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- Herausgeber: Packt Publishing
- Kategorie: Fachliteratur
- Sprache: Englisch
Raspberry Pi is a small, low cost and yet very powerful development platform. It is used to interact with attached electronics by the use of it's GPIO pins for multiple use cases, mainly Home Automation and Robotics.
Our book is a project-based guide that will show you how to utilize the Raspberry Pi's GPIO with Java and how you can leverage this utilization with your knowledge of Java. You will start with installing and setting up the necessary hardware to create a seamless development platform. You will then straightaway start by building a project that will utilize light for presence detection. Next, you will program the application, capable of handling real time data using MQTT and utilize RPC to publish data to adafruit.io. Further, you will build a wireless robot on top of the zuma chassis with the Raspberry Pi as the main controller. Lastly, you will end the book with advanced projects that will help you to create a multi-purpose IoT controller along with building a security camera that will perform image capture and recognize faces with the help of notifications.
By the end of the book, you will be able to build your own real world usable projects not limited to Home Automation, IoT and/or Robotics utilizing logic, user and web interfaces.
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Seitenzahl: 216
Veröffentlichungsjahr: 2017
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Title Page
BIRMINGHAM - MUMBAI
Copyright
Raspberry Pi 3 Projects for Java Programmers
Copyright © 2017 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the authors, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
First published: May 2017
Production reference: 1300517
ISBN 978-1-78646-212-1
www.packtpub.com
Credits
Authors
Pradeeka Seneviratne
John Sirach
Copy Editor
Safis Editing
Reviewer
Rajdeep Chandra
Project Coordinator
Kinjal Bari
Commissioning Editor
Pratik Shah
Proofreader
Safis Editing
Acquisition Editor
Prachi Bisht
Indexer
Rekha Nair
Content Development Editor
Trusha Shriyan
Graphics
Kirk D'Penha
Technical Editor
Varsha Shivhare
Production Coordinator
Shantanu Zagade
Foreword
About the Authors
Pradeeka Seneviratne is a software engineer with over 10 years of experience in computer programming and designing systems. He is an expert in the development of Arduino and Raspberry Pi-based embedded systems.
Pradeeka is currently a full-time embedded software engineer who works with embedded systems and highly scalable technologies. Previously, he worked as a software engineer for several IT infrastructure and technology servicing companies.
He collaborated on the Outernet (free data from space, forever) project as a volunteer hardware and software tester for Lighthouse, and Raspberry Pi-based DIY Outernet receivers based on Ku band satellite frequencies.
He is also the author of three books:
Internet of Things with Arduino Blueprints
by Packt Publishing
IoT: Building Arduino-Based Projects
by Packt Publishing
Building Arduino PLCs
by Apress
John Sirach works as a product owner at Greenhouse Innovation. He has more than 10 years of experience in Internet-related disciplines from connectivity to hosting, and Internet of Things. Currently, he is involved in the open source PiDome home automation platform project as a passionate Java and JavaFX software developer and project maintainer.
In the past ten years, he has gained experience with large-scale web applications committed to online services with most experience gained in frontend web development and application middleware.
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Table of Contents
Credits
About the Authors
Preface
What this book covers
What you need for this book
Who this book is for
Conventions
Reader feedback
Customer support
Downloading the example code
Downloading the color images of this book
Errata
Piracy
Questions
Setting up Your Raspberry Pi
Getting started with the Raspberry Pi
Getting a compatible SD card
Preparing and formatting the SD card
Installing Raspbian
Configuring Raspbian
Installing Java
Installing and preparing the NetBeans Java editor
Our first remote Java application
Running our application on the Raspberry Pi
Summary
Automatic Light Switch Using Presence Detection
Introduction to and installing Fritzing
Billing of materials
How to emulate reading analog values on digital pins
Starting our project and installing the necessary libraries
The Pi4J libraries
Adding the HD44780-compatible 16x2 character display
Showing data on the HD44780-compatible display
Adding the light-dependent resistor to the setup
Reading and displaying the values from the LDR
Using digital out to switch and display a relay status
Automatic switch based on environment lighting
Using the Bluetooth chip on the Raspberry Pi
Bluetooth device discovery
Putting it all together, our first automation project
Summary
A Social and Personal Digital Photo Frame
Bill of materials
Waveshare HDMI display
