Home

Raspberry Pi Android Projects

1. isSendTurnOn true public void sendTurnOffCommand View v throws InterruptedException Your app will look similar to the following screenshot isSendTurnoff true REBOOT TURN ON TURN OFF The final version of the app Be patient to see the effects of the new buttons after clicking on them as it will take a few seconds for the messages to arrive in the Pi and for the the LED lamp to be turned on Playing sounds on your Pi To be able to play sounds on the Pi sound modules should be loaded on reboot To do this we need to add sound module specifications to the etc modules file Add snd bcm2835 in this file if it does not already exist there Tip You can use the 1smod command line tool to see which modules are loaded at the moment sudo modprobe snd_bcm2835 This command loads the sound module without rebooting for the contents of the etc modules file to take effect We even need to find an audio file to play which we can download using the following command cd wget http www freespecialeffects co uk soundfx sirens whistle_blow_01 wav You can now play this sound using the following command aplay whistle_blow_01 wav Tip Note that that the audio channel might default due to HDMI output and you may not hear anything on your 3 5mm jack In this case you can run the following command to set the default audio player to the 3 5mm jack amixer cset numid 3 1 The next step is to add the new w
2. BluetoothGattCharacteristic whistleAndTurnOnCharacteristic service getCharacteristic UUID_WHISTLE_AND_TURNON whistleAndTurnOnCharacteristic setValue whistleturnon gatt writeCharacteristic whistleAndTurnOnCharacteristic Next we ll reset the control variable in the onCharacteristicwrite method as follows isSendwhistleAndTurnOn false Now you will be able to see the LED lamp turned on and hear the whistle sound on the Pi as soon as your phone rings Note that our app needs to be started and visible for this to work This is caused by one of the two main issues with the code we have All the communication with the Pi through BLE should actually be done in side an Android service and phone events need to be handled inside BroadcastReceiver instead of in an activity Both of these implementations that is Pi communication and phone state interception should actually be separated from the activity An activity should actually be a UI component and nothing more However our intention here was to show you only the fun parts and be quick and dirty These further improvements on the Android code will be left as an exercise for you Summary In this chapter we covered a lot of content ranging from BLE implementations on the Pi to details of the Android BLE code We had great fun with the Pi and came up with a useful project that can be developed further In the next chapter we will learn more ways to make use of BLE equipm
3. final String value characteristic getStringValue runOnUiThread new Runnable Override public void run TextView tv if UUID_HUMIDITY equals characteristic getUuid tv TextView MainActivity this findViewById id humidity_textview else tv TextView MainActivity this findViewById id temperature_textview J Ia J Il tv setText value BluetoothGattService service gatt getService UUID_Service readNextCharacteristic gatt characteristic super onCharacteristicRead gatt characteristic status y In this callback implementation we override three important methods called from the Android system on different times The onConnectionStateChange method is called whenever a connection is established to the remote device through Bluetooth In this case we can initiate the service discovery of the device using the discoverServices method The onservicesDiscovered method is then called when services are discovered on the device In such a case we ll read to begin with the temperature characteristics for the sensor service that we ve defined on the Pi using the readCharacteristic method Whenever the value of the characteristic reading operation has succeeded the third overridden method onCharacteristicRead is called where we read the next characteristic which is humidity and then wait for this operation to succeed in the same method Then we take turns to read the humidity and tem
4. gpsd None class GpsPoller threading Thread def _ init__ self threading Thread init_ self global gpsd gpsd gps mode WATCH_ENABLE def run self global gpsd while True gpsd next class OBD_Sender def _ init__ self self port None self sensorlist 3 4 5 12 13 31 32 def connect self self port obd_io OBDPort dev rfcomme None 2 2 if self port print Connected to str self port def is_connected self return self port def get_data self if self port is None return None current 1 while 1 cell_list localtime datetime now cell sh cell current 1 cell value localtime cell_list append cell try gpsd next except print gpsd next error cell sh cell current 2 cell value gpsd fix latitude cell_list append cell cell sh cell current 3 cell value gpsd fix longitude cell_list append cell column 4 for index in self sensorlist name value unit self port sensor index cell sh cell current column cell value value cell_list append cell column column 1 try sh update_cells cell_list print sent data except print update_cells error current current 1 time sleep 10 json_key json load open home pi pyobd pi piandroidprojects json scope https spreadsheets google com feeds credentials SignedJwtAssertionCredentials json_key client_email json_key private_key scope while True
5. Any command line input or output is written as follows sudo apt get install apache2 sudo apt get install php5 libapache2 mod php5 sudo apt get install libapache2 mod auth mysql php5 mysql New terms and important words are shown in bold Words that you see on the screen for example in menus or dialog boxes appear in the text like this Initiate the connection by pressing the Connect button and you should now be able to see the Pi desktop on your Android device Note Warnings or important notes appear in a box like this Tip 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 disliked Reader feedback is important for us as it helps us develop titles that you will really get the most out of To send us general feedback simply e mail lt feedback packtpub com gt and mention the book s title in 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 at 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 from your account at http www packtpub com for all the Packt Publishing books you have purchased If you purchased
6. Raspberry pi Android Projects A mgb ipn mb Im m s pm ul u La us x m where ij i BAFA Rea vor in i i MELT a Te E m kaji L Fa LI IL Hi lr Ma K rl Ll y AA ei Ll If Ny Eie j LE I Oo iJ J het LA I Mitad Ma Mala da lar Android phone G khan Kurt l Ath open source Raspberry Pi Android Projects Table of Contents Raspberry Pi Android Projects Credits About the Author About the Reviewers www PacktPub com Support files eBooks discount offers and more Why subscribe Free access for Packt account holders Preface What this book covers What you need for this book Who this book is for Conventions Reader feedback Customer support Downloading the example code Downloading the color images of this book Errata Piracy Questions 1 Make a Remote Desktop Connection to Your Pi from Anywhere Prerequisites Installing Linux on your Pi Installing using NOOBS Installing using a Raspbian image Extracting the OS image to an SD card Making necessary changes in settings Installing necessary components in the Pi and Android Connecting the Pi and Android 4 Turn Your Pi into a Media Center Installing and setting up a media center on Pi 5 Missed Calls with Pi Installing the necessary components Index Raspberry Pi Android Projects Raspberry Pi Android Projects Copyright 2015 Packt Publishing All rights reserved No part of this book may be reproduced stored in a retrie
7. sudo apt get install libdbus 1 dev libdbus glib 1 dev libglib2 0 dev libical dev libreadline dev libudev dev libusb dev make mkdir p work bluepy cd work bluepy wget https www kernel org pub linux bluetooth bluez 5 33 tar xz tar xvf bluez 5 33 tar xz cd bluez 5 33 configure disable systemd make sudo make install The make step will compile the necessary packages needed for the Pi and will take about 15 minutes to complete However you ll need to be patient as it will lead to something cool and useful at the end Note that the latest version of BlueZ is 5 33 at the time of writing this book and you can instead replace it with the latest version by checking the list of all available versions at https www kernel org pub linux bluetooth Note here that we have disabled the systemd support using the disable systemd option which causes build errors otherwise The preceding commands have also installed some command line tools to let us configure and scan for Bluetooth devices The following command lists all the attached components on the USB ports of the Pi lsusb The output of the preceding command is as follows Bus 001 Device 002 ID 0424 9514 Standard Microsystems Corp Bus 001 Device 001 ID 1d6b 0002 Linux Foundation 2 0 root hub Bus 001 Device 003 ID 0424 ec00 Standard Microsystems Corp Bus 001 Device 004 ID Oa5c 21e8 Broadcom Corp Bus 001 Device 005 ID 148f 5370 Ralink Technology Corp RT5370 Wireless
8. t changed these parameters inside Kodi a de A a Manual configura nn Enter your media center configuration kurt 192 168 1 7 kodi Advanced configuration leave blank for defaults Use TCP g Use EventServer PREVIOUS lt Manual settings in Kore Getting more from your media center There are many things a media center can be used for You can for example download add ons that give you access to lots of online content such as YouTube Khan Academy and TED Talks Watching videos using Kodi on an Android device Another interesting thing you can do is to upload video from your phone to the Pi using the previously discussed AndFTP app from Server Management with Pi and then watch movies using the media center You need to add a directory on to the Pi where you will upload these files as a media location in Kodi Go to Videos Files Files and then navigate to Add Videos Here you should first select Browse and then Root filesystem Note that we were using home pi as the target for uploads in Server Management with Pi It should work even in this case Browse down to this location and click on OK on all three pop ups You should now see the Pi in the list of Videos on Kodi You can even add this folder to favorites for easy access Open the Kore remote control app and browse to the pi folder once again under Videos When the pi folder is highlighted in Kodi press the properties button in
9. try gc gspread authorize credentials break except print Error in GoogleDocs authorize t datetime now sh gc open CAR_OBD_SHEET add_worksheet str t year _ str t month _ str t day _ str t hour _ str t minute _ str t second 100 20 gpsp GpsPoller gpsp start o OBD_Sender o connect time sleep 5 o connect time sleep 5 o get_data The code begins running at the end where we define json_key by loading the JSON key file Then we ll try to authorize using the gspread authorize credentials method The next step is to create a new worksheet with the date timestamp as the title and then start to consume the GPS data in another thread defined by the GpsPoller class Next we ll initiate the OBD_Sender class and connect to the ODB Bluetooth device twice The connect operation may fail when it s executed for the first time but it almost always succeeds when it s run a second time Then we need to run the get_data method of the OBD_Sender class to begin the loop The GpsPoller class consumes all the values of the GPS device connected to the serial USB port This is required in order to get the most recent values whenever we access the gpsd fix latitude and gpsd fix longitude variables The get_data method of the OBD_Sender class sends the local time latitude and longitude values to the spreadsheet and it also sends seven different readings defined in self sensorlist 3 4 5 12 13
10. It is cool to see the streaming from your camera but it is much more useful to be able to run it in surveillance mode We want the camera to react to motion and save images or videos whenever motion is detected so that we can check them later instead of keeping an eye on the video For this purpose we will begin installing a motion recognition software on our Pi which is called for apparent reasons motion sudo apt get install motion This will install the motion software and the following command will add the necessary packages to the kernel sudo modprobe bcm2835 v412 It is a good idea to put this in the etc rc local file so that it can be run at startup You should put it before the exit 0 line though We will even make some configuration changes to be able to access the streaming and control features that motion provides Edit the configuration file of motion using the following command sudo nano etc motion motion conf By default the web access to motion is restricted to the localhost which means that you cannot access it from another computer other than the Pi itself We will change this behavior by finding the following lines in the motion conf file webcam_localhost on control_localhost on Note that these are not consequent lines in the file Also if you use nano as your editor you can press Ctrl W to put it into the search mode We will turn off the localhost only access behavior by replacing the preceding lines
11. 31 32 We can see these values from the SENSORS list in the obd_sensors py file For your information these are the Fuel System Status Calculated Load Value Coolant Temp Engine RPM Vehicle Speed Engine Start MIN and Engine Run MIL values We can change the indexes to read the values that we want Take a look at additional values at https en wikipedia org wiki OBD II_ PIDs We go through these codes read their current values and send them to the different cells of a current row on our worksheet After starting and driving your car around you can see that the data is uploaded to the spreadsheet as shown in the following screenshot E CAR_OBD_SHEET Goog x W CAR_OBD_SHEET M File Edit View Insert Format Data Tools Add ons Help Allchanges saved in Drive DOM TP s x o 091237 Aral m BISA BW BoR 8 19 2015 14 22 42 A 5 c D E 5768671273 11 90639285 CHING 410302 3137254902 186 8 19 2015 14 23 12 5768631771 11 90598166 5 480196078 186 3 729024239 NODATA 8192015 14 23 34 57 68608428 11 90568798 8 62745098 188 4 972032318 NODATA 8 19 2015 14 23 55 576856834 11 90528026 3921568627 188 124300808 NODATA 8 19 2015 14 24 23 5768546366 11 90504617 5 098039216 188 3 729024239 NODATA 8 19 2015 14 24 46 57 685173 11 90478185 6 274509804 190 3 729024239 NODATA 8 19 2015 14 25 10 57 68487147 11 90449767 5 098039216 194 3 107520199 NODATA 8 19 2015 14 25 30 5768457243 11 90435075 4 31372549 194 124300808 NODATA 8 19 2015 14 25
12. Adapter The Bluetooth adapter is named Broadcom in my case To get more details on a specific device use the following command sudo lsusb v d 0a5c Here note that oa5c is the first part of the address of the Bluetooth dongle that I am reusing to get more information on only this device The hciconfig tool will show you which devices support Bluetooth This command outputs the following information on my system hci Type BR EDR Bus USB BD Address 5C F3 70 68 BE 42 ACL MTU 1021 8 SCO MTU 64 1 DOWN RX bytes 564 acl 0 sco 0 events 29 errors 0 TX bytes 358 acl 0 sco 0 commands 29 errors 0 As seen here the device is marked as DOWN We will keep it this way as the next tool we install requires it to be down initially Note There are useful Bluetooth LE commands that you can use to check for other BLE devices We will not use these commands yet but it is a good practice to play with them to check if your BLE devices are working or accessible The same hciconfig tool that we ve used previously helps us bring the Bluetooth device up However do not do this if you want to proceed with the rest of the chapter as the next tool requires it to be down sudo hciconfig hciO up It is a good idea to put this command in crontab as discussed previously using crontab with the e option in order to let you use nano as the editor and install new crontab automatically Add reboot sudo hciconfig hcio up inside the file at the end an
13. Here is the definition for this task class RetrieveWorksheetContent extends AsyncTask lt WorksheetEntry Void List lt List lt Object gt gt gt Override protected List lt List lt Object gt gt doInBackground WorksheetEntry params WorksheetEntry worksheetEntry params 0 URL listFeedUrl worksheetEntry getListFeedur1 List lt List lt Object gt gt values new ArrayList lt List lt Object gt gt try ListFeed feed service getFeed listFeedUrl ListFeed class for ListEntry entry feed getEntries List lt Object gt rowValues new ArrayList lt Object gt for String tag entry getCustomElements getTags Object value entry getCustomElements getValue tag rowValues add value values add rowValues catch IOException e e printStackTrace catch ServiceException e e printStackTrace return values Override protected void onPostExecute List lt List lt Object gt gt values setUpMap values super onPostExecute values Here the most important part is where we iterate through feed getEntries which refers to all the rows in the spreadsheet and the part where we iterate through entry getCustomElements getTags refers to all the columns Then in onPostExecute we ll call the setupMap method with all the values that we have retrieved Inside this method we ll create markers on the map that is contained in MapsActivity Comment out the automatica
14. ID 0a5c 21e8 Broadcom Corp The next thing we need to install is a GPS daemon that receives location information from the adapter sudo apt get install gpsd gpsd clients python gps You might need to reboot in order to get the daemon to start Otherwise you can issue the following command to get it working immediately sudo gpsd dev ttyUSBO F var run gpsd sock The installation script has even provided us with a tool to see the current GPS location and the satellites that are in range through a text based window cgps S Tip The GPS receiver works best outdoors or with a clear view of the sky near a window The output on my system and in my location from the cgps command is shown in the following screenshot The output from the cgps s command Here you can see the GPS satellites that I in particular have in my view and my latitude and longitude as well as other useful information that is available through the GPS system Tip If you get a timeout error from the cgps command you need to restart the GPS daemon using the following commands sudo killall gpsd sudo gpsd dev ttyUSBO F var run gpsd sock If you get this timeout even though you have rebooted the Pi then you can put the following commands in crontab but there is even a better place to put these which will be described later on reboot sudo killall gpsd reboot sudo gpsd dev ttyUSBO F var run gpsd sock It is possible to get the location info
15. Pi and Android media center setting up Installing and setting up a media center on Pi e Plugable Installing the necessary components e port forwarding Connecting from anywhere e pyOBD pi tool Getting the car data to the Pi Raspberry Pi Foundation o URL Hardware and software configurations Raspbian Installing Linux on your Pi Raspbian image o URL Installing using a Raspbian image RaspiCam Remote app o about Streaming video to an Android device o VLC configurations manual Manual VLC configurations reboot command o sending from Android phone to Pi Sending the reboot command from your Android phone to the Pi remote console o to Pi from Android Remote console to the Pi from Android rooting o alternatives An alternative to rooting Screen Stream Mirroring Streaming the Android display to Kodi SD Association o URL Installing Linux on your Pi SD Formatter Installing Linux on your Pi Secure Shell SSH o about Remote console to the Pi from Android sensor o connecting Connecting the sensor sensor service o adding to Bluetooth Low Energy BLE Adding a sensor service to Bluetooth Low Energy servers o managing Simple management of servers sound command o playing Playing sounds on your Pi surveillance images o accessing on Web Accessing surveillance images on the Web surveillance mode o about The surveillance mode V e video o streaming to Android device Stream
