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1. for int r 0 r READINGS r Wire requestFrom 8 2 valO Wire read vall Wire read channelReading int val0 16 int vall gt gt 4 analogReadingArduino channelReading 1023 4095 combinedReadings r analogReadingArduino delay 100 Here we have a loop that grabs the data from the analog pin so we can process it In the request From function we pass in the declaration for the number of bytes we wish to have returned from the pin Here we can see we have two this is the second value in the function call We will combine these values and then write them to an array in total we will do this seven times and then average out the value You will notice we are applying a calculation on the two combined bytes This calculation converts the values into a 10 bit Arduino resolution The value you will see returned after this equation is the same as you would expect to get from the analogRead function on an Arduino Uno if you had hooked up your circuit to it After we have done this calculation we assign the value to our array that stores each of the seven readings Now that we have this value we can calculate the average resistance For this we will use another for loop that iterates through our array of readings combines them and then divides them by the value we set in our READINGS constant Here is the next for loop you will need to accomplish this Grab the average of our 7 readings in order
2. GET PHOTORESISTOR READING Wire requestFrom 8 2 valO Wire read vall Wire read channelReading int val0 16 int vall gt gt 4 analogReadingArduino channelReading 1023 4095 Next we need to add some code that uses the data generated from the photoresistor on A7 if analogReadingArduino gt TH amp amp open state false controlMotor true digitalWrite DIRECTION HIGH delay 5000 open state true controlMotor false else if analogReadingArduino lt TH amp amp open_state true controlMotor true digitalWrite DIRECTION LOW 113 Curtain Automation Open and Close the Curtains Based on the Ambient Light delay 5000 open state false controlMotor false Here we have a conditional statement that checks the light readings against the TH threshold constant If the curtains are shut and the light exceeds the threshold then we do the following Call the controlMotor function and pass the Boolean value of true Switch pin 5 to HIGH which sets the direction to clockwise Allow the motor to run for 5 seconds in order to open the curtain Pre N A Call the cont rolMotor function and pass in the Boolean value of false which turns the motor off Let s now look at the next part of the if statement Here we are checking if the reading from A7 is less than the threshold and the curtains are open If this is true it means the room is dar
3. To start we will add in the include statements for the libraries and headers we need as well as define some constants that will be used in our application for storing key values Add the following block of code to your empty file thermometer cpp in Geany Include ArduPi library include arduPi h Include the Math library include lt math h gt Needed for Serial communication SerialPi Serial Needed for accessing GPIO pinMode digitalWrite digitalRead I2C functions WirePi Wire Needed for SPI SPIPi SPI Nalues need for Steinhart Hart equation and calculating resistance define TENKRESISTOR 10000 our 10K resistor define BETA 4000 This is the Beta Coefficient of your thermistor define THERMISTOR 10000 The resistance of your thermistor at room temperature define ROOMTEMPK 298 15 standard room temperature in Kelvin 25 Celsius Number of readings to take these will be averaged out to get a more accurate reading Xou can increase decrease this as needed define READINGS 7 You will recognize some of the preceding code from the arduPi template as well as some custom code we have added This custom code includes a reference to the Math library The Math library in C contains a number of reusable complex mathematical functions that can be called and which would help us avoid writing these from scratch As you will see later in the program we have used the lo
4. In this book we have aimed to provide you with examples that are useful and slowly build up in difficulty expanding your knowledge of the Raspberry Pi Arduino Linux and related technologies along the way Our projects have covered the application of the Raspberry Pi in home automation and how we can leverage the existing Arduino toolset to augment the Raspberry Pi s abilities As newer and more powerful versions are released we believe the future for this technology is indeed very bright The Raspberry Pi community is growing by the day and the best place to share your projects and look for help is at the Raspberry Pi website forum at http www raspberrypi org phpBB3 The Arduino community is well established and like the Raspberry Pi website has a lively forum where you can turn for help at http arduino cc forum We started the book by looking at the history of home automation and finished by looking at the future With this information it is now over to you the reader to continue your journey 141 References In the appendix we will cover some links and resources that will be useful for you for future projects and will help you learn more about the technologies used in this book These links cover a variety of sites including commercial and open source You will also find URLs that provide further information on some of the commands and programming languages we have used Raspberry Pi The followi
5. www arduino cc e Official Arduino forum http arduino cc forum e Official Arduino store http store arduino cc e Arduino IDE downloads http arduino cc en Main Software e Arduino hardware http arduino cc en Main Products from Main Hardware e Makezine Arduino blog http blog makezine com arduino 145 References SQL There are a variety of flavors of SOL The following URLs are geared towards SQLite that we used in this book for our temperature storage database SQLite homepage http www sqlite org e SQLite downloads http www sqlite org download html e SQLite Documentation http www sqlite org docs html e W3 Schools SQL guide http www w3schools com sql default asp HTSQL The following links provide an in depth guide to HTSQL as well as the HTRAF tools you can use to interact with an HTSQL server via your website e Official HTSOL website http htsql org e HISQL tutorial http htsql org doc tutorial html e HTSOL downloads http htsql org download e HTRAF toolkit http htraf org e HISQL Python page http pypi python org pypi HTSQL e HTSQL mailing list http lists htsql org mailman listinfo htsql users Apache D are many resources on Apache available online these resources provide information on the web server foundation and common documentation e Apache foundation homepage http www apache org Download apache http www apache org dyn clo
6. how to build their own GNU Linux distribution and applications that are particularly useful on the Raspberry Pi www PacktPub com Support files eBooks discount offers and more You might want to visit www Packt Pub com for support files and downloads related to your book Did you know that Packt offers eBook versions of every book published with PDF and ePub files available You can upgrade to the eBook version at www Packt Pub com and as a print book customer you are entitled to a discount on the eBook copy Get in touch with us at service packtpub com for more details At www Packt Pub com you can also read a collection of free technical articles sign up for a range of free newsletters and receive exclusive discounts and offers on Packt books and eBooks PACKT http PacktLib PacktPub com e Do you need instant solutions to your IT questions PacktLib is Packt s online digital book library Here you can access read and search across Packt s entire library of books Why Subscribe Fully searchable across every book published by Packt Copy and paste print and bookmark content Ondemand and accessible via web browser Free Access for Packt account holders If you have an account with Packt at www PacktPub com you can use this to access PacktLib today and view nine entirely free books Simply use your login credentials for immediate access Table of Contents Preface 1 Chapter 1 An Introduction
7. BerryBoot our tool for installing an operating system There are several ways of installing the OS onto the SD card but by far the easiest of them is Berry Boot BerryBoot is a Mac Windows and Linux compatible boot loader It works by being unzipped onto a formatted SD card and then when the Raspberry Pi is powered up it launches Once loaded it allows you to choose the operating system you would like to install and walks you through the process The BerryBoot application also helps you to install multiple operating systems on a single SD card Downloading the BerryBoot zip Our first task is will be to download the BerryBoot zip file This can be found at http www berryterminal com doku php berryboot Find the download link on the page and download the zip file The file is around 21 3 MB Depending on the operating system you have installed your PC Mac you may already have a zip unzip application included If you do not have a zip unzip application you can download the following for Mac Windows and Linux Windows The following two applications are GUI based unzip and zipping tools that can be installed on Windows e 7 Zzip http www 7 zip org e WinZip http www winzip com Mac For Mac OS X you can use one of the following two applications The popular Windows zip tool WinZip also has a Mac version e WinZip for Mac http www winzip com mac e Archiver http archiverapp com 28
8. In this chapter we will look at the Raspberry Pi to Arduino shield We will discuss identifying your Raspberry Pi model and installing the correct software library for it Once you have followed these steps we will briefly touch on the Arduino IDE to give you an idea of what the language looks like After this we will write an application that turns an LED on and off and then compile and run our application Raspberry Pi to Arduino bridge shield In order to use the Raspberry Pi to Arduino shield we will need to set it up This is a two stage process involving the connection of our hardware and installing our software In the process of setting up the hardware we will also connect up an LED to a breadboard with two wires This will act as our first test project to ensure that everything is working correctly For this chapter you will need the following components Your connected up Raspberry Pi The Cooking Hacks Raspberry Pi to Arduino shield e Anelectronics breadboard AnLED Two wires for connecting the breadboard to the shield Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield Checking which version of the Raspberry Pi we have In order to install the correct software package for our Cooking Hacks shield we need to identify the version of the Raspberry Pi we have The quickest and easiest way of doing this is to examine the Raspberry Pi board Version 2 Raspberry Pis have two mounti
9. Prototyping Pi Plate 131 The wiringPi library 133 The Gertboard 134 Introduction to the Gertboard components 134 GPIO PCB expansion board 135 GPIO Pins 135 Motor controller 136 Open collector driver 136 Buffered I O 136 Atmel ATmeg chip microcontroller 137 Convertors analog to digital and digital to analog 137 Writing software for the Gertboard 137 Ideas for next step projects 138 Expanding the curtain automation tool to include temperature sensing 138 Changing the motor on the curtain automation project to a stepper motor 139 Switching lights on with a photoresistor 139 Holiday lights from LEDs 139 The future of home automation 139 3D printing 139 RFID chips 140 EEG headsets 140 Summary 141 Appendix References 143 Raspberry Pi 143 Raspberry Pi to Arduino bridge shield 144 Linux 144 Python 145 C C 145 Arduino 145 SQL 146 HTSQL 146 Apache 146 Electronics 147 Packt Publishing titles 147 Home automation technology 147 v Table of Contents 3D printing EEG headsets Miscellaneous resources Index 148 148 149 151 vi Preface The world of home automation is an exciting field that has exploded over the past few years with many new technologies in both the commercial and open source worlds This book provides a gateway for those interested in learning more about the topic and building their own projects With the introduction of the Raspberry Pi computer in 2012 a small and pow
10. andrew pi raspberrypi var www wsgi scripts ssh 127x25 We can now check that HTSQL is running as expected Load up your web browser either on the Raspberry Pi or remotely and in the URL bar type http ip of raspberry pi 8080 You should now see the following message Welcome to HTSOL Please enter a query in the address bar eo0 192 168 1 72 8080 Q 192 168 1 72 8080 Welcome to HTSQL Please enter a query in the address bar 107 Temperature Storage Setting up a Database to Store Your Results You can then display the room table we created by typing http lt ip of raspberry pi gt 8080 roomdetails The database is now viewable via the web browser and the data can be seen in the temperature table as it gets added In order to query the data we can use the roomdetails id syntax You can place column IDs from your database between the braces separated by commas and only these columns will be returned when you execute the query roomdetails id 1 Placing a question mark after the table name or the braces allows us to provide conditional statements such as show all of the data located in all of the columns where the ID is equal to one In the case of our database this should return a single result and all of the column values for that result HTSQL has an expansive syntax and allows you to write complex queries for returning data in a variety of formats includ
11. in April 2004 and subsequently continued to specialize in publishing highly focused books on specific technologies and solutions Our books and publications share the experiences of your fellow IT professionals in adapting and customizing today s systems applications and frameworks Our solution based books give you the knowledge and power to customize the software and technologies you re using to get the job done Packt books are more specific and less general than the IT books you have seen in the past Our unique business model allows us to bring you more focused information giving you more of what you need to know and less of what you don t Packt is a modern yet unique publishing company which focuses on producing quality cutting edge books for communities of developers administrators and newbies alike For more information please visit our website www packtpub com Writing for Packt We welcome all inquiries from people who are interested in authoring Book proposals should be sent to author packtpub com If your book idea is still at an early stage and you would like to discuss it first before writing a formal book proposal contact us one of our commissioning editors will get in touch with you We re not just looking for published authors if you have strong technical skills but no writing experience our experienced editors can help you develop a writing career or simply get some additional reward for your expertise PAC
12. see a message similar to that shown in the following screenshot eoo fS andrew pi raspberrypi arduPi ssh 127x25 This message informs us that our web server has been assigned its local loopback IP address 127 0 1 1asits server name If you wish you can access Apache from the Midori browser on your Raspberry Pi via http 127 0 0 1 or http localhost In turn we can access the web server on our home network using the IP address assigned to our Raspberry Pi by our router V Youcan always check your Raspberry Pi s IP address using the ip addr show command and looking for the value located next to inet There are several commands that are useful for starting stopping and restarting your web server These are e apachectl start This command starts the Apache web server If the server is already running you will be presented with an error message e apachectl stop As the command suggests running this stops the web server e apachectl restart This command will restart an existing running web server and if none exists will start a new one 95 Temperature Storage Setting up a Database to Store Your Results e apachectl graceful Like the restart command graceful also restarts an existing server and starts a new one if none exists However unlike the restart command currently existing connections to the web server are not aborted apachectl graceful stop This command also stops the
13. var 10og apache2 error log Congratulations You have written your first WSGI Python script for inserting data into the temperature database Conclusion Of course the script is fairly simple and does not do any validation on the data we pass in to see if it is in the correct format nor does it use the query results variable You can expand upon this script to add more functionality to it once you are confident with how everything works Now we are writing data to our database we need a method to view this data via the web and without having to log in to SOLite3 and write queries The tool we are going to use for this is HTSQL HTSQL Hyper Text Structured Query Language HTSQL is a technology that allows us to write queries on the fly for our database and execute them via a URL Developed by Clark Evans and Kirill Simonov of Prometheus Research HTSQL is built upon the Python programming language and provides a HTTP based query language that is translated into SOL This allows complex queries to be written via the web browser and queries to be embedded in client side AJAX code without the need for writing server side applications 104 Chapter 6 Rather than having to learn SOL and a server side programming language such as Java a database with an HTSQL server running on it can be accessed via JavaScript or a web browser such a Midori The benefit of using this technology is that it cuts down on the amount of serve
14. version of Linux we will be using throughout the book Setting up the SD card Before we can install our operating system we need to set up the SD card This involves formatting it to the FAT filesystem format first FAT File Allocation Table is a method used for recording which sectors of a disk files are stored in and which sectors are free to be written to It has its origins in the 1970s where Bill Gates and Marc McDonald developed it for use on floppy disks Due to its robustness and simplicity it is still found on SD cards today and is the format we will need in order to run our operating system selection application 24 Chapter 2 After formatting the SD card we will then install a program called Berry Boot This allows us to install our operating system onto the SD card which the Raspberry Pi will use So take your card and insert it into the SD cart port on your laptop or PC and we will begin by formatting it Formatting our card As explained in the preceding section in order to install BerryBoot we first need to format the SD card to FAT format This is a fairly simple task and can be performed on your PC or Mac When purchasing an SD card you may find it is already formatted to FAT as this format is popular with devices such as digital cameras Many manufacturers ship the card so it is ready to go out of the box and no further formatting is required However we have provided the following instruction
15. 1 Setting up Your Raspberry Pi In this chapter we will look at setting up the Raspberry Pi In order to use your device you will need to start by installing an operating system onto an SD card Once this is in place you can then install extra software for writing code and for controlling devices which you connect to the GPIO pins There are several steps needed to get you up and running e Deciding whether to purchase an SD card with a pre installed OS or a blank card Formatting the SD card Choosing the right version of Linux Installing the operating system Operating system configuration Once we have completed these steps we will be ready to get started with our home automation projects The SD card our Raspberry Pi s storage device An SD secure digital card is a form of portable high performance storage medium available for electronic devices ranging from cameras to PCs The Raspberry Pi comes equipped with an SD card slot allowing us to insert an SD card and use it as our devices main storage mechanism much like a hard disk on a PC Getting Started Part 1 Setting up Your Raspberry Pi While you can use other storage mechanisms such as a USB drive or USB external hard drive the SD card is small and thus lends itself better to embedded devices such as those found in home automation projects There are a variety of brands of SD cards on the market and they come in a range of sizes The Raspberry Pi supp
16. 102 RS Components URL 147 156 S screen installing 77 79 SD card about 23 formatting 25 formatting instructions for Linux 27 formatting instructions for Mac OS X 26 formatting instructions for Windows 7 25 26 setting up 24 SD card port Raspberry Pi 11 setpoint 72 114 setup function 47 119 Shapeways URL 140 Shapeways 3D printing URL 148 software writing for Arduino 16 software components thermostat cURL 79 program adding to test relay 75 77 screen installing 77 78 setting up 75 thermostat code 79 software thermometer about 58 application writing 61 62 Geany IDE 58 Makefiles 59 thermometer code 61 soldering 15 SPI pins Raspberry Pi to Arduino shield 15 SOL about 16 online resources 146 using 16 writing 92 93 SQLite about 89 database creating 91 loading 91 SQL writing 92 URL 146 SQLite documentation URL 146 SQLite downloads URL 146 SQLite Version 3 x about 89 installing 90 square wave 119 Stratasys 3D printers URL 148 Structured Query Language See SQL T temperature calculations about 64 float celsius 64 float fahrenheit 64 float kelvin 64 temperature table datetime 92 id 91 92 roomid 91 roomname 92 temperaturef 92 temperature variable 102 TENKRESISTOR constant 63 thermistor about 55 beta coefficient 55 coefficient 55 THERMISTOR constant 63 thermometer application about 54 building 54 compiling 68 components setting up 56 hardware s
17. Arduino language If you have installed the Arduino IDE you can find the example using the following steps 1 From the Main menu select File 2 Thenselect Examples from the examples menu 3 Select 1 Basics 4 From this menu select Blink The Blink example will now load If you have not installed the IDE you can use the following code located in Blink ino Blink Turns on an LED on for one second then off for one second repeatedly 43 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield This example code is in the public domain xf void setup initialize the digital pin as an output Pin 13 has an LED connected on most Arduino boards pinMode 13 OUTPUT void loop digitalWrite 13 HIGH set the LED on delay 1000 wait for a second digitalWrite 13 LOW set the LED off delay 1000 wait for a second Downloading the example code You can download the example code files for all Packt books you have Q purchased from your account at http www Packt Pub 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 The Arduino language is a subset of C so we will be using Arduino specific functions that form the core of the language in conjunction with standard C code in order to build our applications The previous program contai
18. GPIO pinMode digitalWrite digitalRead I2C functions WirePi Wire Needed for SPI SPIPi SPI define TH 690 Here we have the standard template header but we have also added a new constant called TH This will represent the threshold Like the setpoint constant we declared for the thermostat the threshold is used to calculate whether to perform an operation based upon the room getting lighter or darker BRK KR KKK k k k RR KR RRR RR RR RR RK RR RR k k RK k k k k k ke ke RK KK KK IF YOUR ARDUINO CODE HAS OTHER FUNCTIONS APART FROM setup AND loop YOU MUST DECLARE THEM HERE HK K k KR KR KR RK RRR RK RRR ek kk k KR ke k k ee e ke ke RK RR KR RR KKK RK KR RK KK RR k k k k e ke ke k YOUR ARDUINO CODE HERE KR RR RR RR RR RR RR KK KK KK int main setup 114 Chapter 7 while 1 loop return 0 void setup void Wire begin void loop void byte val0 byte vall int channelReading float analogReadingArduino RRR ke ke ke ke e KK e e ke ke ke k k k k ADC mappings Pin Address 0 OxDC 1 Ox9C 2 OxCC 3 Ox8C 4 OxAC 5 OxEC 6 OxBC 7 OxFC KR KR KK RR RR ek KK e x x OxFC is our analog 7 pin Wire beginTransmission 8 Wire write byte 0xFC Wire endTransmission Wire requestFrom 8 2 valO Wire read vall Wire read channelReading int val0 16 int vall gt gt 4 analogReadingArduino channelR
19. Linux command line Itcomes pre installed with software that will be useful for writing code for the Raspberry Pi and Arduino such as Python It also includes other software that you may be interested in exploring that has an educational bent One example is Scratch a tool for introducing programming to children e The operating system has been tailored to run on the Raspberry Pi The code compilation is optimized for on chip floating point calculations hard float rather than a slower software based method There is wide spread community support for the operating system meaning that as you move forward with projects beyond this book there will be plenty of resources as well as help available to you Next up is a walk through of the process of installing Raspbian and configuring some important settings 30 Chapter 2 Installing Raspbian Once the Raspberry Pi is powered up you will see the BerryBoot Welcome screen Follow the steps to install Raspbian From the Welcome popup select the following settings 1 If you have green borders at the top and bottom of your monitor select the radio button titled Yes disable overscan From the Network connection option select the Wired radio button From the Locale settings select the appropriate options for the Timezone and Keyboard layout fields Once complete select the OK button Once you have clicked on OK you will be taken to the Disk selection s
20. Pi and display them in the terminal window Lets start by setting up the hardware for our thermometer Setting up our hardware There are several components that you will need to use in this chapter You can solder the items to your shield if you wish or use the breadboard if you plan to use the same components for the projects in the chapters that follow Alternatively you may have decided to purchase an all in one unit that combines some of the following components into a single electronic unit We will make the assumption that you have purchased separate electronic components and will discuss the process of setting these up We recommend that you switch Raspberry Pi off while connecting the components especially if you plan on soldering any of the items If your device is switched on and you accidently spill hot solder onto an unintended area of the circuit board this can short your device damaging it Soldering while switched off allows you to clean up any mistakes using the de soldering tool 54 Chapter 4 An introduction to resistors Let s quickly take a look at resistors and what exactly these are A resistor is an electronic component with two connection points known as terminals that can be used to reduce the amount of electrical energy passing through a point in a circuit This reduction in energy is known as resistance Resistance is measured in Ohms Q You can read more about how this is calculate
21. Raspberry Pi to Arduino bridge shield e Breadboard e Wires e 10 K resistor e Photoresistor e Arduino Motor Shield OV battery and battery connector e Flat head screwdriver e A flashlight e 9V DC motor and an optional 12 V DC motor 12V wall wart if you use a 12 V motor Curtain Automation Open and Close the Curtains Based on the Ambient Light Photoresistors A photoresistor is similar to the thermistor in that the device s resistance changes as some ambient property of the room changes With the thermistor this was temperature and with the photoresistor it is light The most common application of these that you see in everyday life is in street lamps which switch on when it starts to get dark outside We can use a photoresistor as part of our circuit to tell when it is getting dark in a room and send this information back to the Raspberry Pi The Raspberry Pi can then process this data and use it to control an electric motor Motor shield and motors For this project we have chosen the official Arduino Motor Shield This is a device we can connect to our Raspberry Pi to Arduino shield and then use it to attach and drive DC motors The specifications for the shield can be found on the following Arduino website http arduino cc en Main ArduinoMotorShieldR3 The shield has an operating voltage of 5 V to 12 V and for our project we will connect a 9 V battery to the screw terminal power connectors This will provide
22. Windows 28 Mac 28 Linux 29 Hooking up the Raspberry Pi 29 Downloading the right operating system 30 Installing Raspbian 31 Installation complete 34 Windows users 35 Mac and Linux users 36 Summary 37 Chapter 3 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield 39 Raspberry Pi to Arduino bridge shield 39 Checking which version of the Raspberry Pi we have 40 Setting up the Raspberry Pi to Arduino shield and LED 41 Installing the software 42 The Arduino IDE 42 A quick look at the language 43 arduPi a library for our Raspberry Pi and Arduino shield 45 Installing arduPi 45 Leafpad a text editor 46 ii Table of Contents Blinking LED application 48 A guide to the code 49 Compiling and running our application 50 Summary 51 Chapter 4 Our First Project A Basic Thermometer 53 Building a thermometer 54 Setting up our hardware 54 An introduction to resistors 55 Thermistor 55 10K Ohm resistor 56 Wires 56 Breadboard 56 Connecting our components 56 Software for our thermometer 58 Geany IDE 58 Installing the IDE 58 An introduction to Makefiles 59 Thermometer code 61 Writing our application 61 Compiling and testing 68 What if it doesn t work 69 Up and running 70 Summary 70 Chapter 5 From Thermometer to Thermostat Building upon Our First Project 71 Safety first 72 Introducing the thermostat 72 Setting up our hardware 73 Relays 74 Connecting the relay 74 Setting up our soft
