Introduction to the Internet of Things

@ProfGastonPerez

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1 week ago 49

Category: Tech | Tags: #RaspberryPi, #TechInnovation, #Arduino, #IoTProjects, #SmartHome

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Key Insights

Introduces fundamental concepts of the Internet of Things (IoT) and offers hands-on DIY projects.
Covers three main development platforms: Arduino, Raspberry Pi, and BeagleBone Black.
Presents projects with step-by-step guidance on building home automation systems, temperature monitoring, and remote video viewing.
Explores various technologies, such as web servers, databases (MySQL), programming languages (Python, Java), and protocols (MQTT).
Provides practical knowledge for integrating sensors, controlling devices, and enabling machine-to-machine communication in IoT applications.

Category: Tech | Tags: #RaspberryPi, #TechInnovation, #Arduino, #IoTProjects, #SmartHome

Introduction to the Internet of Things

@ProfGastonPerez1 week ago

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Copyright © 2015 by McGraw-Hill Education. All rights reserved. Except as permitted
under the Unit…

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MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. McGraw-Hill
Education and its licensors do no…

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This book is dedicated to my wonderful parents, Harry and Esther Norris,
who provided the love and…

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About the Author
Donald Norris has a degree in electrical engineering and an MBA with a specializa…

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Contents at a Glance
1 Introduction to the Internet of Things
2 Home Temperature Monitoring Syste…

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Contents
Acknowledgments
Introduction
1 Introduction to the Internet of Things
Raspberry Pi Pla…

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The Sensor Abstract Class
Child Classes
Real-World Controls
Threads
Java Database Connector
Us…

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Testing the Ethernet Connection
Simplified Garage Door Opener
Actual Garage Door Opener
Modified…

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LCD Operational Test
Message Controller Software
Download and Install the Flask Package
Main App…

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Acknowledgments
Project books such as this one are never created in a vacuum. They are a product o…

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Introduction
I suppose the genesis of this book was from long-term interest in connecting computer…

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by the use of a very clever Java library named Pi4J.
Chapter 5 covers three projects involving a w…

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approximately 1 GHz, if desired, but that does increase power consumption and heat
generation. The…

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Introduction to the Internet of Things
This book offers useful projects that you can build and the…

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Raspberry Pi Platform
The Raspberry Pi has been in existence for almost two years at the time of t…

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FIGURE 1-1 Model B, Raspberry Pi board
A cheaper model, A, is available but it does not have an on…

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digital input and/or output to interface with sensors and actuators. All the different
platforms u…

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FIGURE 1-2 GPIO P1
This multi-pin connector will be the gateway through which the Pi will interfac…

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the functions associated with each of the P1 pins for the Model B, rev 2 Pi.

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FIGURE 1-3 P1 pin functions
I will not review these pin functions at this time but will discuss th…

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your soldering skills. Just don’t add too much solder to the connector pins as they are
close toge…

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monitor, and mouse to the Pi. You will also need a powered USB hub and either a wireless
Wi-Fi ada…

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FIGURE 1-6 Raspberry Pi standalone workstation block diagram
The Pi has both composite and HDMI vi…

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the HDMI output as that provides a much superior video display as compared to the
analog composite…

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FIGURE 1-8 Plugable powered USB hub
Any USB keyboard and mouse combination will suffice for user i…

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FIGURE 1-10 EDIMAX model EW-7811Un USB Wi-Fi adapter
You should note that it is rated at a maximum…

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FIGURE 1-11 Raspberry Pi headless workstation block diagram
The secret to the simplicity of the he…

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adversely affected. However, don’t be deterred if you purchased a Raspberry Pi starter kit
that ca…

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tool must also be extracted before use.
The freshly formatted and NOOBS-loaded SD card has been de…

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TABLE 1-3 Initial NOOBS Selection Menu
I strongly recommend you select the first menu item, which …

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FIGURE 1-12 Default username and password screen
You will next see the raspi-config introduction s…

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story, and it will likely remain gone unless you have done the backups as suggested.
Clicking OK o…

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TABLE 1-4 raspi-config Menu and Recommendations
There are also seven Advanced Options menu selecti…

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TABLE 1-5 raspi-config Advanced Options Menu and Recommendations
Click the Finish button after you…

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startx
NOTE I will use the symbol from now on to denote the ENTER key.
The Desktop screen should …

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interface software for it to function with a specific OS.
Clicking the LXDE icon button located at…

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FIGURE 1-14 Win32 Disk Imager program executing
Notice the over 17MB/sec transfer rate shown in th…

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FIGURE 1-15 Raspbian raw image file listing
Shown in the list near the bottom is a file named conf…

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FIGURE 1-16 config.txt file content
You will need to uncomment the following line:
#hdmi_force_ho…

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one, with the addition of expanding the filesystem. The NOOBS installation does it
automatically b…

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3. Enter the username and password to get to the control web page. These are
normally shown in the…

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Your Pi’s IP address will likely be different than the one I entered into the Host Name
block. Als…

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FIGURE 1-18 Opening Pi login screen over the network
Just enter the default username “pi” and the …

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You will now be able to interact with the Pi in exactly the same way as if you were
sitting in fro…

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FIGURE 1-20 Opening screen for the TightVNC Viewer
Enter your Pi’s IP address in the Remote Host t…

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FIGURE 1-21 The Raspberry Pi VNC authentication dialog box
Enter the password you created when you…

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connection.
FIGURE 1-23 Launching a terminal window in the Desktop
It really is very cool technol…

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It is very mature, having been created and updated for almost 18 years as of the time of
this writ…

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servers and downloads and installs the new versions along with any and all
dependent software. An …