16. and choose to include a Google Maps Activity during the last step of create project wizard I ve used Android 4 3 as the base SDK for this project I will name my main activity as MapsActivity To access Google Docs and download the content of the spreadsheet we will use some of the Java libraries provided by Google They are located at different places Download the ZIP files from the following locations e A general purpose Java client for Google data services is located at https github com google gdata java client and the file is named as gdata src java zip which is found under the Source link e Download the HTTP client from https developers google com api client library java google http java client download which is named as google http java client featured zip We will use this to authorize ourselves e Download the OAuth client contained in google oauth java client featured zip which is available at https developers google com api client library java google oauth java client download Now open these ZIP files locate the following JAR libraries and move them to the libs folder under your Android app directory gdata base 1 0 jar gdata core 1 0 jar gdata spreadsheet 3 0 jar google api client 1 20 0 jar google http client 1 20 0 jar google http client jackson 1 20 0 jar google oauth client 1 20 0 jar guava 11 0 2 jar jackson core asl 1 9 11 jar To include these libraries in your Android project you need to add
17. before We will not need any Activity for this application Create a new java file called StartTetheringAtBootReceiver for BroadcastReceiver and add the following code in it public class StartTetheringAtBootReceiver extends BroadcastReceiver public static void setWifiTetheringEnabled boolean enable Context context wifiManager wifiManager WifiManager context getSystemService Context WIFI_SERVICE Method methods wifiManager getClass getDeclaredMethods for Method method methods if method getName equals setwifiApEnabled try method invoke wifiManager null enable catch Exception ex ex printStackTrace break Override public void onReceive Context context Intent intent if Intent ACTION_BOOT_COMPLETED equals intent getAction Intent ACTION_POWER_CONNECTED equals intent getAction setwifiTetheringEnabled true context This piece of code receives broadcast events whenever the phone is booted or connected to a power source and enables tethering on the device with the default settings If we d like to change the name of the network or the password we ll need to modify the settings on the device Add the manifest definition for the new broadcast receiver to AndroidManifest xml inside the application tag lt receiver android name StartTetheringAtBootReceiver android label StartTetheringAtBootReceiver gt lt intent filter gt lt act
18. build essential libssl dev libffi dev python dev sudo pip install upgrade oauth2client sudo pip install PyOpenSSL The next step is to download and install the client library to access Google Sheets on the Pi using the following commands git clone https github com burnash gspread git cd gspread sudo python setup py install Before we begin coding we need to add a new spreadsheet on the https docs google com website Select Sheets in the menu create a new sheet using the plus sign and change the name from Untitled spreadsheet to CAR_OBD_SHEET It should be saved automatically We need to share this spreadsheet with the Google Developer Console client created for us when we generated the OAuth key pair We ll find aclient_email field in the JSON file we ve downloaded We will share the new spreadsheet with this client Now open the CAR_OBD_SHEET spreadsheet in Google Docs and click on the Share button J E CAR_OBD_SHEET Googli x W N C ff https docs google com spreadsheets d 1D0D51PUI6aM4IEO8siSRMVpM3nnM LE m SY 4 hh CAR_OBD_SHEET Bs piandrokiprojects gmail c v File Edit View Insert Format Data Tools Add ons Help Last edit was 20 minutes ago Comments EE mn Aa T 0 00 123 Arial v 10 X r ur v More Open the spreadsheet in Google Docs In the pop up window paste client_email from the JSON file then click on the Send button on the pop up window This will share the spreadsheet with the client gen
19. button and then the Choose from SD card option You should browse to the CWM Super User ZIP file that you have downloaded on to the SD card Finally choose Yes Reboot the device and you will see a new app called Super User which indicates that you have successfully rooted your device You can even verify that you have super user access to your device by downloading one of the Super User checker apps on Google Play You will see a message box asking you a question from the Super User app that we had installed from the previous step if you want to grant super user privileges to any other app asking to get those Enabling tethering on being connected to a power source As our phone hypothetically stays in the car all the time and only gets powered up when the car is being used we need to find a way to enable Wi Fi tethering or a hotspot as it is as well called whenever the phone is connected to a power source There are two cases that we might encounter though e The battery has run out and the phone is turned off at night Here we need to find a way to turn on the phone whenever it gets powered up again This happens when we start the car When the phone is successfully turned on we need to find a way to enable a hotspot e The phone still has enough battery to keep it turned on but as it hasn t been used the hotspot is disabled Note that the only device using the phone s hotspot is the Pi and it is turned off if the car isn t bei
20. chapter and will be needed to complete the project Raspberry Pi 2 Model B This is the latest addition to the Raspberry Pi family It has replaced the previous Pi 1 Model B The previous model should work fine for the purpose of the projects covered in this book MicroSD card The Raspberry Pi Foundation recommends using an 8 GB class 6 microSD card Android device The device should have at least a 1 5 or higher Android version which is required by the app used in this chapter In some of the exciting projects that follow we will need Android 4 3 or later versions HDMI cable This will be used to connect the Pi to a screen for initial set up Ethernet cable This will be used for network connections Computer This will be used to copy the Raspbian OS on to the microSD card USB mouse This will be used during initial setup The following image shows the Raspberry Pi 2 Model B Raspberry Pi 2 Model B Installing Linux on your Pi We will use Raspbian as the operating system on our Pi My choice is solely based on the fact that it is recommended by the Raspberry Pi Foundation It is based on the Debian version of Linux and optimized for Raspberry Pi hardware Apart from being the most used operating system for Raspberry Pi it contains almost 35 000 packages such as games mail servers office suite internet browsers and so on At the time of writing this book the latest release was dated May 5 2015 There are two main ways o
21. either use the following command to start the service or reboot your Pi which will start the service automatically sudo service motion start To check the status of all the services as well as the motion service you can use the following command sudo service status all Motion software comes in two parts The first part is where you can watch streaming videos and the second part is where you can see image video files when motion is detected You can see the stream from the motion software by opening the http IP_ADRESS_OF_THE_PI 8081 web page For some reason this part of the motion software only works in Firefox but the surveillance part discussed in the next section will work with other browsers Note that you cannot start both the motion server and VLC through the RaspiCam app at the same time as they use the same port The following screenshot shows the streaming of a motion video JPEG Image 320 x 240 pix X fa 77 105 238 132 8081 Transferring data from 77 105 238 132 A motion streaming video on port 8081 You can log on to Pi using AndFTP as discussed in the previous chapter and navigate to the tmp motion folder to see images saved whenever motion is detected Restarting the motion service will empty the contents of the folder Tip Add ports 8080 8081 and FTP port 21 to your port forwarding settings inside your router to access these services from outside your network Accessing surveillance
22. it to a computer through a USB Next we can download a software named Odin to upload a new recovery tool to the phone It can be downloaded from quite a lot of places on the Internet along with different versions The one we will use is called ODIN3_v1 85 zip and it is located at https www androidfilehost com fid 9390169635556426736 Another file we need is a kernel to replace the existing one that will help us with new ways of recovery operations This file is named Jeboo Kernel and can be found at http downloadandroidrom com file GalaxyS2 kemels JB jeboo kernel i9100 v1 2a tar As instructed on the recovery screen on the phone you should press the volume up button to put the device in the download mode Then start Odin and select the newly downloaded Jeboo Kernel as PDA You should see a COM box marked in yellow if the phone is correctly connected and is in the kernel download mode dh Odin3 v1 85 Android SLP Eo IS IIS IO ID E IO GE Option Control Panel Re Partition V Auto Reboot V F Reset Time Flash Lock ID PIT 1 Files Download Phone EFS Clear Phone Bootloader Update BOOTLOADER Message lt 10 0 0115 Add E C jeboo kernel 19100_v1 2a tar PHONE CSC File Dump Odin shows Jeboo as PDA and a connected device on com11 Click on Start to upload upload the new Jeboo kernel you have selected It should not take too much time before you get a PASS n
23. off the shelf module called Keyes DHT11 or DHT11 for short which contains these sensors Tip There is even an improved version of DHT11 which is DHT22 It costs a little bit more but has more accurate sensors on it Using this sensor module instead of the sensors itself will enable us to connect the sensors to the Pi using only three jumper wires and without a breadboard or resistor There is another advantage of using this module instead of the sensors the sensors provide analog data that the Pi cannot handle Pi is capable of handling digital information on its GPIO ports The DHT11 module does the conversion for us The following image illustrates the DHT11 sensor module along with a description of the pins associated with it DHT11 pins The DHT11 sensor module The following image illustrates the Keyes DHT11 sensor module The Keyes DHT11 sensor module Now connect the GND output from the sensor module to Pi s GPIO Ground 5V output to Pi s 5V pin and DATA to Pi s GPIO 4 pin The following diagram shows the layout of Pi s GPIO pins and their names vi vis OOO OO 25T s 17 I 99 1120121 8000 0008000 O00000 Raspberry Pi A B and Raspberry Pi 2 GPIO pins 4 GPIO O sound 3 3v Ds MP Raspberry Pi GPIO pin layout The next step is to read the values these sensors provide For this purpose we will use a widely used library from Adafruit which is specially designed f
24. open the app where you will get an initial view to provide login details such as the IP address username and password Note that by default it uses the default login account details and SSH port You will only need the IP address if you have the default installation in place You can even access your camera from the Internet if you enable port forwarding for port 22 as described in Chapter 1 Make a Remote Desktop Connection to Your Pi from Anywhere The following screenshot displays the login settings of the RaspiCam Remote app 0 Y E 19 37 192 168 1 7 Auto connect on startup Username Password eae 22 Recent connections 192 168 1 7 192 168 1 16 Reset login settings to defaults lt O Initial view for RaspiCam Remote app After waiting a few seconds you should see the first picture taken by the Raspberry Pi camera on your Android device On pressing the camera icon the camera will start streaming as shown in the following screenshot Do U Oy E 18 50 is Raspicam 192 168 1 7 Streaming from Pi The next step is to get better streaming quality using the H 264 setting After connecting to the RaspiCam Remote app you should open settings and check the H 264 checkbox However before connecting through the app again we need to install a VLC server on the Pi using the following command You may experience problems with the install commands from time to time but running it once again almost alway
25. our Pi and set up one of the most widely used media centers and control it remotely from our Android device In the next chapter we will get our hands dirty and begin some Python and Android programming and make use of even more connection possibilities between the Pi and Android Chapter 5 Missed Calls with Pi In this chapter we will implement a much more programming oriented project and dive into Bluetooth Smart or Bluetooth Low Energy BLE programming We will make the Pi and Android phones communicate through Bluetooth and control the Pi using this channel We will cover the following topics in this chapter Installing the necessary components Adding a sensor service to Bluetooth Low Energy Connecting from an Android app Sending the reboot command from your Android phone to the Pi Sending more commands from your Android phone to the Pi Installing the necessary components The hardware component needed for this project is aBLE enabled Bluetooth USB dongle It is important that this hardware supports BLE as we will specifically make use of this part of the Bluetooth stack We will use one by Plugable which is available on Amazon The Bluetooth dongle by Plugable The Raspbian distribution that we have downloaded already contains support for Bluetooth but we need to update Bluetooth packages for better LE support You can build and install a more modern of the Bluetooth package version using the following commands
26. prompt provided by ConnectBot You are now ready to issue commands on your Pi and check the status of different services This connection will be saved with all its properties Next time you want to log in you will not need to provide an address username and password information Note On a Mac or Linux you can use the ssh command installed on your system by default On Windows you can download PuTTY to issue the same commands as the ones in ConnectBot Exchanging files between the Pi and Android In the second part of this chapter we will use the Pi as an FTP server to share files between our Android devices or send files to the Pi to view them on a larger screen that you connect to the Pi HDMI port The FTP server we will use is vsftpd It is a lightweight FTP server used in many small projects To install it on our Pi we use the following command sudo apt get install vsftpd The preceding command will even start the FTP service However we should make some changes in the configuration of the FTP server to use it effectively For this purpose we need to edit the FTP server configuration file using this command sudo nano etc vsftpd conf Find the two lines containing local_enable YES and write_enable YES and remove the comment sign at the beginning of these lines before you save and exit These changes will enable the user pi to login and be able to send files to the Pi To restart the FTP server issue this command s
27. put them in the profile file if you want to continue without rebooting Then use the following command to download the Gatt package source files go get github com paypal gatt Now we will start a simple BLE server using the following command cd home pi gopath src github com paypal gatt go build examples server go sudo server Tip After completing this chapter you might want to put the server startup command inside crontab using the following command crontab e This way the BLE server will start each time you reboot the Pi Add the following line at the end reboot sudo home pi gopath src github com paypal gatt server It is now time to find our Raspberry Pi which behaves like a BLE device from Android We will use the BLE Scanner app by BluePixel Technologies and is available on the Play Store When you start it you will see a list of BLE devices available around you along with their addresses The address of the Bluetooth adapter on the Pi can be seen using the hciconfig command The default implementation of the Gatt server names the device as Gopher The following screenshot illustrates the BLE Scanner app showing the Pi as a BLE device 3H OO B 22 49 BLE Scanner O STOP BLE DEVICES UNKNOWN DEVICE 68 64 4B 0B 24 A7 81 mDb TYPE UNKNOWN NOT BONDED Gopher 5C F3 70 68 BE 42 47 mDb TYPE BLE ONLY NOT BONDED UNKNOWN DEVICE 73 20 50 09 E4 9A 101 mDb TYPE UNKNOWN NOT BONDED The BLE Scanner app sh
28. server is through the Secure Shell protocol known in general as SSH Note Secure Shell SSH is an encrypted network protocol used to send shell commands to a remote machine in a secure way SSH does two things for you It enables through different tools such as the ones we will present to you in a moment you to send commands to the remote machine and it does this using a secure channel established over an insecure network For SSH to work there should be an SSH server already running that can accept and respond to SSH client requests On Raspberry Pi this feature is enabled by default If by any means it is disabled you can enable it using the Pi configuration program by issuing the following command sudo raspi config Then navigate to ssh and hit Enter and then select Enable or disable ssh server On the client side and as we are using Android as our client throughout this book we will download an app called ConnectBot It is one of the most popular SSH clients on Android and the latest version as of today is 1 8 4 Download it to your device and open it You will need to provide the username and IP address that we found out in the previous chapter We do not need to provide the port as ConnectBot will use the default port for SSH in this case Click on Yes if you are asked to continue with the connection because of problems with the authenticity of the host You are asked this question because you are connecting to the Pi for
29. system The core BLE support is actually added to Android 4 3 and the code files distributed on the book s website as well as the GitHub repository of the book will work for Android 4 3 as well as Android 5 0 However for the sake of simplicity and ease the upcoming code is for Android 5 0 only Note that you should have downloaded Android 5 0 SDK during the Android Studio installation in order to be able to choose it in the create project wizard Take a look at the links we ve just mentioned in this section for further details on this Then choose to add a blank activity to the app and do not change the name of the activity in the next step we will keep it as MainActivity We will begin our implementation by adding Bluetooth permissions to the AndroidManifest xml file inside the manifest and before the application tag lt uses permission android name android permission BLUETOOTH gt lt uses permission android name android permission BLUETOOTH_ADMIN gt Then we ll begin making changes to the MainActivity java file Start by making the following class variable definitions private BluetoothAdapter bluetoothAdapter private BluetoothLeScanner bleScanner private BluetoothGatt bleGatt private static final int REQUEST_ENABLE_BT 1 private static final UUID UUID Service UUID fromString 19fc95c0 c111 11e3 9904 0002a5d5c51h private static final UUID UUID_TEMPERATURE UVID fromString 21fac9e0 c111 11e3 9246 0002a5d5
30. that looks like this Temp 25 0 C Humidity 36 0 Installing the database After verifying that the sensor and connections to the Pi work we will save the measurements in a database The database we will use is MySQL Use the following command to install MySQL to the Pi sudo apt get install mysql server python mysqldb During the installation you will be asked to set a password for the administrator account root I will set admin as the password and refer to it in the upcoming code The following command takes you into the MySQL shell where you can issue SQL commands such as inserting data into a database or querying data already in the database You should provide the password you have set when you re asked for it mysql u root p You can exit from the MySQL shell anytime using the exit command The next step in the MySQL shell is to create a database and use it for any further SQL Statement that follow mysql gt CREATE DATABASE measurements mysql gt USE measurements The following SQL statement will create a table in this newly created database that we will use to save sensor measurements mysql gt CREATE TABLE measurements ttime DATETIME temperature NUMERIC 4 1 humidity NUMERIC 4 1 The next step is to implement a Python script that reads from our sensor and saves it to the database Put the following code in a file with the name sense py under the home directory using the previously discussed nano command You