23. You do not need to remove the legs just ensure that they will not connect with the header on the bridge shield 3 You can connect the motor shield to the Raspberry Pi to Arduino shield We will now run some jumper wires to connect digital pins 11 12 and 13 on the motor shield to digital pins 4 5 and 6 on the Raspberry Pi to Arduino shield Take your jumper wires and connect 11 to 4 12 to 5 and 13 to 6 113 Curtain Automation Open and Close the Curtains Based on the Ambient Light 4 Ourtwo shields are now wired together Next connect two wires to the A terminal on your shield you will need a small flat head screwdriver in order to open and close the connection Once these are in place connect your battery connector to the ground and power connectors Ensure that the black wire connects to negative and the red to positive 5 Next connect your electric motor to the two wires connected to the A terminal This completes the motor shield setup 6 Wecan now reconnect our photoresistor Connect the red wire into a 5 V power pin the black back into a ground pin and finally the yellow wire to the analog 7 pin 7 Ourcircuit is now complete The following diagram should aid you in seeing what the final configuration looks like Ground 5V Breadboard Analog 7 d Digital Pins Resistor l Photo Resistor Arduino to Raspberry Pi Shield and moto
24. a Python script called addtemperature wsgi located in the var www wsgi scripts directory you just created and make it available via the browser with the URL addtemperature for example http 192 168 1 122 addtemperature After this add the next block of configuration code below the WGIScriptAlias Directory var www wsgi scripts gt Order allow deny Allow from all Directory This defines a directory var www wsgi scripts and tells Apache to accept traffic to it This tag is responsible for defining configuration options for the directory listed and subdirectories below it Then save and exit your text editor and navigate back up to the apache2 directory cd etc apache2 In this directory we need a file called httpd conf This file provides additional user configuration for Apache If this file does not exist use your text editor to create it otherwise open the existing one We need to add a single line of configuration to this that tells Apache where it can find the WSGI module that is needed to load our site configuration that we created previously If we do not add this to the httpd conf file then Apache will not know what to do with the configuration we added to the default file and will throw an error and not start So with the httpd conf file open if the file already existed look for other references to modules in the file these will take the following format LoadModule module name modules lt module_refere
25. a programming language and an Integrated Development Environment IDE The Arduino platform allows the user to create custom hardware and applications to control it via its namesake programming language 12 Chapter 1 Currently there are several board models on the market ranging in size and components For example the Lilly Pad allows enthusiasts to attach an Arduino board to clothing for electronic textile based projects These boards support a wide range of shields Arduino compatible electronic boards that can be plugged into it and expand its functionality One particular extension has been the introduction of Ethernet shields and wireless Xbee devices to allow communication with home networks and the Web The benefit of the Arduino for amateur enthusiasts has been that little or no knowledge of how electronics are soldered together is required to use the pre built shields However as the user becomes more comfortable with the technology he she can progress to building his her own projects using the numerous kits and sensors available on the market This easy adoption has helped to contribute to the number of websites and books dedicated to home automation projects using the technology In this book we will not be using one of the Arduino microcontroller boards the Raspberry Pi will fulfill this role However we will be using the Raspberry Pi to Arduino shield This will allow us to connect shields and other compo
26. and take a look at its contents Installing arduPi Earlier in this chapter we took note of which version of the Raspberry Pi board we are using Based upon that version number we are going to download one of two files which contain the arduPi library Q Remember you can always run cat proc cpuinfo to get the version number Open the terminal window on your Raspberry Pi and create a new directory in which to install the library and navigate to it mkdir arduPi cd arduPi If you have a Version 1 board run the following command wget http www cooking hacks com skin frontend default cooking images catalog documentation raspberry arduino shield arduPi revl tar gz If you have Version 2 you will need the revision 2 gzip file wget http www cooking hacks com skin frontend default cooking images catalog documentation raspberry arduino shield arduPi rev2 tar gz After wget has run a tar gz file will be saved into the current directory 45 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield From the terminal run the following command the revision version will be specific to the tar gz you downloaded tar xzf arduPi revision version tar gz For example if you downloaded revision 1 then you would type the following command tar xzf arduPi revl tar gz Once the file has finished extracting you will find three new files in the directory Type the following co
27. bc 51 c3 af fe cb 78 e6 Are you sure you want to continue connecting yes no Type yes into the command line and press the Enter key You will then see the following message Warning Permanently added 192 168 1 122 RSA to the list of known hosts Once you have completed this and entered your password you should see the command line for your Raspberry Pi You have now successfully tested the SSH server and if you wish can now control your Raspberry Pi remotely from your second machine 36 Chapter 2 Summary In this chapter we have looked at what an SD card is setting it up for use with the Raspberry Pi installing an operating system and loading up our Raspberry Pi for the first time There are many resources available online if you wish to explore the Raspbian operating system further These include the following e http www e http www e http www e http www raspberrypi org The Raspberry Pi s official homepage raspberrypi org phpBB3 The official Raspberry Pi forum raspbian org Home of the Raspbian version of Linux linux org A Linux education dedicated website Now that we have the operating system in place we can take a look at the Arduino to Raspberry Pi shield and getting it setup ready to use with the Raspberry Pi So grab your Cooking Hacks shield and let s get started 37 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield
28. completing these projects you are now equipped with the skills to expand your existing projects and create exciting new devices This list provides some potential projects for the future Expanding the curtain automation tool to include temperature sensing Your current application from Chapter 7 Curtain Automation Open and Close the Curtains Based on the Ambient Light uses light to decide when to open and close the blinds curtains You can now try combining the thermometer from Chapter 4 Our First Project A Basic Thermometer with curtain control device and re write the software to incorporate temperature data Using the thermistor you can decide to open and close your blinds if the temperature changes in order to conserve heat By expanding the database written in Chapter 6 Temperature Storage Setting up a Database to Store Your Results we can also record the times when the curtains are opened or closed to give us an idea of how many hours of sunlight we received across a day in a certain month of the year This project would need no further components than those used in Chapter 4 Our First Project A Basic Thermometer and Chapter 7 Curtain Automation Open and Close the Curtains Based on the Ambient Light 138 Chapter 8 Changing the motor on the curtain automation project to a stepper motor We currently use a small DC motor in Chapter 7 Curtain Automation Open and Close the Curtains Based on the Am
29. continued to support more of the SOL standard as it has progressed through several versions This means that many of the features you may be familiar within SOL are available to use when creating an SQLite database Temperature Storage Setting up a Database to Store Your Results SQLite has many uses which include creating databases for embedding in applications such as web browsers or for creating lightweight databases for embedded systems running on hardware such as the Raspberry Pi It is also practical for small projects that do not require a more complex and maintenance heavy RDMS such as Oracle or MS SQL and for those looking for a free and easy solution for storing data You can read more about the technology and the latest features it supports on its website http www sqlite org Installing SQLite Version 3 x We will now walk through the process of installing SQLite on our Raspberry Pi Either log in to your Raspberry Pi via SSH or connect over the desktop and open LXTerminal Once logged in we are going to run apt get to install SQLite3 From the command line type the following command sudo apt get install sqlite3 Jfyourunsudo apt get install sqlite this will only install amp SQLite Version 2 x Version 2 x does not support some of the commands GS we will be using such as ALTER TABLE So make sure you use sqlite3 when using apt get The terminal will show you feedback as it installs SQLite Once comple
30. database and running SOL queries against it For this task we are going to use the Python programming language and use the WSGI module we configured to serve this application Navigate to the directory you created in the preceding section to store WSGI scripts in by using the following command cd var www wsgi scripts This will be where we will create our Python script capable of running SOL queries Using your text editor create a new file called addtemperature wsgi We are now going to add our Python code to this file 100 Chapter 6 In the Python language indentation and white spaces are important When typing in the code or copying and pasting make sure that you follow the indentation format in the examples S With addtemperature wsgi open add the following lines to the top of your script import sqlite3 from cgi import escape parse qs These two lines tell our script to include a library that supports SQLite3 and to also import some useful tools from the CGI library that we can use to escape user input and parse incoming query strings received by our script Once you have added them let s add a function that is capable of processing the data sent to the script and then use that data to populate our sqlite3 database Copy the following block of code into your file below the previous two lines you added def application environ start response connection None my response params parse qs
31. de soldering tool Writing software for the Arduino After you set up the Arduino shield and plug it into the Raspberry Pi you will probably be wondering how to interact with it After all it has sensors and LEDs but these are nothing without applications to control them in a meaningful manner Many software languages are available on the Raspberry Pi and we are interested in four These are the Arduino programming language Python SOL and HTSQL The Arduino programming language a subset of C provides us with a tool for programming Arduino compatible shields and the components connected to them One benefit of using this technology is that there is a wealth of programs and libraries online that can be used for future projects You will be using this language in the Geany IDE for writing the core applications that will be reading data from sensors attached to your projects The next language we will be using is Python Python is a high level programming language developed in the late 80s by Guido Van Rossum named after the popular comedy show Monty Python s Flying Circus This language allows you to build web and database applications that can be used to process the output of Arduino programs We will be using Python to build a web application that can process data sent to it and then insert it via SOL Structured Query Language into an SQLite 3 database We will also use SQL for building the database that our Python script connec
32. enough power to drive the single 9 V motor that we are going to connect to it For testing purposes we will use a 9 V battery however if you wish to g install the motor shield based device you may wish to consider attaching GS it to a wall wart or wiring it into the mains A 9 V battery in constant use will not last very long and will not power a 12 V motor It is recommended that you disconnect the power pins on the shield if you connect devices that require more than 9 V For this project we start by using a 9 V motor you can always upgrade to a 12 V once you have your application and circuit up and running Depending on the type of blinds you have using a motor in the 9 V to 12 V range should provide enough torque Setting up the photoresistor We are going to start by wiring up our photoresistor and testing it with some software Once we have tested it we can then hook it up to the motor shield and use the values it returns to turn the motor on and off 112 Chapter 7 Wiring up the components Our first task is to set up our circuit This process is very similar to when you created the thermistor circuit in Chapter 3 Our First Project A Basic Thermometer You ll need your resistor photoresistor three wires black red and yellow are used in the explanation and the breadboard 1 Take the red wire and connect it from the 5 V pin on the shield to the supply voltage on the breadboard Next take th
33. environ QUERY STRING room escape params get room 0 temperature escape params get temperature 0 The first line of our code defines a function called application When a WSGI request comes in Apache will look for the application function and then execute the code located within it The function takes two default parameters environ and start response Following from the function declaration we then define five variables that are used for storing data in our program The first of these is connection this is where we will store the database connection object when we connect to the sqlite3 database my response is an empty string which we will assign our response message to and display in the browser 101 Temperature Storage Setting up a Database to Store Your Results The params variable is used to capture the values passed to the script in the URL query string and makes them available to the Python function for use You may notice here that the parse qs was included from the CGI library at the top of our script The room and temperature variables use values from the params variable we created previously The escape function is responsible for providing some sanitizing on the user input Since only our Raspberry Pi on the home network will be using this script there isn t a big risk of SOL injection attacks however it is good practice to code with this in mind These two variables tak
34. era of home automation technology 17 An Introduction to the Raspberry Pi Arduino and Home Automation X10 a standard is born The beginning of modern home automation technology can be argued to be found with the introduction of the X10 technology standard Conceived in 1975 by Pico Electronics who later partnered with Birmingham Sound Reproducers X10 laid out the framework for allowing remote control access of domestic appliances The X10 standard was designed to allow transmitters and receivers to work over existing electrical wiring systems by broadcasting messages such as turn off and turn on via radio frequency bursts Three years later in 1978 X10 products began to make their way into stores geared towards electronics enthusiasts and shortly after in the 80s the CP 290 computer interface made its way into the market for the Mattel Aquarius computer The CP 290 unit allowed computers to communicate with X10 compatible appliances in the home Over the years support for Windows and Mac has been included and gave those interested in home automation the ability to program their lighting systems thermostats and garage doors from their home computers As revolutionary as X10 has been it unfortunately had a number of flaws These included Wiring and interference issues Commands getting lost in transmission Limited scope of products supporting X10 Limited scope of commands available Slow speed o
35. example location 1 is the 3 3v pin i You will notice that a number of these are labeled as Not used These AN pins are currently not used and are set aside for future expansions of the Raspberry Pi s architecture With this information we can write a custom code to interact with the pins or use other generic libraries that allow us to read and write data The wiringPi library that we will now look at provides some software tools that we can use with our Raspberry Pi Plate 132 Chapter 8 The wiringPi library The wiringPi library written by Gordon Henderson interacts with the Raspberry Pi in a similar fashion to the arduPi library This provides an alternative to the software library you are currently using and can be explored for future projects You will find in wiringPi support for many of the Arduino functions you are familiar with as well as custom support for PWM A comprehensive guide to the available functions is accessible on the wiringPi webpage at https projects drogon net raspberry pi wiringpi The library is available on github and can be accessed via the following link https github com WiringPi WiringPi The following steps will guide you through the installation process via the Raspbian command line Open up a terminal window and type the following command to install git version control software sudo apt get install git core amp Git is a version control software application It allows y
36. find a standard toolbar This includes the File menu where you can open and save files you are working on and menus for Edit Search View Document Project Build Tools and Help 7 The left hand side of the screen contains a window that has a number of features including allowing you to jump to a function when you are editing your code 8 The bottom panel on the screen contains information about your application when you compile it This is useful when debugging your code as error messages will be displayed here Geany has an extensive number of features which are out of the scope of discussion for this book However you can find a comprehensive guide to the IDE at the Geany website http www geany org For our application development at this stage we are only interested in creating a new file opening a file saving a file and compiling a file The options we need are located under the File menu item and the Build menu item Feel free though to explore the IDE and get comfortable with it In order to use the make option for compiling our application under the Build menu we need to create a Makefile we will now take a look at how to achieve this An introduction to Makefiles The next tool we are going to use is the Makefile A Makefile is executed by the Linux command make Make is a command line utility that allows you to compile executable files by storing the parameters into a Makefile and then calling it as needed Th
37. in the script to adjust for the ambient light in the room where your Raspberry Pi is located Connecting to your blinds curtains The final step is to connect your motor up to your blind curtain hardware This will largely depend on the product you are using Remember as well that heavy curtain and blind hardware will require a higher torque motor and you may wish to consider switching over to a 12 V motor at this point 1 Q If you connect the 12 V power supply and motor remember to disconnect the power pins on the motor shield Let s now look at the delay values we set in the loop function Setting the timing Our application has a delay of 5 seconds in the conditional statement that opens and closes the blinds This was an arbitrary amount we set when creating our application When you attach your motor to the blinds curtains you will need to calculate the number of seconds required to open shut the blinds You can also adjust the values in the pwm function to either speed up or slow down your motor Once you have set up the hardware try experimenting with these values until you adjust the settings to your preference For example you may decide you never want the blinds fully closed or open and can adjust the setting so that the closed and open state is 75 percent of the open and closed state of the physical curtain 113 Curtain Automation Open and Close the Curtains Based on the Ambient Light Attaching the h
38. into a readable temperature we are going to need to use an equation that converts resistance into temperature This equation is known as the Steinhart Hart equation The Steinhart Hart equation models the resistance of our thermistor at different temperatures and can be coded into an application in order to display the temperature in Kelvin Fahrenheit and Celsius We will use a simpler version of this in our program called the B parameter equation and can use the values from the datasheet provided with our thermistor in order to populate the constants that are needed to perform the calculations For a simpler version of the equation we only need to know the following values e The room temperature in Kelvin The co efficient of our thermistor should be on the data sheet e The thermistor resistance at room temperature We will use Geany to write our application so if you don t have it open start it up Writing our application From the File menu in Geany create a new blank file this is where we are going to add our Arduino code If you save the file now then Geany s syntax highlighting will be triggered making the code easier to read Open the File menu in Geany and select Save In the Save dialog box navigate to the arduPi directory and save your file with the name thermometer cpp We will use the arduPi template cpp as the base for our project and add our code into it 61 Our First Project A Basic Thermometer
39. is connected to The SETPOINT constant is the value we will use as a base for switching the fan on and off RR KK RK KK RR k k k RR RK RR RR KR RK RR RRR RR KR k k k k ke ke ke ke KK k k IF YOUR ARDUINO CODE HAS OTHER FUNCTIONS APART FROM setup AND loop YOU MUST DECLARE THEM HERE KR K k KR KR RR RRR KR k k RR RR RR RK RR k k k eee ke RK RR KK RR KKK KKK k k k KR k RR k k e ke k k 80 Chapter 5 YOUR ARDUINO CODE HERE KR RR RR RR RR RR ke ek ke e x x boolean running false A flag to let us know if the thermostat is running The running variable is a flag that we will switch to true or false depending on whether the fan is running or not int main setup while 1 loop return 0 void setup void printf Starting up thermostat n The message output has been updated to read thermostat rather than thermometer Wire begin pinMode RPIN OUTPUT We now switch the RPIN 4 in our example to the oUTPUT mode This means the digital pin will be writing data to the relay void loop void float avResistance float resistance int combinedReadings READINGS byte val0 byte vall Our temperature variables float kelvin float fahrenheit float celsius int channelReading float analogReadingArduino Our CURL variables CURL curlInst CURLcode result 81 From Thermometer to Thermostat Building upon
40. log out of our Raspberry Pi without terminating it Finally we connected the fan and used the relay to switch it on and off Now that you have a thermostat device you can try out other projects with it For example you could use it to switch on a small heater when the temperature drops With our hardware and software complete we will move onto our next project This will involve creating a database that can store the values output by our application and then installing some tools to view the stored data via our web browser 87 Temperature Storage Setting up a Database to otore Your Results In this chapter we will cover setting up a database on your Raspberry Pi using SQLite This SOL based database will be used for storing the results from the temperature readings that we captured in the previous chapter We will also look at HyperText Structured Query Language HTSQL a language that allows you to query your database via HTTP requests Along with these technologies we will set up an Apache web server running Python via WSGI a server side programming language that we can use to run SQL queries against our database Let s get started our first step will be to install SOLite Version 3 x and set up our temperature database SQLite SQLite Version 3 x is the latest version of the SQLite series of database technologies Written in the C programming language SQLite is a relational database management system that has
41. provides Windows users with a terminal style window that they can use to connect to Linux machines Windows users Follow the steps to set up PuTTY on your Windows machine 1 Double click on the putty exe file to load the PuTTY configuration screen 2 In the Host Name or IP address text entry field add the IP address of your Raspberry Pi 3 Enter 22 into the Port field and under Connection type select SSH Finally click on Open You may see a pop up box with the title PuTTY Security Alert and a message explaining the server s host key is not cached in the registry You can select the Yes button In the terminal window you will now see the following message Login as 8 Enter your Raspberry Pi user name that is pi 35 Getting Started Part 1 Setting up Your Raspberry Pi 9 You will now see another message asking for the password for example pi 192 168 1 122 s password 10 Enter the password and press the Enter key You will now be logged into the Raspberry Pi Mac and Linux users Once you have your Terminal application ready you can connect via SSH to your Raspberry Pi using the following command ssh pi 192 168 1 122 You will be asked to enter your password and may see a message suggesting that the authenticity of the host can t be established for example The authenticity of host 192 168 1 122 192 168 1 122 can t be established RSA key fingerprint is f6 4a 38 4a 8b c6 04 a9
42. some basic skills in programming and is looking for some simple projects to get started with An in depth knowledge of electronics is not required and the book provides a step by step guide to setting up components and software in each chapter No prior knowledge of the Linux operating system or the Raspberry Pi is needed although exposure to these technologies will certainly be helpful Conventions In this book you will find a number of styles of text that distinguish between different kinds of information Here are some examples of these styles and an explanation of their meaning Code words in text are shown as follows The previous program contains two functions void setup and void loop 0 A block of code is set as follows void setup void printf Starting up thermometer Wn Wire begin Any command line input or output is written as follows mkdir arduPi cd arduPi New terms and important words are shown in bold Words that you see on the screen in menus or dialog boxes for example appear in the text like this Select the Accessories option from the menu 3 Preface d Warnings or important notes appear in a box like this Q Tips and tricks appear like this Reader feedback Feedback from our readers is always welcome Let us know what you think about this book what you liked or may have disliked Reader feedback is important for us to develop titles that you really ge
43. the Raspberry Pi and an output jumper means an output from the Raspberry Pi 136 Chapter 8 Atmel ATmeg chip microcontroller This device is the microcontroller for the Gertboard The microcontroller is a single integrated computer that controls input and output of the devices on the Gertboard The development language for the Arduino can be used with the Gertboard Once you have this installed you can re use Arduino specific applications with a few changes or write new ones to control the Gertboard s microcontroller Convertors analog to digital and digital to analog ADC Analog to Digital Convertor and DAC Digital to Analog Convertor are used to convert data from one format to the other They have applications in music recording and video as well as being useful for converting analog readings from thermostats into digital readings You will be familiar with this concept from the projects you worked on in Chapter 4 Our First Project A Basic Thermometer Chapter 5 From Thermometer to Thermostat Building upon Our First Project and Chapter 7 Curtain Automation Open and Close the Curtains Based on the Ambient Light For those interested in a more in depth look at the Gertboard the user manual is located on the Element14 website The Gertboard user manual provides an in depth look at the electronic components that come as part of the kit and is available at the following URL http www elementi14 com commu