Assembling with Raspberry Pi
Selecting video source
Correcting display resolution
Mounting on desktop
Connecting with Flickr
Obtaining a Flickr API key
Creating an album
Finding Flickr photoset_id
REST request format
Invoking flickr.test.echo
Invoking flickr.photosets.getPhotos
Constructing photo source URL
Writing Java program
Accessing Flickr image URL
Installing feh on Raspberry Pi
Scheduling your application
Writing shell script for Java application
Testing the digital_photo_frame.sh with the terminal
Scheduling digital_photo_frame.sh with crontab
Testing digital_photo_frame.sh with crontab
Writing shell script for slideshow
Starting digital photo frame on Raspberry Pi boot
Photo frame in action
Summary
Integrating a Real-Time IoT Dashboard
Adafruit IO
Bill of materials
Sign in with Adafruit IO
Finding your AIO key
Creating news feed
Understanding topics
Creating a dashboard
Creating a block on a dashboard
Raspberry Pi and I2C pins
Connecting an I2C-compatible sensor to the Raspberry Pi
Serial bus addresses
Configuring the Raspberry Pi to use I2C
Searching I2C devices attached to the Raspberry Pi
Accessing I2C with Pi4J
Eclipse Paho Java client
Writing Java program to publish data to a feed
Publishing temperature sensor data
Publishing system information
Subscribing to a feed
Creating a toggle button on Adafruit dashboard
Subscribe to the button feed
Controlling an LED from button feed
Summary
Wireless Controlled Robot
Prerequisites
The Zumo chassis kit
Assembling Zumo chassis
Preparing motors to reducing the effects of electrical noise
Attaching Raspberry Pi to Zumo chassis
Building the circuit
Wiring them together
Moving and turning
Moving
Turning
Swing turn
Writing your Java program
Running and testing your Java program
Summary
Building a Multipurpose IoT Controller
Prerequisites
Preparing your Raspberry Pi board
Installing and configuring Jetty servelet engine
Writing your first Java web application
Creating a Maven project from Archetype
Creating a servlet
Copying iot.war file to the Raspberry Pi
Summary
Security Camera with Face Recognition
Raspberry Pi camera module
Connecting the camera module to the Raspberry Pi
OpenCV
Downloading and installing OpenCV on Windows
Creating the Java project
Adding the OpenCV library to your Java project
Downloading and building OpenCV on Raspberry Pi
Working with video
Facial recognition
Build and run
Summary
Preface
As Java becomes widely used on different hardware platforms from computers to embedded devices, Raspberry Pi has no limitations to work with it to gain full power of Java. This book presents some basic to advanced projects that can be used to build Raspberry Pi 3 projects with Java as the core development platform.
What this book covers
Chapter 1, Setting up Your Raspberry Pi, teaches you about the hardware available with Raspberry Pi and how to prepare to utilize it from the installed Java Virtual Machine. Setting up the NetBeans editor to be able to write Java applications, which can be deployed from the editor, including the in-editor, available console to be able to interact with Java applications on Raspberry Pi.
Chapter 2, Automatic Light Switch Using Presence Detection, explains how to perform analogue readings using digital pins, as the Raspberry Pi has no analog reading capabilities. By adding a 16x2 character display, you will visualize these readings. By adding logic to the code, you will be able to determine when someone is present, and in combination with detecting light levels, you will be able to set a relay state that turns a light on or off.
Chapter 3, A Social and Personal Digital Photo Frame, offers comprehensive guidance on building a social and personal digital photo frame with the Raspberry Pi as the heart. Flickr will be used the social media platform to grab a set of images that will be shown, on the display. FEH will be used an X11 image viewer to display images as a slide show with customizable configurations. Some advanced configurations for the Raspberry Pi will be needed to automate the photo frame to connect with Flickr, download images to local storage, display them on screen, and frequently sync local storage with Flickr.
Chapter 4, Integrating a Real-Time IoT Dashboard, presents a real-time IoT dashboard to display sensor data and Raspberry Pi’s system information on it, and control actuators from it. The dashboard will be built with Adafruit IO, in conjunction with the Eclipse Paho Java MQTT library and Pi4J. The IC2 communication protocol will be used to read data from the sensors by enabling the 12C interface on Raspberry Pi.
Chapter 5, Wireless Controlled Robot, introduces the Zumo chassis kit and how to build a Raspberry Pi brain on it with Java and Pi4J. The robot uses two gear motors to rotate the drive wheels, and the Pi4J library allows us to build various moving and turning mechanisms to control the robot. The built-in Wi-Fi module of the Raspberry Pi 3 allows you to connect the robot wirelessly to the computer, in order to execute the commands through SSH with a keyboard.