31. the playlpm file and make it an executable file We need to also remount the system directory in order to enable it for write operations mount o rw remount system mv playlpm playlpmbackup echo system bin sh gt playlpm echo sleep 60 gt gt playlpm echo system bin reboot gt gt playlpm chmod 0755 system bin playlpm chown root shell system bin playlpm mount o ro remount system Turn off the device and connect it to a power source You will see that it turns on automatically after one minute We have introduced the one minute delay because if the battery is totally discharged it will not have enough capacity to restart the device We want to wait at least one minute in these kinds of situations for the battery to get charged enough to restart the device If it is not charged sufficiently you might need to charge your phone before it can automatically restart You can charge the phone without getting it restarted by putting it in to the recovery mode and then begin charging it Auto tethering Now we are able to restart the device on connecting it to a power source We need to also enable tethering on the device when it wakes up or is connected to a power source There are apps on the market that already do this but the best ones are paid This is one of the reasons that we will implement our own app for this purpose The other reason is that it is fun We can create a new application in the Android Studio as we did
32. will be directed to the Google Developer Console E Getting started 3 C fi 8 https console developers google com start Google Select a project Sign up for a free tria O Qe o piandroidprojects gmail com s Getting started First steps Deploy a Hello World app Try out the VM quickstart GQ Enable Google APIs for use in your A EEEREN E PEL E O aa A nn apps App Engine lets yc uild and deploy an app pin up virtual machines using g ompute Engine Node js and MongoDB to create a Let your apps take advantage of Google guestbook app Create an empty project Create a Cloud Storage bucket ady ow to get started on you own Store your unstructured data safely and with higt vp right in and put your ideas into actior availability using Google Cioud Storage Pre built solutions MEAN stack f MongoDB Q Start with a prebuilt solution Application stack featuring MongoDB Express NoSQL document oriented database for aunch your favorite software packages on Angular and Node js integrating data ntent driven applications joogle id Platform with just a few cl The Google Developer Console start page Here we ll need to create a new project in the Select a project drop down menu Give it a suitable name accept the agreement and click on Create Select the newly created project APIs amp auth and then select APIs from the menu on the left hand side Then find and select Drive API and press the Enable API button Wh
33. you expand it you will see an option named CAMERA By pressing this button you will be able to start the camera and see the camera capture as well 20 20 Wednesday 26 August Mirroring is STARTED rtsp 192 168 1 10 5000 screen AN Pause Ml stop a CAMERA The Screen Stream Mirroring notification with the camera option Installing the media center using NOOBS Another option for installing the media center onto the Pi is using NOOBS This way users can very easily install the media center without worrying about details related to Raspbian OS as we did in this chapter We have already covered the NOOBS installation in Chapter 1 Make a Remote Desktop Connection to Your Pi from Anywhere However in Chapter 1 Make a Remote Desktop Connection to Your Pi from Anywhere we used the offline installation option We can use the online installation option instead You should download the online NOOBS installer from http downloads raspberrypi org NOOBS lite latest This ZIP file is much smaller but you need to connect the Pi to an Ethernet network before you begin installation Extract the contents of the file to an SD card and restart your Pi with this SD card inserted Now you will see a list of operating systems to install The list contains two media centers as well These are OpenELEC and OSMC Both are based on Kodi which we ve already covered in this chapter Summary This chapter was short but fun We have learned to install on
34. 51 5768423631 11 90429276 5 098039216 195 3 107520199 NODATA 8 19 2015 14 26 12 57 6838763 1190427707 3921568627 197 1 24300808 NODATA 8 19 2015 14 26 38 57683490377 11 90432007 3 137254902 188 1 864512119 NODATA 8 19 2015 14 27 02 5768320845 11 9043683 3 529411765 186 915 0 6215040398 NODATA 8 19 2015 14 27 26 5768294356 11 90441999 3 137254902 188 969 1 864512119 NODATA 8 19 2015 14 27 48 57 68253162 11 90447247 3 137254902 190 950 6215040398 NODATA 8 19 2015 14 28 09 5768188685 1190440314 3 137254902 194 961 6 215040398 NODATA 8 19 2015 14 28 30 57 68113195 1190383564 8 62745098 194 972 20 50963331 NODATA 8 19 2015 14 28 52 576796616 11 90115384 3137254902 192 957 9 322560597 NODATA 8 19 2015 14 29 16 5767948073 1189969305 3 529411765 6 8079552517 NODATA 8 19 2015 14 29 39 57 67859143 11 89760374 3 137254902 192 994 1305158484 NODATA 8 19 2015 14 30 06 57 67771248 11 89650553 6 666666667 190 1132 9944064636 NODATA 8 19 2015 14 30 28 5767641627 1189563947 1137254902 190 1566 2610316967 NODATA 8 19 2015 14 30 49 nan han 13 33333333 188 1842 3293971411 NODATA 1 ne 3 4 Ss 6 7 8 9 s388888835888838888888 e 2015 8 18 7_11_7 2015 8 187 20 42 2015 8 18 14 29 17 2015 8 18 14 41 40 20 4 i mn Fu Data uploaded to the spreadsheet Retrieving measurements We will build our very own app to download the measurement values and show them on a map Create a new blank project in the Android Studio
35. 9246 0002a5d5c51b HandleReadFunc func rsp gatt ResponseWriter req gatt ReadRequest out err exec Command sh c sudo home pi temperature py Output if err nil fmt Fprintf rsp error occured s err log Println Wrote error s err else stringout string out stringout strings TrimSpace stringout fmt Fprintf rsp stringout log Printlin Wrote stringout s AddCharacteristic gatt MustParseUUID 31fac9e0 c111 11e3 9246 0002a5d5c51b HandleReadFunc func rsp gatt ResponseWriter req gatt ReadRequest out err exec Command sh c sudo home pi humidity py Output if err nil fmt Fprintf rsp error occured s err log Println Wrote error s err else stringout string out stringout strings TrimSpace stringout fmt Fprintf rsp stringout log Printlin Wrote stringout return S We need to build and rerun our server code using go The following commands that we used earlier will help us do this Note that you should be in the home pi gopath src github com paypal gatt directory go build examples server go sudo server We can use the BLE Scanner app on Android again to connect to this new service and read the temperature and humidity sensor values The following screenshot illustrates the Gopher services 3 Zum 7 Eur DISCONNECT Peripheral Gopher RSSI 62 db Address 5C F3 70 68 BE 42 Status connected GENE
36. CS12 keystore load getResources openRawResource R raw piandroidprojects notasecret toCharArray PrivateKey key PrivateKey keystore getKey privatekey notasecret toCharArray GoogleCredential credential new GoogleCredential Builder setTransport httpTransport setJsonFactory jsonFactory setServiceAccountPrivateKey key setServiceAccountId 14902682557 e5eecriag0m9jbo500hnt59sest5694d developer gserviceaccount com setServiceAccountScopes SCOPES build service setOAuth2Credentials credential URL SPREADSHEET_FEED_URL new URL https spreadsheets google com feeds spreadsheets private full SpreadsheetFeed feed service getFeed SPREADSHEET_FEED_URL SpreadsheetFeed class List lt SpreadsheetEntry gt spreadsheets feed getEntries return spreadsheets get getWorksheets catch MalformedURLException e e printStackTrace catch ServiceException e e printStackTrace catch IOException e e printStackTrace catch GeneralSecurityException e e printStackTrace return null protected void onPostExecute final List lt WorksheetEntry gt worksheets if worksheets null worksheets size 0 Toast makeText MapsActivity this Nothing saved yet Toast LENGTH_LONG show else final List lt String gt worksheetTitles new ArrayList lt String gt for WorksheetEntry worksheet worksheets worksheetTitles add
37. In the onScanResult method of scanCallback add the following code in the if statement to enable these two buttons just after enabling the reboot button MainActivity this findViewById R id turnon_button setEnabled true MainActivity this findViewById R id turnoff_button setEnabled true In the onCharacteristicRead method of bleGattCallback add new else if statements to the existing check of the control variable for isSendReboot The new code will look similar to the following if isSendReboot BluetoothGattCharacteristic rebootCharacteristic service getCharacteristic UUID_REBOOT rebootCharacteristic setValue reboot gatt writeCharacteristic rebootCharacteristic else if isSendTurnOn BluetoothGattCharacteristic turnOnCharacteristic service getCharacteristic UUID_TURNON turnOnCharacteristic setValue turnon gatt writeCharacteristic turnOnCharacteristic else if isSendTurnoff BluetoothGattCharacteristic turnOffCharacteristic service getCharacteristic UUID_TURNOFF turnOffCharacteristic setValue turnoff gatt writeCharacteristic turnOffCharacteristic else readNextCharacteristic gatt characteristic In the onCharacteristicwrite method add the following code snippet to reset the control variables isSendTurnon false isSendTurnoff false Finally add new functions that can be called on click events for the new buttons public void sendTurnOnCommand View v throws InterruptedException
38. Index A e Android Central o URL Rooting Samsung Galaxy S2 e Android device using as access point Using your Android device as an access point rooting alternative An alternative to rooting Samsung Galaxy S2 rooting Rooting Samsung Galaxy S2 tethering enabling Enabling tethering on being connected to a power source automatic restart on power connect Automatic restart on power connect auto tethering Auto tethering data sending to cloud Sending data to the cloud e Android phone o reboot command sending to Pi Sending the reboot command from your Android phone to the Pi o more commands sending to Pi Sending more commands from your Android phone to the Pi e Android Studio o URL Connecting from an Android app O O O O O O 0 B e BLE Scanner app Installing the necessary components Connecting from an Android app e BluePixel Technologies LLP Installing the necessary components e Bluetooth Low Energy BLE o necessary components installing Installing the necessary components versions URL Installing the necessary components sensor service adding Adding a sensor service to Bluetooth Low Energy Android app connecting from Connecting from an Android app reboot command sending from Android phone to Pi Sending the reboot command from your Android phone to the Pi o more commands sending from Android phone to Pi Sending more commands from your Android phone to the Pi o LED command light
39. PHONE_STATE gt We also need new instance variables in MainActivity java private static final UUID UUID_WHISTLE_AND_TURNON UUID fromString 81fac9e0 c111 11e3 9246 0002a5d5c51b private volatile boolean isSendwhistleAndTurnOn false Then we need to get an instance of a system phone service and attach our own listener to it Add these two lines of code in the onCreate method TelephonyManager TelephonyMgr TelephonyManager getSystemService Context TELEPHONY_SERVICE TelephonyMgr listen new PhoneListener PhoneStateListener LISTEN_CALL_STATE Next define a local PhoneListener class class PhoneListener extends PhoneStateListener public void onCallStateChanged int state String incomingNumber super onCallStateChanged state incomingNumber switch state case TelephonyManager CALL_STATE_RINGING Toast makeText getApplicationContext incomingNumber Toast LENGTH_LONG show Toast makeText getApplicationContext CALL_STATE_RINGING Toast LENGTH_LONG show isSendwhistleAndTurnOn true break default break Here whenever we get a state change on the phone we check if this is a CALL_STATE_RINGING state If it is we can set the control variable for the newly created command in the same way as the button click event handlers did for previously defined commands Then we can add this additional else if statement in the onCharacteristic read method as well else if isSendwhistleAndTurnOn
40. PacktPub com Support files eBooks discount offers and more For support files and downloads related to your book please visit www PacktPub com 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 PacktPub com and as a print book customer you are entitled to a discount on the eBook copy Get in touch with us at lt service packtpub com gt for more details At www PacktPub 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 N PACKTI iR https www2 packtpub com books subscription packtlib Do you need instant solutions to your IT questions PacktLib is Packt s online digital book library Here you can search access and read Packt s entire library of books Why subscribe e Fully searchable across every book published by Packt e Copy and paste print and bookmark content e On demand and accessible via a 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 9 entirely free books Simply use your login credentials for immediate access Preface The most popular gadget in the maker community Raspberry Pi and the most popular smartphone OS Android combine their powers in this book resulting
41. Pi and the phone in the car all the time As soon as the car starts we want the data to be sent automatically and we do not want to carry around the Pi and a phone However if we leave the phone in the car and it is connected to the 12V power output the device will soon run out of battery and shut down Then we ll need to power it on manually and make changes in the hotspot settings again We want all these steps to be undertaken automatically For this reason we need a way to get the device powered on as soon as it is connected to a power source Or the power source it is connected to such as a 12V power output in the car wakes up when we start the car The techniques I will now present require that you have super user privileges to your Android device which means that we need to root the device An alternative to rooting An alternative to rooting a device is using a USB Wi Fi 3G modem to get Internet access in the car Note that most of the 3G USB modems in the market do not provide you with a Wi Fi network They only give network access to the computer into which they are plugged The one we need acts similar to a Wi Fi hotspot when connected to a USB power source You can find these at online retailers such as Amazon or AliExpress The one I personally use is shown in the following image The USB Wi Fi 3G modem If you choose to use one of these you may jump over the rest of this section and go directly to the next Ro
42. RIC ACCESS SERVICE 00001800 0000 1000 8000 00805f9b34fb Primary GENERIC ATTRIBUTE SERVICE 00001801 0000 1000 8000 00805f9b34fb Primary UNKNOWN SERVICE 09fc95c0 c111 11e3 9904 0002a5d5c51b Primary UNKNOWN SERVICE 19fc95c0 c111 11e3 9904 0002a5d5c51b Primary BATTERY SERVICE 0000180f 0000 1000 8000 00805f9b34fb Primary After connecting to the Gopher device you should see the newly added service with the 19fc95c0 c111 11e3 9904 0002a5d5c51b ID and new characteristics for that service as shown in the following screenshot ARO Fu 17 51 DISCONNECT Peripheral Gopher RSSI 62 db Address 5C F3 70 68 BE 42 Status connected UNKNOWN CHARACTERISTIC 21fac9e0 c111 11e3 9246 0002a5d5c51b UNKNOWN CHARACTERISTIC 31fac9e0 c111 11e3 9246 0002a5d5c51b Newly added characteristics one for temperature and the other for humidity measurements The following screenshot illustrates the characteristic details for temperature measurement after pressing the the Read button A WA 17 53 DISCONNECT Peripheral Gopher RSSI 59 db Address 5C F3 70 68 BE 42 Status connected Peripheral Gopher Address 5C F3 70 68 BE 42 Service UNKNOWN SERVICE UUID 19fc95c0 c111 11e3 9904 0002a5d5c51b Characteristic UNKNOWN CHARACTERISTIC UUID 21fac9e0 c111 11e3 9246 0002a5d5c51b Data Type 16BIT FLOAT Properties 0x0002 read Read Notification Write String 27 0 Decimal 38194 Updated 2015 08 02 17 53 24 328 Charac
43. RwdH7qYrQM3j04D 6thAHWMnETq4qjRRAgMBAAECggEAJjXXHrr6EdVSMnzXriPkRmA ZSz1AMrT NOiAWx90Jwtqn9q4KXSGajPM6gaytpvs83W08ewWX 8EQ 3fKjM9hwVwWWJG1R9irACrpN svb4U 9W2AnEQq1EC avngnfyxGoQaNn35F10QyWaDleP1PIJNLZdXvgc5tjyMFWfybwj slaCmRinj5nt V2aY gCEbe6km7L LKC3C7CesIWstUGMHCjh2aPeQT Hpodf23AnLZuSo34j nB 1SI RjnDsd HfazO0ga0Xa yK4S1iTaMWUBiMSXQcwZZsVp RLOVe6W2PSfi092An hATaaRnA8zB8fx7PnAltP hFwVr9 j jbYbq wypoyQKBgQDoLJytaR4wof46MUiL nMWr XDopi5dG2o0fUSXR JEIThe7yyYep ZZdWFL rXNEZD5X9Ucf CodwZOPKLN3u0t nZJ5Iq111bxwwZix5uVStRi6stgGaewF6nkDqN8y5 TJJgnZB9wSBUG3RVCU4zZwXKZ ngj 2 azwWme 7PSyOHKNODbBd9DkwKBgQDh e7nct49 Z00m kKN J NXUjJka S1yF7ninhL HZ2WU1gL8iQjXPxnCcx11Thw7C4rForH esOs f1XMje8NYi7ggslgxo XwFRH6 ny tuCRaY e62xmJAxj 208 InsvQQkSM dtuZiaNg3gCatHKbx2C6SVQal y3yuROc nO Oadgr6f CwKBgQDS1AvzGIFiwLsNqr CR SAbVbExm9EN3bhFgdROONC4 7M2BRe nvlUOPMLCN9 RecZR3syH8fPP1k1c6P7N6vqjAJ9yuIJKOrnjA owKTOjGBQn8HzwMTAnZM 536xWcC IXfDWONNQO 1887SGt2MAavgYYmA2RpLCq2Zw8torFE5NgUu 8wKBgQCeinAiwNy3S0JySu2EevidOcxYJ30zBw IT6p5Vj81UBjBhdkdn01 8qI6p3MFvwtKs8gbAYn rARBeYU9ncI5Jwl4WYhN5CYhWGUCUb28bRER Tp1jxpm10JRo8ns2vGOgpvour fe n78i50dLixklEdGONY j d9vNE MuHveZpvUxFmg8m 7QKBgC GVTkKOXWLpRxuYT M M n28LBgf tHxuOYZdXx8mU9xX6LQYG2aFxho7bkEYiEaNYJn51kdNZqzriIH ebxT dh z nddd5nR93E6WsPuqstZF4ZhJ 12m7 7wmG9u5gfRif rNpc3TKOISwydFPIMNVxMz d nl3cdqtiW6rvWSQoHCObrpcyYL n END PRIVATE KEY n client_email 14902682557 O5eecriagOm9jbo50ohnt59sest5694d developer gserviceac
44. SQL documentation for this purpose The next step is to change the file properties and make it an executable file with the following command chmod x sense py Note that this script saves only a single measurement We need to schedule the running of this script For this purpose we will use a built in Linux utility called cron which allows tasks to be automatically run in the background at regular intervals by the cron daemon crontab also known as CRON TABIe is a file that contains the schedule of cron entries to be run at specified times By running the following command we can edit this table crontab e Add the following line to this file and save it This will make the cron deamon run our script once every five minutes 5 sudo home pi sense py Installing the web server Now we will save our measurements into the database The next step is to view them in a web browser using a web server For this purpose we will use Apache as the web server and PHP as the programming language To install Apache and the packages required for our purpose run the following commands sudo apt get install apache2 sudo apt get install php5 libapache2 mod php5 sudo apt get install libapache2 mod auth mysql php5 mysql Then change your directory to the web server s default directory cd var www Here we will create a file that will be accessed by users through the web server we have installed The file is executed by the web s
45. a password to be used later on xi11vnc storepasswd Next we can get the x11vnc server running whenever the Pi is rebooted and the LXDE desktop manager starts This can be done through the following steps 1 Go into the config directory on the Pi user s home directory located at home pi cd home pi config 2 Make a subdirectory here named autostart mkdir autostart Go into the autostart directory cd autostart Start editing a file named x11vnc desktop As a terminal editor I am using nano which is the easiest one to use on the Pi for novice users but there are more exciting alternatives such as vi nano x11vnc desktop Add the following content into this file Desktop Entry Encoding UTF 8 Type Application Name X11VNC Comment Exec x1l1vnc forever usepw display 0 ultrafilexfer StartupNotify false Terminal false Hidden false Save and exit using Ctrl X Y Enter in order if you are using nano as the editor of your choice Now you should reboot the Pi to get the server running using the following command sudo reboot After rebooting using the sudo reboot command we can now find out what IP address our Pi has been given in the terminal window by issuing the ifconfig command The IP address assigned to your Pi is to be found under the etho entry and is given after the inet addr keyword Write this address down i raspberrypi Example output from the ifconfig command The ne