44. to any list of existing errata under the Errata section of that title Any existing errata can be viewed by selecting your title from http www packtpub com support Piracy Piracy of copyright 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 copyrightepacktpub com 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 You can contact us at questionsepacktpub comif you are having a problem with any aspect of the book and we will do our best to address it 5 An Introduction to the Raspberry Pi Arduino and Home Automation This chapter provides an introduction to the Raspberry Pi Arduino and the subject of home automation We ll look at the history of the Raspberry Pi and how it came to be as well as the Arduino platform an open source microcontroller that provides developers with a means to interact with their surroundings through a variety of sensors and motors Finally we will wrap up the chapter by covering home automation and how technologies such as the Raspberry Pi have put the ability to build complex senso
45. to get a more accurate value avResistance 0 for int r 0 r lt READINGS r avResistance combinedReadings r avResistance READINGS 66 Chapter 4 So far we have grabbed our readings and can now use a calculation to work out the resistance For this we will need our avResistance reading the resistance value of our 10K resistor and our thermistor s resistance at room temperature Add the following code that performs this calculation We can now calculate the resistance of the readings that have come back from analog O0 avResistance 1023 avResistance 1 avResistance TENKRESISTOR avResistance resistance avResistance THERMISTOR The next part of the program uses the resistance to calculate the temperature This is the portion of code utilizing the simpler version of the Steinhart hart equation The result of this equation will be the ambient temperature in degrees Kelvin Next add the following block of code Calculate the temperature in Kelvin kelvin log resistance kelvin BETA kelvin 1 0 ROOMTEMPK kelvin 1 0 kelvin printf Temperature in K printf f WMn kelvin So we have our temperature in degrees K and also have a printf statement that outputs this value to the screen It would be nice to also have the temperature in two more common temperature formats those being Celsius and Fahrenheit These are simple calculations to perfor
46. to the Raspberry Pi Arduino and Home Automation 7 What we will explore in this book 7 History and background of the Raspberry Pi 8 Raspberry Pi hardware specifications 9 Dimensions 10 3 5mm analog audio jack 10 Composite RCA port 10 Two USB 2 0 ports plus one micro USB 10 HDMI port 11 SD card port 11 256 MB 512 MB SDRAM shared with GPU 11 CPU 11 GPU 11 Ethernet port 12 GPIO pins 12 History and background of Arduino 12 Raspberry Pi to Arduino shield connection bridge 13 Shield specifications 13 XBee socket 14 Power source selector 14 UART 14 Digital GPIO pins 14 Serial Peripheral Interface SPI pins 15 In Circuit Serial Programmer ICSP connector 15 Power pins 15 Analog inputs 15 Raspberry Pi GPIO connector 15 Table of Contents Soldering 15 Writing software for the Arduino 16 What home automation is 17 A history of home automation 17 X10 a standard is born 18 The dot com boom and open source a new set of technologies 19 Commercial products 20 Arrival of the Raspberry Pi 21 Summary 21 Chapter 2 Getting Started Part 1 Setting up Your Raspberry Pi 23 The SD card our Raspberry Pi s storage device 23 Pre installed SD card versus a blank one 24 Setting up the SD card 24 Formatting our card 25 Formatting instructions for Windows 7 25 Formatting instructions for Mac OS X 26 Formatting instructions for Linux 27 BerryBoot our tool for installing an operating system 28 Downloading the BerryBoot zip 28
47. we will need to install the arduPi library The arduPI software is a set of custom C files written by the Cooking Hacks team that allows our applications written on the Raspberry Pi to interact with the shield via the functions commonly found in Arduino applications You will also be given the choice to install the Arduino IDE although this is not necessary for any of the applications in this book While we will not use the IDE for compiling programs it will provide a useful resource for exploring existing programs For those of you with an Arduino microprocessor you will be able to use this in conjunction with your Raspberry Pi You will also use Leafpad to write your first application and a simple method to compile and run your sketches from the command line The Arduino IDE The optional step of installing the Arduino IDE can be performed using apt get Open up your terminal window and run the following command to ensure apt get is up to date sudo apt get update You should now see any packages that need updating being downloaded to your Raspberry Pi To download and install the IDE type the following command sudo apt get install arduino You will be prompted that the IDE will use several MB of disk space You can select yes to this to complete the install The Arduino IDE will now be available via the start bar in Raspbian under the Electronics option Navigate to the IDE link and open it on your Raspberry Pi You sh
48. 5 degrees Celsius and the beta coefficient of the thermistor The coefficient can be thought of as the amount the resistance changes by as the ambient temperature around the thermistor changes When you purchase a thermistor you should have been provided with a datasheet that lists these two values If you are unsure of the resistance of your thermistor you can always check it by hooking it up to a voltage detector and taking a reading at room temperature For example if you bought a 10K thermistor you should expect a reading of around 10K Ohms For this project we recommend purchasing a 10K thermistor 55 Our First Project A Basic Thermometer 10K Ohm resistor A 10K Ohm resistor unlike a thermistor is designed to have a constant resistance regardless of temperature change This type of device falls into the fixed resistor category You can tell the value of a resistor by the colored bands located on its body When you purchase resistors you may find they come with a color coding guide otherwise you can check the chart on Wikipedia http en wikipedia org wiki Electronic color codeldResistor color coding in order to ascertain what the value is As part of the circuit we are building you will need the 10K resistor in order to convert the changing resistance into a voltage that the analog pin on your Raspberry Pi to Arduino can understand Wires For this project you will require three wires One will attach to the
49. 5V pin on your shield one to the ground and finally one to the analog 0 pin In the wiring guide we will be using red black and yellow wires The red will connect to 5V pin the black to ground and the yellow to the analog 0 pin Breadboard Finally in order to connect our component we will use the breadboard as we did when connecting up the LED Connecting our components Setting up our components for the thermometer is a fairly easy task Once again at this point there is no need to attempt any soldering if you plan on re using the components Follow these steps in order to connect up everything in the correct layout 1 Take the red wire and connect it from the 5V pin on the shield to the connect point on the bus strip corresponding to the supply voltage There are often two bus strips on a breadboard These can be found on either of the long sides of the board and often have a blue or red strip indicating supply voltage and ground 56 Chapter 4 2 Next take the black wire and connect it from the ground pin to the ground on the breadboard 3 Weare now going to hook up the resistor Connect one pin of your 10K resistor to the supply voltage strip that your red wire is connected to and take the other end and connect it to a terminal strip i Terminal strips are the name given to the area located in GA the middle of the breadboard where you connect your electronic components 4 Now that the resistor i
50. Chapter 2 Linux For Linux one of the best tools for unzipping files is unzip Depending on your Linux distribution you can use the following command to install the unzip package For Red Hat Linux Fedora and RPM compatible versions of Linux yum install unzip For Debian GNU Linux versions apt get install unzip Once you have installed your unzip application extract the contents of the BerryBoot zip file you downloaded to your SD card Contained within the zipped file are the files that will be used when the Raspberry Pi boots up for the first time When the preceding process is complete we are ready to connect up the Raspberry Pi and peripherals so we can install the operating system Hooking up the Raspberry Pi We are now going to set up our Raspberry Pi s hardware You will need to complete the following steps before attempting to power up the Raspberry Pi 1 Bjectthe SD card from your PC Mac and place it into the SD card port on your Raspberry Pi Plug your Raspberry Pi into your monitor Attach your keyboard and mouse to the Raspberry Pi via the USB ports Using a Ethernet cable attach your modem router to your Raspberry Pi s Ethernet port Once these steps are complete you can now power up your Raspberry Pi by connecting the power unit to it On your monitor you should now see the BerryBoot Welcome screen This tells us that we have successfully copied over the files to the SD card and can now configure our oper
51. Database to Store Your Results You should see the terminal window text similar to that in the following screenshot fS andrew pi raspberrypi var www wsgi scripts ssh 127x25 The version number in this example 2 3 2 will be whatever version you downloaded which in the case of pip will be the latest Configuring HTSQL The next step is to configure HTSOL and to point it to our database and then set up a server to allow us to query the database via our web browser We can test our connection to the temperature database we created as follows htsql ctl shell sqlite path temperature db This creates a shell similar to the SOLite3 one on the database we created In the preceding example SQLite is the database type and the path follows this completed by the database file name Once you can log in to the database via the HTSQL shell then you can proceed with running a server Quit the HTSQL shell and then from the command line create a HTSQL server as follows htsql ctl server sqlite path temperature db As with the preceding shell connection the path should be replaced with the path to the database that we added to the folder var www database or if you decided to use another directory use that one instead 106 Chapter 6 Once the server has started you will see the following message on the command line Starting an HTSQL server on raspberrypi 8080 over database temperature db eoo
52. Doc 8m S ity ed Seal BS te hi IPR a ti Rca ot 7 4 P P ae ye Raspberry Pi Home Automation with Arduino Automate your home with a set of exciting projects for the Raspberry Pi Raspberry Pi Home Automation with Arduino Automate your home with a set of exciting projects for the Raspberry Pi Andrew K Dennis PACKT PUBLISHING BIRMINGHAM MUMBAI Raspberry Pi Home Automation with Arduino Copyright O 2013 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 author 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 February 2013 Production Reference 1290113 Published by Packt Publishing
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54. Linux the Raspberry Pi and Arduino open source projects home automation and the use of web technology in this sphere amateur electronics home networking and software engineering Acknowledgement I would like to thank my wife Megen for supporting me throughout this project and putting up with the piles of electronics and computer hardware dotted around the house My parents for their support with my interest in technology while growing up and over the subsequent years The Cooking Hacks team for their great new Raspberry Pi to Arduino Bridge shield and the various contributors over on the Cooking Hacks forum for their insights The people at Prometheus Research for making this a great and interesting place to work Partyka Chevrolet for giving me some experience on the hardware side of networking I would also like to thank Joel Goveya and Ameya Sawant at Packt Publishing for their guidance throughout this process and Stefan Sjogelid for his technical insights and reviews About the Reviewer Stefan grew up in the 1980s with the C64 and the Amiga home computers The ambitious goal of the Raspberry Pi Foundation bringing fun programming back to today s youth resonated strongly with Stefan who immediately ordered his Raspberry Pi on the launch day itself After much tinkering and learning a great deal about the unique properties of the Pi he launched the PiLFS http www intestinate com pilfs website which teaches readers
55. Ltd Livery Place 35 Livery Street Birmingham B3 2PB UK ISBN 978 1 84969 586 2 www packtpub com Cover Image by William Kewley william kewleyekbbs ie Credits Author Andrew K Dennis Reviewer Stefan Sjogelid Acquisition Editor Erol Staveley Commissioning Editor Ameya Sawant Technical Editors Veronica Fernandes Worrell Lewis Nitee Shetty Project Coordinator Joel Goveya Proofreader Stephen Swaney Indexer Hemangini Bari Graphics Valentina D silva Aditi Gajjar Production Coordinator Shantanu Zagade Cover Work Shantanu Zagade About the Author Andrew K Dennis is an R amp D software developer at Prometheus Research Prometheus Research is a leading provider of integrated data management for research and is the home of HTSQL an open source navigational query language for RDMS Andrew has a Diploma in Computing a BS in Software Engineering and is currently studying for a second BS in Creative Computing in his spare time He has over 10 years experience working in the software industry in the UK Canada and the USA This experience includes e learning courseware development custom CMS and LMS development SCORM consultancy web development in a variety of languages open source application development blogging about the integration of web technologies with electronics for home automation and punching lots of Cat5 cables His interests include web development e learning 3D printing
56. Our First Project To the original thermometer code we now add two cURL related variables The curlInst variable will be where we initialize our cURL instance The second variable result will be used to store the output of the cURL request RR KKK KKK e ke ke ke ke ke KK e k k ADC mappings Pin Address 0 0OxDC 1 0x9C 2 OxCC 3 0x8C 4 OxAC 5 OxEC 6 OxBC 7 OxFC KARR RR RRR OxFC is our analog 7 pin Wire beginTransmission 8 Wire write byte 0xFC Wire endTransmission As we mentioned earlier in this chapter we have updated the analog pin to 7 The code for this is oxFC Grab the two bytes returned from the analog 7 pin combine them and write the value to the combinedReadings array for int r 0 r lt READINGS r Wire requestFrom 8 2 valO Wire read vall Wire read channelReading int val0 16 int vall gt gt 4 analogReadingArduino channelReading 1023 4095 combinedReadings r analogReadingArduino delay 100 82 Chapter 5 Grab the average of our 7 readings in order to get a more accurate value avResistance 0 for int r 0 r READINGS r avResistance combinedReadings r avResistance READINGS We can now calculate the resistance of the readings that have come back from analog 0 4 avResistance 1023 avResistance 1 avResistance TENKRESISTOR avResistance resistance avResista
57. Serial communication 75 From Thermometer to Thermostat Building upon Our First Project SerialPi Serial Needed for accesing GPIO pinMode digitalWrite digitalRead I2C functions WirePi Wire Needed for SPI SPIPi SPI RRR KR Kk k k ke RRR RR RK k k k k k e ke RR RR KR RR KR RR RR KK RRR RK ke ke ke ke KKK IF YOUR ARDUINO CODE HAS OTHER FUNCTIONS APART FROM setup AND loop YOU MUST DECLARE THEM HERE FR KR KR KR KK RR KK RR RK RR ke ke ke ke ke kk ke k eee e ke ke ke kx RR KR RR k k k RK KR RK KK RR k k k k e ke k k YOUR ARDUINO CODE HERE KR KR RRR RR RR k k KK KK KK int main setup while 1 loop return 0 void setup pinMode 4 OUTPUT void loop digitalWrite 4 HIGH delay 1000 digitalWrite 4 LOW delay 1000 As you can see this program uses the arduPi template cpp file that you should be familiar with by now 1 Q You may notice that this program is the same as blink test cpp using pin 4 instead of 2 76 Chapter 5 Within the setup function we declare digital pin 4 as an output Following this in the 1oop function we switch the relay on and then off with a second between each command Save this file and now create a new empty file We will use this for our Makefile To the new file you created add the following Relay arduPi o g lrt lpthread Relay cpp arduPi o o Relay Save thi
58. We can test our Makefile by selecting the Build option from the menu and selecting Make In the panel at the bottom of the IDE you will see a message indicating that the Makefile was executed successfully 4 Now from the Terminal window navigate to the directory containing your blink test project Located in this directory you will find your freshly compiled blink test file 5 If you still have your LED example at hand hook it up to the shield and from the command line you can run the application by typing the following command blink test The LED should start blinking Hopefully you can see from this example that integrating the Makefile into the IDE allows us to write code and compile it as we go in order to debug it This will be very useful when you start to work on projects with greater complexity 60 Chapter 4 Once we have written the code to record our temperature readings we will re visit the Makefile and create a custom one to build our thermometer application via Geany Now that you have set up Geany and briefly looked at Makefiles lets get started with writing our application Thermometer code We will be using the arduPi library for writing our code as we did for the LED test As well as using standard Arduino and C syntax we are going to explore some calculations that are used to return the results we need In order to convert the values we are collecting from our circuit and convert them
59. added any operating systems on your SD card there should be the one you just installed called Debian Wheezy Raspbian followed by the version number There are a number of options at the top of the BerryBoot menu editor screen These are as follows Add OS Edit Clone Export Delete 32 Chapter 2 Make default Exit And the icon which will take you to the advanced settings option For the purposes of this installation we are only interested in the Make default and Exit options T Select the operating system you installed and click on Make default This will mean that the Raspbian operating system we installed is launched as the default option when the Raspberry Pi is started up Then select Exit You will now see the Raspi config screen The Raspi config screen is a menu that allows you to assign some values to the settings of your Raspberry Pi You can navigate the screen using the arrows keys and use the Enter key to select an option The menu on this screen consists of the following Info Information about this tool Overscan Change overscan configure keyboard Set keyboard layout change pass Change password for pi user change locale Set locale change timezone Set timezone memory split Change memory split overclock Configure overclocking ssh Enable or disable SSH server boot behaviour Start desktop on boot Update Try to upgrade raspi config Select Select an option F
60. ample First lets cover comments Comments are notes in the code that will not be run by the compiler and are prefixed with two slashes or enclosed in and For example Include ArduPi library We can use these to document our code and note what each function is doing These can be found located throughout the code and we recommend that you include them when writing your own applications They can be useful as a reminder when you revisit some code you haven t worked on for a while Next look at the top of the file Here you can see an include statement include arduPi h This tells the compiler to include the code located in the arduPi h header file when we run the g compiler and output our application After this we see some statements that allow the application to use the Arduino functions An example of this being Needed for accessing GPIO pinMode digitalWrite digitalRead I2C functions WirePi Wire This block of code allows us to invoke functions that read and write to the digital pins on the shield We will be using this in our LED example in order to write to pin 2 on the shield Following this is the main function which calls setup and then places the 1oop function into a infinite while loop Our setup function contains a single statement that initializes pin 2 on the shield and sets it to output When we set up our hardware at the beginning of the chapter you will remember we connected via the brea
61. ardware At this point you will need to attach the DC motor to the curtain drawstring The preferred method for doing this is via a pulley wheel A variety of grooved pulley wheels can be found online or in hardware and craft stores Select one that fits the profile of your hardware M Make sure you are not running the curtain control application while attempting to attach the wheel and blinds as this may make things difficult Attach the wheel to the axle on your DC motor it should fit snuggly so it does not fall off when the motor is switched on Try testing your configuration out by launching the curtaincontrol program Once you are sure this works you can now attach the drawstrings of your curtains or blinds to the wheel This setup will largely depend on how the blinds are opened or closed Commonly there is a drawstring loop that can be pulled to open or close the blinds This loop should be attached around the groove in the pulley wheel and fit tightly Now try changing the delay value in your application to 1 second Next run the make again to recompile the application Our application will now run the open close cycle for 1 second Execute the application via the command line and note how far the curtain blind will open close in 1 second With this information you should be able to estimate how many seconds are required to open and close your hardware At this point you can try refining the numbers until you reach the desi
62. as Blender Ethernet port The Ethernet port is the Raspberry Pi s main gateway to communicating with other devices and the Internet You will be able to use the Ethernet port to plug your Raspberry Pi into a home router such as the one you currently use to access the Internet or a network switch if you have one set up GPIO pins The General Purpose Input Output GPIO pins on the Raspberry Pi are the main way of connecting with other electronic boards such as the Arduino As the name suggests the GPIO pins can accept input and output commands and thus can be programmed on the Raspberry Pi The Arduino shields will be attached to the GPIO via a bridge shield allowing us to transfer data from sensors soldered to the device back to the Raspberry Pi This is especially useful in home automation projects where we may wish to store sensor data or manipulate motors based upon a program running on the Raspberry Pi s operating system Having touched upon the technical capabilities of the Raspberry Pi we will now look at the Arduino and the Raspberry Pi to Arduino shield a way to connect the two technologies via the GPIO pins History and background of Arduino One of the most popular open source hardware products to have hit the market is the Arduino platform a branch off of the earlier open source Wiring platform Developed in Italy by Massimo Banzi and David Cuartielles in 2005 Arduino is an open source hardware technology coupled with
63. at will be ready to send data to the database that we will create in Chapter 6 Temperature Storage Setting up a Database to Store Your Results For this chapter you will need e Your Raspberry Pi and Arduino shield The thermometer device you built in Chapter 4 Our First Project A Basic Thermometer e Arduino compatible relay shield component From Thermometer to Thermostat Building upon Our First Project Asmalllow voltage electric desktop fan Some wire cutters and strippers Away of stimulating the thermistor for both cold and hot temperatures for example some ice and a hair dryer Safety first In this chapter we will be using a device plugged into mains electricity usually AC the fan We will also be cutting the cable that connects the fan to the plug socket This cable will be run through our relay circuit It is important to remind you at this point that working with mains electricity is dangerous You should only attempt the fan portion of this project if you feel 100 percent confident in your ability to safely attach the thermostat device to the mains Also it is important that you select the correct relays for your electrical system Attempting to use a 130 V AC relay on a 240 V AC electrical system for example can result in melting your device or worse Depending on your country of residence the mains voltage can be between 110 V and 240 V Before attempting this project we recommend you read
64. ating anything in our database we should consider what tables and columns we are going to need For this project we only need a simple database and two tables should be enough to record the data we want to store One table will be responsible for storing the temperature data and the other for recording the details of the room the Raspberry Pi is located in Let s look at the temperature table first A table to record our temperature The temperature table will be responsible for storing the data written back from the Arduino shield We will need the following columns Id This will be the unique ID for each temperature reading written to the database With each new value added it should auto increment and should also be the Primary Key for our table e Roomid The roomid will serve the purpose of linking the temperature reading to a table containing information about the room it was taken from For example in our project we will store the name of the room here 91 Temperature Storage Setting up a Database to Store Your Results Temperaturec This column will be used to store our temperature reading in Celsius This value will have been calculated by the Arduino shield and sent back ready to be inserted into the database e Datetime We will calculate a time stamp for each reading when inserting data into the table This can be useful when querying the database and trying to find out for example which time pe
65. ating system selection 29 Getting Started Part 1 Setting up Your Raspberry Pi Downloading the right operating system We now need to choose from the variety of operating systems that are available to install the Raspberry Pi For the purposes of our home automation project we are going to use the operating system called Raspbian There are several reasons for choosing this over another operating system Raspbian is based upon the Debian Wheezy Linux operating system and has been optimized for use with Raspberry Pi Mike Thompson and Peter Green of raspbian org developed it and while not an official product of the Raspberry Pi foundation is the operating system the foundation recommends for beginners on their website For those of you not familiar with Linux it is a group of open source operating systems that uses the Linux Kernel and provides an alternative to applications such as Windows Mac OS X users may be familiar that they are using a Unix like operating system that gives them many of the command line functionalities that Linux users are familiar with They will also find some similarities with the Raspbian operating system which we are installing on the Raspberry Pi There are several reasons for deciding to go with the Raspbian operating system that are listed as follows e Raspbian has a desktop environment similar to Windows and Mac called LXDE so it provides an easy transition for those not familiar with
66. between them and close them as necessary When we launch our thermostat application we will demonstrate how to leave the application running when exiting the terminal session cURL We are now going to briefly look at cURL Originally standing for Client for URLs this technology allows us to craft URLs in our code and then execute them For example if we want to connect to a Python application from our script and pass it some of the values of the variables we have generated such as our temperature reading we can use cURL by installing the 1ibcurl developer headers In fact this example is exactly what we will be doing with our code in Chapter 6 Temperature Storage Setting up a Database to Store Your Results when we build a database application to accept the data we generate Raspbian comes with cURL installed by default however we will need to add the development library libcur14 openss1 dev via apt get Load up your screen window and navigate to the directory where you are developing your code and follow these steps 1 Type the following command into your terminal sudo apt get install libcurl4 openssl dev 2 When prompted that the install will use disk space type Y and press Enter to continue Now we have 1ibcurl developer headers installed we can build our thermostat code Make a copy of your thermometer code and name it thermostat cpp Thermostat code We will now modify the thermostat code to switch our relay