Chapter 6, Building a Multipurpose IoT Controller, teaches you how to build a simple web-based IoT controller by installing and configuring a Jetty servlet engine on the Raspberry Pi. Pi4J is used to control an LED or any other actuator from the web interface through a local network or from the Internet, by configuring port forwarding on the router.
Chapter 7, Security Camera with Face Recognition, explains how to build a security camera with face recognition using the OpenCV library for Java and the Raspberry Pi camera module. It uses built-in cascade classifiers to detect human faces and highlights them with a square in real-time video.
What you need for this book
The following software and hardware components are essential in order to build all the projects that presented in this book:
Raspberry Pi 3
Micro SD card
HDMI screen or HDMI enabled TV
HDMI to HDMI cable
5V power supply
Breadboard and wires
Raspberry Pi 3 T-Cobbler or male to female jumper wires
Kohm resistors
Hitachi HD44780 16X2 LCD
A device capable of being detected by Bluetooth, such as a mobile phone
Phillips head screw driver
One Zumo Chassis kit (no motors)
Two 100:1 micro metal Gearmotor HP 6V
One H-bridge motor driver - SN754410 breakout board
Aluminum Standoff
Machine screws
Two 0.1µF ceramic capacitors
Four rechargeable NiMH AA batteries
One USB battery pack for Raspberry Pi - 10000 mAh - 2 x 5V outputs
3mm LED
Raspberry Pi camera module with mount
Hookup wires
Who this book is for
This book is suitable for those who have experience in Java application development and are interested in developing applications on the Raspberry Pi development environment. A basic level of Java-based development skills is essential to develop the projects that will be discussed in this book.
Reader feedback
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Customer support
Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase.
Downloading the example code
You can download the example code files for this book from your account at http://www.packtpub.com. If you purchased this book elsewhere, you can visit http://www.packtpub.com/support and register to have the files e-mailed directly to you.
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The code bundle for the book is also hosted on GitHub athttps://github.com/PacktPublishing/Raspberry-Pi-3-Projects-for-Java-Programmers. We also have other code bundles from our rich catalog of books and videos available athttps://github.com/PacktPublishing/. Check them out!
Downloading the color images of this book
We also provide you with a PDF file that has color images of the screenshots/diagrams used in this book. The color images will help you better understand the changes in the output. You can download this file from https://www.packtpub.com/sites/default/files/downloads/RaspberryPi3ProjectsforJavaProgrammers_ColorImages.pdf.
Errata
Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you find a mistake in one of our books-maybe a mistake in the text or the code-we would be grateful if you could report this to us. By doing so, you can save other readers from frustration and help us improve subsequent versions of this book. If you find any errata, please report them by visiting http://www.packtpub.com/submit-errata, selecting your book, clicking on the Errata Submission Form link, and entering the details of your errata. Once your errata are verified, your submission will be accepted and the errata will be uploaded to our website or added to any list of existing errata under the Errata section of that title.
To view the previously submitted errata, go to https://www.packtpub.com/books/content/support and enter the name of the book in the search field. The required information will appear under the Errata section.
Piracy
Piracy of copyrighted material on the Internet is an ongoing problem across all media. At Packt, we take the protection of our copyright and licenses very seriously. If you come across any illegal copies of our works in any form on the Internet, please provide us with the location address or website name immediately so that we can pursue a remedy.
Please contact us at [email protected] with a link to the suspected pirated material.
We appreciate your help in protecting our authors and our ability to bring you valuable content.
Questions
If you have a problem with any aspect of this book, you can contact us at [email protected], and we will do our best to address the problem.
Setting up Your Raspberry Pi
In the first part of this chapter, we will be setting up a Raspberry Pi 3 with the installation of the official, by the Raspberry Pi foundation, released Raspbian Linux distribution with the help of the NOOBS installer. This will be followed up with any preparations needed to be able to use the onboard hardware and the installation of Java. The second part will cover preparing NetBeans as the editor of choice to write, compile, and deploy our Java applications with a simple Hello World application at the end of the chapter to confirm that our setup works.
Getting started with the Raspberry Pi
With the release of the Raspberry Pi 3, the Raspberry Pi foundation has made a very big step in the history of the Raspberry Pi. The current hardware architecture is now based on a 1.2 GHz 64 bit ARMv7. This latest release of the Raspberry Pi also includes support for wireless networking and has an onboard Bluetooth 4.1 chip available.
Even though the Raspberry Pi 3 has 64-bit ARMv8, the operating system of the Raspberry Pi which is Raspbian confusingly report it is an 32-bit ARMv7. This is because of the Raspbian OS is currently only available in 32-bit.