46. and after a few minutes we ll see that it is automatically connected to a hotspot on the Android device in the hotspot settings window hotspot lt LE Portable Wi Fi D IfsLabs Allow all devices to conn Connected devices raspberrypi 00 C1 40 48 11 58 192 168 43 78 How to connect from other devices 1 Turn on Wi Fi on the device 2 Find IfsLabs in Wi Fi network list 3 Connect to IfsLabs by entering lfsiabsuser 2 as the password 4 Enjoy Internet with portable Wi Fi hotspot Allowed devices Configure The list of connected devices is shown in hotspot settings in Android You must be wondering why we have covered this content at this point This is because in order to implement the next section you ll most probably need to sit in your car and communicate with the Pi inside your car where you most probably do not have more network access than the hotspot Android provides you with Now if you connect to the same hotspot on Android from your computer you will be able to SSH to the Pi with a tool called PuTTY that you can install on Windows machines or using built in SSH terminal tool on a Mac Sending data to the cloud We will use a Google Docs spreadsheet to save data and a special Python library developed for this purpose We begin doing this by creating an API key to access Google services Browse to https console developers google com project and create an account for this purpose When it s ready you
47. aracteristics we will send the reboot command to the Pi Let s begin by editing the sensor go file again and put the following code at the end of it s AddCharacteristic gatt MustParseUUID 41fac9e0 c111 11e3 9246 0002a5d5c51b HandlewWriteFunc func r gatt Request data byte status byte log Printlin Command received exec Command sh c sudo reboot Output return gatt StatusSuccess Build and restart the BLE server using the following commands cd home pi gopath src github com paypal gatt 90 build examples server go sudo server Now test the characteristics mentioned previously using the BLE Scanner app Whenever you write something to these characteristics the Pi will reboot The next step is to implement this new reboot function in the Android app that we have been building First add the UUID of the this new write characteristics we have just defined and a variable to control the operation sequences as shown in the following code private static final UUID UUID_REBOOT UUID fromString 41fac9e0 c111 11e3 9246 0002a5d5c51h private volatile boolean isSendReboot false The boolean variable isSendReboot will be used to initiate the write characteristic operation and orchestrate it together with the read operations previously defined The BLE stack cannot handle read write operations that are too close to each other and we want to avoid performing one operation before the previous one is comp
48. available on the Internet You need Raspberry Pi2 and an Android device In some chapters we will even use a USB Wi Fi dongle DHT11 or DHT22 temperature sensor jumper cables an LED light a USB Bluetooth dongle Pi camera USB GPS receiver and an OBD Bluetooth interface all of which are available on online stores Who this book is for Raspberry Pi Android Projects targets those of you who want to create engaging and useful projects with the Pi which are controllable through an Android phone No prior knowledge of Pi or Android is required At the end of each chapter you will have succeeded in creating a project that can be used daily and will be equipped with skills that could help you develop even more exciting projects in the future The projects covered in this book will contain some minor programming steps and these steps will be described in detail even for the most inexperienced readers Conventions In this book you will find a number of text styles that distinguish between different kinds of information Here are some examples of these styles and an explanation of their meaning Code words in text database table names folder names filenames file extensions pathnames dummy URLs user input and Twitter handles are shown as follows The next step is to install a component called x11vnc A block of code is set as follows networ k ssid THE ID OF THE NETWORK YOU WANT TO CONNECT psk PASSWORD OF YOUR WIFI
49. c3 generate bindto chart data x ttime xFormat Y m d H M S keys x ttime value temperature humidity ho json json axes temperature y humidity y2 axis x type timeseries tick format Y m d H M 17 y label temperature ty y2 show true label humidity lt script gt lt body gt lt html gt We want this page to be the default start page that web browsers get whenever they access the server directly with only an IP address You can back up the old default start page for Apache as follows sudo mv index html oldindex html Navigating to the IP address of the Pi from a browser will result in a view similar to the following screenshot after a few hours of sensor measurements Here I can access the Pi using the external IP address outside my home network as I have added the HTTP port of 80 to the port forwarding settings of my home router So el a le C fi D 77 105 238 132 2 2 z a G E 2 2015 08 20 21 50 2015 08 20 23 10 2015 08 21 00 30 2015 08 21 01 50 2015 08 21 03 10 2015 08 21 04 30 2015 08 21 05 50 2015 08 21 07 10 2015 08 21 08 30 2015 08 21 09 50 temperature W humidity Now we have a running FTP database and web servers Let s administer these using ConnectBot Simple management of servers The following command simply checks the status of the FTP server service vsftpd status This command
50. c51b private static final UUID UUID_HUMIDITY UUID fromString 31fac9e0 c111 11e3 9246 0002a5d5c51h The bluetoothAdapter definition represents the local device s Bluetooth adapter and lets you perform fundamental Bluetooth tasks such as discovering other devices and getting the properties of the discovered devices bleScanner provides methods to perform scan related operations specific to Bluetooth LE devices and bleGatt provides the Bluetooth GATT functionality to enable communication with Bluetooth Smart devices The UUIDs we have defined here are the same as the ones we have used in the sensor go file that we saved on the Pi previously for the identification of the new service and its two new characteristics Tip In the Android Studio you can use the Alt Enter shortcut key to automatically import missing packages The cursor should be located on the class for which the import is missing in the java file Or alternatively place the cursor on the class keep the mouse pointer on it and you will see a light bulb menu In this menu you can select the import class option Inside the oncreate method which is called by the Android system when the app starts for the first time we can initialize bluetoothAdapter BluetoothManager bluetoothManager BluetoothManager getSystemService Context BLUETOOTH_SERVICE bluetoothAdapter bluetoothManager getAdapter We need to define the startScan method that will be called whenev
51. can use the cd command without parameters to go back to the home directory from any place in the pi directory structure Note an important fact that the file should not contain any empty preceding lines which means that the line referring to the Python command should be the first line in the file The following code forms the content of our sense py file usr bin python import sys import Adafruit_DHT import MySQLdb humidity temperature Adafruit_DHT read_retry Adafruit_DHT DHT11 4 temperature temperature 1 8 32 fahrenheit print str temperature str humidity if humidity is not None and temperature is not None db MySQLdb connect localhost root admin measurements curs db cursor try sqlline insert into measurements values NOW 0 0 1f 1 0 1f format temperature humidity curs execute sqlline curs execute DELETE FROM measurements WHERE ttime lt NOW INTERVAL 180 DAY db commit print Data committed except MySQLdb Error as e print Error the database is being rolled back str e db rollback else print Failed to get reading Try again Note You should change the password parameter in the MySQLdb connect method call to the one you have assigned to the root user on the MySQL server You should even consider creating a new user with access to just the measurements table for security reasons as the root user has full access to the database Refer to the My
52. card to your Pi and connect it to a screen using an HDMI cable Do not forget to connect the USB mouse When the Pi is attached to a power source you will be presented with a list of choices you can make Check the Raspbian installation option on the list and then click on Install This will install Raspbian on your SD card and restart the Pi Installing using a Raspbian image The latest version of the Raspbian OS can be found at http downloads raspberrypi org raspbian latest The ZIP file is almost 1 GB in size and contains a single file with an img extension which is 3 2 GB in size Unzip the contents and follow the steps in the next section to extract it to a suitable microSD card Extracting the OS image to an SD card To extract an image file we need a disk imaging utility and we will use a freely available one called Win32 Disk Imager on Windows It can be downloaded at http sourceforge net projects win32diskimager On Mac OS there is a similar tool called ApplePi Baker available at http www tweaking4all com hardware raspberry pi macosx apple pi baker Download and install it on to your computer The installation will contain an executable file win32DiskImager which you should start in the administrator mode by right clicking on it and selecting Run as administrator In the Win32 Disk Imager window you should choose the image file you ve extracted and the drive for SD card similar to what is shown in the following scr
53. count com client_id 14902682557 O5eecriagom9jbo500hnt59sest5694d apps googleusercontent com type service_account We can choose to generate a new key from the Developer Console site using the Generate new JSON key button for our project At this stage we need to generate a P12 key using the Generate new P12 key button This file will be used later on We will also be provided with a secret key when we download the file which we need to note down The following screenshot illustrates the Google Developer Console after successful creation of the API key a 2 o sos x E J ee s console developers google com oldprojects Service account Client ID APls amp auth Email address Certificate fingerprints ent scree Pus Create new Client ID Monitoring Source Code Deploy amp Manage Key for Android applications Compute API key Networking Android applications Storage Activation date Big Data Activated by Google Developer Console after successful API key creations Before we can install the Google Python library we need to install a tool called pip which will help us install an OAuth client we will use to connect to Google services Use the following commands to do this curl O https raw githubusercontent com pypa pip master contrib get pip py sudo python get pip py Then use this new pip tool to install the OAuth clients sudo apt get update sudo apt get install
54. d save and exit There are two other commands we can use sudo hcitool lescan This command lists the BLE devices Now let s take a look at the following command sudo hcitool lecc 68 64 4B 0B 24 A7 And this command tests the Bluetooth connection to the device Note that the address provided to the latter command was returned by the former We will even need a programming support for Bluetooth We will use Go as the language and the Gatt package for Go that gives support for Bluetooth LE in the Go language The Generic Attribute Profile Gatt is a general specification to send and receive small amounts of data known as attributes over a BLE link Let s run the following commands to install the go language cd git clone https go googlesource com go cd go git checkout 901 4 1 cd src all bash You might want to go and grab a cup of coffee here as the last command will take about 40 minutes to complete At the end of the output you will see that the go installer asks you to add a binary directory to your path for easy access The following commands can accomplish this PATH PATH home pi go bin export PATH export GOROOT home pi go export GOPATH home pi gopath Tip It is a good idea to put these commands in the etc profile file in order to execute them for each session that you start in the future Be sure to add them at the end of the file though Also do not forget to actually execute them even though you have
55. dler for the bleGattCallback variable else if isSendwhistle BluetoothGattCharacteristic whistleCharacteristic service getCharacteristic UUID_WHISTLE whistleCharacteristic setValue whistle gatt writeCharacteristic whistleCharacteristic Add a new statement to reset the control variable in the onCharacteristicwrite method isSendwhistle false Now the whistle command is ready to be tested from our app Combining the commands and being informed on incoming calls In this last section we will combine the whistle and LED light up commands and initiate this new command whenever our phone rings By now we are used to creating new characteristics Here is a new one to be added to sensor go file s AddCharacteristic gatt MustParseUUID 81fac9e0 c111 11e3 9246 0002a5d5c51b HandlewriteFunc func r gatt Request data byte status byte log Println Command received to turn on and whistle exec Command sh c aplay home pi whistle_blow_01 wav Output exec Command sh c gpio g mode 17 out Output exec Command sh c gpio g write 17 1 Output return gatt StatusSuccess We can combine these two commands to save ourselves from the development details of sending two separate commands as a single transaction We need a new permission in the AndroidManifest xml file to get an incoming call state from the Android system lt uses permission android name android permission READ_
56. e Linux installation on Pi o about Installing Linux on your Pi NOOBS used Installing using NOOBS Raspbian image used Installing using a Raspbian image OS image extracting to SD card Extracting the OS image to an SD card O O M e media center O O O O installing Installing and setting up a media center on Pi setting up Installing and setting up a media center on Pi Kodi starting on boot Starting Kodi on boot connecting via remote control from Android Connecting to the media center via remote control from Android about Getting more from your media center Watching videos using Kodi on an Android device Streaming the Android display to Kodi installing NOOBS used Installing the media center using NOOBS N e NOOBS o URL Installing using NOOBS Installing the media center using NOOBS o used for installing media center Installing the media center using NOOBS O e OAuth client o URL Retrieving measurements e Odin Rooting Samsung Galaxy S2 e On board diagnostics OBD Collecting the car data e Pi O O O O 0 0 o prerequisites Prerequisites settings changes making Making necessary changes in settings components installing Installing necessary components in the Pi and Android and Android connecting Connecting the Pi and Android remote console from Android Remote console to the Pi from Android and Android files exchanging between Exchanging files between the
57. e and video files when motion detected accessed through the Web Summary We have moved away from administration of Pi to more real life projects and installed a camera on the Pi thereby viewing streams from the Pi on both an Android device and the Web We have even learned how to use the Pi as a surveillance camera and see motion detected by it We will continue using the Pi in an even more interesting scenario in the next chapter and turn itinto a media center Chapter 4 Turn Your Pi into a Media Center We have been administering our Pi and implementing useful projects in the previous chapters In this chapter we will use our Pi more as a source of entertainment and turn it into a media center The topics covered are as follows e Installing and setting up a media center on the Pi e Connecting to a media center via remote control from Android e Getting more from your media center e Installing a media center using NOOBS Installing and setting up a media center on Pi The media center software we ve chosen for the purpose of this project is Kodi formerly known as XBMC It is open source and widely used with lots of add ons As usual we will start by installing the necessary software on our Pi using the apt get command sudo apt get install kodi Then we ll run the kodi standalone executable which will start Kodi and show its user interface on the HDMI port of the Pi It is therefore important that you connect the Pi t
58. e commands have helped us to install a command line tool called gpio which you can now use to light the LED lamp gpio g mode 17 out gpio g write 17 1 You can turn it off using the following comand gpio g write 17 0 We need to add two new characteristics to our BLE server implementation the first to turn the light on and the second to turn it off Add the following lines to the end of the sensor go file and note that we have new UUIDs for each new characteristic that we create s AddCharacteristic gatt MustParseUUID 51fac9e0 c111 11e3 9246 0002a5d5c51b HandlewWriteFunc func r gatt Request data byte status byte log Println Command received to turn on exec Command sh c gpio g mode 17 out Output exec Command sh c gpio g write 17 1 Output return gatt StatusSuccess s AddCharacteristic gatt MustParseUUID 61fac9e0 c111 11e3 9246 0002a5d5c51b HandlewriteFunc func r gatt Request data byte status byte log Println Command received to turn off exec Command sh c gpio g mode 17 out Output exec Command sh c gpio g write 17 0 Output return gatt StatusSuccess Now build and restart the BLE server again If you have added the BLE server command inside the crontab you might need to reboot the Pi Next connect to the Pi using the BLE Scanner app again and use the Write button on characteristics section in the app to write values to these character
59. e will first download an app from Google Play that will stream an Android display and publish it using a URL on your internal network The app we will use for this purpose is called Screen Stream Mirroring and comes both as a free and a paid version For the sake of this project it is enough to download the free version After starting the app you will need to close a few advertisements and press the Start Now button on the pop up Se O FE 20 14 Screen Stream Mirroring STREAMING Media players Connect to the mirroring url with your media player VLC XBMC KODI OBS Android Stream Play to start mirroring Mirroring is PAUSED Mirroring available at e rtsp 192 168 1 10 5000 screen Screen Stream Mirroring Here you will see the address that the streaming is published to We will now save this rtsp YOUR_ANDROID_IP_ADRESS 5000 screen link in a file we will call stream strm on the Pi under the home directory of the user pi which is home pi Then browse to the pi directory in Kodi find this file and open it Remember that we have saved this directory under the Videos section in Kodi and as a favorite as well Now you should be able to see whatever you do on the Android device s screen attached to the Pi s HDMI port used by Kodi Another option here is to show the Android camera capture through this channel The Screen Stream Mirroring app we use has a notification in the Android notification area If
60. ed void onActivityResult int requestCode int resultCode Intent data if requestCode REQUEST_ENABLE BT startScan super onActivityResult requestCode resultCode data Override protected void onResume startScan super onResume Override protected void onPause if bleScanner null bleScanner stopScan scanCallback if bleGatt null bleGatt close bleGatt disconnect bleGatt null super onPause The onActivityResult method is called whenever a user enables Bluetooth and we need to start scanning in this case as well as every time the user starts an app where onResume is called If the user closes the app the Bluetooth connection can be stopped through the onPause method This is a great opportunity to test our the first version of our app that we have implemented so far and verify that it works Select Run app in the Run menu in the Android Studio and you will be given an option to select the location to install the app You will then see the Android device that you have attached to your computer in the list Sending the reboot command from your Android phone to the Pi Until now we have been receiving data from the Pi through BLE Now we will send commands to it using the same channel We will implement a new write characteristic in the same service as our temperature and humidity read characteristics are which were defined on the Pi Using these new ch