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FIGURE 1-24 Screenshot resulting from the ifconfig command
As you can see, the local IP address sh…

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appear in the browser confirming that the Apache web server was working.
FIGURE 1-25 First web pag…

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After you have entered the code, save it by simultaneously pressing the CTRL and O
keys. Simply pr…

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When you visit this web page, you must specifically request it or else the default
index.html file…

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FIGURE 1-27 hello.php test results
The remaining step in creating a complete LAMP project is to in…

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not really occupy a lot of memory, so why not increase your options and overall website
reliabilit…

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This would constitute a sample record that would be part of table structure that, in
part, makes u…

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program doesn’t distinguish between capitalized and lowercase commands but other SQL
programs are …

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FIGURE 1-28 SHOW TABLES command screenshot
This figure shows not only the field names and data typ…

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should be entered in case there is no actual value present in the input record. Usually this
is no…

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FIGURE 1-29 tempData table with three records
But take heart—all the book projects use a program t…

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Be cautious as this is a powerful command that will irretrievably delete all the data
records. The…

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If you wish to remove only certain select records, you can use what is known as a
“where_clause”. …

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FIGURE 1-31 tempData table after the DELETE FROM with a where_clause command
The where_clause is a…

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Up until now, I have been logging into the MySQL as “root” using the following
command:
mysql -u …

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FIGURE 1-32 tester 1 error message
This last error check ends this section and chapter. In the nex…

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IoT. I listed the platforms and software that I use in the book projects to demonstrate how
to bui…

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Home Temperature Monitoring System
The project in this chapter walks you through the steps in buil…

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FIGURE 2-1 Temperature monitoring system block diagram
Wires were used in the first system design …

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FIGURE 2-2 Analog Devices model TMP36 temperature sensor

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FIGURE 2-3 Model TMP36 functional block diagram
The TMP36 has only three leads, which are shown in…

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TABLE 2-1 TMP36 Pin Details
The voltage representing the temperature is dependent upon the TMP36 s…

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FIGURE 2-5 Graph of VOUT voltage versus temperature for a +VS = 3V
The actual temperature measurem…

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accomplishes the analog-to-digital conversion process.
Inner Workings of the Microchip MCP3008 ADC…

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which is the largest number that can be represented with 10 bits. Now each increment
increases the…

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FIGURE 2-8 SPI simplified block diagram
These registers may be hardware or software depending upon…

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will then put the MCP3008 CS pin high, ending the ADC process.
Connecting and Testing the MCP3008 …

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FIGURE 2-9 Digital soldering station
Of course, the station is only as effective as the soldering …

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FIGURE 2-11 Good soldering technique
Another issue regarding a good solder joint is the use of lea…

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shows the test schematic for the Pi Cobbler, MCP3008, and TMP36. I connected the
TMP36 Voutlead to…

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FIGURE 2-13 Physical test setup
On the left side of the breadboard, you can see the TMP36 sensor c…

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code that relies on those circuits. Initially you should check to determine if the native SPI
devi…

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Run the preceding program by entering the following:
sudo python SingleSensorTest, py
Figure 2-14…

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FIGURE 2-14 Initial test results
I put a comment in the code listing explaining that I needed to a…

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to be underreported by approximately 5°C. I also used a non-contact, precision infrared
temperatur…

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FIGURE 2-16 RJ45 connector attached to a breakout board
Next, take three of the boards and attach …

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side breakout board pins with the sensor’s flat side pointing up, as shown in the figure.
FIGURE 2…

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FIGURE 2-18 RJ45 board with an attached TMP36 sensor
You will now need the interconnecting RJ45 ca…

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the temperature to be measured 2°C less than the real temperature. The drop in voltage is
likely d…

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FIGURE 2-19 TMP36 current boost circuit
Instead of building the boost circuit, I found it simpler …

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However, the current boost circuit is likely essential if you plan on setting up a long cable
run …

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FIGURE 2-21 Physical system arrangement
Multiple Sensor Software
The software controlling the mul…

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program’s flexibility but in the interests of simplicity I don’t believe it is too much of a
compr…

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FIGURE 2-22 Sample display from the MultipleSensorTest.py program
I also wanted to point out that …

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become quite large and tedious to enter.
I will now change focus slightly and discuss how to creat…

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database in lieu of combination field lookups.
The channelLocation table’s schema is detailed in T…

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CREATE TABLE channelLocation(tchan NUMERIC NOT NULL, tloc
TEXT,
PRIMARY KEY(tchan));
Note that t…

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An open-source Python package named python-mysqldb contains all the libraries
necessary to establi…

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FIGURE 2-23 mysqlTest program results
Running this program has demonstrated how relatively easy it…

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Inserting Data into a MySQL Database Using a Program
I will demonstrate how to insert data into th…

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There is a hidden problem with the preceding program in that it will continue to run
without any p…

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FIGURE 2-24 Portion of sensorTemp records created by the SensorDatabase program
You can also view …

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FIGURE 2-25 SensorDatabase records displayed by the ViewRecords program
I next modified the ViewRe…

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cur.execute(‘SELECT * FROM sensorTemp WHERE tchan = 0’)
I renamed ViewRecords.py to Chan0ViewRecor…

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FIGURE 2-26 SensorDatabase records displayed by the Chan0ViewRecords program
To view the sensor lo…

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Figure 2-27 shows a portion of the output from the program where the location
description is shown…

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FIGURE 2-27 SensorDatabase records displayed by the ViewRecords program with the
channelLocation t…

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FIGURE 2-28 SensorDatabase records displayed by the ViewRecords program with the
channelLocation t…

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Database Access Using a Web Browser
This is probably one of the easier portions of the project as …

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To run the script on the Pi, you will need to open a web browser on the Pi. Simply
type in the fol…

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FIGURE 2-29 Portion of the sensorTemp records displayed on the Pi web browser
You should next try …

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FIGURE 2-30 Portion of the sensorTemp records displayed on a separate networked
computer
Note tha…

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FIGURE 2-31 ChannelSelector form
Nothing will happen regarding database access until the Submit bu…

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Figure 2-32 shows the browser display after channel 0 was selected via the input
form.