67. bient Light in order to control the blinds in the project We can replace the regular DC motor with a DC stepper motor A stepper motor is a motor that divides a full revolution into steps This allows greater control over the revolutions of the motor when it is operating and thus a greater point of accuracy when controlling the drawstring Switching lights on with a photoresistor We learned how to switch on a fan using relays and a thermistor The principles used in this project can be applied to a desktop lamp or similar lighting device Using the relay shield and the photoresistor we can change out thermostat application to switch on the lighting device when the room gets dark Holiday lights from LEDs One application of the PWM code we wrote in Chapter 7 Curtain Automation Open and Close the Curtains Based on the Ambient Light is to cause LEDs to fade in and out This provides us with the technology to make holiday lights that can blink and fade along to a pattern To build on this project you can time the lights to switch on and off in synchronization with music to provide an even more interesting experience The future of home automation The Raspberry Pi and Arduino have provided us with two great technologies to create home automation projects As the technology continues to grow the tasks we will be able to achieve at home using homebrew devices will grow ever larger Lets take a look of some of the other tools that wil
68. ccessing it via a web browser Chapter 7 Curtain Automation Open and Close the Curtains Based on the Ambient Light teaches you how to integrate motors into your projects for opening and closing blinds and curtains using the skills learned in previous chapters Chapter 8 Wrapping up provides an overview of other technologies you can use in your project and a look towards the future of home automation Appendix References lists a collection of links pointing you towards the resources used in this book and other interesting information What you need for this book For this book you will need the following components and software e A computer running Mac OS X Windows or Linux e A Raspberry Pi computer e AnSD card e HDMI cable e Access to an HDMI television or HDMI computer monitor e AUSB keyboard and mouse e USB power supply for the Raspberry Pi e Cooking Hacks Raspberry Pi to Arduino bridge shield e Electronics breadboard e 10K resistor e Thermistor e Photo resistor e Jumper wires with male connectors e AnLED e 9V DC motor e OV battery with connector for screw terminals e Arduino Motorshield e Asoldering iron e Adesoldering iron gun 2 Preface Other software required for the projects in this book will be downloaded from the Internet with step by step instructions in the relevant chapters Who this book is for This book is aimed towards the amateur home automation enthusiast who has
69. ceful 95 apachectl graceful stop 96 apachectl restart 95 apachectl start 95 apachectl stop 95 components Gertboard See Gertboard components composite RCA port Raspberry Pi 10 constants BETA 63 READINGS 63 ROOMTEMPK 63 TENKRESISTOR 63 THERMISTOR 63 contact points relay Common Connection 74 Normally Closed 74 Normally Open 74 controlMotor function 124 Cooking Hacks about 13 URL 13 40 144 147 Cooking Hacks shield 13 core components Raspberry Pi 3 5mm analog audio jack 10 256 MB 512 MB SD RAM shared with GPU 11 composite RCA port 10 CPU 11 dimensions 10 Ethernet port 12 GPIO pins 12 GPU 11 HDMI port 11 micro USB port 10 SD card port 11 USB 2 0 ports 10 CP 290 unit 18 CPU Raspberry Pi 11 cURL 79 curlInst variable 82 curtain automation tool expanding for including temperature sens ing 138 motor changing to stepper motor 139 curtain control application about 119 blinds curtains connecting to 125 code writing 120 123 152 debugging 125 hardware attaching 126 problems debugging 126 PWM 119 threads 119 timing setting 125 curtaincontrol program launching 126 D DAC Digital to Analog Convertor 137 database SOLite creating 91 table creating for recording rooms 92 table creating for recording temperature 91 David 3D scanner URL 148 digital I O pins Raspberry Pi to Arduino shield 14 digitalWrite function 47 dimensions Raspberry Pi 10 domotics 17 E ECHO 17 EEG articl
70. command to see if it fixes the error e chmod 777 temperature db If this turns out to be the case try changing the files read write settings to something more secure that works You can read more about chmod on its man page by typing man chmod Now we have added data to our database and created some text information to return to the browser we need to wrap up the script by sending a response back Below the lines you added previously paste in the following code Status 200 OK response headers Content Type text plain Content Length str len my response Start response status response headers return my response 103 Temperature Storage Setting up a Database to Store Your Results This final block of code returns a successful HTTP response with our text string located in it This response is then interpreted by our web browser and the string is displayed on the screen So we have reached the end of our Python script and while it is pretty simple it demonstrates what is possible Save this script and we can now test it Using your browser go to http lt your Raspberry Pi s IP address addtemperature temperature 85 amp room 1 For example http 192 168 1 122 addtemperature temperature 85 amp room 1 If the request is run successfully you should see Inserted 85 for room 1 in your browser NI If you have problems with your script you can check the Apache error logs at
71. creen Here you will choose which storage device you want to install your operating system on If you have other storage devices beyond your SD card connected to the Raspberry Pi you will also be given the option of using these However we are going to use the SD card T Select your SD card from the list and then change the File system select box to ext 4 no discard Like FAT ext4 is a filesystem and in this instance is geared towards Linux Now select the Format button Once the formatting is complete we are presented with the Install operating system screen from which we can choose Raspbian 31 Getting Started Part 1 Setting up Your Raspberry Pi 4 Clickon the Debian Wheezy Raspbian option Install operating system Select the operating system you would like to download and install and press ok to contin p Linaro Ubuntu ALIP 2012 08 268 MB o ubuntu For A10 devices not for rPi Debian Wheezy Raspbian 2012 09 430 MB The official rPi Raspbian version debian OpenELEC r11791 71 MB Media center software for playing videos Proxy settings Cancel This download is around 430 MB and depending on the speed of your Internet connection will take a few minutes Once complete you will be presented with the BerryBoot menu editor This is a screen with a menu and a list of operating systems currently installed on your SD card Providing you haven t previously
72. d REFERENCES roomdetails id The preceding command has now created our second table called temperature This table will be used to store each of our temperature readings The SOL command has created two columns the first being the ID that like the roomdetails table is an integer and auto incremented 92 Chapter 6 The second column created will be used to store the room IDs This column references roomdetails and creates a foreign key link to it Now that we have the temperature table we can add the other two columns to it those being temperaturec and datetime For this task we can use the SOL command ALTER TABLE in order to add a new column to an existing database From within the SOLite3 shell enter the following SOL command ALTER TABLE temperature ADD COLUMN temperaturec FLOAT 8 We have now updated our temperature table and added the column for storing the temperature readings from the sensor on the Arduino shield This column accepts numeric float values eight characters long which means we can store decimal numbers such as 52 3 48 4 and so on Finally let s add the date stamp column to our database so we can check when our temperature readings were stored Using the shell execute the following command ALTER TABLE temperature ADD COLUMN datetime DATETIME We have now added our final datetime column to the table this column takes a date formatted value in the following format YYYY MM DD HH MM SS N
73. d at the Wikipedia link http en wikipedia org wiki Ohm s law You will find resistors are usually classified into two groups fixed resistors and variable resistors The typical types of fixed resistor you will encounter are made of carbon film with the resistance property marked in colored bands giving you the value in Ohms Components falling into the variable resistance group are those with resistance properties that change when some other ambient property in their environment changes You will be exploring some of these throughout the book Let s now examine the two types of resistors we will be using in our circuit a thermistor and a 10K Ohm resistor Thermistor A thermistor is an electronic component which when included in a circuit can be used to measure temperature The device is a type of resistor that has the property whereby its resistance varies as the temperature changes It can be found in a variety of devices including thermostats and electronic thermometers There are two categories of thermistors available these being Negative Thermistor Coefficient NTC and Positive Thermistor Coefficient PTC The difference between them is that as the temperature increases the resistance decreases in the case of a NTC or increases in the case of a PTC There are two numerical properties that we are interested in with regards to using this device in our project These are the resistance of the thermistor at room temperature 2
74. d hooking up the LED components Un pack your shield and locate the black connector on the bottom of the board Attach the shield via this to the GPIO pins on your Raspberry Pi If you are unsure what these are you can refer to the figure in the Raspberry Pi hardware specifications section in Chapter 1 An Introduction to the Raspberry Pi Arduino and Home Automation With the shield firmly attached to the Raspberry Pi you can now hook up the LED Take two wires and attach one to the grounding pin and the second to the digital pin 2 Place each of these into your breadboard Now insert the LED into the breadboard so that the wire running from digital pin 2 is connected to the longer of the two legs on the LED and the ground pin is connected to the shorter of the two The following figure provides a guide to this setup Connection from ground pin to short pin on LED Connection from pin 2 to long pin on LED There is no need to solder any of the components at this time as the LED application we are writing is purely to test that our setup is working correctly 41 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield Once you have completed the hardware setup we can then install the software needed to control our Raspberry Pi to Arduino shield Installing the software In order to allow our Raspberry Pi to communicate with our Arduino shield
75. d test our application Compiling and testing When discussing Geany earlier we demonstrated how to run the make command from inside the IDE Now that we have our Makefile in place we can test this out 1 From the Build menu select Make You should see the compilation pane at the bottom of the screen spring to life and providing there are no typos or errors in your code a file called thermometer will be successful output The thermometer file is our executable that we will run to view the temperature 2 From the terminal window navigate to the arduPi directory and locate your thermometer file 3 Thiscan be launched using the following command sudo thermometer 68 Chapter 4 The application will now be executed and text similar to the following in the screenshot should be visible eoo f andrew pi raspberrypi arduPi ssh 96x16 Try changing the temperature by blowing on the thermometer placing it in some cold water if safe to do so or applying a hair dryer to it You should see the temperature on the screen change If you have a thermostat or similar in the room that logs the temperature try comparing its value to that of your thermometer to see how accurate it is You can run an application in the background by adding an amp after the command for example sudo thermometer amp In the case of our amp A application it outputs to the screen so if you attempt to use the sa
76. dboard the long leg of the LED to pin 2 on the shield Next we have the 1oop function This is called from inside the while loop located in the main function Inside the 1oop function like we saw with the Blink example there are four statements Two of these are responsible for turning the LED on and off and the other statements creates a 1 second delay so the LED has a blinking effect Now that we have an application we can use to control our LED we need to compile and run it 49 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield From the Leafpad file menu select File then Save As Save the file with the name blink test cpp to the same directory as your arduPi library and template Exit Leafpad and via the terminal window navigate to the arduPi directory you created Inside this directory you should see the file you created called blink test cpp Now that we have saved our test application we can compile and run it Compiling and running our application If not already open launch another terminal window In the window make sure you are located in the arduPi directory and run the following command g lrt lpthread blink test cpp arduPi o o blink test The g compiler will now compile our blink test cpp file and link it with the arduPi o file finally outputting a binary file called blink test So we have created our file and compiled it The next and final test is to run
77. dered board includes the following components Buttons GPIO PCB board Ribbon cable LEDs Light emitting diodes ADCs Analog to digital convertor DACs Digital to analog convertor 48V Motor controller ATmega microcontroller The following diagram shows the layout of the board which we will now explore DAC ADC Micro controller Motor controller Buffered 1 0 Open collector driver GPIO Pins GPIO PCB expansion board The GPIO expansion board is a pre populated printed circuit board This is the item that the components are soldered to and forms the foundation of the Gertboard This board is what is connected to the Raspberry Pi via its GPIO pins GPIO Pins The Gertboard like the Raspberry Pi comes equipped with its own set of GPIO pins The ribbon cable provided in the Gertboard kit is used to hook the Raspberry Pi up to some of the GPIO pins in order to provide a physical communication medium between the two devices 135 Wrapping up Motor controller A motor controller can be used to control an electronic motor hooked up to it Some examples of its functionality include switching a motor on and off controlling its speed and changing the torque and direction The Gertboard s motor controller supports hooking up a DC direct current electric motor which can be controlled via the motor controllers pins It also comes eq
78. download link 146 online resources 146 apachectl graceful command 95 apachectl graceful stop command 96 apachectl restart command 95 apachectl start command 95 apachectl stop command 95 Apache documentation URL 146 Index Apache foundation homepage URL 146 Apache Version 2 x using 94 Apache web server about 89 94 commands 95 conclusion 104 setting up 94 97 URL 146 WSGI 97 apt get user manual URL 144 Arduino background 12 13 benefit 13 history 12 online resources 145 software writing for 16 URL 43 145 Arduino forum URL 145 Arduino hardware URL 145 Arduino IDE Arduino language 43 44 installing 42 Arduino IDE downloads URL 145 Arduino language about 16 44 features 44 HTSQL 16 Python 16 SQL 16 Arduino shields about 12 testing with database 108 Arduino store URL 145 arduPi about 45 installing 45 arduPi library board revision 1 URL 144 arduPi library board revision 2 URL 144 arduPi software 13 Atmel ATmeg chip microcontroller 137 B BerryBoot about 24 28 URL 143 zip file downloading 28 BETA constant 63 blinking LED application about 48 code 49 compiling 50 running 50 breadboard using 56 buffered YO 136 byte val0 variable 64 byte vall variable 64 C C C online resources 145 programming reference 145 CherryPy Essentials Rapid Python Web Application development URL 147 Chmod manual page URL 144 Chown manual page URL 144 commands Apache web server apachectl gra
79. ducts 20 dot com boom 19 EEG Headsets 140 future 139 history 17 online resources 147 open source technologies 19 RFID chips 140 X10 technology standard 18 Honeywell URL 148 HTRAF toolkit URL 146 HTSOL about 16 104 configuring 106 108 downloading 105 online resources 146 URL 146 HTSQL downloads URL 146 HTSQL mailing list URL 146 HTSQL Python page URL 146 HTSQL tutorial URL 146 Hyper Text Structured Query Language See HTSQL ICSP connector Raspberry Pi to Arduino shield 15 i materialise URL 148 include statement 49 installation Geany IDE 58 59 SOLite 90 Interaxon Muse URL 140 148 int main function 47 Iris Smart Kit URL 148 L Leafpad about 46 loading 46 47 lights switching on with photoresistor 139 Linux online resources 144 SD card formatting instructions 27 URL 37 URL screen users manual 144 zipping tools downloading 29 Linux Kernel Archive URL 144 Linux shell scripting cook book URL 147 loop function 47 68 LXTerminal about 34 loading 34 M Mac and Linux users PuTTY setting up 36 Mac OS X Archiver downloading 28 SD card formatting instructions 26 WinZip downloading 28 make command manual URL 144 154 Makefiles about 59 creating 60 running 60 Makerbot URL 140 Makerbot 3D printers URL 148 Makeshed URL 147 Makezine Arduino blog URL 145 Making Things introduction to electronics URL 147 micro USB port Raspberry Pi 10 Midori 34 miscellaneous res
80. e Next we check if there was an error in executing the URL and if the request failed we output an error message Finally we run the curl easy cleanup function to close the connection Three second delay before taking our next reading delay 3000 This completes the modifications to the thermometer code needed to switch the relay on and off and write the temperature data in a URL format We can now create a new Makefile to compile our new code From within Geany create the new file and add the following Thermo arduPi o g lrt lpthread lcurl thermostat cpp arduPi o o thermostat Once you have saved the Makefile you can try running it from the Build menu If you have any compilation errors fix these and then try building again Once complete you can now test the code with your fan Testing our thermostat and fan We have our hardware setup and the code ready Now we can test the thermostat out and see it in action First we will attach the fan and then run the application generated by our previous Makefile 85 From Thermometer to Thermostat Building upon Our First Project Attaching the fan Make sure that your Raspberry Pi is powered down and that the fan is not plugged into the wall Using a wire stripper and cutters cut one side of the cable connecting the plug to the fan body Take the end of the cable attached to the plug and attach it to the COM point on the relay Use a screwdriver to e
81. e cpp file Include ArduPi library include arduPi h Needed for Serial communication SerialPi Serial Needed for accesing GPIO pinMode digitalWrite digitalRead I2C functions WirePi Wire Needed for SPI SPIPi SPI BORK KKK KK k ke e k k KR RR RR RR RR RR RK RR RR k k RK RRR e ke ke ke ke KK KK IF YOUR ARDUINO CODE HAS OTHER FUNCTIONS APART FROM getup AND loop YOU MUST DECLARE THEM HERE HR KK KK KR RR RRR RR k k RRR ek ke RR KR ke k k RK RK RR KR RR KKK k k kk k KK RR KR k k k e ke ke k YOUR ARDUINO CODE HERE KR RR RR RR RR RR RR KK KK KK int main setup while 1 loop 1 return 0 Looking at this file we can see some similarities to the Blink ino file we opened earlier One main difference though is the inclusion of the int main function It is within this function that we reference the Arduino functions that are used to run an application As you can see in the preceding code snippet there is a reference to a setup function and a loop function The top of the file contains arduPi specific code that is needed to use the standard Arduino function calls such as the digitalWrite function we saw in the Blink program When writing your own code you can take a copy of the template file and insert your own setup and loop functions as well as any other custom functions you wish to run 47 Getting Started Part 2 Set
82. e 1880s Johnson was known throughout his lifetime as a prolific inventor who worked in a variety of fields including electricity These electric room thermostats became common features in homes across the course of the twentieth century as larger parts of the world came to be hooked up to the electricity grid Now with open source electronic tools such as the Raspberry Pi and Arduino available we can build custom thermostats for a variety of home projects They can be used to switch on baseboard heaters control heat lamps and turn on air conditioner units It can also be used for the following e Fish tank heaters Indoor gardens Electric heaters e Air conditioning e Fans Now that we have explored the uses of thermostats let s take a look at our project Setting up our hardware This project builds up on our last project by reusing the thermometer we created The thermometer is a key component of our thermostat as we use this to test the ambient temperature and switch the device connected to our Raspberry Pi on off based upon this We will start by explaining the relay device 73 From Thermometer to Thermostat Building upon Our First Project Relays A relay is a type of switch controlled by an electro magnet It allows us to use a small amount of power to control a much larger amount for example using a 9 V power supply to switch 220 V wall power Relays are rated to work with different voltages and curr
83. e black wire and connect it from the ground pin on the Raspberry Pi to the Arduino bridge shield to the ground on the breadboard As we did with the thermistor before we will now connect a resistor to the breadboard Connect one pin of your resistor to the supply voltage strip that your red wire is connected to and then connect the other end to a terminal strip We can now connect our photoresistor Insert one leg of the photoresistor into the ground on the bus strip and place the second leg into the same row as you placed the resistor Finally connect one end of your yellow wire from the analog 7 A7 on your shield to the terminal strip you selected Your completed layout should look similar to the following image Arduino to Raspberry Pi Shield Breadboard Resistor ILI Photo Resistor Analog 7 113 Curtain Automation Open and Close the Curtains Based on the Ambient Light Now that we have the hardware in place we can write an application to test our setup Testing the photoresistor with software As with our earlier programs we will use the arduPi template to create our test code Open up Geany and create a new file Add the following code to the file Include ArduPi library include arduPi h Include the Math library include lt math h gt Needed for Serial communication SerialPi Serial Needed for accessing
84. e have looked at various tools and technologies in order to build devices to help automate our homes The previous chapter should have given you a good introduction to the Raspberry Pi and Arduino technologies that you can now expand upon In this chapter we will review what we have learned and then look at how you can grow your skills and start to design your own shields for the Raspberry Pi We will look at a Raspberry Pi prototyping shield and then following this we will explore the GPIO pins of the Raspberry Pi so that you can interact with them via the shield Next we will look at the wiringPi library and the Gertboard both of which can be used for home automation projects Following this we suggest some next step projects that use the techniques you have learned in this book and in some cases build upon previous projects Finally we wrap up with an eye to the future In order to complete the prototype board task you will need e Raspberry Pi e Adafruit Raspberry Pi prototyping shield AnLED e Asoldering iron e Protective glasses Solder The Gertboard is available via Newark Element14 at http www newark com Let s start by recapping on what we have covered so far Wrapping up A brief review of what we have learned Chapter 1 An Introduction to the Raspberry Pi Arduino and Home Automation and Chapter 2 Getting Started Part 1 Setting up Your Raspberry Pi provided us with some background on the Raspberry Pi and
85. e on Wikipedia URL 148 EEG headsets about 148 online resources 148 EEG Headsets 140 141 Electronic Computing Home Operator See ECHO electronics online resources 147 Element14 URL 147 eLinux Raspberry Pi Hub URL 143 Emotiv headset URL 140 148 Ethernet port Raspberry Pi 12 except statement 103 Expert Python Programming URL 147 F FAT 24 File Allocation Table See FAT flaws X10 technology standard 18 float avResistance variable 64 float celsius variable 64 float fahrenheit variable 64 float kelvin variable 64 float resistance variable 64 G G compiler URL 145 Geany IDE about 58 installing 58 59 URL 144 Gertboard about 134 components 134 Gertboard components about 134 ADC 137 Atmel ATmeg chip microcontroller 137 buffered I O 136 DAC 137 GPIO expansion board 135 GPIO Pins 135 kit and pre soldered board 135 motor controller 136 open collector drivers 136 software writing 137 Gertboard user manual URL 143 GPIO expansion board 135 GPIO pins 135 GPIO pins Raspberry Pi 12 GPU Raspberry Pi 11 H Hackaday blog URL 148 hardware components thermometer 10K Ohm resistor 56 153 breadboard 56 connecting 56 57 resistors 55 setting up 54 thermistor 55 wires 56 hardware components thermostat about 73 relay 74 HDMI port Raspberry Pi 11 High Definition Multi media Interface port See HDMI port holiday lights from LEDs 139 home automation 3D printing 139 about 17 commercial pro
86. e the values of specific parts of the query string which in this case have the same name as the variable We can then use these two variables in the SQL query we are going to write Next up we will write the code that creates a query and uses the value of the room and temperature variables After the variable declarations paste the following code my query INSERT INTO temperature roomid temperaturef datetime VALUES s sS CURRENT TIMESTAMP room temperature tty connection sqlite3 connect var www database temperature db isolation_level None cursor connection cursor cursor execute my_query query results cursor fetchone my response Inserted s for room s temperature room except sqlite3 Error e my response There is an error s e finally connection close In the Python script you added we start by creating a variable called my query and into this variable we add our SOL query string The query string inserts into the temperature table in our database the values from our room variable and temperature variable Following from this we then use our try except block to create a connection to our database The database connection is stored in the connection variable if successful You will notice that we have included the path to the temperature db file when creating the connection object You should make sure that this path matches your own 102 Chapte
87. eading 1023 4095 113 Curtain Automation Open and Close the Curtains Based on the Ambient Light The preceding code will be familiar to you from the thermostat project Here we are setting up analog pin 7 so we can read the values returned by the photoresistor Next let s add some code that displays a message if the photoresistor is recording more light or less if analogReadingArduino gt TH printf Getting lighter n else printf Getting darker n delay 3000 As you can see in the if statement we check if the light is greater than the threshold value and if it is then the program displays the message Getting lighter Otherwise we display the message Getting darker Save the file as Light Sensor cpp and then create the following Makefile Photo arduPi o g lrt lpthread LightSensor cpp arduPi o o lightsensor Once the Makefile is complete save the file run the make from the build menu and then return to the terminal window From the command line we can now test the code by running lightsensor Now that the application is running we can try out our photoresistor Depending on the ambient light in the room you will see the message Getting lighter or Getting darker If you see the Getting darker message try shining your flashlight on the sensor once the threshold is passed the message will change to Getting lighter If however you see the message Getting ligh
88. ease of the Apple II and earlier seeds planted by such technology as the TV Typewriter and Apple I this was rapidly changing As the 80s rolled into view the public saw low cost home computers such as the ZX Spectrum and Commodore 64 hit the mass market and subsequently give birth to a whole generation of amateur programmers By the 90s these programmers brought up on tinkering with their home computers and writing BASIC were heading into academia and the computer industry and helping to forge the dot com boom with game web open source and business technologies The genesis of the Raspberry Pi is in many ways linked to this A group of computer scientists lead by Eben Upton at the University of Cambridge s Computer Laboratory in 2006 struck upon the idea of producing a cheap educational micro computer geared towards the amateur computer enthusiast budding students and children The aim was to help to provide the skills to future Computer Science undergraduate applicants that many of those applying in the 90s possessed thanks to the home computers of the 80s However it would be another two years before the project became viable and not until 2012 before the Raspberry Pi was being shipped out to the public The 2000s saw a huge growth in mobile computing technologies a large segment of this being driven by the mobile phone industry By 2005 ARM a British manufacturer of CPU core components and a by product of the 80s home compu
