self contained Android/Linux double DIN OS-S/HW unit
It has been a few years since I have been active here. Back then I was working on a mac mini install. That project unfortunately had to be abondend. This time around my efforts seem to have been a bit more fruitful and I wanted to share my approach with the community. I have a fully working self contained double din unit running android os build from easily available hardware (manufacturer do provide source documentation). It has internet access (tethered via phone right now, working on build in solution), provides GPS (via bluetooth GPS unit right now, will be integrated via gsm module once software problem is resolved) , music via streaming and local files (no FM yet, pandaboard is a bit tricky as noted by salpula here in the OSH thread), touch screen functionality (resistive right now but can be exchanged to be capcitative) as well as user buttons for android / volume functions, and OBDII (via bluetooth). I had it out on a 5 hour road trip last week and it performed fine (appart from spotty cell reception for music streaming). There were a few criteria for me that needed to be fulfilled, and having a self contained unit was the number one priority. I want to go from this
by just attaching an aftermarket radio adapter (no amp in the car)
I will post more details on my build in the next days.
Here are some more pictures of the UI, navigation, streaming, and OBDII
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android double din build details
Ok, here are more details on my android open source build. Since the goal behind this build is total freedom from manufacturer restrictions, most all components are open source (I will highlight which are not, why not and how they easily can be replaced by opensource-hardware). This ensures that I can use and modify my carpc the way I want without having to first "jailbreak" or otherwise modify it in order to use the full potential of the device/hardware. And if I feel the need to modify any of the components all the information necessary to do so is available.
It has a 1GHz dual-core CPU, USB host connector, bluetooth, and wifi. More detailed info is available on the pandaboard website (pandaboard.org).
Expansionboard: Chipsee Pandaboard Expansion
Provides a 7inch resistive touch screen (can be replaced by a capacitative one, connector are on board), user input buttons (useful for android), mini pci expansion slot (support for data, voice, and GPS), accelerometer+compass+gyro sensor (last two are provided with the board). Comes with prebuild Android version and newer version also comes with ubuntu.
Voice/Data: pci card from a Sierra Wireless AirCard 881U
Not opensource, but that would be asking too much. Right now I am tethered to my phone via wifi hotspot until I get the card included in the linux kernel.
Audio: Philips TDA1524A pre-amplifier (the one I used is sold as Kit100 on the web) and amplifier STMicroelectronics TDA7850, and a power noise filter for the TDA7850
The TDA7850 is available here in the store as prebuild unit: http://store.mp3car.com/TDA7850_Inte..._p/com-140.htm).
The K100 pre-amplifier kit was modified for use with digital potentiometer (push-button version for volume, such as the intersil FN8205, and an i2c version with multi-potentiometer circuit for the tone control).
Housing: Black Double Din Nano-ITX Carputer Enclosure
This is one of the non-opensource components which is available in the mp3car store: http://store.mp3car.com/New_Black_Do...p/enc-041b.htm. The housing is a perfect fit for the Chipsee 7inch screen, leaving about 5mm for the button setup.
Push-button setup: Tactile switches for volume, power, and android control
Simple illuminated tactile switches are used for the volume and user control. In order to make them accessible from the front of the housing I used 4.8mm acrylic rods which you can find in any good hobby store. They can be shaped in any which way when applying heat with a heat-gun.
Below is an inside view of the button setup:
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Power: Pololu Pushbutton Power Switch and CarNetix CNX-P1900 powersupply
The Pololu switch is connected to the ignition wire leading to the P1900 (which is available in the store here: http://store.mp3car.com/Carnetix_CNX..._p/pwr-010.htm) allowing control of the carpc in addition to the ignition state via a tactile switch. The P1900 is not opensource, however it provides the needed power output (5V for the pandaboard, and 18V for the pre-amp). If you wanted to truly opensource approach, just replace the P1900 with a 5V regulator, diode, and some capacitors on a breadboard to power the pandaboard. The pre-amp can be run at 12V if the 12V regulator is removed from the pcb board. However you will loose the cranking capability of the P1900 and its power management.
All of this is tucked into the double din housing:
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Right now I am in the process of setting up a website with a lot more details on the build, in particular the wiring and pcb board layout.