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FIGURE 2-32 Portion of the channel 0 sensorTemp records displayed on a separate
networked computer…

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Note that there are two underscores before and after the words “name” and “main.”
Flask is set up …

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FIGURE 2-34 Console messages from the Flask web server
Flask also supports templates, which is a h…

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Then change directories by entering cd templates.
Now that you are in the proper place, create the…

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Summary
The chapter began with a discussion of a three-sensor home temperature monitoring
system.…

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Introduction to Object Orientation Programming
(OOP) with Java
To begin your exploration into obj…

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• Racecar
• Plane
FIGURE 3-2 Unknown object
The answer really lies with your life experience. Mo…

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goals in controlling sensors, it is time to examine some fundamental principles underlying
all obj…

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object instantiation. Abstract classes are useful only when used with the inheritance core
princip…

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The four child classes, namely Dallas_18B20,SEN_12064, SEN_11084, and DEV_12081,
get their names e…

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An interface is a specialized class that contains only methods but no attributes.
Classes using in…

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FIGURE 3-4 Eclipse screen for the Hello World program
There are several things to discuss concerni…

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There is a problem inherent in this somewhat naive code, which I will point out later
in the discu…

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The method Dallas_18B20() is known as a constructor and is called any time a new
object is created…

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The test class shown is named TestSensors and is the only class in the package that
contains the m…

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The Console output for this test class is shown in Figure 3-5. It should be easy to see
how messag…

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FIGURE 3-5 Console output for the TestSensors class
The following is an example of sending a messa…

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FIGURE 3-6 Sensor class diagram with interfaces
Don’t be deterred by the apparent complexity shown…

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There are also two new methods in this class: performCommand() and performData()
will be used in t…

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I have set the interface references commandBehavior and dataBehavior to TempStart and
XferTemp chi…

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following listing. It is associated with the commandBehavior interface, which can readily
be seen …

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The Console output generated by executing the preceding
TestSensorsWithInterfaces program in the E…

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FIGURE 3-7 Console output for the TestSensorsWithInterfaces class
The previous discussion was leng…

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the patterns early on, you will develop good code design practices that will help you in all
your …

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FIGURE 3-8 Console output for the TestSensorsWithInterfacesDynamic class
Some additional text, “Th…

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actually interfacing with real sensors. In the next chapter, I will be using code that will
direct…

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There is now much greater flexibility using the Runnable interface as the target class
may now ext…

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What follows now are transcribed snippets from the Console displays. I did this to
minimize the nu…

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controls the threads. A thread scheduler within the JVM controls when threads are run and
when the…

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Notice that the JobA thread sleeps for 50 ms and the JobB thread sleeps for 100 ms.
This yields th…

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ms.
Java provides yet another way of controlling thread behavior to some degree: method
synchroni…

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FIGURE 3-9 Terminal window for starting and logging into the MySQL server
I next selected a databa…

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FIGURE 3-10 Terminal window showing the database procedural steps
Incidentally, you can log off My…

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Figure 3-11 shows the console output that results from executing the program. Notice
that the reco…

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FIGURE 3-11 Console output that results from executing the program.

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These two declarative statements set up references for Connection and Statement
objects, which are…

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id, tdate, and ttime now hold the current values from the selected record. They have to
be convert…

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This concludes my introduction to a Java database connector, which is all that you
really need bef…

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You are now well prepared to tackle the next chapter’s Java-based project.

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______________
1 Gamma, Helm, Johnson and Vlissides, Design Patterns, Addison-Wesley Pub.,
1995

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Home Weather Station
This chapter’s project will show you how to build a home weather station that…

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FIGURE 4-1 Raspberry Pi 26 pin GPIO header connector
A GPIO pin is a single-bit digital port, whic…

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an output, depending upon how it has been configured. The voltage levels that can be
applied as an…

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FIGURE 4-2 Ribbon cable attached to the Raspberry Pi’s P1 connector
I have provided Table 4-1 for …

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TABLE 4-1 GPIO Pin Descriptions
Neither the BCM2835 or the RasPi pin labels are used in this chapt…

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TABLE 4-2 P1 GPIO Connector
Please note the differences between board revisions 1 and 2, shown as …

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FIGURE 4-3 P1 GPIO pin connector
You should crosscheck your connections with Table 4-2 and Figure …

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FIGURE 4-4 Additional GPIO pins available for expansion
Table 4-3 describes all these additional p…

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FIGURE 4-5 P5 GPIO pin expansion connector
Figure 4-6 is an excellent reference diagram that was t…

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FIGURE 4-6 P5 connector pins with labels
Interrupts
Java programs created to interface with senso…

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Every GPIO pin can also accommodate an interrupt. An interrupt is an event that stops or
“interrup…

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developer named Robert Savage, who freely made available a fairly complete Java class
library that…

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two new subdirectories (lib and examples) created within it as follows:
/opt/pi4j/lib
/opt/pi4j/e…

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The statement
final GpioController gpio = GpioFactory.getInstance();
is an excellent representati…

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working as planned.
The main operating code in this class is a forever loop as shown here:
This a…

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FIGURE 4-8 Blink program test schematic
The schematic shows both the header pin numbers and the wi…

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FIGURE 4-9 Physical setup for the Blink program

