Raspberry PI CarPC April 2014 updates

Hello!

I have made a lot of work on the project, with great help from Doru Ignat(idorel@gmail.com) and now the complete list of features is:

• latest Raspberry PI firmware(which supports new models and has fixes for analog sound - no pops any more, you can use the analog out of RPI)
• linux kernel 3.10.30 with various touch screens support and also lirc
• reworked XBMC CarPC skin
• XBMC 13 Gotham beta3(1080p video support, any music and picture format, support playing from archives and more)
• reworked XBMC touch screen calibration algorithm
• XBMC calibration plugin for touch screens(eGalax and others)
• reworked FM Radio plugin
• latest Navit build from source
• fixed Navit to alllow using espeak for speech guidance
• support for WIFI(Airplay, XBMC remotes)

The latest image can be downloaded from the right side of this blog, from the Downloads page.

Cost of the needed hardware parts: 193$
  - Raspberry PI model B: 45$
  - 7 inch display with touch screen for car reverse: 80$
  - HDMI male to HDMI male golden plated cable: 5$
  - 8GB SDHC card: 6$
  - 5V(2A) micro USB charger: 3$
  - Columbus V800 GPS module(or any other): 37$
  - SI4703 FM Radio breakout board: 13$
  - 2 rotary encoders: 4$

After installing the image on an sd card, you have to configure the system for your needs.

Calibrate the touch screen
The touch screen calibration involves two steps and you need a keyboard connected:
  1. Calibrating the touch screen for X11 applications(like Navit). Open the terminal from Desktop and type xinput_calibrator and follow the indications. After the calibration is completed you have to put the output in a file to make this permanent:
    sudo nano /usr/share/X11/xorg.conf.d/01-input.conf
Put here the output of xinput_calibrator. It will be something like:
    Section "InputClass"
        Identifier    "calibration"
        MatchProduct    "eGalax Inc. USB TouchController"
        Option    "Calibration"    "121 1917 317 1741"
        Option    "SwapAxes"    "1"
    EndSection
  2. Calibrating the touch screen for XBMC. In XBMC use the keyboard to go to Programs/Touch Screen Calibration and follow the informations on screen.
Note, that in order to make a better calibration you can move the finger on screen towards the point, before pressing enter(as can be seen on minute 0:52 in the video).
Touch each point and then press enter to go to the next one. At the end, you have to unplug the touch from usb and then plug it back(works on XBMC Gotham).
After this, he calibration is stored permanently in the file /home/pi/touchscreen_axes_calib. You can edit this file to fine tune the position of the cursor if the calibration isn't perfect.
    calib_x_d and calib_y_d - control the cursor displacement up/down/left/right
    calib_x_fact and calib_y_fact - some factors obtained in the calibration process(don't edit them)
    click_confines - defines the area that will be used for click(if the touch moves outside of this area then a drag action will occur) - this area is measured from the first touched point
    touch_mouse - if you want to use a mouse you have to set this to 0, but some touch screens behave as mouses and you have to set this to 1 in order for them to work(with single click). For the most of the touches this can be 0 if you want to also use a mouse, but if you don't want to use a mouse it doesn't mater, let it be 1.

Change the resolution
[XBMC] Using ssh you have to edit the file /home/pi/.xbmc/userdata/advancedsettings.xml and set your resolution. After this restart the whole system and XBMC should run with your new resolution.
[LXDE] Connect with ssh and type
tvservice -mDMT && tvservice -mCEA
and get the desired resolution mode
Edit /boot/config.txt and modify according to your preference, for example:
hdmi_group=2
hdmi_mode=27
CEA group is 1 and DMT 2.

Add a new map for Navit
  1. Go to Navit Planet Extractor and download a .bin file for your area.
  2. Copy the .bin file in your RPI card in /home/pi/.navit/ folder
  3. Edit the file /home/pi/navit_src/build/navit/navit.xml and search for the entry:
       <mapset enabled="yes">
           <map type="binfile" enabled="yes" data="/home/pi/.navit/Romania.bin"/>
       </mapset>
  4. Add your map name here like this:
       <mapset enabled="yes">
           <map type="binfile" enabled="yes" data="/home/pi/.navit/Romania.bin"/>
           <map type="binfile" enabled="yes" data="/home/pi/.navit/new_map.bin"/>
       </mapset>

Setup the GPS receiver
  1. For USB devices. After plugging the device into the usb port type dmesg and you should see somewhere that a new device was mapped on /dev/tty... Most probably the file name would be /dev/ttyACM0.
  2. For Serial(UART) modules. The device will have the file name as /dev/ttyAMA0.
You can test that the device is connected to a file name by calling cat/dev/ttyAMA0, for example and you should see some NMEA output.
Now, copy this file name and put it in the file /home/pi/StartCarPC in the section:
    # Start gpsd
    # /dev/ttyAMA0 - RPI serial port
    # /dev/ttyACM0 - usb port
    sudo killall gpsd
    gpsd /dev/ttyAMA0

Voice configuration for Navit
Each time a road indication has to be made, Navit will execute the file /home/pi/.navit/speech.sh with the indication text. This file will play a sound and the speak the indication, through speakers.
    aplay -r 44100 /home/pi/.navit/notification3.wav & sleep 0.7 && espeak -ven+f4 -s150 -a 150 -p 50 "$1" --stdout | aplay
    /home/pi/.navit/notification3.wav - the sound that will be played each time before an indication
    -ven+f4 - female voice number 4
    -s150 - speed 150 words per minute
    -a150 - amplitude
    -p50 - pitch
You can find more settings in the espeak manual
If you don't want the voice guidance you can press the speaker button in Navit and it will be turned off.

Configure the Controller
The controller can be easily used with Steering wheel controls or other physical controls in your car. To enable this controller, you have to edit the file /home/pi/StartCarPC and search for the entry:
    # Start the GPIO Remote
    #sudo opencarpc-controller /home/pi/gpio_description &
You have to change it to:
    # Start the GPIO Remote
    sudo opencarpc-controller /home/pi/gpio_description &
Now, you can set the configuration file like in this post

Change the car logo in the Home screen
If you want to put another car logo you have to edit the file /home/pi/.xmc/addons/skin.CarPC-touch/16x9/Home.xml and find the entry:
    <posx>580</posx>
    <posy>205</posy>
    <width>550</width>
    <height>550</height>
    <texture>bmw_logo.png</texture>
Here, you can set your new image instead of bmw_logo.png you can put a complete path of the new image.

Set up a WIFI connection
If you want to have internet connection, or airplay or control the whole system using the XBMC remotes, you have to setup a wifi hotspot with your phone and then use an USB WIFI dongle(I am using EDIMAX EW-7811UN dongle).
The system is configured to automatically connect to a wifi hotspot with the following settings:
    wpa-ssid "opencarpc"
    wpa-psk "opencarpc123"
You can find these settings in the file /etc/network/interfaces.

Some pictures with my setup: