. He started
tinkering with it with the first Developer Preview, which lead to adding the IoT category on
his Google Developer expert profile.
About the reviewer
Gautier Mechling is a software craftsman who's passionate about Android, and a Google
Developer expert for IoT.
I would like to personally thank Raul for giving me the opportunity to be among the first
readers of this book. It was an interesting and enjoyable read.
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Table of Contents
Preface 1
Chapter 1: Introducing Android Things 8
Technical requirements 8
What is Android Things? 9
Internet of Things (IoT) vs. smart devices 10
Android Things vs. other platforms 10
Emulators and testing 11
Android Studio 12
Design concepts behind Android Things 13
Displays are optional 13
Home activity support 14
Permissions 14
Android Things Console 15
Supported APIs 16
Hardware you will need 16
Android Things developer kits 17
Raspberry Pi 17
NXP Pico iMX7D 18
Rainbow HAT 20
Components, circuits, and so on 21
Wires and breadboards 23
Setting up a developer kit 24
Installing Android Things 24
Configuring Wi-Fi using the script 27
Configuring Wi-Fi using the system UI 28
Connecting to your Android Things 30
Creating an Android Things project 32
Manifest 35
Gradle configuration 36
Activity code 37
Summary 38
Chapter 2: The Rainbow HAT 39
Technical requirements 40
Android Things architecture 41
Peripheral lifecycle 41
User space drivers 42
LEDs 42
The Arduino way 43
Table of Contents
Threads 45
Coroutines 46
Using Handler and Runnable 48
Using Timer and Timertask 49
Buttons 51
Button driver 51
Debouncing 52
Button input drivers 53
Piezo buzzer 55
Alphanumeric display (Ht16k33) 57
Temperature and pressure sensor (Bmx280) 58
Direct read 58
Continuous updates with sensor driver 61
Adding pressure driver 63
LED strip (Apa102) 64
Summary 67
Chapter 3: GPIO - Digital Input/Output 70
Technical requirements 71
Making the code work on any developer kit 71
Using GPIO for output 73
LEDs 73
Relays 76
Using GPIO for input 78
Buttons 78
Button driver 78
Input drivers 80
Controlling buttons directly with GPIO 80
Other sensors 81
Other usages of GPIO 84
DC motor controller (L298N) 84
Stepper motor (28BYJ-48) with controller (ULN2003) 87
Ultrasonic distance sensor (HC-SR04) 89
LCD display (TM1637) 92
Summary 94
Chapter 4: PWM - Buzzers, Servos, and Analog Output 95
Technical requirements 96
PWM overview 96
Piezo buzzers 98
Servos 100
Using the servo driver 101
Tweaking the servo configuration 106
PWM as analog output 107
Summary 110
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