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I ran the blink program for a short time and observed that the LEDs did blink as
programmed and th…

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Pi if you have been successful in completing all the previous steps. The following sections
demons…

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TABLE 4-4 I2C Signal Lines
The I2C bandwidth is fairly low, with 400 Kbps maximum and 100 Kbps
no…

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FIGURE 4-13 SEN_11824 with header pins attached
Figure 4-14 is a block diagram showing how the Pi …

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FIGURE 4-14 Weather system block diagram

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FIGURE 4-15 Physical test system setup
Everything from this point on depends upon the software, wh…

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FIGURE 4-16 Screenshot for the i2cdetect command
It is now time to create a Java program, which wi…

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measurement data. The BMP180 pressure/temperature sensor that is mounted on the
SEN_11824 BoB uses…

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The following is the SEN_11824 class source code. Notice that the constructor has an
integer argum…

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This class is quite lengthy and I considered separating the calibration portion into a
separate cl…

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The other DataBehavior child class is named XferPres. The XferPres is similar to
the XferTemp clas…

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The methods getCal() and read() perform similar functions for the XferPress class
as the identical…

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Figure 4-17 is a screenshot of the TestTemp1 program output after running for
several minutes. And…

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FIGURE 4-17 TestTemp1 program output
Thermostatic Application
In this section, I describe how to …

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monitored by the BMP180 sensor. A GPIO pin will be set high if the measured
temperature is below t…

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Figure 4-18 shows the screenshot from the PiThermostat program with two set points
separately ente…

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FIGURE 4-18 PiThermostat program output
I also observed the LED turn on when the set point was set…

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FIGURE 4-19 Browser screenshot for the initial SPInput PHP program
FIGURE 4-20 After clicking the …

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The following is the code for the displaySP.php program, which is executed when the
Submit button …

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Figure 4-21 shows the Pi’s screen when the RemotePiThermostat program was run.
Note that the syste…

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FIGURE 4-21 RemotePiThermostat program output display
Database Classes
It is now time to discuss …

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the Java database connector. The obvious first step is to define the MySQL schema or
structure. I …

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I next ran a simple adaptation of the Pi TestTemp1 program, which I named
TestTemp to check if all…

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FIGURE 4-22 Eclipse TestTemp program output
I next created a client class named FillDB2 that conta…

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Figure 4-23 shows a portion of the sensorMeasurement table contents after the
program had run for …

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FIGURE 4-23 Portion of the sensorMeasurement table records
At this point, I have demonstrated that…

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The client class, which is shown next, will instantiate all the required objects, collect
the meas…

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FIGURE 4-24 First 20 and last 20 records from the sensorMeasurement table
Remote Access to the HWS…

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Webcam and Raspberry Pi Camera Projects
Remotely accessing webcams is a fairly common activity tha…

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FIGURE 5-1 Logitech C920 webcam
This a high-definition camera capable of producing excellent video…

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one of the Pi’s USB ports and then type the following into a command line:
lsusb
Figure 5-2 is a …

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FIGURE 5-2 lsusb output screenshot
Note that I have found this particular webcam to be somewhat se…

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Motion Software Package
I selected an open source software package named Motion to enable remote v…

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Again, be a bit patient as this package is over 20MB in size and has many component
parts.
Motion…

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One nice feature of having the Motion web server running as a daemon is that it is
automatically s…

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The entry RASPBERRYPI has the IP 192.168.1.43 on the wired portion of my home
network. This is all…

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FIGURE 5-4 Video screen capture from the Pi webcam
This completes the first webcam project, which …

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FIGURE 5-5 Raspberry Pi camera
This camera was specifically designed to operate solely with the Pi…

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connector is for the display serial interface (DSI), which is designed to work with a
display devi…

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I would like to now discuss the Pi camera hardware and its properties before
discussing the camera…

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photograph taken of a Beaglebone Black development board using the preceding
command.
FIGURE 5-7 …

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FIGURE 5-8 Pi Camera stand with a camera holder support
There is also a substantial amount of meta…

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FIGURE 5-9 Test photograph metadata
The raspistill application has many more options, which I have…

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Start Python and enter the following commands to test the library and see how well it
functions wi…

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FIGURE 5-10 Composite image of six sequential images
You will quickly realize that the 10-second i…

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TABLE 5-3 Pi Camera Properties with Default Values
I recognize that many readers will not know wha…

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regarding the Pi Camera, its properties, operational modes, and a lot more. Best of all, just
abou…

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sudo unzip mjpg-streamer-code-182.zip
5. You now need to compile some of the many downloaded and e…

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FIGURE 5-11 Initial MJPG-Stream screen capture
The last paragraph in Figure 5-11 states:
“The ima…

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FIGURE 5-12 Result of clicking on the initial snapshot
So far, so good. What I really wanted was t…

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FIGURE 5-13 One of the continuing streamed pictures from MJPG-Streamer
The streamed pictures may a…

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8. Replace the motion.conf file found in the /etc directory to this one, which you
can download fr…

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FIGURE 5-14 MacBook screen capture of the Safari browser connected with the Motion
web server
Thi…

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program that automatically takes a series of time-lapsed still pictures and stores them on
the SD …

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Internet-Enabled, Arduino Powered Garage Door
Opener
This chapter’s project will use the classic …

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FIGURE 6-1 Arduino Uno rev 3 board
You can quickly identify rev 3 boards as the reset button was r…

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TABLE 6-1 Arduino Uno Key Specifications
Don’t be concerned if you do not understand some of the s…

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underlying the Arduino boards.
Ethernet Shield Board
Figure 6-2 shows the Ethernet Shield board t…