89. eenshot K e00 192 168 1 72 gt C 192 168 1 72 It works This is the default web page for this server The web server software is running but no content has been added yet Congratulations You have successfully set up a web server capable of serving HTML and other content on your home network For our home automation projects however we would also like to be able to do more than serve static content such as the index html page packaged with Apache In order to do this we will need to be able to run server side code such as Python Python will allow us to not only serve up static content but also allow us to connect to our database to read and write data from it To gain this functionality we will need to expand the capabilities of Apache by including WSGI WSGI Web Server Gateway Interface WSGI is a Python standard used by web servers to allow communication between Python web applications and themselves For the Apache web server that we installed its functionality can be expanded to serve Python applications by including a module that provides support for WSGI With this installed we can then build server side applications accessible via a web browser that can write data to our SOLite database 97 Temperature Storage Setting up a Database to Store Your Results Setting up WSGI The copy of Apache installed on the Raspberry Pi does not include WSGI by default There
90. ents for example the Seeed Arduino shield s relays can work with up to 130 V of AC power A relay has three contact points these are Normally Open Common Connection and Normally Closed Two of these points will be wired up to our fan In the context of an Arduino project the relay will also have a pin for ground 5 V power and a data pin that is used to switch the relay on and off Connecting the relay Depending on the relay device you purchased for your Raspberry Pi there are several ways to connect the relays to the Arduino shield The method that follows relies on your relay being connected to a digital input the 5 V power and ground For those of you using a relay shield in the thermostat program we have moved the connection of the thermistor from analog 0 to analog 7 as this pin is located on an area of the board not used by a third party shield Carry out the following steps to connect your relay 1 Connecta wire from your Arduino to Raspberry Pi shield s 5 V power to the power pin on your relay s board 2 If necessary you can use the breadboard and connect the wire from the supply voltage strip to the board If you are using a relay shield then the pin will automatically be connected to the 5 V power pin 3 Take another wire and connect this from the ground on your shield to the ground on your relay Once again you can use the breadboard as an intermediary or if you are using a shield this is automatically taken ca
91. erful tool is now available to the home automation enthusiast programmer and electronic hobbyist that allows them to augment their home with sensors and software Combining the Raspberry Pi with the power of the open source Arduino platform this book will walk you through several projects for building electronic sensors and introduce you to software that will record this data for later use What this book covers Chapter 1 An Introduction to the Raspberry Pi Arduino and Home Automation introduces you to the technologies used in this book and provides a background to the world of home automation Chapter 2 Getting Started Part 1 Setting up Your Raspberry Pi teaches you about the Raspberry Pi and how to set it up ready to use on your projects Chapter 3 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield provides you with a guide to setting up your Raspberry Pi to Arduino bridge shield and downloading the necessary libraries Chapter 4 Our First Project A Basic Thermometer helps you to build a thermometer and introduces you to a variety of electronic components Preface Chapter 5 From Thermometer to Thermostat Building upon Our First Project expands upon our Thermometer project turning it into a working thermostat that can switch relays on and off Chapter 6 Temperature Storage Setting up a Database to Store Your Results explores storing data output from your Thermostat and then a
92. ermometer You will need the following hardware items for this chapter e Raspberry Pi e The Raspberry Pi to Arduino shield e lt A thermistor The breadboard and wires we used to test the LED e A10k resistor From a software standpoint you will also be introduced to the Geany IDE and the Linux make command Using these tools we will write an application that converts the resistance returned from the circuit into three types of temperature namely Celsius Kelvin and Fahrenheit The key concepts we will be covering will form a basis that will be expanded upon in the next chapter Chapter 5 From Thermometer to Thermostat Building upon Our First Project Our First Project A Basic Thermometer Building a thermometer A thermometer is a device used for recording temperatures and changes in temperatures The origins of the thermometer go back several centuries and the device has evolved over the years Traditional thermometers are usually glass devices that measure these changes via a substance such as mercury which rises in the glass tube and indicates a number in Fahrenheit or Celsius The introduction of microelectronics has allowed us to build our own digital thermometers This can be useful for checking the temperature in parts of your house such as the garage or monitoring the temperature in rooms where it can affect the contents for example a wine cellar Our thermometer will return its readings to the Raspberry
93. ess of the Raspberry Pi Gert Van Loo worked upon a project that would expand what the Raspberry Pi could do further the Gertboard The Gertboard is a printed circuit board PCB with a combination of components that can be soldered together and connected to the Raspberry Pi thus extending its capabilities via its GPIO pins Like its counterparts it allows electronic components to be controlled via applications written on the Raspberry Pi While not an official product of the Raspberry Pi foundation it has been given support by its members and distributed along side the Raspberry Pi through Newark Element 14 Much like the Raspberry Pi to Arduino shield you will now be able to build embedded systems for your home that can perform a range of tasks from recording temperatures and controlling your thermostat to using ambient light sensors that open and close your blinds Thanks to the combination of components that come as part of the kit you will have sensors LEDS DACS and motors available for home projects This allows you to record analog data and convert it to digital as well as move physical objects via motors and communicate error codes and states via LEDs Introduction to the Gertboard components The first wave of Gertboards was shipped as a kit of separate components that needed soldering together An updated kit which comes pre soldered is being re released at end of 2012 134 Chapter 8 The kit and pre sol
94. etting up 54 hardware setup verifying 57 58 running 70 software 58 testing 69 writing 61 67 thermometer code 61 thermostat about 72 73 157 fan attaching 86 hardware setting up 73 software setting up 75 testing 85 thermostat application problems debugging 87 running 86 thermostat code modifying 79 85 Thingiverse URL 148 threshold 114 U UART Raspberry Pi to Arduino shield 14 USB 2 0 ports Raspberry Pi 10 V Vacuum Fluorescent Display VFD 136 void loop function 44 void setup function 44 W W3 Schools SQL guide URL 146 Web Server Gateway Interface See WSGI Wget user manual URL 144 Wikipedia article on electronic symbols URL 147 Windows 7 zip downloading 28 PuTTY setting up 35 SD card formatting instructions 25 26 WinZip downloading 28 WiringPi downloads about 133 URL 143 WiringPi library URL 143 wiringPi webpage URL 133 wires 56 WSGI about 89 setting up 98 100 WSGI homepage URL 145 X X10 com URL 147 X10 knowledge base URL 147 X10 technology standard about 18 flaws 18 Xbee sockets Raspberry Pi to Arduino shield 14 Z zip unzip application downloading for Linux 29 downloading for Mac OS X 28 downloading for Windows 28 158 PAC KT Thank you for buying pusLisuinc Raspberry Pi Home Automation with Arduino About Packt Publishing Packt pronounced packed published its first book Mastering phpMyAdmin for Effective MySQL Management
95. ettings in our homes This chapter should have whetted your appetite for bigger projects Summary In this chapter we learned how to wire up two new components a thermistor and resistor Our application taught us how to use these components to log a temperature reading and we also became familiar with Makefiles and the Geany IDE Let s move on to a more complex project using the skills we have gained from building your thermometer In the next chapter you will be using the same components you used previously and also expanding upon the application you wrote 70 From Thermometer to Thermostat Building upon Our First Project In this chapter we look at building a thermostat device This will build upon our previous chapter where we learned how to use a thermistor We will cover how to use the temperature data to switch relays on and off Relays are the main component that you can use to interact between your Raspberry Pi and high voltage electronic devices Our example project will involve switching on an electric fan when the temperature rises above a set point of 15 degrees Celsius and then switching it off when the temperature drops We can use an ice cube and a hair dryer or a similar device to stimulate the thermistor Upon completion of this chapter you will have a thermostat device that you can use in your home to control a variety of devices beyond the fan example Finally we will also write some code th
96. evelopment environment both of which we will be using Also of note is the LXTerminal This icon launches the Linux terminal window which allows us to run applications via the command line One optional final test you can perform is to connect to your Raspberry Pi via SSH There are several ways of getting the IP address assigned to your Raspberry Pi one of which is to check the DHCP table on your home modem router However an easier method is to check it on the Raspberry Pi itself To do this load up the LXTerminal again and type the following command ip addr show eth0 34 Chapter 2 You can find your IP address after the word inet For example Inet 192 168 1 22 24 brd 192 168 1 255 scope global eth0 You need the portion before the that reads 192 168 1 22 An IP address is a way of assigning a unique identifier to a computer or device on a local network or Internet The most common form of IP CIS address at the moment is IPv4 which takes the format 192 168 1 0 gt You may also encounter the newer IPv6 which has the 2001 0ab1 255b9 0047 0000 8a2e 0110 7444 format Once you have the IP address for your Raspberry Pi you can try connecting to it from your other machine Mac and Linux users can use the terminal that comes shipped with their operating system Windows users can download a terminal executable file called PuTTY from http www chiark greenend org uk sgtatham putty download html PuTTY
97. f signal transmission e Lack of encryption Lack of confirmation message without expensive two way devices By the late 90s home automation still hadn t penetrated the home market on a truly wide scale however the technological advancements of the dot com boom were providing a whole new set of tools protocols and standards that addressed many of the flaws that the X10 standard has been limited by 18 Chapter 1 The dot com boom and open source a new set of technologies With the explosion of technologies that followed the birth of the web in the 90s home computing and networking technologies were now available to the public and could easily and cheaply be installed at home These technologies would later provide ideal candidates for pushing the boundaries of what could be achieved by home automation enthusiast and provide the industry with the tools for building smart home appliances and systems It was only a small step from PC to PC communication to appliance to PC communication Home networks running on Ethernet and later WiFi provided a mechanism that could allow computers and electronic appliances to communicate with one another across a home without needing to use the existing electrical wiring In the case of WiFi no extra cabling was required As protocols such as FTP and HTTP became the norm for accessing information across the Internet hardware developers saw the opportunity to leverage these communica
98. fore we will need to use apt get to install the module onto Raspbian Open up the terminal and run the following command sudo apt get install libapache2 mod wsgi Once the process has completed you will now have the necessary code on your machine to support Python web applications However before we can serve these applications Apache will need to be configured to let it know which directory the files are located in where the WSGI module is located and which URL to serve them on From the command line navigate to the following directory cd var www Within this directory add a new folder with the following name sudo mkdir wsgi scripts This is the directory where we will store our Python WSGI scripts Using the command line or whichever tool you are using to edit text files navigate to the following directory etc apache2 sites available Open the file called default When working from the Raspbian desktop you can open a CE terminal window and launch Leafpad with the command GS sudo leafpad This will allow you to edit the files located in etc apache2 and var www This file contains the settings for our website and is where we will need to add the additional configuration for allowing Python applications to be run on it Navigate to the bottom of the file and add the following line WSGIScriptAlias addtemperature var www wsgi scripts addtemperature wsgi 98 Chapter 6 This tells Apache to take
99. garithm function log when calculating the temperature in Kelvin 62 Chapter 4 Following are a number of constants we use the amp de ine statement here to initialize them e TENKRESISTOR This is the 10K Ohm resistor you added to the circuit board As you can see we have assigned the value of 10 000 to it BETA This is the beta coefficient of your thermistor e THERMISTOR The resistance of your thermometer at room temperature e ROOMTEMPK The room temperature in Kelvin this translates to 25 degrees Celsius READINGS We will take seven readings from the analog pin and average these out to try and get a more accurate reading The values we have used previously are for a 10K thermistor with a co efficient of 4000 These should be updated as necessary to reflect the thermistor you are using in your project Now that we have defined our constants and included some libraries we need to add the body of the program From the arduPi template cpp file we now include the main function that kicks our application off BORK KKK KK ee KR RK RR RR RRR RR RRR RRR e ke ke ke ke RK KK IF YOUR ARDUINO CODE HAS OTHER FUNCTIONS APART FROM gsetup AND loop YOU MUST DECLARE THEM HERE KR KR RR RRR RR RR KR RR RR k k KR RR RR RK RR KK ke k k k RK ke kx RRR RR KKK ke KKK KKK k kk k KKK KK YOUR ARDUINO CODE HERE KR RR RR RR RR RR KR KK KK KK int main setup while 1 l
100. hen hooking up a device to the shield For example a device drawing power from the shield and writing data back to it will need to use one of the power options 5V or 3 3V and also the grounding pin Analog inputs The analog inputs can be used to hook up devices such as potentiometers commonly found as twisting knobs for changing things such as volume which send an analog signal to the shield This is the analog counterpart of the digital GPIO pins described earlier Raspberry Pi GPIO connector The Raspberry Pi GPIO connector can be found on the bottom of the shield This is where you will connect your Raspberry Pi to Arduino bridge shield to the Raspberry Pi s GPIO pins Soldering Soldering is the process of attaching electronic components together using a heated metal filler the solder in order to allow the electrical current to flow between them At this point it is worth mentioning that practicing some soldering before you start building the projects in this book is worth the effort but not strictly necessary If you are a novice do not worry as there will be minimal soldering 15 An Introduction to the Raspberry Pi Arduino and Home Automation Also if you have any old PC hardware sitting around like a graphics card no longer in use you can practice un soldering and re soldering the components until you get comfortable with the process These will also help you get used to handling the soldering iron and
101. in float fahrenheit and float celsius as their names suggest are used for recording temperature in three common formats 64 Chapter 4 After declaring these variables we need to access our analog pin and start to read data from it Copy the following code into your 1oop function RRR ke e eee e ke k ke ke KK k k k ADC mappings Pin Address 0 OxDC 1 Ox9C 2 OxCC 3 0x8C 4 OxAC 5 OxEC 6 OxBC 7 OxFC RRR KR RK RR ke ke RK e e ke ke ke x OxDC is our analog 0 pin Wire beginTransmission 8 Wire write byte 0xDC Wire endTransmission Here we have code that initializes the analog pin 0 The code comment contains the mappings between the pins and addresses so if you wish you can run the thermistor off a different analog pin We are using pin 0 so we can now start to take readings from it To get the correct data we need to take two readings of a byte each from the pin We will do this using a or loop The Raspberry Pi to Arduino shield does not support the 4 analogRead and analogWrite functions from the GA Arduino programming language Instead we need to use the Wire commands and addresses from the table provided in the comments for this code 65 Our First Project A Basic Thermometer Add the following or loop below your previous block of code Grab the two bytes returned from the analog 0 pin combine them and write the value to the combinedReadings array
102. ing JSON XML CSV text and YAML You can read more about these at the HTSOL website and get a better idea of other methods of querying the data in your temperature database http www htsgl org Testing our Arduino shield with our database Now that we have a way to write data to our database we can now start taking and storing readings from our Raspberry Pi to Arduino hardware From the command line run the thermostat application located in the arduPi directory Once this is running the shield will start to take temperature readings In turn the Arduino code references the Python script we have just written and will start to send the temperature data to it for the room you associated with the ID 1 Make sure that both Apache and the HTSQL server are running 108 Chapter 6 The Python script will then generate a connection to the SOLite database and execute the query inserting the temperature data timestamp and the room ID We can test that our data has made its way through the system by querying the temperature database via HTSQL If for example we wanted to see the room temperature and time stamp we could use the http ip of raspberry pi 8080 temperature room temperaturec datetime roomid 1 query You should now see an HTML table listing the room data temperature and time stamp You have now successfully set up your Raspberry Pi to store data from the Arduino shield and made it accessible to o
103. inish Finish using menu 33 Getting Started Part 1 Setting up Your Raspberry Pi From this menu we are going to change the password enable SSH and start the desktop environment on loading 1 First navigate to and select the change pass menu option and enter and re enter your new password The default password for the Raspberry Pi is raspberry If NON you plan on opening up your Raspberry Pi to the Internet to allow connections from outside your home network then it is advisable to change the password to something strong After this we need to set up SSH so that it allows us to connect to the Raspberry Pi remotely via the command line on a different machine Select the ssh option and enable the ssh server 3 Finally we want to change the boot behavior of the Raspberry Pi so that the desktop environment is started when the operating system boots up To do this change the boot_behaviour option to start desktop on boot 4 We have now finished configuring the settings we need to on the Raspi config screen and can exit so now navigate to the lt Finish gt option and press the Enter key to complete your setup Installation complete You have now successfully completed the Raspberry Pi setup and will see the Raspbian Linux desktop This desktop contains a number of icons which will load the programs installed by default including Midori a fast and light web browser and the Python IDE integrated d
104. is method allows us to store common compilation directives and re use them without having to type out the command each time As you are familiar with we have used the following command in order to compile our LED example g lrt lpthread blink test cpp arduPi o o blink test Using a Makefile we could store this and then execute it when located in the same directory as the files using a simpler command make 59 Our First Project A Basic Thermometer We can try out creating a Makefile using the code we wrote in the previous chapter Load up Geany from the programming menu if you don t currently have it open If you don t have a new document open create a new one from the File menu Now add the following lines to Blink test Makefile making sure to tab the second line once Blink arduPi o g lrt lpthread blink test cpp arduPi o o blink test If you dont tab the second line containing the compilation instructions J then the Makefile won t run Now that you have created the Makefile we can save and run it with the following steps 1 From the File menu select Save 2 From the Save dialog navigate to the directory where you saved your blink test cpp and save the file with the title Makefile 3 Now open the blink test cpp file from the directory where you saved your Makefile You should see the code we wrote in Chapter 3 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield
105. it In the terminal window type the following command sudo blink test You should now see the LED on the breadboard start to blink on and off with a one second interval Q Pressing Ctrl C at any time in the terminal will exit the application If the LED starts blinking then the compilation and setup of your hardware has been successful Congratulations You have written your first application using the Arduino programming language compiled it and ran it Now that the basics are out of the way and you have explored outputting to a pin on the shield we can move onto more complex projects 50 Chapter 3 Summary In this chapter we have set up our Raspberry Pi to Arduino shield The software library for interacting with the Arduino shield is installed and ready for further projects You have also been introduced to the Arduino programming language and C and learned how to compile code Following from this you have written an application that turns an LED on and off Now that we have the basics of controlling components attached to our Raspberry Pi to Arduino shield we can move onto our first home automation project building a thermometer 51 Our First Project A Basic Thermometer Now that we have our Raspberry Pi to Arduino shield set up we can start to build projects using it In this chapter we are going to build our first project with the Raspberry Pi and Arduino shield a th
106. ius and Fahrenheit First up we are going to look at a new code editing application This IDE allows you to develop code in the Raspberry Pi X Window System environment and compile the code via a Makefile We will start by looking at the Geany IDE Geany IDE Geany is a lightweight Linux integrated development environment It can be installed onto Raspbian and then used for writing code in the Arduino C programming language An added benefit of using this IDE is that we can set up a custom Makefile with the commands we have been using to compile arduPi based projects By combining the Makefile and Geany we have an IDE that mimics the functionality we would use in the Arduino IDE but with the added benefit we can save files without renaming them and compile our applications with one click Installing the IDE We are going to use the apt get tool to install Geany on to your Raspberry Pi 1 Start off with loading up your Terminal window From the prompt run the following command sudo apt get install geany 2 You ll get the prompt alerting you to the fact that Geany will take up a certain amount of disk space You can accept the prompt by selecting Y 3 Once complete you will now see Geany located under the Programming menu option 58 Chapter 4 Select the Geany icon from the previous menu to load the application Once loaded you will be presented with a code editing interface Along the top of the screen you can
107. iv com Neurosky http www neurosky com Interaxon Muse http interaxon ca muse faq php EEG article on Wikipedia http en wikipedia org wiki Electroencephalography 148 Appendix Miscellaneous resources We also provide a list of miscellaneous resources based on some of the topics touched upon in this book and other areas of interest Popular mechanics back issues at Google books http books google com books id 49gDAAAAMBAJ amp source gbs all issues r amp cad 1l amp atm aiy 196048all issues anchor Wikipedia article on mains electricity http en wikipedia org wiki Mains electricity Wikipedia article on relays http en wikipedia org wiki Relay Wikibooks embedded systems http en wikibooks org wiki Embedded Systems Open Source Initiative http opensource org IO programming language http iolanguage org IO programming language Raspberry Pi binary http iobin suspended chord info linux iobin linux armhf deb current zip 149 Symbols 3 5mm analog audio jack Raspberry Pi 10 3D printing about 139 148 online resources 148 10K Ohm resistor about 56 Wikipedia URL 56 256 MB 512 MB SD RAM shared with GPU Raspberry Pi 11 A Adafruit industries URL 147 ADC Analog to Digital Convertor 137 addtemperature wsgi 100 analog inputs Raspberry Pi to Arduino shield 15 analogRead function 66 Android developer resources URL 148 Android operating system URL 147 Apache
108. kening and the blinds need to be closed 1 Once again we call the controlMotor function and switch the motor on 2 Next the direction is set to counterclockwise by writing Low to the digital pin 5 Next we apply a 5 second delay to allow the blinds to close fully Finally we switch the motor off This wraps up the application We can now test it against our circuit Create a Makefile for the curtain control application in Geany and add the following directives Curtain arduPi o g lrt lpthread CurtainControl cpp arduPi o o curtaincontrol Run the make command from the build menu and then return to the command line Start the application up curtaincontrol Your curtain control application should now be running If you try changing the light on the photoresistor you will notice that the motor changes direction and eventually will stop 124 Chapter 7 Applying less and more light will cause the values returned by the photoresistor to pass the threshold and thus switch the motor on and off Debugging problems If the application is not working try the following steps to debug 1 Recheck the steps involving rewiring the pins with jumper wires 2 Check that all of the wires on the breadboard and the shield are connected firmly 3 Ensure that you have enough power supplied to the motor shield You can test it by using a 9 V battery hooked up to the power connectors 4 Try changing the threshold value
109. l become increasingly available to home enthusiasts 3D printing Rapid prototyping commonly known as 3D printing is a method of taking a 3D image and then printing it out in a substance such as plastic or metal 139 Wrapping up The advent of cheaper 3D printing is providing home automation enthusiasts with a new tool in their arsenal 3D printing s ability to create custom cases and brackets for devices and to then print these out in plastic provides a gateway to a whole new world of exciting designs Printers such as the Makerbot have opened up 3D printing to the home market For those who can t afford a 3D printer at home services such as Shapeways at www shapeways com provide a service that allows the customer to upload a 3D image to the website Shapeways will then take this 3D image and print the object in a variety of materials and then ship it Raspberry Pi cases are a popular offer on their website Q Check out the Makerbot at http www makerbot com RFID chips Radio Frequency Identification RFID is a method where microchips are embedded into items such as passports When these chips are read they provide information encoded in them Consumer goods are increasingly approaching the realm where embedded RFID chips will become commonplace When this takes place home automation devices will be able to read the frequencies of products that enter the house and leave Thus a system can be built that reads
