Thread: self contained Android/Linux double DIN OS-S/HW unit

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.

Motherboard: Pandaboard
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:




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:




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.

this looks awesome!! I would love android in the car, just got one of these http://www.ebay.co.uk/itm/Google-HD-...item1c25d24783 but need to add drivers for gps, touchscreen and bluetooth etc but dont know the first thing about programming

Excellent project Nordman!

Awaiting more implementation details

Thanks adzxjr, it took me quite a bit to get to this stage.

I had a quick look at your device, and seems to be a nice little device for the car. Your best bet to get it going is to see if anyone was able to put their own version of android on it. That will allow you to build a kernel with all your modules. The fact that most of these devices are locked down was the reason for me to go with open source hardware. You don't have to break the device first to get it going. Also, drivers are available and usually there is enough of a crowd to move things forward.

Thanks DigitalVampire, enjoyed building it a lot.

Right now I am focusing on building my own kernel. Want to get GSM and GPS working without tethered phone or bluetooth GPS. Also tried Android 4.0 (running 2.3 right now). It works on the big screen (HDMI out to desktop screen) but needs kernel patching for the small screen and touch interface.

Will post updates as I go along.

Are you in PA? I don't know anywhere else with a Pomfret St :P

Really awesome build, me and a friend were actually talking about doing EXACTLY this. It's really awesome that you've gone and done it, so we see that not only is it possible, but it's really seriously affordable. I'm hoping you didn't just disappear, and can post some more pictures/information or the website you were talking about putting your details on

Originally Posted by malcom2073

Are you in PA? I don't know anywhere else with a Pomfret St :P

Really awesome build, me and a friend were actually talking about doing EXACTLY this. It's really awesome that you've gone and done it, so we see that not only is it possible, but it's really seriously affordable. I'm hoping you didn't just disappear, and can post some more pictures/information or the website you were talking about putting your details on

malcom2073:
yes, I am in Central PA (did not know, though, that Pomfret St is that unique to pinpoint my location that easily ).

Thanks, as I mentioned this is not my first attempt at a car computer. I learned a great deal from it and what needed to be changed to get a feasable solution that is practical as well as simple and of course works. And no, I did not disapper, just crippled by my inability to post (or it just takes 5+ days to go through posting approval, not able to find my last posts in this thread). Right now I am working in parallel on my website and the carpc. To give a small update I have android 4.0 (ICS) running with touch screen and accelerometer working (thanks to input from the guys at chipsee and linaro). My next focus is to get the pandaboard FM radio working (found some useful hints here: http://code.google.com/p/androidonplatform/).
Most what I posted above should give you a good start, the only thing missing is the power layout and push button setup. I hope to get those things up on my website as soon as possible (just too focused to get the FM radio working, because the cell network is just not cutting it). And of course there is going to be options for android source/compiled image downloads (or a detailed HowTo).

I just joined this site and this is exactly what I was looking for. I'm interested in this setup as well. Tired of the limited software of my Pioneer and like the idea of having a Android interface (i've never messed with Android before), or something that would work nicely with Windows or Linux. I want GPS NAV built in, the ability to connect to my phones wifi hotspot for streaming / internet phone tools, Bluetooth, Voice control, a large capacity 2.5" hard drive (SSD) for storing media files/OS, , 7" touchscreen, all inside that double din case. I've built my own desktop pc's before so it seems like building the pc is easy enough, but I'm not a car wiring expert.I'm unfamiliar on how to hook it up to the car (power supply/fuses/etc)

Originally Posted by murphdog

I just joined this site and this is exactly what I was looking for. I'm interested in this setup as well. Tired of the limited software of my Pioneer and like the idea of having a Android interface (i've never messed with Android before), or something that would work nicely with Windows or Linux. I want GPS NAV built in, the ability to connect to my phones wifi hotspot for streaming / internet phone tools, Bluetooth, Voice control, a large capacity 2.5" hard drive (SSD) for storing media files/OS, , 7" touchscreen, all inside that double din case. I've built my own desktop pc's before so it seems like building the pc is easy enough, but I'm not a car wiring expert.I'm unfamiliar on how to hook it up to the car (power supply/fuses/etc)

I am looking to do something very similar. A few things I want to change are
1)No physical buttons, it will all be touch screen
2)Power up at each car start (no need to have a battery I think but this can be modified later)
3)Integrate with Ford Sync enough to work. This will be the hardest part. There is a PAC audio adapter that might work. The only issue I am trying to think out is how to map the volume buttons and track change buttons on my steering wheel to the buttons on the expansion board. I have sent an email to PAC hoping to get more info
4) Add GPS and possible cell data
5)Somehow combine the SYNC audio with the Pandaboard audio. My idea so far is to use the AUX in SYNC but that isnt an ideal solution

Any comments will be very helpful