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FIGURE 6-2 Ethernet Shield board
The word “shield” in the board title simply refers to any one of …

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FIGURE 6-3 W5100 block diagram
It is important to point out that while the W5100 chip does contain…

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FIGURE 6-4 Arduino IDE startup screen
The IDE automatically created a default sketch entitled sket…

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FIGURE 6-5 Blink code
I’m including the following Blink code in order to point out some key progra…

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Compile and upload the changed program by pressing the right-facing arrow and watch
the LED slowly…

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FIGURE 6-6 Ethernet Shield attached to the Uno
Next, connect the Uno’s power and USB cables and al…

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have configured your LAN. In my case, I connected to a 10/100 switch that is on my
development wor…

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selections: Open | Examples | Ethernet menu.
All the current Ethernet library menu selections are …

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FIGURE 6-8 IP address displayed
My network router assigned a 192.18.1.29 IP address to the Uno/Eth…

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come with any sticker showing the actual firmware mac address assigned to the chip. I
think this s…

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Floating input voltage = 5.0 * (300 / 1023) = 1.47V
I soldered a jumper wire between ground and th…

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operating as I expected to see a 0V level when I next opened a browser to the WebServer
page. My e…

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LED’s cathode to ground. Figure 6-12 shows the physical setup. Note that I soldered wires
directly…

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The code starts with two include statements that refer to all the dependencies
necessary for this …

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FIGURE 6-13 The client after it has connected to the Uno’s web server program
The loop method will…

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system before proceeding with the actual project.
Actual Garage Door Opener
In this section I wil…

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FIGURE 6-14 Garage door opener
I believe this opener is fairly typical of the garage door openers …

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FIGURE 6-15 Garage door opener connection terminals
If you refer to Figure 6-14, you can see these…

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normally open contacts. Figure 6-16 is a schematic for this straightforward control circuit.
Almos…

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easy modification if necessary. Both the breadboard and the Uno board were mounted in a
plastic ca…

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FIGURE 6-17 Uno and relay switcher mounted in plastic case
I ran both power and an Ethernet cable …

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Figure 6-18 shows the browser connected to the Uno web server for this door opener
program.

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FIGURE 6-18 The browser display for the garage door opener
Selecting the checkbox either opened or…

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not use this garage door software with an open Wi-Fi connection. You might as well hang
your house…

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FIGURE 6-20 Visual Studio 2012 IDE
The second software item is the Arduino IDE, which you have lik…

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Follow the website installation instructions to initially set up the MegunoLink Pro
software. You …

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FIGURE 6-21 MegunoLink Pro build-tool installation
You will need to enter the directory location f…

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file extension.
3. Select OK.
Figure 6-23 shows the HelloArduino project screen with the source c…

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the F7 function key to do an immediate build. The compiled code that is first created uses
the pro…

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dialog box.
3. Select the solution file (Garage Door Opener.sln).
4. Select OK.
Figure 6-24 show…

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explanation of all these files as that would be well beyond the scope of this chapter and
book. Ho…

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FIGURE 6-25 Include file list
The source code will be displayed in the VS2012 main editor window. …

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I only changed the constant LOCAL_IP_ADDRESS to match the Uno’s assigned IP
address as I have prev…

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FIGURE 6-26 MegunoLink Pro password configuration
You need first to select the initialize button, …

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Testing the Enhanced Garage Door Opener
The newly programmed Uno with the relay switching circuit …

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FIGURE 6-28 Garage door activation web page
Selecting the Activate Door button either opened or cl…

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FIGURE 6-29 iPad access to garage door opener
This concludes the garage door opener project, which…

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the Uno. Incidentally, no additional parts were required for this demonstration as the
program mak…

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Arduino Irrigation Control System
This chapter’s project will use the Uno development board with a…

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FIGURE 7-1 Home irrigation block diagram
This system is relatively uncomplicated wherein the contr…

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Figure 7-2 shows the irrigation controller.
FIGURE 7-2 Home irrigation system controller

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In the figure you can also see a wireless rain sensor module located above the
controller, which s…

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FIGURE 7-3 Arduino development board
I purchased two inexpensive, 4-channel relay-switching module…

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FIGURE 7-5 Arduino-controlled irrigation system block diagram
I need to discuss the new Uno contro…

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The new program uses the same Ethernet connectivity logic that was used in the garage
door opener …

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The logic to find which zone is selected is to match the beginning portion of the
HTTP request str…

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FIGURE 7-7 Physical installation
The relay modules were connected to the zone water solenoids by s…

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FIGURE 7-8 Zone water solenoid interconnections
CAUTION The wire currently in the existing solenoi…

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FIGURE 7-9 Ribbon cable to relay module connections
The connections made to the 24VAC transformer …

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FIGURE 7-10 24VAC transformer connections
You can even connect two 12VAC bell transformers in seri…

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which is needed to operate the solenoids.
The Uno must also be connected to a 7-12V DC supply alon…

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FIGURE 7-11 Moisture sensing subsystem block diagram
You should immediately notice from the block …

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FIGURE 7-12 XBee Pro transceiver
There are two rows of 10 pins on each side of the module. These p…

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FIGURE 7-13 XBee Arduino Shield
This shield contains all the functionality needed to effectively i…

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you can see in Figure 7-14.
FIGURE 7-14 Close-up of the XBee electronics case

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If you look closely at the figure, you should see the bottom of the antenna wire,
which is located…

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TABLE 7-1 Freescale MC13192 Features and Specifications
The XBee module implements a full network …

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perspective, it means that there must also be a microprocessor present in the electronics
case. Fr…

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FIGURE 7-15 Logical XBee pinout diagram
All the pin and function descriptions are shown in Table 7…