To get started with the Raspberry Pi you will need the following components:
Keyboard and mouse:
Having both a keyboard and mouse present will greatly help with the installation of the Raspbian distribution. Almost any keyboard or mouse will work.
Display:
You can attach any compatible HDMI display, which can be a computer display or a television. The Raspberry Pi also has composite output shared with the audio connector. You will need an A/V cable if you want to use this output.
Power adapter:
Because of all the enhancements made, the Raspberry Pi foundation recommends a 5V adapter capable of delivering 2.5 A. You would be able to use a lower-rated one, but I strongly advise against this if you are planning to use all the available USB ports. The connector for powering the device uses a micro USB cable.
MicroSD
card
: The Raspberry Pi 3 uses a MicroSD card. I would advise using at least an 8-GB class 10 version. This will allow us to use the additional space to install applications, and as our projects will log data, you won't be running out of space soon.
The Raspberry Pi 3:
Last but not least, a Raspberry Pi 3. Some of our projects will be using the on-board Bluetooth chip, and this version will also be focused on in this book.
Our first step will be preparing a SD card for use with the Raspberry Pi. You will need a MicroSD card as the Raspberry Pi 3 only supports this format. The preparation of the SD card is being done on a normal PC, so it is wise to purchase one with an adapter fitting a full-size SD card slot. There are webshops selling preformatted SD cards with the NOOBS installer already present on the card. If you have bought one of these preformatted cards you can skip to the Installing Raspbian section.
Getting a compatible SD card
There is a large number of SD cards available. The Raspberry Pi foundation advises an 8-GB card, which leaves space to install different kinds of application and supplies enough space for us to write log data. When you buy an SD card, it is wise to keep your eyes open for the quality of these cards. Well-known and established manufacturers often supply better quality than the counterfeit ones. SD cards are sold with different class definitions. These classes explain the minimal combined read and write speeds. Class 6 should provide at least 6 MB/s, and class 10 cards should provide at least 10 MB/s. There is a good online resource available that provides tested results of using SD cards with the Raspberry Pi. If you need a resource to check for compatible SD cards, I advise you to go to the embedded Linux page at http://elinux.org/RPi_SD_cards.
Preparing and formatting the SD card
To be able to use the SD card, it first needs to be formatted. Most cards are already formatted with the FAT32 filesystem, which the Raspberry Pi NOOBS installer requires, unless you have bought a large SD card it is possible it is formatted with the exFAT filesystem. These then should also be formatted as FAT32. To format the SD card, we will be using the SD association's SDFormatter utility, which you can download from http://elinux.org/RPi_SD_cards, as default OS supplied formatters do not always provide optimal results.
In the following screenshot, the SDFormatter for the Mac is shown. This utility is also available for Windows and has the same options. If you are using Linux, you can use GParted. Make sure when using GParted you use FAT32 as the formatting option. As shown in the screenshot, select the Overwrite format option and give the SD card a label. The example shows RPI3JAVA, but this can be the label of your choice so you can quickly recognize the card when it's inserted:
Press the Format button to start formatting the SD card. Depending on the size of the SD card, this could take some time, enabling you to get a cup of coffee. The utility will show a done message in the form of Card Format complete when the formatting is done. You will now have a usable SD card.
To be able to use the NOOBS installer, you will need to follow the following steps:
Download the NOOBS installer from
https://www.raspberrypi.org/downloads/
.
Unzip the file with your favorite unzip utility. Most OSes already have one installed.
Copy the contents of the unzipped file into the SD card's
root
directory so that the copy result is as shown in the following screenshot:
After we have copied the required files into the SD card, we can start installing the Raspbian OS.
Installing Raspbian
To install Raspbian, we need to get the Raspberry Pi ready for use. As the Raspberry Pi has no power on and off button, the powering of the Raspberry Pi will be done as the last step:
At the bottom of the Raspberry Pi on the side you will see a slot to insert your MicroSD card. Insert the SD card with the connectors pointing to the board.
Next, connect the HDMI or the composite connector and your keyboard and mouse. You won't need a network cable as we will be using the wireless functionality built into the Raspberry Pi.
We will now connect the Raspberry Pi with the micro USB power supply.
When the Raspberry Pi boots up, you will be presented with the OSes available to be installed. Depending on the download of NOOBS you have done, you will be able to see if the Raspbian OS is already available on the SD card or if it will be installed by downloading it. This is visualized by showing an SD card image or a network image behind the OS name. In the following screenshot, you see the NOOBS installer with the Raspbian image available on the SD card.
At the bottom of the installation screen you will find the
Language
and
Keyboard