61. eenshot Eg Win32 Disk Imager Image File Device 3 2015 05 05 aspbian wheezy 2015 05 05 aspbian wheezy img 5 EN y y E MDS Hash Progress Version 0 9 5 The Win32 Disk Imager window Clicking on the Write button will start the process and your SD card will be ready to be inserted into the Pi Making necessary changes in settings When the Pi is still plugged into a screen with HDMI connect it to a network using Ethernet The first time the Pi starts you will be presented with a settings utility as shown in the following screenshot Raspberry Pi Software Configuration Tool raspi config Setup Options Ensures that all of the SD card storac 1 Change User Password Change password for the default user pi Enable Boot to Desktop Scratch Choose whether to boot into a desktop environment Scratch or the command line Internationalisation Options Set up language and regional settings to match your location Enable Camera Enable this Pi to work with the Raspberry Pi Camera Add to Rastrack Add this Pi to the online Raspberry Pi Map Rastrack Overclock Configure overclocking for your Pi Advanced Options Configure advanced settings About raspi config Information about this configuration tool 1 2 3 4 5 6 7 8 9 lt Select gt lt Finish gt Raspberry Pi Software Configuration Tool You can optionally select the first option in the list to Expand Filesystem Select the third option as well to Enable B
62. en it is enabled go to Credentials on the left hand side menu under APIs amp auth Credentials piandroidp C fi 8 https console developers google com project piandroidproj piandroidprojects OAuth No client IDs found Permissions APIs auth APIs Credentials Learn more Consent screen Push Create new Client ID Monitoring Source Code Deploy amp Manage Public API access No keys found Compute Networking Storage Big Data Learn more The menu to enable OAuth in the Google Developer Console Here under OAuth click on the Create new Client ID button In the message box that appears select the Service account and click on the Create Client ID button We ll see a box telling us that we have successfully created New public private key pair for the project We ll even see that the site has sent us a JSON file with credentials in it For the dummy account I created the contents looks similar to this private_key_id ed5a741ff85f235167015d99a1ladc3033f0e6f9f orivate_key BEGIN PRIVATE KEY nMIIEvg IBADANBgkqhkiG9wOBAQEFAASCBKgwggSkAgEAAOIBAQDM9Y J20t xwdhcL nQJ8ipZO uILkq9dzwDJ Jgt j SgFUXTJvj gzTDNa2wxGy9p9i4wuzr j50J1i M5dMwr n CVZCpsfV7Xt7igk eCEoOdN225HDiAXXMvWKhDsiof auOxLCTFLDnLZFWgAd55ec naENYQKp6ZEc6dGaA7Kp701 7L tEB2a4yqgZIelL6FfTSSLQqyV4770S2Dkq nz5Sz nRyTexcDWioDNp2vdGadqDfRKsI7ELwgwsc aV6j rbHz2uDuC844UnTL4wkMugpini n0ObTuGD11igldEIWLk2xXSLFkGfY301LYV7XwrUQGgc85AG
63. ent on the Pi and use our phones not just as Android devices but also as access points for the Pi Chapter 6 The Vehicle Pi We will continue to use Bluetooth on our Pi in this chapter to track the location and data from our car The following sections will be covered in this chapter Finding out the location of the car Using your Android device as an access point Collecting the car data Sending data to the cloud Putting it all together Finding out the car location In this chapter we will collect the engine data from our car but things will get more exciting if we can gather some for of location data as well For this purpose we will connect a USB GPS receiver to the Pi and receive our location through this piece of equipment We will use one of the cheapest receivers available in the market as shown in the following image The Globalsat BU 353 GPS receiver After connecting the GPS to the Pi you can issue the 1susb command to see if it is registered correctly The output from this command on my system is as follows and here Prolific is the GPS adapter Bus 001 Device 002 ID 0424 9514 Standard Microsystems Corp Bus 001 Device 001 ID 1d6b 0002 Linux Foundation 2 0 root hub Bus 001 Device 003 ID 0424 ec00 Standard Microsystems Corp Bus 001 Device 004 ID 148f 5370 Ralink Technology Corp RT5370 Wireless Adapter Bus 001 Device 005 ID 067b 2303 Prolific Technology Inc PL2303 Serial Port Bus 001 Device 006
64. er we want to initiate ascan of BLE devices private void startScan if bluetoothAdapter null bluetoothAdapter isEnabled Intent enableBtIntent new Intent BluetoothAdapter ACTION_REQUEST_ENABLE startActivityForResult enableBtIntent REQUEST_ENABLE_BT else bleScanner bluetoothAdapter getBluetoothLeScanner if bleScanner null final ScanFilter scanFilter new ScanFilter Builder build ScanSettings settings new ScanSettings Builder setScanMode ScanSettings SCAN_MODE_LOW_LATENCY build bleScanner startScan Arrays asList scanFilter settings scanCallback Here we check if Bluetooth is enabled on the device first If not we ll present a message box to let the user enable Bluetooth If it is enabled we ll get an instance of bleScanner which is used to start a scan using the startScan method We can give a callback implementation name such as scanCallback which will be called whenever a scan returns some results Now we need to define this callback variable as shown in the following code private ScanCallback scanCallback new ScanCallback Override public void onScanResult int callbackType ScanResult result if Gopher equals result getDevice getName Toast makeText MainActivity this Gopher found Toast LENGTH_SHORT show if bleScanner null bleScanner stopScan scanCallback bleGatt result getDevice connectGatt getApplicationConte
65. erated when we created the OAuth key pair in the previous step Poste e E CAR_OBD_SHEET Googl x YN gt C fi 8 https docs google com spreadsheets d 1D0D5 1PUI6aM4IEO8siSRMVpM3nnM yy E Sad Share with others Get shareable link co People 14902682557 05eecriagom9jbo500hnt59sest5694d Add more people Add a note Advanced Sharing the spreadsheet with the generated client Now we will test to see if everything works fine Create a file on the Pi name it send_to_sheet py and put the following content in it Do not forget to create the OAuth JSON file and put the contents of the one we have downloaded from the Google Developer Console and name it as piandroidprojects json import json import gspread from datetime import datetime from oauth2client client import SignedJwtAssertionCredentials json_key json load open piandroidprojects json scope https spreadsheets google com feeds credentials SignedJwtAssertionCredentials json_key client_email json_key private_key scope gc gspread authorize credentials t datetime now sh gc open CAR_OBD_SHEET add_worksheet str t year _ str t month _ str t day _ str t hour _ str t minute _ str t second 100 20 sh update_cell 1 1 0 23 Now run the file using the python send_to_sheet py command and we will see the update on the Google Docs sheet The code will create anew
66. erver and the result of this execution is sent to the clients connected We will name it index php sudo nano index php The contents should look like the following code Here you should again change the password for the MySQL user root to the one you have chosen in the call to the new mysqli constructor method lt php Create connection conn new mysqli localhost root admin measurements Check connection if conn gt connect_error die Connection failed conn gt connect_error sql SELECT ttime temperature humidity FROM measurements WHERE ttime gt NOW INTERVAL 3 DAY result conn gt query sql gt lt html gt lt head gt lt Load c3 css gt lt link href https rawgit com masayuki0812 c3 master c3 min css rel stylesheet type text css gt lt Load d3 js and c3 js gt lt script src https rawgit com mbostock d3 master d3 min js charset utf 8 gt lt script gt lt script src https rawgit com masayuki0812 c3 master c3 min js gt lt scrip gt lt head gt lt body gt lt div id chart gt lt div gt lt script gt lt php if result gt num_rows gt 0 2 gt var json lt php while row result gt fetch_assoc gt ttime lt row ttime gt temperature lt row temperature gt humidity lt row humidity gt lt gt lt php conn gt close gt var chart
67. f installing Raspbian You can either use the OS image as a whole or you can begin with an easy to use tool operating system bundle called NOOBS We will cover both cases here Note There are SD cards for sale with NOOBS or Raspbian already installed It might be a good idea to get one of these and skip the OS installation part of this chapter However before we begin we might need to format our SD card as previous OS installations may corrupt the card You ll notice this if only a fraction of free space on the card is shown to be available even though you have formatted the card using the formatting utility provided by your computer s OS The tool we will use is called the SD Formatter and is available for Mac and Windows from SD Association at https www sdcard org downloads formatter_4 index html Install and start it You will see the following interface asking you to select the SD card location iJ SDFormatter V4 0 Format your drive All of the data on the drive will be lost when you Ss ec format it GIs SD SDHC and SDXC Logos are trademarks of __SD 36 LLC Drive E y Refresh Size 734 GB Volume Label BOOT Format Option QUICK FORMAT FORMAT SIZE ADJUSTMENT OFF Format The SD Formatter interface Installing using NOOBS The latest version of NOOBS can be found at http downloads raspberrypi org NOOBS _ latest Download and extract the contents on to the SD card Attach the
68. i In order to use a Wi Fi dongle on the Pi first of all open the wpa_supplicant configuration file using the nano editor with the following command sudo nano etc wpa_supplicant wpa_supplicant conf Add the following to the end of this file networ k ssid THE ID OF THE NETWORK YOU WANT TO CONNECT psk PASSWORD OF YOUR WIFI Note I assume that you have set up your wireless home network to use WPA PSK as the authentication mechanism If you have another mechanism you should refer to the wpa_supplicant documentation LXDE provides even better ways to connect to Wi Fi networks through a GUI It can be found on the upper right comer of the desktop environment on the Pi Connecting from anywhere Now we have connected to the Pi from our device which we need to connect to the same network as the Pi However most of us would like to connect to the Pi from around the world as well To do this first of all we need to now the IP address of the home network assigned to us by our network provider By going to http whatismyipaddress com URL we can figure out what our home network s IP address is The next step is to log in to our router and open up requests to the Pi from around the world For this purpose we will use a functionality found on most modern routers called port forwarding Note Be aware of the risks contained in port forwarding You are opening up access to your Pi from all around the world even to malicious use
69. ield In the background method after loading the key file and defining the credentials we ll authorize ourselves to Google Spreadsheets service using OAuth We ll simply get the first spreadsheet that I assume is CAR_OBD_SHEET and return the worksheets in it We could go through all the spreadsheets and search for the title as well but I will skip this part of the code and assume that you have only one spreadsheet in your account with the title as CAR_OBD_SHEET The second function we ll define is onPostExecute This function is called inside the UI thread by the Android system whenever background processing is performed It is important that this is run in the Ul thread as we cannot touch Ul elements if we run Ul related code in non UI threads Note here that the return value of the doInBackground method is sent as a parameter to the onPostExecute method which is a list of worksheets found in a sheet in the Google Docs service We ll go through this list and collect the titles in another list Then we ll show this list in a pop up dialog box which a user can click on and select Whenever the user selects one of the worksheets Android calls the onc1ick method of DialogInterface OnClickListener which we have sent in as a parameter to the adapter of AlertDialog This method calls the execute method of another AsyncTask that we ll call RetrieveworksheetContent which as the name implies retrieves the content of the selected worksheet
70. ield The required information will appear under the Errata section Piracy Piracy of copyrighted material on the Internet is an ongoing problem across all media At Packt we take the protection of our copyright and licenses very seriously If you come across any illegal copies of our works in any form on the Internet please provide us with the location address or website name immediately so that we can pursue a remedy Please contact us at lt copyright packtpub com gt with a link to the suspected pirated material We appreciate your help in protecting our authors and our ability to bring you valuable content Questions If you have a problem with any aspect of this book you can contact us at lt questions packtpub com gt and we will do our best to address the problem Chapter 1 Make a Remote Desktop Connection to Your Pi from Anywhere In this project we will make a gentle introduction to both Pi and Android platforms to warm us up Many users of the Pi face similar problems when they wish to administer it You have to be near your Pi and connect a screen and a keyboard to it We will solve this everyday problem by remotely connecting to our Pi desktop interface The chapter covers following topics Prerequisites Installing Linux in your Pi Making necessary changes in settings Installing necessary components in the Pi and Android Connecting the Pi and Android Prerequisites The following items are used throughout this
71. images on the Web In almost all scenarios where surveillance is involved we want to access saved images from when motion was detected through the Internet To do this we will connect the directory to which motion saves images to the Apache Server we have already installed in the previous chapter Running the following command will do this trick sudo In s tmp motion var www motion You should also add this directory to which motion saves images and videos into the motion conf file using the following line in the file target_dir tmp motion Now open the http IP_ADRESS_OF_THE_PI motion link in a browser and you will see the image listing that motion has saved whenever motion is detected in front of the camera Note that you may get an access forbidden fault from the web browser if motion has not yet detected any motion and created the tmp motion directory The following screenshot illustrates the image listing that motion has saved Index of motion E C A D 77 105 238 132 motion Index of motion Name Last modified Size Description Parent Directory 01 20150824142751 00 pg 24 Aug 2015 14 27 9 1K 01 20150824142751 01 pg 24 Aug 2015 14 27 9 2K 9 01 20150824142751 swf 24 Aug 2015 14 27 25K 01 20150824142753 00 jpg 24 Aug 2015 14 27 9 2K 01 20150824142753 01 jpg 24 Aug 2015 14 27 9 2K 01 20150824142754 00 jpg 24 Aug 2015 14 27 8 9K s Mes 4 7 Apache 2 2 2 2 Debian Server at 77 105 238 132 Port 80 Imag
72. in exciting useful and easy to follow projects The projects covered come in handy in your daily interaction with the Pi and can be helpful as building blocks for even more amazing projects What this book covers Chapter 1 Make a Remote Desktop Connection to Your Pi from Anywhere teaches you how to make the initial setup to get started with your Pi and connect remotely to the Pi desktop from an Android device from anywhere in the world Chapter 2 Server Management with Pi builds on the previous chapter to manage the Pi and the different servers we install on it We will even introduce an interesting useful project on the way that makes use of these servers Chapter 3 Live Streaming of a Surveillance Camera from the Pi shows you how to turn your Pi into a webcam and then introduces you to the techniques to use it in surveillance mode which is accessible through an Android device and the Internet Chapter 4 Turn Your Pi into a Media Center shows you how you can turn your Pi into a media center that is controllable from an Android device Chapter 5 Missed Calls with Pi introduces the techniques required to access sensors and components on the Pi from Android through Bluetooth and shows how the Pi can notify you about the calls you receive on your phone Chapter 6 The Vehicle Pi helps you connect the Pi to your car and follow it from your Android phone What you need for this book All the software used in this book is freely
73. ing Lighting the LEDs o sound command playing Playing sounds on your Pi commands combining Combining the commands and being informed on incoming calls O O O O camera o hardware configurations Hardware and software configurations o software configurations Hardware and software configurations car data o collecting Collecting the car data o collecting from Pi Getting the car data to the Pi car location o finding out Finding out the car location ConnectBot o about Remote console to the Pi from Android cron Installing the database crontab Installing the database CWM Super User file Rooting Samsung Galaxy S2 D e data o sending to cloud Sending data to the cloud e database o and web server implementation A simple database and web server implementation o installing Installing the database E e ELM327 Bluetooth Collecting the car data F e files o exchanging between Pi and Android Exchanging files between the Pi and Android G e Generic Attribute Profile Gatt Installing the necessary components H e HTTP client o URL Retrieving measurements J e Java client o URL Retrieving measurements e Jeboo Kernel Rooting Samsung Galaxy S2 K e Keyes DHT11 DHT11 Connecting the sensor e Kodi o starting on boot Starting Kodi on boot e Kore Connecting to the media center via remote control from Android L e LED command o lighting Lighting the LEDs
74. ing video to an Android device o VLC configurations Manual VLC configurations e VLC configurations o manual Manual VLC configurations W e web server o installing Installing the web server e Wi Fi o using on Pi What if I want to use Wi Fi on the Pi e Win32 Disk Imager o URL Extracting the OS image to an SD card
75. ion android name android intent action BOOT_COMPLETED gt lt action android name android intent action ACTION_POWER_CONNECTED gt lt intent filter gt lt receiver gt Add the following permission declarations inside the manifest tag lt uses permission android name android permission CHANGE_WIFI_STATE gt lt uses permission android name android permission RECEIVE_BOOT_COMPLETED gt Now install this app to your phone and see if the tethering is enabled whenever you reboot the device or connect a power cable to it We can optionally add a shortcut button for tethering in MainActivity In the activity_main xml file add the following button definition lt Button android text string enable android layout_width wrap_content android layout_height wrap_content android onClick click gt Next in the MainAcitivty java file define the handler for the button public void click View v StartTetheringAtBootReceiver setwifiTetheringEnabled true this Next we need to connect the Pi to the hotspot that we have created so far Connecting the Pi to a Wi Fi network was covered earlier but let s remind ourselves about this concept again Add the upcoming lines of code to the etc wpa_supplicant wpa_supplicant conf file We can configure the hotspot to apply WPA PSK security instead of PSK2 network ssid YOUR_NETWORKID_FOR_HOTSPOT psk YOUR_PASSWORD_FOR_HOTSPOT Now we ll reboot the Pi
76. istics You will need to provide some text to write to otherwise the BLE Scanner app will not send commands Once you do this you will be able to turn the LED on and off Tip It is always a good idea to check the new characteristics you ve added in BLE Scanner app before you try to access it with the app that we are building This way we can be sure that we have added the characteristics correctly on the Pi side The next step is to implement this new function in our app We can begin by introducing two new buttons in the activity_main xml file lt Button android id id turnon_button android layout_width wrap_content android layout_height wrap_content android layout_below id reboot_button android text Turn on android onClick sendTurnOnCommand android enabled false gt lt Button android id id turnoff_button android layout_width wrap_content android layout_height wrap_content android layout_below id turnon_button android text Turn off android onClick sendTurnoffCommand android enabled false gt In MainActivity java define the new UUID and control variables for the new characteristics private static final UUID UUID_TURNON UUID fromString 51fac9e0 c111 11e3 9246 0002a5d5c51h private static final UUID UUID_TURNOFF UUID fromString 61fac9e0 c111 11e3 9246 0002a5d5c51h private volatile boolean isSendTurnOn false private volatile boolean isSendTurnoff false
77. iting the server go source file for the server example in the home pi gopath src github com paypal gatt examples path You only need to add three lines of code in the function definition for onStateChanged in between other service definitions In the following content note that the count service and battery service already exist We only need to add the sensor service A simple count service for demo si service NewCountService d AddService s1 A sensor service for demo sSensor service NewSensorService d AddService sSensor A fake battery service for demo s2 service NewBatteryService d AddService s2 Additionally in the same file change the line where new services are advertised to the following code in order to advertise the new service as well Advertise device name and service s UUIDs d AdvertiseNameAndServices Gopher gatt UUID s1 UUID sSensor UUID s2 UUID We need to add the definition for the new service also The following code should be placed in a file named sensor go under the service directory of the Gatt examples at the same level as other service definition files such as count go and battery go package service import fmt log os exec strings github com paypal gatt func NewSensorService gatt Service s gatt NewService gatt MustParseUUID 19fc95c0 c111 11e3 9904 0002a5d5c51b s AddCharacteristic gatt MustParseUUID 21fac9e0 c111 11e3
78. ktop based console to a text based one that gives more power to the user and lets you perform more advanced tasks compared to the desktop We will access the Pi s Linux console from an Android device and control it remotely In the second half we will send and receive files between the Pi and Android through FTP We will even combine the two parts by managing our newly installed FTP server remotely using the text based console In this chapter we will even install database and web servers on to the Pi to show how to manage them later on To make it even more fun we will implement a simple but useful mini project that makes use of both web and database servers The following topics will be covered Remote console to the Pi from Android Exchanging files between the Pi and Android A simple database and web server implementation Simple management of servers Remote console to the Pi from Android The administrators of Linux and Unix computers have been using text based command line interfaces called shell for many years to manage and administer their servers As the Pi s OS Raspbian is a Linux variant the most natural way to access and issue commands or check the status of running programs services and different servers on the Pi is again by issuing commands on this text based shell There are different shell implementations but the one that is used on Raspbian by default is bash The most well known way of accessing shell remotely on a Linux
79. lder size 0 bytes 2 items x Go up a folder W Desktop Current home pi W python_games LIST 150 Here comes the directory listing 226 Directory send OK The home directory of user pi Now you will be able to upload files from your Android device to the Pi by pressing the mobile phone like icon in AndFTP and choosing a file to upload afterwards You can set up AndFTP from another Android device on the same network or even another computer using a built in FTP client and download the newly uploaded file to view it this way you have shared your first file between different Android clients using Raspberry Pi as an FTP server A simple database and web server implementation Next we ll take our project one step further and install both a database and web server which we can administer later on using ConnectBot We will even make it more fun by implementing a real project that makes use of these servers The best candidate for this purpose is a sensor measurement scenario We will connect a temperature humidity sensor to our Pi and save the measurements into a database that we will install on the Pi which a web server will make available to clients We can later on manage these servers remotely which is the main objective in this chapter Connecting the sensor For the purpose of this project we will use a sensor DHT11 which measures both temperature and humidity but for the sake of easier connections we will use an
80. leted Then in the onCharacteristicRead function of bleGattCallback change the line where we call readNextCharacteristic with the following piece of code if isSendReboot BluetoothGattCharacteristic rebootCharacteristic service getCharacteristic UUID_REBOOT rebootCharacteristic setValue reboot gatt writeCharacteristic rebootCharacteristic else readNextCharacteristic gatt characteristic Here we will write a value reboot to the reboot characteristic if the control variable is set by clicking a button that we will soon implement We can override another method in bleGattCallback Override public void onCharacteristicWrite BluetoothGatt gatt BluetoothGattCharacteristic characteristic int status isSendReboot false readNextCharacteristic gatt characteristic super onCharacteristicwWrite gatt characteristic status This method is called whenever the write characteristic operation succeeds when we reset our control variable and continue with the read operations Those of you who are observant might see a minor problem with this code namely that we are sending a reboot command to the Pi but at the same time we re also trying to read characteristics from the Bluetooth device located on the same device that we are trying to reboot These readings will not work when the Pi reboots and our app will not be able to reconnect if we do not close and reopen it after the reboot has been completed successf
81. lly defined setupMap method if you do not want a marker at location 0 0 which Android Studio has defined for you as an example private void setUpMap List lt List lt Object gt gt values for List lt Object gt value values String title values get 0 toString try double latitude Double parseDouble value get 1 toString double longitude Double parseDouble value get 2 toString if latitude 0 amp amp longitude 0 mMap addMarker new MarkerOptions position new LatLng latitude longitude setTitle title catch NumberFormatException ex When you start the app you will see a list of spreadsheets to choose from U Oy 10 15 Select a worksheet 2015_8_11_18_40_19 2015_8_11_19_15_32 2015_8_12_7_59_54 2015_8_12_16_49_8 2015_8_15_11_12_56 2015_8_15_11_37_23 2015_8_16_7_55_19 2015_8_16_12_33_1 2015_8_16_13_3_3 2015_8_16_16_19_20 2015_8_16_18_43_12 2015_8_16_19_33_9 The list of spreadsheets Next after selecting one of these sheets you can see the data on the map A PE 10 19 on a storabillingen 4 perget Hagen Torp re The data points on the map Summary In this chapter we covered a lot of content ranging from car diagnostics to Android device root process We even covered a lot of Android code I hope that all of you have fun implementing these exciting projects will try to enhance them and making them better than I did
82. n connect the remote control application on Android to the Kodi installation on the Pi you need to make some setup changes on Kodi Go to the SYSTEM menu in Kodi and then Settings Services and Webserver Here you should select Allow control of Kodi via HTTP Then go to the Remote control settings in same menu and enable the Allow programs on this system to control XBMC and Allow programs on other systems to control XBMC settings Now open Kore on Android and let it search for the media center If both the phone and media center are on the same network Kore should be able to find it When succeeded with the search you will see a view similar to the following screenshot Tip Note that the default HTTP port for Kodi collides with the motion server s default HTTP port which we saw in the previous chapter You should either change the port setting in Kodi or stop the motion server before making these changes in Kodi s settings VICUIG found these media centers on your network Select one to add or press Next to manually add a new one Kodi raspberrypi 192 8 1 8080 SEARCH AGAIN lt Kore has found the media center Now click on the newly found media center to connect and start controlling it remotely If it does not identify the media center automatically you can press the Next button and enter the parameters manually Port 8080 is the default port and kodi is the default username you should use if you haven
83. na followed suit in 2008 and by then some light vehicles in China were required by the Environmental Protection Administration Office to implement OBD On most cars the OBD interface is found under the steering wheel On a Toyota Aygo from 2008 it is found on the right hand side under the steering wheel Some car manufacturers do not have standard port connections So you might have to buy an extra OBD converter cable The port in the car looks like this The OBD connection in the car We will connect an ELM327 Bluetooth sender to this OBD connection and the Bluetooth dongle from the previous chapter to the Pi and make the two communicate The ELM327 is aprogrammed microcontroller produced by ELM Electronics to translate the on board diagnostics OBD interface The ELM327 command protocol is one of the most popular PC to OBD interface standards implemented You can buy one of these pieces of hardware in any price range with different properties on Amazon The one that I have is by Goliton The ELM 327 OBD Bluetooth sender The easiest way to get data from a car is to use an app on Android that can translate the data for you Search for OBD on the Play Store and you will find lots of great apps that can connect to ELM327 and show you all the details of your car data However we want to have a lot more fun than this Getting the car data to the Pi To collect car data from the Pi using Python via Bluetooth we need to install s
84. ng used When we start the car again the phone gets powered up from the USB contact In this case we need to enable the hotspot again Automatic restart on power connect When we connect a turned off Samsung device to a power source we will see a gray battery image with a turning arrow inside it Then when it begins charging the battery we will see another colored battery image showing the current charge level This second image is generated by a program that is triggered whenever a turned off device begins charging the battery It is a binary file located in system bin playlpm on the phone We will change this file to a script of our own to reboot the device In order to be able to edit this file we need super user privileges This is why we have rooted the phone As an Android system is actually a Linux OS under the hood we can run any Linux command on it We can do this using an app that we can download from the Play Store called Terminal Emulator H all 10 38 3 m Window 1 ddexe reboot debuggerd renice requestsync rild rm rmdir rmmod route rtc_log sh Fun as samsungpowersoundplay schedtest schedtop fsck exfat screencap fsck_msdos screenshot sdcard sdptool android system bin cd system bin android system bin ls la playlpm FWXT XrT X 1 root shell 13648 Mar 19 2 013 playlpm u0_a131 android system bin The Terminal Emulator app screen Now issue the upcoming commands to change the contents of
85. o a screen using the HDMI port instead of a remote desktop to see Kodi s user interface Now you can connect a USB keyboard or mouse to navigate inside Kodi Starting Kodi on boot We definitely do not want to run a command to start the media center no matter how easy it is to run commands from Android as discussed in previous chapters For this reason we need to start the command on startup using the crontab e command Add the following line at the end of the file the crontab command command opens reboot usr bin kodi standalone amp Now whenever you restart the Pi Kodi will be restarted automatically Note that here you access the media center through the HDMI port of the Pi but you will also be able to access via remote desktop using the tools discussed in Chapter 1 Make a Remote Desktop Connection to Your Pi from Anywhere Connecting to the media center via remote control from Android The main problem with the current setup is that you can only control the media center using a connected keyboard or mouse making it not as comfortable to use as a media center should be However there is a remote control for Kodi on Android called Kore that makes it really easy to remotely control the media center You can download it from Google Play Its official name is Kore Official Remote for Kodi and it is published by the XBMC Foundation which is a nonprofit organization that operates the Kodi Media Center project Before you ca
86. of code with the following ones respectively webcam_localhost off control localhost off In addition we want the motion service to execute in the background mode as well being run as daemon For this purpose we should locate the following line of code in the same file daemon on We should replace it with this line daemon off If we start motion now we will get the following error Exit motion cannot create process id file pid file var run motion motion pid No such file or directory To get rid of this error we can create this folder that motion is complaining about sudo mkdir var run motion Note that this directory might get deleted at startup so it is a good idea to add this command in the etc rc local file as well Now you can finally start and stop your Pi camera in the surveillance mode issuing the following commands preferably using the ConnectBot app or any other SSH client that we discussed in the previous chapter The following command will start motion sudo motion To stop motion issue the following command sudo pkill f motion If you always want to run it on startup which I would not recommend as you can run out of storage space on your Pi you should edit the etc default motion file using the following command sudo nano etc default motion In this file you will find the following line start_motion_daemon no You should replace it with this one start_motion_daemon yes You may
87. ome tools Run the following update command to download Bluetooth related packages Note that I am assuming that you have a new Raspbian installation Same packages have been installed in previous chapters as well sudo apt get install bluetooth bluez utils blueman python serial python wxgtk2 8 python wxtools wx2 8 i18n libwxgtk2 8 dev git core fix missing Tip You are most probably sitting in your car and working right now If you are struggling to figure out how to connect to the Internet you can always use your Android device as a hotspot and connect to the Internet using the Wi Fi dongle that we need for this chapter later on anyway Connecting the Pi to a Wi Fi network was covered previously but lets remind ourselves about how it works Add the following lines to the etc wpa_supplicant wpa_supplicant conf file You need to have configured the hotspot to apply the WPA PSK security instead of PSK2 network ssid YOUR_NETWORKID_FOR_HOTSPOT psk YOUR_PASSWORD_FOR_HOTSPOT Now reboot the Pi and after a few minutes you will see that it is automatically connected to the hotspot on the Android device in the hotspot settings window Once again we can use the 1susb command to list the connected USB devices The output on my system is shown as follows Bus 001 Device 002 ID 0424 9514 Standard Microsystems Corp Bus 001 Device 001 ID 1d6b 0002 Linux Foundation 2 0 root hub Bus 001 Device 003 ID 0424 ec00 Standard Micros
88. oot to Desktop In the following menu select the second item in the list which is Desktop Log in as user pi at the graphical desktop Then choose lt Finish gt and select Yes to reboot the device Chose boot option Desktop Log in as user pi at the graphical desktop Scratch Start the Scratch programming environment upon boot lt Cancel gt Choose desktop startup in the configuration tool After reboot you will be presented with the Raspbian s default desktop manager environment called LXDE Installing necessary components in the Pi and Android As the following screenshot shows the LXDE desktop manager comes with an initial setup and a few preinstalled programs 8 Menu yy E A Q gramming gt Ga Internet gt af Games gt wae Bd bic A 23 Help gt E a TAS Preferenc gt et riet ia mag 3 Rur ya N E Shutd er a Term Pe The LXDE desktop management environment By clicking on the screen image on the tab bar located at the top you will be able to open a terminal screen that we will use to send commands to the Pi The next step is to install a component called x11vnc This is a VNC server for X the window management component of Linux Issue the following command on the terminal sudo apt get install x11vnc This will download and install x11vnc to the Pi We can even set a password to be used by VNC clients that will remote desktop to this Pi using the following command and provide
89. or these kinds of sensors developed in the Python programming language Before we can use it we need to install some software components to our Raspberry Pi Firstly we need to update our Pi and install some dependencies using these commands sudo apt get update sudo apt get install build essential python dev The sensor library itself is on GitHub and we will download it from there onto our Pi using the following command git clone https github com adafruit Adafruit_Python_DHT git This command downloads the library and saves it in a subdirectory Now go into this subdirectory using the following command cd Adafruit_Python_DHT Next you need to actually install the sensor library using the following command sudo python setup py install Here we use the standard Python third party module install functionality which installs the Adafruit library globally onto your system at the standard Python library install location usr local lib python2 7 dist packages This is why we need superuser privileges which we can get using sudo command Now we are ready to begin reading measurements from the sensor using the example code that we downloaded together with the library Assuming that you are still in the Adafruit_Python_DHT directory the following command does the job sudo examples AdafruitDHT py 11 4 In this command 11 is the descriptor used to identify DHT11 sensor and 4 denotes the GPIO pin 4 You should now get an output
90. otification dh Odin3 v1 85 a Android SLP E Eee Il y Option Control Panel Re Partition v Auto Reboot V F Reset Time Flash Lock ID PIT Files Download Phone EFS Clear Phone Bootloader Update BOOTLOADER Message lt ID 0 011 gt Initialzation PDA lt ID 0 011 gt Get PIT for mapping lt ID 0 011 gt Firmware update start lt ID 0 011 gt zImage lt ID 0 011 gt NAND Write Start lt ID 0 011 gt RQT_CLOSE lt ID 0 011 gt RES OK lt ID 0 011 gt Completed lt OSM gt All threads completed succeed 1 failed 0 File Dump lt ID 0 011 gt Removed C jeboo_kernel_i9100_v1 2a tar Odin has been completed successfully Now your phone should reboot and you should see a warning triangle on the restart screen indicating that you have a new kernel with the recovery from SD card feature The next step is to save the CWM Super User file from http downloadandroidrom com file tools SuperSU CWM SuperSU v0 99 zip to the SD card and attach it to the device Now power off your device and put it into recovery mode again this time using a slightly different key combination that is volume up power home Note that we press volume up instead of volume down as we did before You will see a different recovery screen called CWM based Recovery You can scroll up and down using the volume up and volume down keys Select the Install Zip item using the home
91. oting Samsung Galaxy S2 There are different ways of rooting different devices I will use one of the most common second hand Android devices in the market namely Samsung Galaxy S2 If you have another phone there are plenty of resources available on the Internet on how to root each device The most popular one is located at http www androidcentral com root the Android Central website Note Note that rooting a device will make the guarantee invalid This may cause damage to your phone and is not a secure process Do it on your own risk But the steps provided here worked for me You should backup any files you would like to keep before you continue with the rest of this chapter Samsung devices can be put into recovery mode by pressing the volume down power home buttons at the same time By pressing these buttons you will get Samsung s standard recovery screen with a warning sign on it We should replace this recovery program with another one as the standard recovery is only to be done through a computer connected via a USB and downloads a complete OS image However what we really need to do is only replace a kernel with one that gives us super user rights We also want to make sure that we do this from an SD card attached to an Android device That is why we need to replace Samsung s default recovery program We can do this again using the recovery operation provided by Samsung When you put the device in this recovery mode attach
92. owing the Pi as a BLE device The BLE stack is designed in a way that a device supports some number of services that users can connect to and each service can provide read write or notification characteristics which is mainly data that you can write to read or get notifications from Click on the device in the app and you will connect to the Pi s newly started BLE server You will be presented with four services The one we are interested in is called UNKNOWN SERVICE which is unnamed because it is not a standard service and it is implemented to only demonstrate the Gatt example server Click on this service and you will see three characteristics provided by this service READ WRITE and Notification You can recognize the type of characteristic by looking at which one of the three buttons on BLE Scanner app is enabled The following screenshot illustrates the READ Characteristics u 4 m 23 17 DISCONNECT Peripheral Gopher RSSI 50 db Address 5C F3 70 68 BE 42 Status connected Peripheral Gopher Address 5C F3 70 68 BE 42 Service UNKNOWN SERVICE UUID 09fc95c0 c111 11e3 9904 0002a5d5c51b Characteristic UNKNOWN CHARACTERISTIC UUID 11fac9e0 c111 11e3 9246 0002a5d5c51b Data Type 16BIT FLOAT Properties 0x0002 read Read Notification Write String count 10 Decimal 86627 Updated 2015 07 26 23 17 05 780 The READ characteristic Adding a sensor service to Bluetooth Low Energy We will add a ne
93. perature values using the readNextCharacteristic method that we ll define in the same callback implementation This is because the BLE protocol does not let us read both characteristics at the same time Let s take a look at the following code private void readNextCharacteristic BluetoothGatt gatt BluetoothGattCharacteristic characteristic BluetoothGattService service gatt getService UUID_Service if UUID_HUMIDITY equals characteristic getUuid BluetoothGattCharacteristic temperatureCharacteristic service getCharacteristic UUID_TEMPERATURE gatt readCharacteristic temperatureCharacteristic else BluetoothGattCharacteristic humidityCharacteristic service getCharacteristic UUID_HUMIDITY gatt readCharacteristic humidityCharacteristic Whenever the respective read operation succeeds we get the value of the measurement using the getStringValue method of the returned characteristic object and then show it in the UI elements that we will define in the activity_main xml file as follows lt TextView android id id temperature_textview android layout_width wrap_content android layout_height wrap_content android layout_alignParentEnd true gt lt TextView android id id humidity_textview android layout_width wrap_content android layout_height wrap_content gt For the code to be complete we need to define the following methods as well in the MainActivity java file Override protect
94. restarts the FTP server if there s any problem with it sudo service vstfpd restart The service utility that we have used lets you restart the database and web server using these two commands sudo service mysql restart sudo service apache2 restart Use the following command to check the status of the MySQL server mysqladmin u root p status If you believe that the database has grown too much in size you can start the MySQL console and run a SQL query to see the database size mysql u root p mysql gt SELECT table_schema DB Round Sum data_length index_length 1024 1024 1 Size in MB FROM information_schema tables GROUP BY table_schema You can even delete records that are older than three days using the following query select measurements delete from measurements where ttime lt NOW INTERVAL 3 DAY Or as an alternative you can check the size of the filesystem using the shell command df h Summary This chapter introduced you to the management of Raspberry Pi as a server and how to issue commands to it from Android We installed an FTP server on the Pi and shared files between Android clients To show an example of database and web servers we implemented a useful project and learned to manage these servers remotely as well The next chapter will introduce you to the Pi camera and help you implement a surveillance solution Chapter 3 Live Streaming of a Surveillance Camera from the Pi In thi
95. rite characteristic to the sensor go file as shown in the following code s AddCharacteristic gatt MustParseUUID 71fac9e0 c111 11e3 9246 0002a5d5c51b HandleWriteFunc func r gatt Request data byte status byte log Println Command received to whistle exec Command sh c aplay home pi whistle_blow_01 wav Output return gatt StatusSuccess Do not forget to build and restart the Pi using the go build examples server go command Next define a new button in the activity_main xml file lt Button android id id whistle_button android layout_width wrap_content android layout_height wrap_content android layout_below id turnoff_button android text Whistle android onClick sendwhistleCommand android enabled false gt Define a new event handler for the onclick event in the MainActivity java file public void sendwhistleCommand View v throws InterruptedException Next add new the UUID and control variables to the same file isSendwhistle true private static final UUID UUID_WHISTLE UUID fromString 71fac9e0 c111 11e3 9246 0002a5d5c51b private volatile boolean isWhistle false Enable the new button in the onScanResult method of the scanCallback instance variable inside the if statement for the bleGatt null check MainActivity this findViewById R id whistle_ button setEnabled true Add the following code in the new else if statement in the onCharacteristicRead han
96. rmation programmatically from Python as well We will make use of this possibility later on But for now the following Python code in a file named getgps py to test the Python gps library usr bin python from gps import import math gpsd gps mode WATCH_ENABLE starting the stream of info count 0 while count lt 10 wait max 50 seconds gpsd next if gpsd fix latitude and not math isnan gpsd fix latitude print gpsd fix latitude gpsd fix longitude break count count 1 time sleep 5 The only thing this tiny program does is to output the GPS location whenever there is one to report We can call it using the python getgps py command Collecting the car data For the purpose of collecting the car data we will use a standard On board diagnostics OBD interface found on most cars and referred to as OBD II or EOBD in Europe These are equivalent standards used to connect to the OBD port of the car you can also read diagnostics data and fault codes about the car from this port Note In 1996 the OBD II specification was made mandatory for all cars manufactured and sold in the United States The European Union followed suit in 2001 by making EOBD mandatory for all gasoline petrol vehicles sold in the European Union followed by all diesel vehicles in 2003 In 2010 the HDOBD heavy duty specification was made mandatory for certain select commercial non passenger car engines sold in the United States Even Chi
97. roduction systems During this time he became a principal systems engineer and also moved to Sweden in 2007 where he started working at the head office of IFS in Link ping Sweden From 2014 to date he has been working on product benchmarking for IFS He has mainly worked with technologies such as Oracle RDBMS J2EE systems and Jboss Oracle WebLogic He is also knowledgeable about various scripting technologies and languages such as PowerShell and VB scripting In recent years he s been active in monitoring tools written in Angular JS and Google graphs In the field of product benchmarking he has worked with data science especially generating synthetic data for load simulations He has also spent considerable time at work on performance testing tools such as HP LoadRunner In his spare time apart from travelling and enjoying different cultures with his son daughter and wife he spends time with Android Google App Engine and Raspberry Pi home brewing projects Eric Wuehler lives in the Pacific Northwest with his lovely wife and three children He has been working in the technology field professionally for over 20 years His likes tinkering with mobiles and other small devices He is involved in a large number of projects in various states of completeness which are strewn about the man cave this is coincidentally the same room and his lovely wife refers to it as the basement He can be reached online at ericwuehler com www
98. rs I strongly recommend that you change the default password of the user pi before performing this step You can change passwords using the passwd command By logging onto the router s management portal and navigating to the Port Forwarding tab we can open up requests to the Pi s internal network IP address which we have figured out previously and the default port of the VNC server which is 5900 Now we can provide our external IP address to androidVNC from anywhere around the world instead of an internal IP address that works only if we are on the same network as the Pi P NETGEAR Router x WIN C fi D routerlogin net start htm NETGEAR S MAR TWIZARD router manager Wireless G Router Setup Wizard Port Forwarding Port Triggering Basic Settings Please select the service type Wireless Settings Port Forwarding Port Triggering Logs Service Name Server IP Address Age of Empire hd 192 168 j1 E Add Block Sites Block Services Se AA e rn EngPon severa Router Status KOLBE 7 E E a Attached Devices poo ao a a ww el Lo HE CC BIC INCITA ee INICIO ANCIANO INNATA Pos we EEE IC INCA INCITA Wireless Settings gt __ _ III Wireless Repeating Edit Service Delete Service Function Port Forwarding Add Custom Service Port Triggering ee WAN Setup LAN Setup Set Password Router Upgrade Dynamic DNS Static Routes Remote Management UPnP Knowledge Base Documenta
99. s Android API and finally click on the Enable API button Next navigate to Credentials and click on the Create new key button under the Public API access section We need to choose Android key in the window that pops up Copy the generated API key and replace it with the YOUR_KEY_HERE string in the google_maps_api xml file Now we are ready with our Android project setup and it is time to code now The first thing to do in the code is download a list of sheets from Google Docs There is one sheet for each restart of the Pi Add the following code inside the onCreate method of the MapsActivity java file new RetrieveSpreadsheets execute This piece of code will create an asynchronous task that is implemented as an Android AsyncTask which downloads and presents the spreadsheets Let s define the task class in the same file as well class RetrieveSpreadsheets extends AsyncTask lt Void Void List lt worksheetEntry gt gt Override protected List lt wWorksheetEntry gt doInBackground Void params try service new SpreadsheetService MySpreadsheetIntegration vi HttpTransport httpTransport new NetHttpTransport JacksonFactory jsonFactory new JacksonFactory String SCOPESArray https spreadsheets google com feeds https spreadsheets google com feeds spreadsheets private full https docs google com feeds final List SCOPES Arrays asList SCOPESArray KeyStore keystore KeyStore getInstance PK
100. s chapter we will connect a camera to Raspberry Pi and stream a live video from it We will then be able to watch the streaming of this content from our Android device This chapter will move us closer to usage and away from administration of Raspberry Pi In this chapter we will cover the following topics e Hardware and software configurations e Streaming video to an Android device e The surveillance mode Hardware and software configurations We will use a standard camera developed for the Pi that costs about 30 in many major electronics stores The Pi camera Pi has a camera port where you can plug in the camera cable The plug on the Pi can be opened by pulling it upwards If you have problems connecting the camera to the Pi you can find many videos on the Internet showing how to do it You can watch one from Raspberry Pi Foundation at https www raspberrypi org help camera module setup The next step is to configure the Pi and enable the camera hardware This is done using the Pi configuration program accessed by issuing the following command sudo raspi config In the menu provided select Enable Camera and hit Enter Then click on Finish where you ll be prompted to reboot Streaming video to an Android device The easiest way to stream from the Pi to Android is using the RaspiCam Remote app that logs in to the Pi and executes the necessary commands It then automatically gets the stream from the Pi Download and
101. s solves the problem sudo apt get install vlc The next step is to install a better VLC client on the Android We will use the VLC for Android beta app After installing it open RaspiCam Remote app again and then start streaming by clicking on the camera icon At this point Android will ask you to select the standard video player or the newly installed VLC for Android beta Choose the latter and you will experience a much better streaming quality Do not forget to add port 8080 to the port forwarding settings on your router to get access to the streaming video over the Internet Manual VLC configurations The RaspiCam Remote app automatically configures VLC on the Pi before it streams video content Some of you might want to connect to the video stream directly from the VLC app and skip RaspiCam on Android The following command is the same as the one that RaspiCam issues from the account that you provide before you start streaming using RaspiCam on your Android device opt vc bin raspivid o n t 0 fps 25 rot 0 w 640 h 480 usr bin vlc I dummy stream dev stdin sout standard access http mux ts dst 8080 demux h264 amp If you issue the preceding command you will be able to view the streaming content from the VLC app You can initiate a connection by clicking on the antenna like icon on the action bar of the VLC app It will prompt for the stream address which is http PI_IP_ADDRESS 8080 The surveillance mode
102. t the reboot command from Android to the Pi In this section we will send two new commands One to light up a LED that we will connect to the Pi and another to play sound on the Pi These commands will be reused in the forthcoming sections Lighting the LEDs We ll begin by connecting a LED light to the GPIO ports of the Pi The LEDs usually come with a short and long leg Connect a resistor to the short leg of the LED and connect a female female jumper to the other side of the resistor This jumper should then be connected to one of the ground pins of the Pi Take a look at the schema in Chapter 2 Server Management with Pi to identify the pins Note that we already used one of the ground pins when we connected our temperature humidity sensor to the Pi However there are plenty of ground pins available The long leg of the LED should be connected to one of the GPIO pins We will choose number 17 You can take a look the GPIO port mappings diagram in Chapter 2 Server Management with Pi to identify port 17 Tip It is a good idea to choose a resistor in the span of 270Q to 4709 This resistor to protects the LED lamp from unexpected voltage changes If you choose a resistor with lower ohm values then the LED will be brighter We will access the GPIO and LED lamp using a software utility called wiringPi We can download and install it using the following commands cd git clone git git drogon net wiringPi cd wiringPi build Thes
103. teristics for temperature measurement showing a current value of 27 degrees Connecting from an Android app We have used an existing app to connect to the BLE service that we implemented on Raspberry Pi This app called BLE Scanner is very general purpose and would work for any kind of BLE device However we need a more specialized app that only reads measurements and abstracts away details of the BLE protocol such as device scan services and service characteristics In this section we will implement an Android app to connect to the Raspberry Pi BLE We need to install the Android Studio for this purpose Android studio is specifically designed for Android app development by Google You can read more about it by visiting http developer android com tools studio You can find instructions for installation at http developer android com sdk We will use a real device to test our app and not the built in emulator For this purpose you may need to install device drivers specific to your Android phone and make configuration changes to the Android Studio installation The http developer android com tools device html link will help you carry out these actions Now start the Android Studio and choose a new project to create I will name the application BLEPi and the domain example com You should choose Phone and Tablet as the form factor and at least Android 5 0 as the minimum SDK as better BLE support is introduced with this SDK to the Android
104. the Kore remote control app Then select Add to favorites by scrolling down using the arrows on Kore L Connected to kurt The button that lists the choices in Kore that is the properties button Next open AndFTP from Chapter 2 Server Management with Pi and connect to the Pi or select the connection that is already saved from previous sessions You should now see the contents of the home pi directory which is the default location for the user pi we have used This is the target location Then select the mobile phone image on the action bar in AndFTP to select a video located on your mobile phone and upload it to Kodi m A Y Y 18 04 ag Ep As 8 Folder size items 202 2 MB Go up a folder The AndFTP interface to select the upload location from the phone to the Pi Recorded videos are generally located under DCIM Camera Select the videos you want to upload Then click on the upload icon in the action bar D P 4 18 04 I3 a t 1 314 Folder size items 11 3 GB BJ _ i 5 21 15 09 40 iy VID_201 50521_094127 mp4 79 MB The AndFTP interface to begin upload from the phone to the Pi Next you can browse down to the pi directory in Kodi that we have added to the Videos section and see the videos you have just uploaded on your media center Streaming the Android display to Kodi Another very interesting thing you can do is to stream your Android screen and make Kodi show this stream For this purpose w
105. the first time through a remote SSH Note that in the following screenshot I have provided the internal IP address of my home network You might want to use an external IP address and connect to the Pi from outside your home network For this purpose you ll need to add the standard FTP ports 21 and 20 to your port forwarding settings as well The same applies to the SSH protocol which has a default port number of 22 Note As we have discussed earlier there is a security risk in opening ports this way and also keeping the default password for the user pi on the Pi The following screenshot illustrates connection details on ConnectBot AO Beer Use the quick connect box below to connect to a host ssh pi 192 168 1 7 1284547890 OFEXA ee ee he ae ABC Svenska Connection details on ConnectBot Now provide the default password for the pi account which is raspberry or the one you have changed it to After this step you will be connected to the Pi remotely using SSH as seen in the following screenshot EN IA 275 14 59 ConnectBot Linux raspberrypi 3 18 11 v7 781 SMP PREEMPT Tue Apr 21 ST 2015 armv7l The programs included with the Debian GNU Linux system are free soft ware the t distribution terms for each am are described in the individual files in usr share doc Debian GNU Linux comes o the extent permitted by applicab Last login Tue Jun Y ask N LAS ty V O a The
106. them to the build gradle file for Module app To do this add the following code under the dependencies tag compile files libs gdata spreadsheet 3 0 jar compile files libs gdata core 1 0 jar compile files libs guava 11 0 2 jar compile files libs gdata base 1 0 jar compile files libs google http client 1 20 0 jar compile files libs google http client jackson 1 20 0 jar compile files libs google api client 1 20 0 jar compile files libs google oauth client 1 20 0 jar compile files libs jackson core asl 1 9 11 jar When you edit the build gradle file you might get a message in Android stating that Gradle files has changed since last project sync A project sync maybe necessary for the IDE to work properly Click on the Sync Now link located near this notification to update the project The next step is to move the P12 key file which we have downloaded from the Google Developer Console and include it in our Android project We need to copy this file in the raw directory located at PROJECT_HOME app src main res raw and rename it as piandroidprojects p12 As we plan to show the content on a map we will use Google s Map API for this purpose To use it we need an access API key Go to the developer console again at https console developers google com project and select the project that we ve created previously In the menu located on the left hand side choose APIs under APIS amp auth then Google Map
107. this book elsewhere you can visit http www packtpub com support and register to have the files e mailed directly to you You can also download the code bundle of this book from https github com kurtng Raspberry Pi Android Projects Downloading the color images of this book We also provide you with a PDF file that has color images of the screenshots diagrams used in this book The color images will help you better understand the changes in the output You can download this file from https www packtpub com sites default files downloads Raspberry_Pi Android Projects Errata Although we have taken every care to ensure the accuracy of our content mistakes do happen If you find a mistake in one of our books maybe a mistake in the text or the code we would be grateful if you could report this to us By doing so you can save other readers from frustration and help us improve subsequent versions of this book If you find any errata please report them by visiting http www packtpub com submit errata selecting your book clicking on the Errata Submission Form link and entering the details of your errata Once your errata are verified your submission will be accepted and the errata will be uploaded to our website or added to any list of existing errata under the Errata section of that title To view the previously submitted errata go to https www packtpub com books content support and enter the name of the book in the search f
108. tion Port Forwarding settings on Netgear router administration page Note Refer to your router s user manual to see how to change the Port Forwarding settings Most routers require you to connect through the Ethernet port in order to access the management portal instead of Wi Fi Problems with dynamic LAN IP addresses and external IP addresses There is one minor problem with this setup The Pi might get anew LAN IP address each time you restart it making the Port Forwarding setting useless To avoid this most routers provide the Address Reservation setting You can tell most routers that each time a device with a unique MAC address is connected it should get the same IP address Another problem is that your Internet Service Provider ISP might assign new IP addresses to you each time you restart your router or for any other reason You can use a dynamic DNS service such as DynDNS to avoid such problems Most routers are capable of using dynamic DNS services Alternatively you can get a static IP address by contacting your ISP Summary In this project we installed Raspbian warmed up with the Pi enabled the desktop environment on it and connected to the Pi using an Android device In the next chapter we will access the console of the Pi directly and even transfer files to and from it using FTP from our Android devices Chapter 2 Server Management with Pi In the first half of this project we will move from a des
109. udo service vsftpd restart Now we need to install an FTP client on Android For this purpose we will use AndFTP It is enough to use the free version for our project We see the following initial view on the Android device after opening it P A 20 31 AndFTP is a FTP SFTP SCP FTPS clie several FTP Click butto on item t ect or long click to update its configuration An initial view of the AndFTP client Pressing the plus button will take you to the following view where you will be asked for connection properties Ys 5 20 35 33 FTP server settings GENERAL ADVANCED Hostname FTP File Transfer Protocol storage emulated 0 2123 G amp oe V O O E Connection properties on AndFTP Provide the IP address of the Pi you found out in the first chapter pi as username and raspberry as the password or the one you have changed to Then scroll down to the end of the view and press the Save button This will save the connection properties and send you back to the main view V4 5 20 42 AndFTP is a FTP SFTP SCP FTPS clie several FTP Click butto on item t ect or long click to update its configuration 192 168 1 7 The list of connections in AndFTP Clicking on the newly created connection shown as a blue folder will initiate the FTP connection to the Pi and log the user pi in This will get you into the home directory for the pi user as shown in the following screenshot LATA FPE 21 17 EN Fo
110. ully The solution to this issue will be left as an exercise for you The last part of the implementation is to add a button for the command to our user interface and connect this button to a method in the MainAcitivity java file which will be executed whenever the button is pressed Add the following lines to the activity_main xml file inside the RelativeLayout tag to begin with lt Button android id id reboot_button android layout_width wrap_content android layout_height wrap_content android layout_below id humidity_textview android text Reboot android onClick sendRebootCommand android enabled false gt Define the sendRebootCommand method in the MainActivity java file public void sendRebootCommand View v throws InterruptedException isSendReboot true The only thing this function does when the Reboot button is clicked on is set the control variable that we have defined previously You can also add the following code in the onScanResult method of the ScanCallback class instance after the call to the device connectGatt method to enable the button when we connect to Raspberry Pi via Bluetooth if bleGatt null MainActivity this findViewById R id reboot_button setEnabled true This is a good place to test the app again and see if you can successfully restart the Pi through an Android device Sending more commands from your Android phone to the Pi In the previous section we have sen
111. upta About the Author G khan Kurt has been trying to keep up with the the latest developments in technology and IT in his 15 year long development career For the past 4 years he has been working at IFS Labs one of the top innovation departments of the Swedish software industry Currently he is involved in the Internet of Things and has been developing prototype IoT implementations using Raspberry Pi He has a master s of science degree from Chalmers University of Technology and a bachelors degree from the Middle East Technical University You can connect with him on Twitter KurtGok and on LinkedIn http se linkedin com in kurtgokhan I would like to thank my dear wife Hediye for her patience during the writing of this book Special thanks to my 3 year old son Derin for providing me with the intellectual support needed for writing this book with his Lego building skills I would also like to thank my 3 month old daughter Eliz for keeping me awake at night so that I was able to think about exciting projects to include in this book About the Reviewers Thushara Jayawardena is in his fourteenth year of working in the software development industry Right after he graduated from university in 2001 he joined the IFS world operations http www ifsworld com development center in Colombo Sri Lanka His early years were spent as a junior SW engineer He then moved into SW systems as a system engineer overseeing mission critical p
112. use the MAC address of your own ODB Bluetooth which we found out previously using the hcitool scan command Now issue the following Bluetooth pairing command to pair the Pi with OBD and use the MAC address of OBD sudo bluez simple agent hci0 00 1D A5 15 A0 DC The PIN is usually either 0000 or 1234 RequestPinCode org bluez 2336 hci0 dev_00_1D A5 15 AO DC Enter PIN Code 1234 Release New device org bluez 2336 hci0 dev_00_1D A5 15 AO DC We should even add the dbus connection support before we continue to the next command sudo update rc d f dbus defaults sudo reboot Make the OBD device trusted by the Pi in order to skip manual pairing the next time using the following command sudo bluez test device trusted 00 1D A5 15 A0 DC yes Tip The following command will let you test the connection if you have any problems Replace the MAC address with your OBD adapter s MAC address sudo 12ping 00 1D A5 15 A0 DC We will use a tool called py0BD pi to access the data that the OBD dongle makes available Download and start the logger using the git command This is a more developer friendly version of a well known library located at https github com peterh pyobd git clone https github com Pbartek pyobd pi cd pyobd pi sudo python obd_recorder py Tip Do not forget to turn your ignition on Also don t forget to connect via Bluetooth using the upcoming command It is a good idea to put this in crontab other
113. val 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 September 2015 Production reference 1210915 Published by Packt Publishing Ltd Livery Place 35 Livery Street Birmingham B3 2PB UK ISBN 978 1 78588 702 4 www packtpub com Credits Author G khan Kurt Reviewers Thushara Jayawardena Wolf Paulus Eric Wuehler Commissioning Editor Nadeem Bagban Acquisition Editor Vivek Anantharaman Content Development Editor Arwa Manasawala Technical Editor Rahul C Shah Copy Editor Sonia Cheema Project Coordinator Shweta H Birwatkar Proofreader Safis Editing Indexer Monica Ajmera Mehta Production Coordinator Arvindkumar Gupta Cover Work Arvindkumar G
114. w service to the already existing example from Gatt This new service will publish two new characteristics to begin with one for humidity and the other for temperature measurements We will read the measurements the same way using the techniques we ve discussed in Chapter 2 Server Management with Pi To read these measurements we will create two new files with content similar to the sense py file that we discussed Chapter 2 Server Management with Pi Let s create two files under the home directory and name them humidity py and temperature py The temperature py file has the following content usr bin python import sys import Adafruit_DHT humidity temperature Adafruit_DHT read_retry Adafruit_DHT DHT11 4 print str temperature The humidity py file has similar content The only difference is that it prints out the humidity part of the measurement instead of the temperature usr bin python import sys import Adafruit_DHT humidity temperature Adafruit_DHT read_retry Adafruit_DHT DHT11 4 print str humidity We need to change the file access mode to executable as well using the following command chmod x temperature py humidity py Now you can test sensor measurements using the following commands sudo temperature py sudo humidity py The next step is to publish these readings via the Bluetooth channel We will create a new service inside the existing Gatt server example For this purpose you can start ed
115. wise you ll need to use it every time you reboot the Pi sudo rfcomm connect hci0 00 1D A5 15 A0 DC The command will save the data traffic to the log directory If you get errors regarding 0100 response CAN ERROR then you have problems with protocol selections and you simply need to edit the obd_io py file and find the following line self send_command 0100 Then add the following lines of code just before it self send_command ATSPO select auto protocol wx PostEvent self _notify_window DebugEvent 2 ATSPO response self get_result In this way we have forced the communication protocol to be chosen automatically Tip You may want to run the init server script on reboot You cannot put it in cronbtab as the Bluetooth or GPS might not be ready when it is run Put the commands at the end of etc rc local file before the exit line instead sudo killall gpsd sudo gpsd dev ttyUSBO F var run gpsd sock sudo rfcomm connect hci0 00 1D A5 15 A0 DC amp Using your Android device as an access point We will send the data we have gathered so far to a location on a cloud but we need to connect the Pi to the Internet before we do this Making an Android device an Internet access point or a hotspot is trivial and can be done from the settings of a device We can then connect the Pi to this network that Android provides However there is a major problem with this setup First of all we want to be able to leave the
116. worksheet getTitle getPlainText AlertDialog Builder alertDialogBuilder new AlertDialog Builder MapsActivity this alertDialogBuilder setTitle Select a worksheet alertDialogBuilder setAdapter new ArrayAdapter lt String gt MapsActivity this android R layout simple_list_item_1 worksheetTitles toArray new String new DialogInterface OnClickListener Override public void onClick DialogInterface dialog int which new RetrievewWorksheetContent execute worksheets get which alertDialogBuilder create show Before we describe the preceding code define an instance variable for the spreadsheet service which is used in the task we have just defined SpreadsheetService service The Android AsyncTask requires us to override the doInBackground method which is executed in a new thread whenever we call the execute method of the task that we performed in onCreate In doInBackground we will define KeyStore and load the P12 file that we ve downloaded from the Google Developer Console and copied to the raw directory of our Android project Note that notasecret was the secret that the Developer Console informed me about when I created and downloaded the P12 file Also inside the setServiceAccountId method you ll need to use your own account name You can find it in the Developer Console under the Service account section in the Email address field as well as in the JSON key file client_email f
117. worksheet named as the current timestamp and save a single value in this sheet Note that Google allows 200 worksheets per sheet and by default 100 rows per worksheet in our code we create a new worksheet each time we run it We need to clean the sheet from time to time in order to not to go beyond the limit Putting it all together In the next two sections we will put together what we have done so far First we ll begin by sending data to the Google Docs sheet Then we will build an Android app to show the data on a map Sending measurements We will use a Python script to access GPS data on the Pi that we ll need to run on system reboot For this purpose add the following code at the end of the etc rc 1local file sudo killall gpsd sudo gpsd dev ttyUSBO F var run gpsd sock sudo rfcomm connect hci0 00 1D A5 15 A0 DC sleep im current_time date Y m d H M S file name home pi log_sender txt new_filename file_name current_time sudo home pi pyobd pi sender py gt new_filename 2 gt 1 amp Here we can restart the GPS services connect to the OBD Bluetooth dongle create a log file and start the sender py script that we will implement next usr bin env python import obd_io from datetime import datetime import time import threading import commands import time from gps import import math import json import gspread from oauth2client client import SignedJwtAssertionCredentials
118. xt false bleGattCallback super onScanResult callbackType result The ScanCallback implementation overrides one important method onScanResult which is called whenever there is any new device to report We then check if the device name is the same as the one that was defined in the server go file on the Pi If so we can save the device properties and connection information to the bleGatt variable We can even connect to the device using the connectGatt method and provide another callback implementation bleGattCallback which will be called whenever an Android system establishes a connection to the device We stop the scan if we have found the device we are looking for Here is the definition for this callback private BluetoothGattCallback bleGattCallback new BluetoothGattCallback Override public void onConnectionStateChange BluetoothGatt gatt int status int newState gatt discoverServices super onConnectionStateChange gatt status newState Override public void onServicesDiscovered BluetoothGatt gatt int status BluetoothGattService service gatt getService UUID_Service BluetoothGattCharacteristic temperatureCharacteristic service getCharacteristic UUID_TEMPERATURE gatt readCharacteristic temperatureCharacteristic super onServicesDiscovered gatt status Override public void onCharacteristicRead BluetoothGatt gatt final BluetoothGattCharacteristic characteristic int status
119. xt step is to download a VNC client to your Android device In this project we will use a freely available client for Android namely androidVNC or as it is named in the Play Store VNC Viewer for Android by androidVNC team antlersoft The latest version in use at the writing of this book was 0 5 0 Note Note that in order to be able to connect your Android VNC client to the Pi both the Pi and the Android device should be connected to the same network Android through Wi Fi and Pi through its Ethernet port Connecting the Pi and Android Install and open androidVNC on your device You will be presented with a first activity user interface asking for the details of the connection Here you should provide Nickname for the connection Password you enter when you run the x11vnc storepasswd command and the IP Address of the Pi that you found out using the ifconfig command Initiate the connection by pressing the Connect button and you should now be able to see the Pi desktop on your Android device In androidVNC you should be able to move the mouse pointer by clicking on the screen and under the options menu in the androidVNC app you will find out how to send text and keys to the Pi with the help of Enter and Backspace Note You may even find it convenient to connect to the Pi from another computer I recommend using RealVNC for this purpose which is available on Windows Linux and Mac OS What if I want to use Wi Fi on the P
120. ystems Corp Bus 001 Device 004 ID 148f 5370 Ralink Technology Corp RT5370 Wireless Adapter Bus 001 Device 005 ID 067b 2303 Prolific Technology Inc PL2303 Serial Port Bus 001 Device 006 ID Oa5c 21e8 Broadcom Corp The 005 device is the Bluetooth dongle that I am reusing from the previous section Issue the hcitool scan command to see if you can reach the OBD Bluetooth device connected to the car Scanning 00 1D A5 15 A0 DC OBDII You can see the MAC address of the OBD device as well write it down as it will be used later Tip If you get into problems such as scanning or reaching the OBD you can use the following commands to see the status of the connected Bluetooth dongle and the bluetooth service on the Pi hciconfig hci0 etc init d bluetooth status Let s take a look at the following command etc init d bluetooth restart The preceding command is used to restart the bluetooth service Now we need to give the pi user access to the Bluetooth device Edit the etc group file find the row containing the bluetooth text and add pi to the end of this row It needs to look something similar to bluetooth x 113 pi We can now connect the Pi s Bluetooth dongle to the OBD Bluetooth device using the rfcomm command This command should be the first thing you execute before connecting to OBD You can hang up before continuing using the Ctrl C key combination sudo rfcomm connect hci0 00 1D A5 15 A0 DC Here you should

Raspberry Pi Android Projects

Contents

Download Pdf Manuals

Related Search

Related Contents