110. l box or replace an existing thermostat device on a wall 3 5mm analog audio jack The 3 5mm analog audio jack allows you to connect headphones and speakers to the Raspberry Pi This is especially useful for audio and media player based projects Composite RCA port You are probably familiar with the composite cables used to hook up your DVD player to the TV They usually come in the red white and yellow plug variety The Raspberry Pi has a port for attaching the yellow video cable from your TV to it allowing you to use your TV as a monitor Two USB 2 0 ports plus one micro USB USB is one of the most common methods for connecting peripherals and storage devices to a computer The Raspberry Pi comes equipped with two of them allowing you to hook up a keyboard and mouse when you get started and a micro USB port for powering your device 10 Chapter 1 HDMI port The High Definition Multi media Interface HDMI port allows the Raspberry Pi to be hooked up to high definition televisions and monitors that support the technology This provides an additional option to the composite RCA port for video and additionally supports audio Should you wish to stream video and audio from the web to your TV this is the port you would want to use SD card port The main storage mechanism of the Raspberry Pi is via the SD card port The SD card will be where we install our operating system and will act as our basic hard disk Of cou
111. liance a consortium of 84 companies operating in the mobile sphere Google backed and eventually purchased the Android mobile operating system The aim has been to create an open source operating system that can compete with companies such as Apple and provide a robust system that can work across multiple manufacturer devices As a result of this commercial manufacturers of home appliances have begun to embed the technology and software into their products and a generation of smart devices has started to appear in stores around the world Commercial products If you are interested in a smart refrigerator that can tell you the weather and keep track of your groceries or an oven that can be controlled via your smartphone then you are in luck Products such as the Samsung RF4289HARS refrigerator running Android and the LG smart washing machine are paving the way for smart homes by embracing open source and web based technologies It is also not just appliances that are getting the makeover Thermostat systems such as the Nest a company founded by ex Apple employees are re thinking how smart thermostats work Barcodes and OR codes on products now allow the consumer to scan them with their smartphone and download information directly from the web providing details on the item This can be extended to allow scanning and inventory management of products in the home recording data such as consume by dates of products in the refrigerat
112. lication performs other tasks In the context of our program this allows us to generate PWM outside of the 1oop function that will run continuously until we tell it otherwise For example in the setup function we can create a thread that generates PWM on pin 3 of the shield In the loop function we can perform other tasks and then pause the PWM thread update the values used to generate PWM and restart it This new value will then be used in the PWM thread You will see this concept in action next in our curtain control application 113 Curtain Automation Open and Close the Curtains Based on the Ambient Light Writing our code Let s take the light sensor code we wrote and expand it to start controlling the motor shield Start up Geany and create a new file called CurtainControl cpp Add the following code into this file Include ArduPi library include arduPi h Needed for Serial communication SerialPi Serial Needed for accesing GPIO pinMode digitalWrite digitalRead I2C functions WirePi Wire define TH 690 define DIRECTION 5 define PWMPIN 3 Here we have our standard template headers as well as the threshold we defined in LightSensor cpp After this we have added two new constants DIRECTION and PWMPIN The constant DIRECTION stores the pin on the motor shield that is used to define which way the motor is running that is clockwise or counterclockwise We use the PWMPIN cons
113. m Let s start by adding the Celsius code Convert from Kelvin to Celsius celsius kelvin 273 15 printf Temperature in C printf f n celsius Now that we have the temperature in degrees Celsius we can print this to the screen Using this value we can convert Celsius into Fahrenheit Convert from Celsius to Fahrenheit fahrenheit celsius 1 8 32 printf Temperature in F printf sf n fahrenheit 67 Our First Project A Basic Thermometer Great So now we have the temperature being returned in three formats Let s finish up the application by adding a delay of 3 seconds before the application takes another temperature reading and close off our 1oop function Three second delay before taking our next reading delay 3000 So there we have it This small application will use our circuit and return the temperature We now need to compile the code so we can give it a test Remember to save your code now so that the changes you have added are included in the thermometer cpp file Our next step is to create a Makefile for our thermometer application If you saved the blink test Makefile into the arduPi directory you can re use this or you can create a new file using the previous steps Place the following code into your Makefile Thermo arduPi o g lrt lpthread thermometer cpp arduPi o o thermometer Save the file with the name Makefile We can now compile an
114. me a g Sc terminal window your typing will be interrupted To kill an application running in the background you can type g to bring it to the foreground and then press Ctrl C to cancel it What if it doesn t work Providing you had no errors when compiling your code then the chances are that one of your components is not connected properly is connected to the wrong pin or may be defective Try double checking your circuit to make sure everything is attached and hasn t become accidently dislodged Also ensure that the components are wired up as suggested at the beginning of this chapter If everything seems to be correct you may have a faulty component Try substituting each item one at a time in the circuit to see if it is a bad wire or faulty resistor 69 Our First Project A Basic Thermometer Up and running If you see your temperature being output successfully then you are up and running Congratulations you now have a basic thermometer This will form the basis for our next project which is a thermostat As you can see this application is useful However returning the output to the screen isn t the best method it would be better for example if we could see the results via our web browser or an LCD screen Now that we have a circuit and an application recording temperature this opens up a wide variety of things we can do with the data including logging it or using it to change the heat s
115. mmand to list the directories contents 1s You will now see the files arduPi cpp arduPi h and arduPi_template cpp The files arduPi cpp and arduPi h contain the code that will be used to provide support for interacting with your Arduino to Raspberry Pi shield The arduPi_template cpp provides a basic template file that you can use to create applications The arduPi cpp file will need to be compiled into an object file in order for us to use it For this task we will be using a C compiler From the command line type the following command g c arduPi cpp o arduPi o This command invokes the g compiler takes the arduPI cpp as an input file and outputs an object file called arduPi o Now that we have the code compiled lets take a look at the template files Leafpad a text editor Leafpad is a simple open source text editor similar to Notepad on Windows or TextEdit on the Mac It is already installed in Raspbian so is ready to use without any further setup To load Leafpad you can access it via the following steps 1 Click on the start button located on the bottom left of your Raspbian task bar 2 Select the Accessories option from the menu 3 Select the Leafpad icon from the list of applications Leafpad will now open presenting you with a blank document Using the Open option under the File menu load the arduPi template cpp file 46 Chapter 3 You will see the following in the arduPi templat
116. nce THERMISTOR Calculate the temperature in Kelvin kelvin log resistance kelvin BETA kelvin 1 0 ROOMTEMPK kelvin 1 0 kelvin printf nTemperature in K printf sf n kelvin Convert from Kelvin to Celsius celsius kelvin 273 15 printf Temperature in C printf sf n celsius Convert from Celsius to Fahrenheit fahrenheit celsius 1 8 32 printf Temperature in F printf sf n fahrenheit We are now going to add the code that switches the thermostat on and off depending on whether the temperature is higher or lower than our setpoint if celsius gt SETPOINT amp amp running false printf Switching fan on digitalWrite RPIN HIGH 83 From Thermometer to Thermostat Building upon Our First Project running true else if celsius SETPOINT amp amp running true printf Switching fan off digitalWrite RPIN LOW running false Our code here checks to see if the fan is off and the temperature has risen above the setpoint If these conditions are met then we set the RPIN 4 to HIGH and set the boolean flag running to true Setting the digital pin 4 to HIGH changes the switch in the relay and completes the circuit turning our fan on If however the fan is running and the temperature drops below the setpoint then we set the digital pin to Low this switches the relay to the off positi
117. nce gt so If you created a new httpd conf file or no LoadModule references already exist then you can paste the following configuration into the empty file otherwise add this under the existing LoadModule references LoadModule wsgi module modules mod wsgi so Save the file and exit your text editor Now restart Apache using the restart command sudo apachectl restart 99 Temperature Storage Setting up a Database to Store Your Results Finally before we write our web application to add temperature recordings to our database let s copy it over to the www directory Using the command line navigate to the web directory using the code cd var www From within this directory create a new folder to store your database in and change directory into it sudo mkdir database cd database Let s take a copy of the database we created earlier and used to test SOLite and copy it to our new database directory cp home pi database temperature db We now have Apache set up with a directory to add our new Python scripts to and a database located locally which we can write data to When we added our configuration to the default file for Apache we included a reference to a script called addtemperature wsgi Our next step is to create this script Creating a Python application to write to our database In order to write data to our SQLite database we will need a server side application capable of connecting to the
118. nents 10 forum URL 37 genesis 8 hardware specifications 9 history 8 hooking up 29 online resources 143 operating system deciding 30 pre installed SD card versus blank SD card 24 SD card 23 SD card setting up 24 setting up 23 URL 37 143 Raspberry Pi forum URL 143 Raspberry Pi GPIO connector 15 Raspberry Pi Prototyping Pi Plate shield about 131 guide to soldering URL 131 Raspberry Pi to Arduino shield about 13 analog inputs 15 digital I O pins 14 ICSP connector 15 key components 14 online resources 144 power pins 15 power source selector 14 Raspberry Pi GPIO connector 15 specifications 13 SPI pins 15 UART 14 using 39 XBee socket 14 Raspberry Pi to Arduino shield connection bridge 13 Raspberry Pi to Arduino shield set up about 39 Arduino IDE installing 42 arduPi installing 45 blinking LED application 48 connecting up to Raspberry Pi 41 LED hooking up 41 Raspberry Pi version checking 40 software installing 42 Raspberry Pi to Arduino shield specifications 13 Raspberry Pi to Arduino tutorial URL 144 Raspbian about 30 features 30 installing 31 34 URL 37 143 Raspbian Linux desktop 34 Raspbian package URL 144 READINGS constant 63 relay about 74 connecting 74 75 contact points 74 testing 75 requestFrom function 66 resistance 55 resistance readings about 64 byte val0 64 byte vall variable 64 float avResistance 64 float resistance 64 resistors 55 RFID chips 140 ROOMTEMPK constant 63 room variable
119. nents to the Raspberry Pi and control them via the Arduino programming language Raspberry Pi to Arduino shield connection bridge For our project the particular Raspberry Pi to Arduino shield we will be using is produced by Cooking Hacks an offshoot of the Libelium wireless communications company based in Spain Their website can be found at http www cooking hacks com The Cooking Hacks shield is connected to the Raspberry Pi s GPIO pins and with the inclusion of the arduPi software you will be able to communicate between your electronic devices the Raspberry Pi s operating system and web based projects Let s take a quick look at the shield and its components Shield specifications The Raspberry Pi to Arduino shield is a credit card sized electronics board that mimics an Arduino microcontroller in its layout The Raspberry Pi connector is under the board and the top of the board contains typical pins and connectors you would find on an Arduino board such as the Uno 13 An Introduction to the Raspberry Pi Arduino and Home Automation The following figure highlights some of the key components of interest and a description of each is also listed UART ping Digital GPIO and SPI pins Xbee socket ICSP Xbee socket Power source selector Power analog and 12C pins XBee socket The two Xbee sockets on the shield provide supp
120. ng devices without the need for a separate PC or Mac giving us an alternative to solutions that currently exist Also thanks to the Raspberry Pi s mission of providing an educational tool for those interested in programming the addition of the Arduino shield will provide a mechanism for those who wish to move from writing software that manipulates the Raspberry Pi to software that manipulates their environment and provides a pathway for learning about electronics This could have the positive effect of bolstering the ranks of home brew and Maker clubs with an eye towards home automation and lead to an ever greater diversity of tools being produced for the public Summary In this chapter we have familiarized ourselves with the Raspberry Pi and Arduino We have also looked at some of the existing technologies used in home automation and their history Where as Sutherland s ECHO IV filled a room in his house the Raspberry Pi fills a space not much larger than a credit card Home automation now seems to be taking the next step to becoming widely adopted and the Raspberry Pi neatly fits into this world by providing those who want to customize control of their devices with an easy and a cheap tool for achieving it and by also expanding what can be done with Arduino technology currently out in the market place With this in mind we will get started on our first project setting up the Raspberry Pi 21 Getting Started Part
121. ng holes located on them and Made in the UK printed on the board The earlier versions of the board have neither of these two items The Cooking Hacks website includes a guide to examining which version of the board you have It can be found at http www cooking hacks com index php documentation tutorials raspberry pi to arduino shields connection bridge step3 It is also possible to check the revision number via the command line which in turn can be used to work out the board version Typing the following command will show the hardware details of the Raspberry Pi cat proc cpuinfo eoo A andrew pi raspberrypi ssh 96x16 Look for the revision entry where you will see the revision number in the preceding screenshot this is 0002 You can cross reference the revision number with the Raspberry Pi documentation located on the Element 14 website http www element14 com community docs DOC 42993 1 raspberry pi single board computer Here you will find a table with a document link titled Revision Note Clicking on this will take you to a document with the latest revision numbers present This will then allow you to identify the board version 40 Chapter 3 Now that we have noted which version of the Raspberry Pi board we have let s set up our hardware Setting up the Raspberry Pi to Arduino shield and LED We will now walk through the process of connecting up the shield to the Raspberry Pi an
122. ng links provide information and support for the Raspberry Pi and Raspbian operating system Official Raspberry Pi website http www raspberrypi org Official Raspberry Pi forum http www raspberrypi org phpBB3 Raspbian website http www raspbian org BerryBoot http www berryterminal com doku php berryboot WiringPi library https projects drogon net raspberry pi wiringpi WiringPi downloads https github com WiringPi WiringPi Gertboard user manual http www element14 com community servlet JiveServlet downloadBody 48860 102 3 256002 Gertboard User Manual Rev 1 200 F pdf eLinux Raspberry Pi Hub http elinux org RPi Hub References Raspberry Pi to Arduino bridge shield Information on the Cooking Hacks Raspberry Pi to Arduino Bridge can be found at the following locations Cooking Hacks website http www cooking hacks com Raspberry Pi to Arduino tutorial http www cooking hacks com index php documentation tutorials raspberry pi to arduino shields connection bridge arduPi library board revision 1 http www cooking hacks com skin frontend default cooking images catalog documentation raspberry arduino shield arduPi revl tar gz arduPi library board revision 2 http www cooking hacks com skin frontend default cooking images catalog documentation raspberry arduino shield arduPi rev2 tar gz Linux There are a wide range of resources available for Linux online The following links pro
123. nity servlet JiveServlet downloadBody 48860 102 3 256002 Gertboard User Manual Rev 1 200 F pdf The Gertboard assembly manual is also available online at Element14 and provides an easy step by step guide to assembling the kit You can view the assembly manual at the following URL http www elementi14 com community servlet JiveServlet downloadBody 48916 102 1 256003 Gertboard Assembly Manual Revi1 1 F pdf Writing software for the Gertboard There are several example programs written for the Gertboard in C that you may be interested in checking out These can be downloaded from Element14 at the following URL http www element14 com community solutions 6438 1 gertboard application library for gertboard kit linux These applications can be opened in Geany and compiled via a makefile 137 Wrapping up Gordon Henderson s website also provides a guide to installing the Arduino IDE onto the Raspberry Pi and configuring it to work with the Gertboard The instructions can be found at the following URL https projects drogon net raspberry pi gertboard So with two new boards to explore and some different libraries let s look at some future projects that can leverage your existing hardware or use one of the other shields we have looked at Ideas for next step projects This book has provided you with a variety of projects that provide tools for sensing and automating your home environment Armed with the knowledge from
124. ns two functions void setup and void loop 0 Within void setup we can see the statement pinMode 13 OUTPUT This tells the application to set the pin labeled 13 on the Arduino board to output mode If a device such as an LED is connected to pin 13 then it can be switched on and off The second function we can see is void loop The function executes continuously so any statements located within it will run in an infinite loop Within this function youcanseedigitialWrite 13 High anddigitalWrite 13 LOW Thesetwo commands switch the LED on and off creating a blinking effect The delay 1000 statement causes a 1 second pause between each statement so the LED does not blink too fast The Arduino programming language supports many features you can see a full list of these in the Arduino documentation located online at http arduino cc en Reference HomePage 44 Chapter 3 Now that we have briefly looked at the Arduino blink code we will take this example and demonstrate how it works with our Raspberry Pi shield and the LED we connected to it arduPi a library for our Raspberry Pi and Arduino shield In order for the previous blink example to work with our Arduino shield we need to install the arduPi library by Cooking Hacks This library will allow us to write Arduino applications and use them on the Raspberry Pi without needing a separate microcontroller such as an Uno board So lets install the library
125. nsure that it is fastened correctly Now take the other portion of the cut cable that is attached to the fan body and attach this to the NO point Once again use a screwdriver to ensure it is fastened securely to the relay Your connection should look as follows Relay No Com Nc S Fan body Plug You can now power up your Raspberry Pi relay and fan Starting your thermostat application From the command line launch screen create a new tab and label this Thermostat Then from within this screen session start your application thermostat Your application will be launched in the screen session When you log out of your Raspberry Pi or close you SSH session it will continue to run in the background You can reconnect to it by typing screen r in the terminal window when logging back in Now that our application is running you should see that when the temperature of the thermistor passes the setpoint the fan switches on You can test this by warming up the thermistor if the room temperature is not greater than the setpoint In order to test if it switches off correctly try cooling down the thermistor Tf using ice to cool down the thermistor avoid placing the ice directly near GS the circuitry to avoid accidents Instead use the ice to cool your hand down and then place this over the thermistor Ensure you hand is dry before touching it 86 Cha
126. of techniques that use similar ideas but are transferable to devices that have different applications at home We can now use these methods to build custom devices which we will look at now Next steps We have refreshed ourselves on the subjects covered so far Let s look at the future projects that you can try First we review the Prototyping Pi Plate We will then look at the Gertboard and provide some background on it Finally we ll provide some ideas for future projects that can use either the Cooking Hacks shield the Gertboard or the Prototype shield 130 Chapter 8 Prototyping Pi Plate The Raspberry Pi Prototyping Pi Plate shield is a kit provided by Adafruit industries and can be accessed from the following URL http learn adafruit com adafruit prototyping pi plate overview It allows you to create a prototyping shield that connects to the GPIO pins on the Raspberry Pi You will be familiar with this principle from the Cooking Hacks shield you used to build your previous projects Unlike the Raspberry Pi to Arduino shield this is a kit that needs to be soldered together By building this shield you will provide yourself with a platform that you can use for custom projects The Prototyping Pi Plate consists of a single board which is divided up between perfboard style and breadboard style pins Access to the Raspberry Pi GPIO pins is located around the edge of board where a number of screw terminals a
127. on httpd which provided a method for Linux servers to deliver content over the HTTP protocol After support for the HTTP daemon waned following Rob McCool s departure from NCSCA several users of the daemon came together and combined their patches using httpd Version 1 3 as a base This combination of patches into a single open source web server became known as Apache Apache provided a free open source alternative to the other web servers on the market We will be using Apache Version 2 x to host web based applications on our home network These applications can then be used to perform tasks such as write data to a database or provide a web interface to the data generated by our temperature sensors Now we have briefly looked at Apache and why we are interested in using it Let s get started with setting it up Setting up a basic web server If you are not already in a shell session after exiting SOLite3 open up the terminal window In the command line type the following sudo apt get install apache2 This will install Apache Version 2 x via the apt get tool While installing you will be prompted to continue a message will be displayed noting how much disk space will be used on your SD card by the installation process After this operation 4 990 kB of additional disk space will be used Do you want to continue Y n 94 Chapter 6 You can type Y to continue The installation process will complete and you will then
128. on and breaks the circuit from the plug to the fan After this the running flag is set to false The portion of our code that sets the relay on and off based upon the temperature is now complete We will now finish the modifications to our code by creating a URL with the temperature data we recorded stored in it Add the following block of code Call to the temperature database curlInst curl easy init if curlInst char url 40 The IP address below should be the IP address of your Raspberry Pi Sprintf url http 192 168 1 72 addtemperature temperature S f amp room 1 celsius curl easy setopt curlInst CURLOPT URL url result curl easy perform curlInst If our request fails output the errors if result CURLE OK fprintf stderr curl easy perform failed s n curl easy strerror result curl easy cleanup curlInst 84 Chapter 5 Here we initialize CURL and then create a new variable called ur1 which will store the HTTP address we are going to call Following this we use the sprintf function to create a URL string containing the Celsius reading from the thermistor The curl easy setopt function is then responsible for telling 1ibcurl how to behave Here we are setting the option for the URL this will be the value we stored in the ur1 variable given previously We then fire off the URL using the curl easy perform function The result of this call is stored in the result variabl
129. on and off when the temperature changes and to create a URL with the temperature data located in it Modify your new thermostat cpp file as follows Include ArduPi library include arduPi h Include the Math library include lt math h gt Include standard io include lt stdio h gt Include curl library include lt curl curl h gt 79 From Thermometer to Thermostat Building upon Our First Project In the preceding block of code we have included the stdio h file and the curl h file The stdio h file provides us with some tools for string manipulation Needed for Serial communication SerialPi Serial Needed for accessing GPIO pinMode digitalWrite digitalRead I2C functions WirePi Wire Needed for SPI SPIPi SPI Nalues need for Steinhart Hart equation and calculating resistance define TENKRESISTOR 10000 our 10K resistor define BETA 4000 This is the Beta Coefficient of your thermistor define THERMISTOR 10000 The resistance of your thermistor at room temperature define ROOMTEMPK 298 15 standard room temperature in Kelvin 25 Celsius Number of readings to take these will be averaged out to get a more accurate reading Xou can increase decrease this as needed define READINGS 7 Relay Pin define RPIN 4 Setpoint define SETPOINT 15 0 We have added two new constants to our code RPIN and SETPOINT RPIN 4 is the digital pin that our relay
130. on the Cooking Hacks shield We saw that we can take a third party shield and attach it to the Raspberry Pi This provided us with the ability via the Raspberry Pi s GPIO pins to control devices hooked up to the shield Chapter 3 Getting Started Part 2 Setting up Your Raspberry Pi to Arduino Bridge Shield and Chapter 4 Our First Project A Basic Thermometer covered connecting up devices via a breadboard and writing this data back to Raspberry Pi We covered writing applications that leverage this data and using a third party library to mimic many of the functions found in the Arduino programming language In Chapter 5 From Thermometer to Thermostat Building upon Our First Project we covered using the data that the Raspberry Pi had recorded to control another device in this instance a relay We also looked at how to use our device to control mains electricity So far these chapters covered the basics of interacting with our environment controlling it and tapping into our home s power supply Following this in Chapter 6 Temperature Storage Setting up a Database to Store Your Results we set up some technologies to record our data and store it Chapter 7 Curtain Automation Open and Close the Curtains Based on the Ambient Light brought together some of our techniques from earlier chapters and using an Arduino Motor Shield allowed us to control a DC motor You should see from the preceding part we slowly built up a set
131. oop return 0 e Remember that you can use both and for commenting your code 63 Our First Project A Basic Thermometer We have our reference to the setup function and to the loop function so we can now declare these and include the necessary code Below the main function add the following void setup void printf Starting up thermometer Wn Wire begin The setup function prints out a message to the screen indicating that the program is starting and then calls Wire begin This will allow us to interact with the analog pins Next we are going to declare the 1oop function and define some variables that will be used within it void loop void float avResistance float resistance int combinedReadings READINGS byte val0 byte vall Our temperature variables float kelvin float fahrenheit float celsius int channelReading float analogReadingArduino As you can see in the preceding code snippet we have declared a number of variables These can be broken down into Resistance readings These are float avResistance float resistance and byte valo and byte vali The variables avResistance and resistance will be used during the program s execution for recording resistance calculations The other two variables valo and vali are used to store the readings from analog 0 on the shield Temperature calculations The variables float kelv