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TABLE 7-2 XBee Pin Descriptions and Functions
A considerable number of functions are available to …

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FIGURE 7-16 Moisture sensor
It is a simple design consisting of two, one-foot-long, one-quarter-in…

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FIGURE 7-17 Soil moisture calibration setup
I added water to the pail to change the soil compositi…

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condition and recorded the resistance for each stage. Figure 7-18 is the result of this
calibratio…

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FIGURE 7-18 Soil resistance versus soil condition chart

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I estimated that irrigation should be started once the sensor resistance level is
measured at 40KΩ…

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FIGURE 7-19 Sensor equivalent circuit
It turns out that 1.6 KΩ is the closest standard resistor va…

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FIGURE 7-20 Soil moisture sensor schematic
Note that I included a 12VDC solar panel in the design …

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FIGURE 7-21 Moisture sensor system
Figure 7-22 shows the interior of the enclosure where you can s…

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FIGURE 7-22 Interior of the moisture system enclosure
NOTE I did not install the system outdoors u…

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test all the outdoor components on a bench top before proceeding to install them
outdoors.
Moistu…

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FIGURE 7-23 XBee jumpers in the USB position
This program reads the ADC value and then selects a n…

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TABLE 7-3 Soil Moisture Zones
I do recognize that these categories may not be very precise, but th…

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FIGURE 7-24 Transmitter calibration setup
This allowed me to vary the ADC input voltage, simulatin…

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Figure 7-25 is a schematic for this receiver’s calibration test circuit, which must be
used with t…

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rotation. Recheck your receiver wiring if you do not see the LEDs blink on and then off as
the pot…

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FIGURE 7-27 XBee receiver module connected to Arduino development board
A revised control program …

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I next used the calibration circuit to send various simulated soil conditions and
checked the corr…

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FIGURE 7-28 Browser screenshot—Very dry condition
I then increased the voltage to the mid-point an…

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you install it. I did find that my local bird population seemed to like “bombing” the solar
panel,…

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control function via the Web.
The moisture sensor capabilities can also be easily extended to incl…

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FIGURE 7-31 Mini soil moisture probe
The electronics portion seen on the left-hand side of the fig…

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The chapter ended with some suggested enhancements, including a possible potted
plant monitoring s…

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Arduino Lighting Controller
This chapter’s project will use the Uno board with an Ethernet Shield …

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FIGURE 8-1 System block diagram
The controller node is the key system component that supports mult…

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9600 baud rate. The Transparent operational mode allows either XBee S1 or S2
radios to seamlessly …

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ZigBee networks will normally have only one coordinator node and two or more
end nodes. There coul…

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that the XBee jumpers located on the XBee Shield are set in the USB position. I
discussed these ju…

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FIGURE 8-4 Controller node
However, there is a serious issue that requires a minor modification of…

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must be soldered onto the Ethernet Shield’s ICSP solder points such that the XBee Shield
can be po…

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FIGURE 8-7 Soldered ICSP extension pins
After soldering these pins, you are all set to finish buil…

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FIGURE 8-8 Ethernet Shield board
You probably already noticed that this Ethernet Shield board is d…

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for what appears to be the same board. I don’t think you should pay more than $20USD
for this boar…

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FIGURE 8-9 Controller node case
Its overall dimensions are 125mm × 175mm × 75mm, which is more tha…

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especially for homes with small children present.
I next mounted the controller stack on a piece o…

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FIGURE 8-10 Controller node mounting arrangement
The Uno board and a small, solderless breadboard …

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Figure 8-12 shows the interior of the controller node with all the components
mounted and wired. T…

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I will defer discussing the program that runs this node until I complete my coverage
of the remain…

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FIGURE 8-13 Four-channel key fob
The channels are labeled A through D on the fob. The fob RF trans…

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FIGURE 8-14 RF four-channel latching receiver
The receiver may be purchased from Adafruit Industri…

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I found it very useful to use jumper wires to make all the interconnections between
the breadboard…

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FIGURE 8-16 Uno XBee receiver node
It is identical to the moisture sensor transmitter node that I …

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FIGURE 8-17 XBee receiver node case
I mounted the XBee receiver node stacks on Lexan sheets just a…

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FIGURE 8-18 XBee receiver node mounting arrangement
I didn’t add any measurements to this figure a…

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FIGURE 8-19 XBee receiver node interior
PowerSwitch Tail II
The PowerSwitch Tail II is a power co…

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FIGURE 8-20 PowerSwitch Tail II
It is essentially a power cord that is controlled by a low-level d…

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be directly connected to an Uno’s GPIO pin. The PowerSwitch Tail II, which I will now
refer to as …

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FIGURE 8-22 Uno XBee receiver node to PST2 schematic
Not much is required for the connection other…

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part of the Ethernet Shield. I will discuss this HTML file after I discuss the main program.

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I know this is a long code listing, but much of it is involved with LED states and
status, which i…

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leave this bit of code in place as it didn’t slow the program and I have included some
project enh…

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preceding code except that the values used are 3 and 4 instead of 1 and 2. I suggest
identifying t…

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The test sequence, which I have detailed here, is fairly easy to follow:
1. Ensure that all the no…

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Attaching a light intensity sensor to the A2 analog input could also enable a feature
by which a u…

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BeagleBone Black Message Controller
This chapter’s project will use the BeagleBone Black (BBB), wh…

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FIGURE 9-1 BBB top view
The first board in the series leading up to the BBB was known simply as the

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BeagleBoard. It was a design project that was begun in 2007 by the non-profit
BeagleBoard.org whos…

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at very fast 1 GHz clock speed and have 4GB of onboard flash memory in which the
Linux OS is store…

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FIGURE 9-2 Micro SD memory cardholder
A 4GB, FAT-formatted, micro SD card may be inserted into the…

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possible to overwrite the OS stored in the flash memory with a new or different version if
that is…

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FIGURE 9-3 Pluggable USB 2.0 7-port hub
I have found that this particular hub model provides suffi…

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FIGURE 9-4 Initial Debian Desktop screen
NOTE You should not have the Run dialog box appear. I jus…

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mini USB connector and then into the laptop. A new disk icon should appear on the
laptop’s Desktop…

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FIGURE 9-5 BeagleBone 101
You should explore this web page to learn about the BBB and how to progr…

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The prompt shows that you connect as the root user, which means you now have total
control of the …

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FIGURE 9-7 SSH over Ethernet connection
Windows users should use the PuTTY application and enter b…

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two 46-pin sockets aligned at the top and bottom edges. The pins are in groups of two with
pin num…

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FIGURE 9-8 P8 and P9 pin headers
As you can readily see, a significant number of GPIO pins are ava…

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FIGURE 9-9 TRM P9 header table
I have also used a Python library that preconfigures the GPIO pins …

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I used a generic 16 × 2 LCD display wired to the BBB to show a brief text message
received from a …

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FIGURE 9-11 LCD to BBB interconnection schematic
The next step is to load some test software once …

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FIGURE 9-12 Test result
Please recheck your jumper wire interconnections if you do not see the exp…

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FIGURE 9-13 Directory structure
The primary or main application is based upon the Python testLCD.p…

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Much of the code is concerned with interfacing with the HTML code that creates the
web page where …

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The index.html code is dependent on additional code that is contained in the
base.html file. Reade…

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This file is created with the Jinja2 script; it also contains references to JQuery Mobile
librarie…

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FIGURE 9-14 Laptop browser screen
Note that the message that was sent is also shown at the bottom …

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FIGURE 9-15 LCD display for message sent from laptop
You can see clearly that some of the trailing…

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displayed on the second line. Obviously, any characters beyond 32 cannot be displayed
with a 16 × …

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FIGURE 9-16 Android smartphone browser screen
This time I intentionally kept the message very shor…

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The last demonstration involved sending a message from an iPad connected to the
LAN. Figure 9-18 s…

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FIGURE 9-19 LCD display for message sent from an iPad
This last demonstration concludes the BBB me…

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the BBB. I demonstrated a simple Python script to test the BBB to LCD display interface
to show th…

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BeagleBone Black with Cloud Service
This chapter’s project will demonstrate how to connect a Beagl…

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FIGURE 10-1 TMP36 to BBB connection schematic
Only three connections are required: 5V, output sign…

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encountered when using this project in a typical residence or office environment.
Figure 10-2 show…

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FIGURE 10-2 Physical system
Nothing else was required from the hardware prospective, so all that’s…

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The program is very simple in that it converts a voltage applied to the P9_40 ADC
input every seco…

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FIGURE 10-3 Test program output
The next step in this project is to connect a cloud service once t…

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Xively is the latest version of a data-based cloud service that began in 2007 as a UK
startup know…

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You are now ready to create the Python program, which will run on the BBB and
send temperature dat…

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If you are the root level, you run the program by entering this:
python xively-temp.py
Non-root u…

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FIGURE 10-4 Terminal console display for the xively-temp.py program
You should now go to the Xivel…

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I used my MacBook Pro browser to go to the Xively website and observe the active
data streaming. F…

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FIGURE 10-7 Specific data and time values
This data set was taken from a sensor located in my offi…

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There is also an HTTP Request Log window shown on the Workbench just to the
right of the graph win…

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Additional TMP36 Sensors
The TMP36 sensor connection system was designed from the beginning to be …

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FIGURE 10-9 Expanded TMP36 to BBB connection schematic
I also used a longer cat5 cable to connect …

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FIGURE 10-10 Expanded physical system
I next created an expanded test program to prove that all th…

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FIGURE 10-11 Expanded test program output
It is time to work on an expanded xively-temp program no…

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I named the expanded xively-temp program ExpandedXively.py; it is essentially the
same as the orig…

511/582

Note that all three Datastream function calls are all contained in the same set of
square brackets…

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FIGURE 10-12 Current values for three channels
You should notice from the Request Log that only on…

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FIGURE 10-13 Outdoor temperature channel graph
Configuring Angstrom to Auto Start the Application
…

514/582

4. Save and exit the nano editor.
5. You use an Angstrom Linux command called systemctl to enable,…

515/582

FIGURE 10-14 xively-logger status
One interesting artifact that I discovered while testing this se…

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FIGURE 10-15 Systemctl status displays immediately after a reboot
Now, the ExpandedXively.py progr…

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located in the same /lib/systemd/system directory as is the xively-logger.service file.
Using the …

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FIGURE 10-16 BBB and RJ45 connectors mounted on Lexan board
The bottom of the plastic case must ha…

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FIGURE 10-18 Complete assembly
This section wraps up this chapter’s project and it is time to move…

521/582

I reviewed some basic facts about the analog TMP36 temperature sensor, which I
first used in the C…

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Machine-to-Machine (M2M) Communications
The focus of the chapter, as its name implies, is machine-…

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FIGURE 11-1 Project block diagram
There is a block named MQTT Broker located between the BeagleBon…

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broker on behalf of the publisher. It is obviously the quickest message delivery
method, but it is…

526/582

Initially, I just need to demonstrate the temperature-monitoring program without any
messaging fea…

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FIGURE 11-2 Physical hardware setup
Figure 11-3 shows the terminal display after I entered the fol…

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FIGURE 11-3 Terminal screen showing the tmp36.py program output
sudo python tmp36.py
This figure …