132. or and dynamically generating shopping lists This combination of hardware software and information now provides the potential for the home to become part of an Internet of Things to quote Kevin Ashton Thanks to the open source and open standard technology being used in these devices it is easy to combine home brew projects built with the Raspberry Pi and commercial products by companies such as LG to build a smart home that creates a network of devices that can communicate with one another to combine the execution of tasks As we mentioned home brew systems such as the Raspberry Pi can form part of this network let s now look at the effects of the arrival of the Raspberry Pi on the world of home automation 20 Chapter 1 Arrival of the Raspberry Pi With the arrival of the Raspberry Pi and the Raspberry Pi to Arduino shield a set of open source technologies now exist that combine the power of the PC the communication and multimedia technologies of the web the ability to interact with the environment of a microcontroller and the portability of a mobile device This provides the perfect set of factors allowing us to build cheap devices for our homes that can interface with commercial devices but can be tailored for our own needs while also providing a great tool for learning about technology For those familiar with Arduino devices the Raspberry Pi combined with its shields provide an all in one medium for creati
133. ort for Xbee wireless radio communication modules Our Raspberry Pi comes equipped with an Ethernet port so we will not need to use these for any of our home automation projects If however you wish to switch out Ethernet for Xbee devices instead these are the connectors you can use Power source selector The power source selector is a small switch located on the side of the shield that can be used to enable an external power source UART The Universal Asynchronous Receiver Transmitter UART is the serial input and output port for your bridge shield and is marked with Rx and Tx This can be used to transmit serial data such as text and is useful for debugging code for example Digital GPIO pins The digital I O pins provide a place where you can hook up other electronic components For example you can solder a temperature sensor to pin 2 and then via the Arduino programming language read the data transmitted from it 14 Chapter 1 Serial Peripheral Interface SPI pins SPI pins can be used to connect a peripheral device to your Arduino shield The SPI includes the SCK Serial Clock MISO Master In Slave Out and MOSI Master Out Slave In pins In Circuit Serial Programmer ICSP connector The ICSP allows us to program the Arduino microcontroller For our project we will not need this as the Raspberry Pi will be taking the place of the Arduino microcontroller Power pins The power pins can be used w
134. orts larger SD cards such as those with 64 GB of storage space For the projects in this book you should be using an SD card with a minimum of 2 GB storage We will now look at the options available with regards to purchasing an SD card pre installed with the operating system and formatting and installing it ourselves Pre installed SD card versus a blank one Since the Raspberry Pi has been released a number of websites are offering preloaded SD cards that come installed with one of the operating systems that are available for the Raspberry Pi These are a good option for amateur enthusiasts looking to get started with the Raspberry Pi who do not want to go through the setup process and are happy with a pre loaded single operating system For our project though we are going to suggest that you purchase a blank SD card and follow the instructions in this chapter After you have finished formatting the card you will be introduced to an application called Berry Boot Berry Boot allows you to choose which operating system you would like to install This will set you up for future projects when you may wish to install more than one operating system or choose one other than the option that comes on a pre loaded card With this in mind though if you do not have a home PC or Mac to use in order to format a blank SD card we would recommend purchasing a pre formatted card This should come loaded with the Debian Wheezy Raspbian OS as this is the
135. ou to check out x software code from github which acts as a repository for various projects Once git is installed you can then clone the library from github In the terminal window type the following command git clone git git drogon net wiringPi This will create a copy of the wiringPi library on your machine You will find a makefile located in the wiringPi directory that will install the library on your system Once complete there are a number of examples you can try out One that may be of interest to you is test2 c in the example directory This program simulates PWM and if you connect a LED up to pin 2 you will see the LED slowly fade on and off The Prototyping Pi Plate and wiringPi library provide you with an interesting alternative to the Cooking Hacks shield Let s now look at another technology that is available for the Raspberry Pi the Gertboard 133 Wrapping up The Gertboard The Gertboard is a device that connects to the Raspberry Pi s GPIO pins like we have seen with the previous shields and provides the user with a variety of tools they can use to interact with electronic components The Gertboard was developed and named after Gert Van Loo Gert Van Loo while working with Ebon Upton at Broadcom took on the challenge of building a stripped down computer Using a multimedia optimized processor the BCM2835 he developed the prototype of the Raspberry Pi s alpha hardware Following from the succ
136. ould be presented with a window containing an empty pane This empty pane is where you can write code and load examples In the Arduino world this is known as a sketch 42 Chapter 3 You will notice on the top menu a small play button with a triangle in it When using the IDE to upload code to an Arduino board this button is used to compile the code and upload it to the microcontroller Since we are using the Raspberry Pi instead of an Arduino we will use a C compiler on the command line that will perform the role that the play button does in the IDE We will cover this in more detail when we come to write our first application For experienced developers there are a number of other tools available for creating and running Arduino applications A list of them can be found at http arduino cc playground Main DevelopmentTools If you own a Windows machine there is also a plug in for Visual Studio that allows you to modify the Arduino IDE skin and add your own buttons to it You could therefore expand the IDE toolbar to run custom commands that build your Arduino sketch with the arduPi library In this chapter we will use Leafpad to write our application and then compile it via the command line In Chapter 4 Our First Project A Basic Thermometer we will look at the Geany IDE and Makefiles which combine these functions A quick look at the language We are going to quickly take a look at a simple program written in the
137. ources reference link 149 Modwsgi URL 146 motor controller 136 motor shield components wiring up 117 setting up 117 my query variable 103 my response variable 103 N Negative Thermistor Coefficient NTC 55 Nest Learning Thermostat URL 147 Neurosky URL 148 Newark Element14 URL 129 Next Engine 3D scanner URL 148 O Ohms 55 open collector drivers 136 Open Remote URL 148 Open source automation URL 148 P Packt publishing homepage URL 147 params variable 102 photoresistor about 112 components wiring up 113 debug 117 motor shield and motors 112 setting up 112 testing with software 114 116 using 112 Positive Thermistor Coefficient PTC 55 POSIX threads URL 145 power pins Raspberry Pi to Arduino shield 15 power source selector Raspberry Pi to Arduino shield 14 pre installed SD card versus blank SD card 24 printed circuit board PCB 134 Prototyping Pi Plate about 131 132 building 131 reviewing 130 URL 131 pthread library 119 Pulse Width Modulation See PWM PuTTY about 35 on Mac and Linux users 36 on Windows 35 36 PWM 119 Python about 89 download link 145 online resources 145 URL 145 Python application creating for writing database 100 103 Python documentation URL 145 Python IDE 34 155 Python pip URL 145 Python script 16 Q query results variable 103 R Radio Frequency Identification See RFID chips Raspberry Pi arrival 21 background 8 9 core compo
138. ow we have our two tables in place let s add a room to the roomdetails table This could be the room that you have your Raspberry Pi thermostat running in In the following example we have used Kitchen as the value From within the SOLite3 shell execute the following command INSERT INTO roomdetails room VALUES Kitchen Now you can check to see if our room is present by using SELECT FROM roomdetails This command selects all values from the roomdetails table and displays them If you added Kitchen as your room you should see 1 Kitchen So we now have a room in our database with an ID of 1 that we can use when writing data back from the Arduino application 93 Temperature Storage Setting up a Database to Store Your Results In Chapter 5 From Thermometer to Thermostat Building upon Our First Project you may remember that we included the value 1 as the room ID parameter when executing Arduino code Also you may remember that we included a reference to a URL called addtemperature We will now set up a web server and create a script with this name that accepts that room ID parameter so that the Arduino shield can communicate with our new database From the shell type the following command to exit SOLite3 quit Apache web server The Apache web server was first developed in 1995 It sprung out of a project at the National Center for Super Computing Applications developed by Rob McCool called the HTTP daem
139. pen and Close the Curtains Based on the Ambient Light There is a conditional statement that checks whether the motor should be switched on or off If the variable is set to false then this means the curtain is either fully open or shut thus we switch the voltage applied to pin 3 to o Low We next need a function to control the motor s state This function pauses the thread updates the on off state and then restarts the thread void controlMotor boolean state pthread mutex lock amp pwmmutex off on state pthread mutex unlock amp pwmmutex This allows us to switch off the PWM at any point in our application that in turn stops the motor int main void setup while 1 loop delay 100 return 0 void setup pthread_create amp pwmthread NULL amp pwm NULL pinMode DIRECTION OUTPUT Wire begin To the setup function we have added two new statements One creates the new PWM thread and the second sets the direction pin stored in the DIRECTION constant to OUTPUT void loop byte val0 byte vall int channelReading float analogReadingArduino 122 Chapter 7 RRR ke ke ke kkk k kk ke ke ke k k k k ADC mappings Pin Address 0 OxDC al Ox9C 2 OxCC 3 0x8C 4 OxAC 5 OxEC 6 OxBC 7 OxFC KR KR KR RRR ee ke RR KK e x x OxFC is our analog 7 pin Wire beginTransmission 8 Wire write byte 0xFC Wire endTransmission
140. pter 5 If the fan switches off and on as the temperature changes then you have successfully built your first thermometer Debugging problems If the fan does not switch on there could be one of several problems You can then try the following steps 1 Check that the code compiled without any errors and started correctly 2 If your application was not running in screen and you logged out of the shell session then it probably shut down Try launching the thermostat program in screen 3 Make sure that you are applying enough of a change in temperature to the thermistor in order to exceed the setpoint 4 If none of the above works power down your Raspberry Pi and unplug the fan Check that the fan s wires run to the correct points on the relay and are secured correctly Completely power your Raspberrry Pi back up reconnect the fan and then try rerunning the thermostat application 5 If your relay needs an external power supply check if this is plugged in and connected Q Always remember to unplug the power when adjusting the connections to the relay to avoid an electrical shock Summary In this chapter we learned about relays and how they work We modified our existing code to expand its functionality This enabled it to switch the relay on and off based upon our temperature readings We also set our program up ready to write the temperature data to a database We launched this program in a screen session so that we can
141. r 6 Once we have a connection to the database we can run our query against it we achieve this by creating a cursor object and then executing the SOL stored in the my query variable The results from the query are then stored in the query results variable While we do not use this at the moment you can expand your script in the future to use this variable in the values returned to the browser For example if your query used a SELECT statement to return a value it would be stored here The my response variable that we declared earlier is now assigned a string containing the message that the values we sent to the script were inserted into the database Finally we close the connection to the database The except statement will return an error to the browser if a connection could not be established This could be because the path you declared in the connection variable is wrong or because your script does not have permission to open the database If you have problems with connecting to the temperature db file from your WSGI script these may be permissions related The database directory needs to be owned by the user www data Try setting the directory ownership to the www data user with the following command chown R www data var www You can also try using the chmod command and changing the permissions on the file While we would not normally recommend using this setting for a database file in general you can try the following
142. r based systems in the hands of the open source community Let s start by looking at what we will be covering in the coming chapters What we will explore in this book We have a number of exciting projects ahead that will slowly introduce you to home automation via the technologies of the Raspberry Pi and Arduino These projects include Writing software to control hardware Building a thermometer using a thermistor Turning the thermometer into a thermostat using relays Controlling electric motors using a motor shield Writing software for storing sensor data generated by your projects An Introduction to the Raspberry Pi Arduino and Home Automation By completing each chapter in the book you will gain a basic knowledge of building circuits and hardware for home automation projects You will learn about writing software to both control your projects and record the data generated by them Finally we will look towards future projects you can build with your new skills Our next step is to learn a little about the background of the technologies we are going to be using We will start with the Raspberry Pi History and background of the Raspberry Pi From the first vacuum tube computers to the tape and punch card machines of the 60s and the first microprocessor mainframes of the 70s computing had very much been the preserve of large businesses and university research departments However by the late 70s with the rel
143. r be moved to the UK with Sony taking over the process After several setbacks including the wrong Ethernet port being attached to the early batches and several compliance regulations having to be passed the Raspberry Pi was making its way into the hands of tech enthusiasts across the globe to a great reception So what exactly does the Raspberry Pi Model B you re holding include Raspberry Pi hardware specifications We will briefly go over some of the core components that make up the Raspberry Pi to give you a better feel for what it is capable of The Raspberry Pi is built off the back of the Broadcom BCM2835 The BCM2835 is a multimedia application processor geared towards mobile and embedded devices On top of this several other components have been included to support USB RCA and SD card storage 9 An Introduction to the Raspberry Pi Arduino and Home Automation We will now look at some of the core components of the Raspberry Pi board The following figure highlights some of these with a description of each provided GPIO Pins RCA Audio SD card port CPU GPU USB Micro USB Ethernet Power HDMI Dimensions The Raspberry Pi is a small device coming in at 85 60mm x 53 98mm x 17mm and weighing only 45g This makes it perfect for home automation where a small device can be placed in a case and mounted inside an electrica
144. r shield Analog 7 118 Chapter 7 Curtain control application We will now write an application that leverages the photoresistor and uses this to control the motor There are a few concepts we will cover quickly before we write the application in order to provide you with a better understanding of how our software works Pulse Width Modulation Pulse Width Modulation PWM is a method that leverages the digital pins to create an analog result If a digital pin is switched on it has a value of 5 V and if switched off it has a value of 0 V PWM allows us to simulate a value between these two ends Using our software we can create what is known as a square wave This method involves switching a pin on and off to create a steady signal to the device connected to the digital pin In our project this is a DC motor so varying the modulation that is changing the number of milliseconds that the pin is switched off versus on will result in a steady voltage being applied to the motor This results in a change of speed in the DC motor In order to create PWM in our application we will need to use threads We will look at these next Threads You may have noticed that when running our Makefile the compilation directives include a reference to 1pthread The pthread library allows us to create threaded applications A thread is essentially a fork in the program that can continue to run while the app
145. r side code such as Python we have to write and also provides us with a simpler syntax than SQL for querying a database You may remember we wrote the following SOL query for returning the values in our roomdetails table SELECT FROM roomdetails In order to execute this we had to be connected to our database via the SOLite3 shell or we would have to write a Python application with the query in and access it via WSGI To access the same data via HTSOL we would simply use roomdetails in the URL bar of our browser after the URL of our Raspberry Pi for example http localhost 8080 roomdetails An HTSQL server is very simple to set up on our Raspberry Pi so let us get started by installing the necessary packages Download HTSQL We are now going to install HTSQL however first we will need to install Python pip Pip is a Python based package management system that we will be using to install HTSQL sudo apt get install python pip A message will be displayed informing you that the installation will take 14 5 MB of disk space You can select Y and press Enter to continue with the installation process Once installation is complete we can use pip to install HTSQL Type the following in the command line sudo pip install HTSQL The HTSQL installation process will kick off and once complete we can check that it was successful In the command line type htsql ctl version 105 Temperature Storage Setting up a
146. re of by a header pin 4 We will now connect the data pin Run a wire from a digital data pin for example 4 to the relay If you are using a shield then all of the data pins will be connected 5 If your thermometer is not already connected reconnect it to the shield this time running the data wire to analog 7 instead of analog 0 74 Chapter 5 Finally if your relay requires an external power supply connect this Your circuit when connected should look similar to the following diagram Arduino to Raspberry Pi Shield Breadboard Resistor ermistor Digital Data 4 Analog 7 This circuit makes up the core of our thermostat For the moment we will not connect the fan to the relay but work on the software needed to run the thermostat We will also quickly test our relay to make sure everything is connected correctly Setting up our software Let s start with writing a simple program that opens and closes a relay connected to the Raspberry Pi Once we have confirmed this works we can then modify the application we wrote in the previous chapter to switch the relays on and off and construct a URL to post the data to the web A program to test the relay Load up Geany and add the following program to a file called Relay cpp in the same directory as your arduPi library Include ArduPi library include arduPi h Needed for
147. re fixed and also doubled up with standard pins located further in on the board The shield allows you to solder individual components to it and also place a miniature breadboard between the screw terminals for prototyping Using an example from Chapter 4 Our First Project A Basic Thermometer we could solder our thermometer components directly to the prototype shield and thus have a compact device that uses a single shield A comprehensive guide to soldering the shield can be found at the following URL http learn adafruit com adafruit prototyping pi plate solder it gt lt Remember to wear protective eyewear when soldering to avoid risk of injury to your eyes Also make sure to solder in a well ventilated area Let s look at the GPIO pin arrangement and naming convention on the Raspberry Pi so you can cross reference these with the Prototyping Pi Plate when you come to wire up your projects 131 Wrapping up This layout is based upon looking at the Raspberry Pi with the GPIO pins located at the top right corner of the board The pin arrangement is as follows 1 3 3v 2 Sv 3 SDAO 4 Not used 5 SCLO 6 Ground 7 107 8 TxD 9 Not used 10 RxD 11 100 12 101 13 102 14 Not used 15 103 16 104 17 Not used 18 105 19 MOSI 20 Not used 21 MISO 22 106 23 SCLK 24 CEO 25 Not used 26 CE1 The pins are located in two columns with each pin labeled with its role For
148. red result Debugging problems If the curtains aren t opening and shutting there could be one of several problems here e Check that the pulley wheel is attached tightly to the axle e Make sure that the drawstring is attached to the pulley wheel and is tight enough to have grip when the motor starts 126 Chapter 7 e If the motor is having problems opening the blinds and you are using a 9 V motor try upgrading to the 12 V motor e If the curtains are opening or shutting too quickly adjust the delay as described earlier in the chapter You now have an application and circuit that can control your curtains or blinds based upon the ambient light in the room Remember to check the tension of the drawstring as they may change over time and affect the accuracy of your open and close settings Summary This chapter introduced us to several new concepts including Pulse Width Modulation and using threads in our application We also learned how to use a photoresistor and read the values from it Another important step we performed was modifying our motor shield This provided an introduction to doctoring off the shelf Arduino shields to work with the Raspberry Pi Next we will wrap things up by reviewing what we have learned so far and looking at future projects that build upon the knowledge you have gained in building the various projects in this book 113 Wrapping up Throughout the previous chapters w
149. riods are coldest in a given room A table to record our rooms The second table we will create will store the name of the room in it This table can then be expanded in the future to include extra details about the room To start with though we will only need two columns Id This will be a unique ID for the room and will be incremented with each room added When we add data to the temperature table we will insert this room ID This way if we decide to rename the room we only have to make an update to a single value in one table rather than replace multiple instances which would be the case if we had recorded the room name next to each temperature reading in the temperature table e Roomname The second column we are adding is for storing the room name Here we can store a value such as bathroom or kitchen Writing some SQL Now that we have mapped out our two tables we can create them using SOL From the SQLite3 shell enter the following SOL command CREATE TABLE roomdetails id INTEGER PRIMARY KEY AUTOINCREMENT room VARCHAR 25 This command creates a new table called roomdetails it adds an ID column that takes integer values it is the primary key of the table and with each new value that is added the ID is incremented by one Next we will create the temperature table Type the following SOL command into the SOLite3 shell CREATE TABLE temperature id INTEGER PRIMARY KEY AUTOINCREMENT roomid INTEGER FOREIGN KEY roomi
150. rse this storage can be expanded upon using the USB ports 256 MB 512 MB SDRAM shared with GPU The Raspberry Pi comes equipped with 256 MB of SDRAM on older versions of the model B and 512 MB on the newer revisions This isn t a huge amount and much less than you would expect on a PC where RAM is available in gigabytes However for the type of applications we will be building 256 MB or 512 MB of RAM will be more than enough CPU Early in this chapter we touched upon ARM the British manufacturers of central processor unit CPU cores The Raspberry Pi comes equipped with a 700 MHz ARM1176 ZF S core part of the ARM 11 32 bit multi processor core family The CPU is the main component of the Raspberry Pi responsible for carrying out the instructions of a computer program via mathematical and logical operations The Raspberry Pi is in good company using the ARM 11 series and has joined the ranks of the iPhone Amazon Kindle and Samsung Galaxy GPU The graphics processing unit GPU is a specialized chip designed to speed up the manipulation of image calculations In the case of our Raspberry Pi it comes equipped with a Broadcom VideoCore IV capable of hardware accelerated playback and support for OpenGL 11 An Introduction to the Raspberry Pi Arduino and Home Automation This is especially useful if you want to run games or video via your Raspberry Pi or work on 3D graphics in an open source application such
151. s and technology we have provided several resources including those related to X10 X10 knowledge base http kbase xi0 com wiki Main Page X10 com http www x10 com homepage htm Nest Learning Thermostat http www nest com Android operating system http www android com 147 References Android developer resources http developer android com index html Open source automation Windows based http www opensourceautomation com Open Remote http www openremote org display HOME OpenRemote Honeywell for your home http yourhome honeywell com home Hackaday blog http hackaday com Iris Smart Kit http www lowes com cd Products 1337707661000 __ 3D printing 3D printing will provide home automation enthusiasts with the tools to build custom cases brackets gears and other tools for their systems The following links cover 3D printers and 3D printing services Makerbot 3D printers http www makerbot com Thingiverse http www thingiverse com Shapeways 3D printing on demand http www shapeways com Stratasys 3D printers http www stratasys com i materialise http i materialise com Next Engine 3D scanner http www nextengine com David 3D scanner http www david laserscanner com EEG headsets EEG headsets are an upcoming technology The following resources provide links to devices that can be bought and developed against Emotiv headset http www emot
152. s file with the name Makefile and then run it from the Build menu Once completed you can then run the application from the command line in the arduPi directory Relay If you listen to the relay you should hear a clicking sound This is the relay opening and closing This indicates that the relay is hooked up correctly and ready for us to write the thermostat program Next up we are going to install an application onto Raspbian called screen Screen allows us to run multiple windows within a terminal session that are not shut down when we close this session down For example if you now close the terminal window running your relay application then you will hear the clicking sound of the relay stop Ideally we would like to be able to close down a terminal window or end a shell session and leave our application running Installing screen Screen can be installed via apt get From the command line run the following sudo apt get install screen Once screen has completed installing we are going to change a few settings to make it easier to use Open up a new file in Geany and add the following configuration hardstatus on hardstatus alwayslastline hardstatus string B Lw c 50 gt n f t Lw lt defmonitor on shelltitle w Rename with ctrl a A This configuration allows us to give a title to each of the windows we create in a screen session and display this title at the bottom of the terminal window We
153. s for Windows 7 Mac OS X and Linux so you can re format the card if it is pre formatted or currently has data on it or format it for the first time if necessary As newer versions of operating systems are released sometimes menus are moved around In such instances you can usually find out where the SD card formatting instructions are online via Google or via the operating system s help menu Formatting instructions for Windows 7 The instructions that follow will guide you through formatting your SD card under the Windows 7 operating system Once complete you will be ready to install BerryBoot onto your SD card 1 Click on the Start button on the Windows taskbar 2 From the Start menu click on Computer 3 You will now be presented with a window containing a left hand panel listing items such as Favorites Libraries Computer and Network The right hand panel will show your PCs storage devices From the list of devices in the right hand panel right click on your SD card From the pop up menu left click on Format You will now see the Format Removable Disk popup From the File system drop down select FAT32 Default if not already selected ND FO e 8 You can leave the other settings dropdowns as they are 25 Getting Started Part 1 Setting up Your Raspberry Pi 9 In the Volume label text entry field type your SD card name as RASPBERRYPI 10 Check the Quick Format checkbox 11 You are now ready
154. s in place our next task will be to connect the thermistor 5 Insert one leg wire of the thermistor into the ground on the bus strip and place the second leg into the same row as you placed the resistor 6 The thermistor and resistor are daisy chained together with the supply voltage This leaves us now with the final task which is connecting up the analog pin to our daisy chain 7 Finally connect one end of your yellow wire from the analog 0 A0 on your shield to the terminal strip you selected for the preceding components Sanity check The setup of your circuit is now complete However before switching on your Raspberry Pi check that you have connected up everything correctly You can compare your setup to the following diagram Arduino to Raspberry Pi Shield Breadboard SV Resistor Thermistor Ground Analog O 57 Our First Project A Basic Thermometer Our thermometer circuit is now complete and you can now boot up your Raspberry Pi Of course without any software to return readings to the screen the circuit is little more than a combination of electronic components So let s get started on the software portion of our project Software for our thermometer Now that we have the hardware for our thermometer we will need to write some code that is capable of converting the values returned from the thermistor into a readable temperature in Cels
155. ser cgi e Apache web server http httpd apache org e Apache documentation http httpd apache org docs e Modwsgi http code google com p modwsgi 146 Appendix Electronics You can order electronic components online from a variety of sources These URLs are for major suppliers who stock the components used in this book We also provide some links to basic electronic guides Adafruit industries http www adafruit com Cooking Hacks http www cooking hacks com Makeshed http www makershed com Element14 http www element14 com RS Components http www rs components com Making Things introduction to electronics http www makingthings com teleo products documentation teleo user guide electronics html Wikipedia article on electronic symbols http en wikipedia org wiki Electronic symbol Packt Publishing titles Packt Publishing has a variety of books on many of the technologies used in this book We provide links to titles that may interest you Packt Publishing homepage http www packtpub com Expert Python Programming http www packtpub com expert python programming book Linux shell scripting cook book http www packtpub com linux shell scripting cookbook book 0 CherryPy Essentials Rapid Python Web Application development http www packtpub com CherryPy book Home automation technology For those interested in commercial and open source home automation application
156. st recent version of Backtrack 2 The first and only book that covers wireless testing with BackTrack 3 Concepts explained with step by step practical sessions and rich illustrations Metasploit Penetration Testing Cookbook Metasploit Penetration Testing Cookbook ISBN 978 1 84951 742 3 Paperback 268 pages Over 70 recipes to master the most widely used penetration testing framework 1 More than 80 recipes practicaltasks that will escalate the reader s knowledge from beginner to an advanced level 2 Special focus on the latest operating systems exploits and penetration testing techniques 3 Detailed analysis of third party tools based on the Metasploit framework to enhance the penetration testing experience Please check www PacktPub com for information on our titles
157. stems essentially the automation of the home and housework A history of home automation Concepts for home and building automation were around for decades before becoming reality and featured in the writing of the 19th century sci fi author HG Wells comics and cartoons such as the Jetsons American industrialist George Westinghouse helped to pioneer the AC Alternating Current electrical system which the X10 home automation standard would later run over and in 1966 the company that bears his name Westinghouse Electric employed an engineer who developed what could arguably be called the first computerized home automation system the ECHO IV The Electronic Computing Home Operator ECHO was featured in the April 1968 edition of Popular Mechanics and had been expanded from a set of spare electronics both in the physical and literal sense to include computing its founder Jim Sutherland s family household finances and storing their shopping lists amongst an array of other tasks You can still read the original Popular Mechanics article online at Google books http books google com books id AtQDAAAAMBAJ amp pg PA77 amp source gbs toc r amp cad 2t4 v onepage amp g amp f fal se The ECHO never went commercial and through the 60s hobbyists and a number of large companies such as Honeywell toyed with the idea of computerizing the home however it was the 70s much as with personal computing that saw the birth of the modern
158. t the most out of To send us general feedback simply send an e mail to eedbackepacktpub com and mention the book title via the subject of your message If there is a topic that you have expertise in and you are interested in either writing or contributing to a book see our author guide on www packtpub com authors 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 all Packt books you have purchased 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 4 Preface 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 would 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 support 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 on our website or added
159. tant to store the pin number of the pin on which we create a Square wave PWM on Now add the following code pthread t pwmthread pthread mutex t pwmmutex PTHREAD MUTEX INITIALIZER These declarations are used for the thread that we will generate when we create PWM on pin 3 The thread is stored under the variable name pwnthread Next we add in two Boolean variables that act as flags boolean off on boolean open state 120 Chapter 7 One is used to store whether the motor is switched on or off and the second records the open closed state of our blinds BORK KR KK k k RR k k RRR KR KR k k RR RR k k RK RRR k k k ke ke ke ke ke ke KK IF YOUR ARDUINO CODE HAS OTHER FUNCTIONS APART FROM getup AND loop YOU MUST DECLARE THEM HERE KR K k KR KR KK RR RK RR RR KR RR RR RR KR ke k k eee ke ke RK RR KR RK KK KAR KR KR KK RK k k k k k ke ke k YOUR ARDUINO CODE HERE KR RR RR RR RR RR RR KK KK RK void pwm void args while 1 if off on true digitalWrite 3 HIGH delayMicroseconds 100 digitalWrite 3 LOW delayMicroseconds 1000 100 else digitalWrite 3 LOW return NULL This function is concerned with the process of generating Pulse Width Modulation The while loop runs indefinitely and the code within it is tasked with switching pin 3 between HIGH and Low with a pause between each command to control speed 113 Curtain Automation O
160. te navigate to your home directory if not already there and then create a new directory within which we will work Type the following commands into your terminal window cd home pi mkdir database cd database This database directory will be used to store our temperature database for testing and for demonstrating how to use SQLite Once we set up our web server we will copy the database to a directory where the Apache can access it 90 Chapter 6 If you are already proficient with Linux and SQLite or as you gain experience with this technology you may wish to change the configuration of where your databases are stored and not keep it located with the website For the purposes of this project and to get you up and running with the technology we will keep the files in the same directory structure under the www folder however feel free to change this if you wish Creating a database To load SQLite you simply type the command line name sqlite3 followed by the database name and the extension db If it does not exist SOLite3 will create this database for you for example mydatabase db For our project we will name the database temperature On the command line type the following Sqlite3 temperature db You will now be dropped into the SQLite3 shell From the SQLite shell we can type commands that will create tables in the database and assign columns to them within which we will store data Before cre
161. ter company Acorn had grown to where 98 percent of mobile phones were using their technology This translated into around 1 billion CPU cores ARM technology would later end up being featured on the Raspberry Pi with the ARM ARM1176 ZF S processor core being used 8 Chapter 1 During the same period Ebon Upton designed several concepts for the Raspberry Pi and by 2008 thanks to a by product of the increasing penetration of mobile phone technology the cost of building a miniature portable microcomputer with many of the multimedia functions that the public were accustomed to was becoming viable Thus the Raspberry Pi foundation was formed and set about the task of developing and manufacturing the Raspberry Pi computer By 2011 the first Alpha models were being produced and tested and the public finally got to see what the Raspberry Pi was capable of Demos of Quake III Arena and full HD 1080p video showed that the tiny computer could pack a big punch for low cost Finally in 2012 the Raspberry Pi was ready for public consumption Two versions of the Raspberry Pi were scheduled to be manufactured namely models A and B with B being released first The model A board which will not include an Ethernet port and will consume considerably less power than the model B was given a price tag of 25 The model B that includes an Ethernet port was given a target price of 35 USD and manufacturing in China started This would late
162. ter you can try placing a finger over the sensor and once the threshold is passed the message will change to Getting darker 116 Chapter 7 Debug Experiment with the photoresistor if you have any problems with the sensor not working try the following steps e Check if the components are connected securely on the breadboard and shield Try changing the threshold in the application to ensure that you are providing enough variance between the darkness and light being applied to the photoresistor Setting up the motor shield The first part of the circuit is complete we have a device that can record the change in light and send this back to our application via an analog pin We now need to connect our photoresistor to the motor shield Once these are combined we will then have a device that can be used to control curtains or blinds Let s start by setting up our hardware Wiring up the components Unlike previous steps we will be making some small modifications to an Arduino shield Our motor shield uses pins 11 through 13 however the Raspberry Pi already has these pins set aside for SPI so we will need to disable some of the current pins on the motor shield You will also need to use your flat head screwdriver for some of these steps 1 Unplug the red black and yellow wires connecting your breadboard to the Raspberry Pi to Arduino shield 2 Bend the metal legs out on digital pins 4 5 6 11 12 and 13
163. the signals and adds to an inventory the groceries you have brought home On throwing out the empty cans and packaging the inventory system will be able to track these leaving the kitchen and remove them from the database Therefore inventory management of goods in the home will become an almost seamless process EEG headsets EEG headsets are devices that allow people to interact with their computers through thought This sounds like something from science fiction however products such as the Emotiv headset refer http www emotiv com and the upcoming Interaxon Muse refer http www indiegogo com interaxonmuse are carving the way for home EEG devices 140 Chapter 8 As software becomes widespread for EEG devices it will only be a matter of time before home automation projects are touched by this technology The ability to think the lights on is going to provide home automation enthusiasts with plenty of exciting projects A benefit of this will also be for the disabled who will be provided with ways to interact with their home With technologies such as these on the horizon we believe there will be many great opportunities to leverage the power of the Raspberry Pi and many exciting projects for enthusiasts such as you Summary The Raspberry Pi is an inexpensive computer with a lot of potential By choosing this technology you have provided yourself with a fantastic tool to build home automation projects
164. ther machines on your home network Summary We have now demonstrated a simple method for writing data to a database and to then be able to read it via our web browser This combination of technologies opens itself up to all sorts of interesting possibilities We could expand the SOLite3 database to hold more information about each of the rooms we plan to store data on We could expand our Python program to check that the data being written back to it is in the format we expect HTSQL opens up a variety of ways for writing interesting queries that we can use in our web browser to check our temperature readings and one of the benefits is we can save these queries as bookmarks in our browser and use them whenever we need Hopefully this chapter has provided you with an interest in learning more about Python HTSQL and SQLite so that you can expand your home thermostat project further 109 Curtain Automation Open and Close the Curtains Based on the Ambient Light In this chapter we will be looking at how to use a photoresistor and a motor shield in conjunction with your Raspberry Pi Once these are combined into a single device it can be used to open and close blinds or curtains In previous chapter we used temperature to change a relay s settings and in this chapter we will use the same concepts however we will use a photoresistor to turn a motor on and off What you will need for this chapter e Raspberry Pi e
165. ting up Your Raspberry Pi to Arduino Bridge Shield We are now going to demonstrate this by combining the Blink example with the arduPi template Blinking LED application Our next step is creating a custom application that combines the template code and the blink code with some modifications to work with the LED we wired up earlier You can think of the blinking LED test as the electronics equivalent of the simple Hello World application you learn to write when starting a new programming language Open Leafpad and enter the following code in Blink test cpp Include ArduPi library include arduPi h Needed for Serial communication SerialPi Serial Needed for accessing GPIO pinMode digitalWrite digitalRead I2C functions WirePi Wire Needed for SPI SPIPi SPI int main setup while 1 loop return 0 void setup pinMode 2 OUTPUT set pin 2 on the shield as an output This function will run in an infinite loop void loop digitalWrite 2 HIGH turn the LED on delay 1000 wait a second digitalWrite 2 LOW dim the LED delay 1000 wait another second Now lets walk through this code to see what our application is doing 48 Chapter 3 A guide to the code We will briefly go over the syntax we have used to create the blinking LED application It should be familiar to you from looking at the arduPi template cpp and the Blink ex
166. tions technologies in open source hardware devices Where as X10 appliances had no way of knowing if a signal had been successfully sent without the purchase of costly two way devices web technologies provide a whole framework for returning error codes and messages At approximately the same time as the Arduino platform we introduced earlier was being developed the first tablet computers were beginning to be released From 2005 until now there has been an explosion in mobile tablet and smartphone devices This growth has been commonly referenced to as the post PC era These devices have provided mobile computing platforms that can run complex software and be small enough to fit in the user s pocket As a result of this applications have been developed for the iPhone and Android that allow the user to control consumer electronics such as the TV Due to their size portability and in some cases low cost they have provided the perfect platform for interfacing with home appliances and devices and provided an extension to a medium the user is familiar with Along side the explosion in hardware there was also an equivalent explosion in software One particular product of interest that we will look at is the open source Android operating system 19 An Introduction to the Raspberry Pi Arduino and Home Automation The Android OS is a Linux based operating system geared towards mobile devices As part of the Open Handset Al
167. to format the card 12 Click on the Start button Windows will now format your SD card using the preceding settings Once successfully formatted you will be presented with a popup informing you that the process is complete Select OK to close the popup You are now ready to install BerryBoot on your SD card Formatting instructions for Mac OS X The steps that follow will walk you through formatting the SD card on a Mac OS X machine Once complete your SD card will be ready to copy over the BerryBoot application 1 2 3 4 eg ye 8 9 Open your Applications folder Select the Utilities folder icon From the open folder now select Disk Utility The Disk Utility window will now open On the left hand side you will see a list of Disks Volumes and Disk Images Select your SD card from the left hand menu Once selected you will be presented with information about the disk in the right hand panel From this panel select the Erase tab You will now be presented with a set of options for formatting your SD card From the Format drop down menu select MS DOS FAT 10 Name your SD card RASPBERRYPI 11 We are now ready to format the card 12 Click on the Erase button Mac OS X will now format your SD card using the specifications you provided You can now move onto the next step of installing Berry Boot 26 Chapter 2 Formatting instructions for Linux For formatting an SD card in Linu
168. ts to In conjunction with the SOLite database management system we will construct a repository for storing some of the results from our projects for example temperature data Finally we will also be using HTSOL Hyper Text Structured Query Language to provide a web interface to our database that is easy to query via the web browser HTSQL allows us to set up a server pointed to our database and then query it without having to write further server side code Now that we have looked at our tools for building home automation systems the Raspberry Pi and Arduino lets look at what home automation is 16 Chapter 1 What home automation is Having picked up this book you may already have an idea of what home automation is but just in case we ll give you a quick overview of the subject and the open source technology that is driving many projects out there today Home automation is more than just a remote control for your TV Examples include programming your DVR to record your favorite shows setting the AC unit to come on when it reaches 76 degrees Fahrenheit and installing a fancy alarm system that contacts the police in the instance of a break in Also known as domotics a portmanteau between domestic and informatics home automation can be summed up as the mechanism of removing as much human interaction as technically possible and desirable in various domestic processes and replacing them with programmed electronic sy
169. uipped with a fuse for current protection and internal temperature protection to help prevent overheating This removes the need to use a separate motor shield as we did in Chapter 7 Curtain Automation Open and Close the Curtains Based on the Ambient Light Open collector driver The open collector drivers are used to turn devices connected to the Gertboard on and off This is especially useful when the device connected requires a higher voltage than available via the Gertboard One common application of the OC driver is to hook up devices for displaying visual data such as a Vacuum Fluorescent Display VFD These are types of display you commonly find on home appliances such as your cooker or microwave and are used to communicate information such as cooking time and temperature Buffered I O The input output ports on the Gertboard are where you will connect up your buttons and LEDs These are controlled via jumpers which set the port to input or output mode The button for example is an input mechanism and the LED an output Switching on an LED will result in sending the command from the Raspberry Pi via an output to the Gertboard as an input A push button works opposite to this whereby an input from the button is sent to the Gertboard and an output from the Gertboard is received as an input to the Raspberry Pi When using jumpers it is important to think of the above in the following terms An input jumper means an input to
170. up on your electric system Wikipedia provides an overview of mains electricity that you can use as a starting point http en wikipedia org wiki Mains electricity Feel free to build the thermostat device and stop when it comes to the final steps of wiring it up if you do not feel comfortable with your ability You can always revisit this project at a later date if you wish With that said let s explore what a thermostat does Introducing the thermostat A thermostat is a control device that is used to manipulate other devices based upon a temperature setting This temperature setting is known as the setpoint When the temperature changes in relation to the setpoint a device can be switched on or off For example let s imagine a system where a simple thermostat is set to switch an electric heater on when the temperature drops below 65 degrees Fahrenheit 72 Chapter 5 Within our thermostat we have a temperature sensing device such as a thermistor that returns a temperature reading every few seconds When the thermistor reads a temperature below the setpoint 65 degrees Fahrenheit the thermostat will switch a relay on completing the circuit between the wall plug and our electric heater and providing it power Thus we can see a simple electronic thermostat can be used to switch on a variety of devices Warren S Johnson a college professor in Wisconsin is credited with inventing the electric room thermostat in th
171. vide some overviews of commands and packages used in this book Screen user s manual http www gnu org software screen manual screen html Raspbian package information http elinux org Raspbian apt get user manual http linux die net man 8 apt get Wget user manual http www gnu org software wget manual wget html Linux Kernel Archive http www kernel org Geany IDE http www geany org Make command manual http linux die net man 1 make Chmod manual page http linux die net man 1 chmod Chown manual page http linux die net man 1 chown 144 Appendix Python A variety of Python resources that are useful to you including information on the WSGI technology are available at the following links e Official Python website http www python org e Python documentation http docs python org e WSGl homepage http www wsgi org Python pip http pypi python org pypi pip e Download Python http www python org getit C C The following collection of links provide further information on the C and C programming languages e Cand C programming reference http www cprogramming com POSIX threads https computing llnl gov tutorials pthreads e G compiler http linux die net man 1 g Arduino We have provided some useful resources on the Arduino hardware and software that you can use to learn more about the open source technology e Official Arduino homepage http
172. ware 75 A program to test the relay 75 Installing screen TT cURL 79 Thermostat code 79 Testing our thermostat and fan 85 Attaching the fan 86 Starting your thermostat application 86 Debugging problems 87 Summary 87 ii Table of Contents Chapter 6 Temperature Storage Setting up a Database to Store Your Results 89 SQLite 89 Installing SQLite Version 3 x 90 Creating a database 91 Atable to record our temperature 91 A table to record our rooms 92 Writing some SQL 92 Apache web server 94 Setting up a basic web server 94 WSGI 97 Setting up WSGI 98 Creating a Python application to write to our database 100 Conclusion 104 HTSQL 104 Download HTSQL 105 Configuring HTSQL 106 Testing our Arduino shield with our database 108 Summary 109 Chapter 7 Curtain Automation Open and Close the Curtains Based on the Ambient Light 111 Photoresistors 112 Motor shield and motors 112 Setting up the photoresistor 112 Wiring up the components 113 Testing the photoresistor with software 114 Debug 117 Setting up the motor shield 117 Wiring up the components 117 Curtain control application 119 Pulse Width Modulation 119 Threads 119 Writing our code 120 Debugging problems 125 Connecting to your blinds curtains 125 Setting the timing 125 Attaching the hardware 126 Debugging problems 126 Summary 127 iv Table of Contents Chapter 8 Wrapping up 129 A brief review of what we have learned 130 Next steps 130
173. web server but like the graceful command does not abort existing connections The Apache web server is run under the www data user You may need to add a www data group and the www data user to this group in order for Apache to start You can do this by using the commands sudo addgroup www data and sudo usermod a G www data www data Further commands and help can be found in the manual man page for Apache Version 2 x To access this document type in the terminal the following command man apache2 To exit you can press Q Now that we have Apache Version 2 x installed and know how to access the manual let s try restarting the server gt You will need to prefix your commands with sudo in order to V perform tasks such as restarting the Apache server If you do not wish to do this you can switch user to root using sudo su root In the command line type the following command sudo apachectl restart You should now see the Apache server restarting Once complete we can check that it is indeed running by seeing if the test index html page located in var www is available via our browser Using your web browser navigate to either the IP address assigned to your Raspberry Pi by your router for example http 192 168 1 122 or navigate from the browser on your Raspberry Pi for example Midori to http 1ocalhost 96 Chapter 6 You should now see in your browser a web page similar to that in the following scr
174. will now see this in action 77 From Thermometer to Thermostat Building upon Our First Project Save this file to the root of your home directory with the name screenrc In the terminal window type the following command screen You will now see the screen welcome message You can press Space bar to exit We can now rename this window session from within screen by performing the following key command Ctrl A then Shift A Name this window Test screen Now perform the following command Ctrl A C This will create a second window Name this window Thermostat Your screen session should look similar to the following screenshot eoo andrew pi raspberrypi ssh 96x16 Pressing Ctrl A N will help you switch between the two windows You ve now seen how we can create windows rename them and switch between them Finally let s close the Test screen that we created Switch to this window and then type exit This window will now close and you will be taken back to the thermostat window Q Pressing Ctrl A D will detach you from an existing screen session If you need to reconnect to an existing screen session type screen r in the command line There is an extensive manual for screen that can be accessed via the man screen command 78 Chapter 5 If you need to load multiple applications you can create a new screen for each and run them from within it allowing you to switch
175. x we are going to use the mkdosfs program via the terminal window There are a number of tools available for formatting and partitioning disks in Linux The mkdos s program formats a device to use an MS DOS filesystem for example FAT16 or FAT32 For our project we need the SD card formatted in FAT to install Berry Boot so this tool is perfect for the job 1 2 3 ND a 10 11 Load the terminal window Type the command df h at the prompt You will now see a list similar to the following Filesystem Size Used Avail Capacity Mounted on dev diskl 465G 119G 345G 26 dev mmcblk0p2 7 3G 671M 6 3G 10 media SDcard Find the filesystem name of your SD card and note it down Also note down the directory it s mounted on If you are not logged in as root switch user to root using su In order to format the SD card you will need to un mount it In order to do this you will need to use the command unmount and pass it the filesystem name you noted for example unmount dev mmcb1k0p2 We can now use the mkdosfs command to format the SD card Type the following command mkdosfs dev mmcblk0p2 F32 Your SD card will now be formatted to FAT 32 Now remount the SD card using the filesystem name and mounted on name you recorded earlier mount dev mmcblk0p2 media SDcard Your SD card is now formatted and ready for copying BerryBoot onto it 27 Getting Started Part 1 Setting up Your Raspberry Pi

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