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adding the messaging features into the application. Please follow these steps to load the
Python l…

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incoming messages from the broker.
The following two statements contain references to what are kno…

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FIGURE 11-4 Terminal screen showing the mqttTMP36.py program output
The data in the mqttTMP36.py p…

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The web server located at m2m.eclipse.org is a public sandbox hosted by the Eclipse
Foundation as …

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TABLE 11-2 Public MQTT Brokers
The HTTP bridge is one of the features in the m2m.eclipse.org broke…

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to show you in the next section, that provides an interesting insight into the popularity of
the M…

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FIGURE 11-8 MQTT Dashboard
In the Recently used Topic box, you can see my mv and f topics as well …

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a published topic. The Last Message box on the lower-left side of the figure shows one of
my publi…

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I have included this figure to point out the public nature of these MQTT brokers,
which allow your…

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MqttClient.generateClientId());client.connect();
Notice that one of the arguments in the instantia…

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definition named PahoMqttSubscribe.java. You should use the nano editor to enter it or
download it…

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class file.
1. Enter the following while in a Raspberry terminal window:
curl -O https://repo.ecl…

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FIGURE 11-10 Raspberry Pi subscriber client terminal screen
This last step completes the initial M…

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method named messageArrived. The next part of this M2M demonstration project is to
slightly expand…

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I have really only added some new functionality to the messageArrived method
where the payload val…

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FIGURE 11-11 Two-phase thermostat terminal display
This last figure concludes this M2M demonstrati…

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Index
Please note that index links point to page beginnings from the print edition. Locations
are…

551/582

authentication in VNC, 20–22
auto starting applications, 302–305
B
backups, 11
bandwidth of IC2…

552/582

BBB, 267–269
garage door opener project, 173–176
lighting controller, 247, 250
braces ({}) in Ja…

553/582

Python with, 163–165
remote viewing, 165–169
software, 160–163
camera serial interface (CSI) con…

554/582

Configuration.h file, 199–201
Connection Manager, 195–196
Connection object, 102–103
connections…

555/582

home weather station classes, 142–150
Java connections, 98–104
MySQL installation, 27–28
tempera…

556/582

EDIMAX EW-7811Un adapter, 6–7
Elev-8 quadcopter, 158
.elf file extension, 197
encapsulation in O…

557/582

forName() method, 102
Freescale MC13192, 218–219
FTDI driver utility, 243
full duplex communicat…

558/582

gold plated electrical contact surfaces, 45
GPIO. See general purpose input output (GPIO)
GpioCon…

559/582

home temperature monitoring system, 37
Flask platform, 71–74
MCP3008 connections and testing, 43–…

560/582

OOP, 79–80
threads, 94
initialization code for interrupts, 114
Input Channel Multiplexers, 41
I…

561/582

moisture sensing subsystem, 216–235
operating, 216, 235
program, 209–212
“is a” relationships, 8…

562/582

late binding, 92
LCD display for message controller
operational test, 279–280
setting up, 277–27…

563/582

Logout option, 13
loop() method
garage door opener project, 178–179, 185–187, 191–192
irrigation…

564/582

MJPG Streamer application, 165–169
mkdir command, 47, 73
moisture sensing subsystem
design, 222–…

565/582

multi-drop networks, 122
multiple sensor system
building, 49–53
software, 53–56
MultipleSensorT…

566/582

P
Pachube company, 292–293
Paho project, 309
PahoMqttSubscribe class, 319–323
PahoMqttSubscribe…

567/582

polling, 114–115
polymorphism in OOP, 79
POST method, 69
power and power supplies
BBB, 272
gar…

568/582

python-mysqldb package, 58–60
python-picamera library, 163
Q
Quality of Service (QoS) in MQTT pr…

569/582

receivers in lighting controller, 248–250
reconnecting in MQTT protocol, 311
records in databases…

570/582

S1 firmware, 240–241
S2 firmware, 240–241
safety features for garage door opener, 193
Sample and…

571/582

setDataBehavior() method, 91–92
setDescription() method, 84
setLEDs() method, 259–260
setName() …

572/582

SPData.txt file, 140
SPI (serial peripheral interface) protocol, 39, 42–43
SPInput.php program, 1…

573/582

sudocp command, 170
sudonano command, 156
synchronization methods, 98
system software for lighti…

574/582

remote setting, 138–150
two-phase, 323–325
Thread class, 95
ThreadDemo class, 94–96
threads
Mo…

575/582

Linux software, 23
Upton, Eben, 2
USB tether mode for BBB, 272
USE command, 57
usernames, 10, 1…

576/582

viewing in, 157–158
webLCD.py program, 281–283
WebServer program, 180–182
Wheezy distribution, 2…

577/582

website, 295–297
Xively Developer Workbench, 293
xively-logger.service, 302–303
xively-temp.py p…

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Table of Contents
Title Page
Copyright Page
Dedication
About the Author
Contents at a Glance
…

579/582

Summary
3 Introduction to Object Orientation Programming (OOP) with Java
Java Software Developmen…

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Arduino Uno Software
Testing the Ethernet Connection
Simplified Garage Door Opener
Actual Garage…

581/582

Message Controller Software
Download and Install the Flask Package
Main Application
HTML Code
T…

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@ProfGastonPerez

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Ask a Question 1 Comments 1

1 week ago @amitranjan

What are the three operating systems listed in the contents at a glance

According to the "Contents at a Glance" on page 8, the three platforms discussed in the book are:

Arduino
Raspberry Pi
BeagleBone Black

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Introduction to the Internet of Things

What are the three operating systems listed in the contents at a glance

@ProfGastonPerez

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