CarPC Project

Discussion in 'Multimedia' started by AudiA4B6US, Mar 25, 2006.

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    AudiA4B6US Super Moderator

    - Set up a media library PC using the RNS-E for all communication with the driver and allowing acces to any media file stored on devices that are connected to the PC via USB.
    - Use PC to connect to OBD and display vehicle data fully integrated into RNS-E MMI user interface

    So far completed:
    - Mini-PC (Aopen Pandora) connected to RNS-E TV-in via VGA to RGBS converter (still requires Dietz AV adapter to enable TV on RNS-E)

    - Install mini Windows XP containing only the absolutely required components to play audio/video, minimizing boot time and RAM/HD requirements
    - Setup front end to simplify in-car use
    - Integrate media library PC into CAN-Bus to allow control via RNS-E and output data on Driver Information System (DIS)
    - Replace Dietz AV adapter with custom application enabling TV on RNS-E by sending certain CAN message via CANUSB adapter.
    - Replace Dietz Video in Motion adapter by custom application utilizing CANUSB adapter instead
    - Create plug and play harness to connect media library PC to RNS-E


    And this is how everything began...

    If you are a geek, what would you do if your computer produces a screen like this:


    Windows XP SP2, ATI Mobility Radeon, PowerStrip are the tools installed right now. I can get a clear 400x234 picture when I control the PC remotely (so the card does support the resolution) but I'm lost at how to tweak the frequencies to make the picture show up on the RNS-E.

    In case you know what I'm talking about, here are the PowerStrip settings:

    PowerStrip timing parameters:

    Generic timing details for 800x600:
    HFP=48 HSW=128 HBP=80 kHz=31 VFP=1 VSW=4 VBP=23 Hz=50

    VESA detailed timing details:
    PClk=32.95 H.Active=800 H.Blank=256 H.Offset=32 HSW=128 V.Active=600 V.Blank=28 V.Offset=1 VSW=4

    Linux modeline parameters:
    "800x600" 32.950 800 848 976 1056 600 601 605 628 +hsync +vsync

    800x600 is definitely to much but I can't get the picture to not roll with any other resolution.

    Any hint would be appreciated,
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    I guess this subject isn't very high on anybodies angenda. Anyway, I made some progress and got a stable screen at 720x540 interlaced, somehow based on the PAL standard. The RBGH wires from the PCs VGA port are now directly connected to the 54pin AMP connector on the RNS-E. Once Windows is up and PowerStrip loaded, the screen is stable but the text is unreadable because the RNS-E scales the 720x540 down to its own 400x234 pixels.


    RoadRunner is one of the more popular front ends for CarPCs and just as a test I made a skin with only one static page. Surprisingly, images are pretty clear, much better than text at any resolution.


    Hard to see on the picture but there is a little mouse pointer between the MP3 List and MP3 Card1 text, just to confirm that this is not the normal MP3 screen. The quality is acceptable, not as clear as the other screens, maybe 90% or so.

    Now the next step will be to figure out how to keep the TV option enabled without having that multimedia interface connected. And of course how to use the controls on the RNS-E to control RoadRunner running on the PC.
  2. takuem New Member

    I am interested... Just have NO idea what you are talking about.
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    AudiA4B6US Super Moderator

    Me neither, but that's the fun part of the project. Eventually I hope to have a fully integrated MP3/AAC/WMV/MOV/whatever player, maybe with VAG-COM and some other tools integrated, that gets controlled via RNS-E and MFSW. But that's a long way to go...
  3. PROXUS Administrator

    Nice ;) do you think it will be possible to use custom resolution (hardware based or software based) to match RNS-E screen resolution? This way text would be perfect sharp.
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    AudiA4B6US Super Moderator

    So far it looks like you cannot access the display directly. The RGB in connects to a cicuit that expects a PAL/NTSC signal, even though the signal comes in via RGB and not RCA/S-Video. Makes somehow sense because all the RNS-E was supposed to do is to display the picture of the OEM TV Tuner and rearview camera (in the Lamborghini that is). I'm still looking around to see if there is a way to use 1/4 PAL or so (something like 360x270 or so) which is scaled closer to the native resolution. But so far I had no luck with that. The other option would be to switch to Linux and see if there is a better way to adjust the resolution. But I'm not really the Linux guy.
  4. todd1010 Member

    I'm definitely interested, and have always wanted a little setup like this. I would like to try and put one of these in there:

    The thing is that I don't know where to start.

    It's just like the Mac mini but a PC. I just sold my Mac Mini because it just wasn't user user friendly. Plus I've always been a PC user, so the change was a little different.
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    AudiA4B6US Super Moderator

    I got the Aopen Pandora for this project but it has only the Intel GMA integrated graphics. PowerStrip doesn't support custom resolutions and timings with the Intel GMA. Therefore I'm using now a ThinkPad X22 that comes with the Ati Mobility Radeon and supports all kind of tweaks. And the Pandora will probably end up as Media Center at home.

    I have also access to a HP T5710, a thin client with an 800MHz Transmeta booting Windows XP Embedded from a flash disk. That one has the onboard ATI Mobility Radeon 7000 and supports similar tweaks. Once I'm done with the X22 and know where I want to go I probably get one of those HPs. They are small, passive cooled, have USB 2.0 and serial ports and run on 12V. I already got XP Professional down to about 400MB (with Nlite), booting of a CF card in a couple of seconds.

    There are still many questions to be answered but it's still an interesting project...
  5. todd1010 Member

    So one of those Aopen Mini PC's won't work because of the graphics card?
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  6. takuem New Member

    Can you use the mouse to select functions native to the RNS-E and navigate using the mouse? This would be nice since Audi doesn't give us TOUCHSCREENS! :evil:
  7. timothyadam New Member

    Connections on 54pin input?

    Any updates on the progress, AudiA4B6US?

    I'm also wondering if you can put any sort of schematic for your input setup to from VGA to the AMP connector? i'm attempting to do the same with a Powerbook or Mac Mini, and could use a little direction....
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    AudiA4B6US Super Moderator

    No, no updates for now. This is one of the longer lasting projects, at least for me as I have only limited time between all the other things to do.

    There are two options to connect a PC to the RNS-E. The first is via Composite (RCA) through a Dietz 1417 or similar. This will allow you to use whatever TV out your computer has and display it on the RNS-E screen in TV mode.

    Advantages: Easy to connect
    Disadvantages: Expensive (you need an AV adapter just to get the picture on the screen), poor quality (TV alone is bad but the stretched picture on the RNS-E is not really worth to be called a computer desktop), computer must support TV out

    The other otpion is to use the RGB in directly. The AMP connector has the 5 pins you need labeled but there is no information as to what kind of signal it expects. It looks like it's a RGB Video signal with composite synch supporting both PAL and NTSC. The issue is to find a video card that supports the frequencies and resolution used for a TV. The other issue is that the software required to tweak the video settings only runs under Windows which means you won't see anything while the PC boots nor can you use a Mac for this.

    Advantages: Cheap (assuming you already have a computer with the correct video card
    Disadvantages: no know "perfect" setup, may be a Windows only solution

    The 3rd option would be to use Linux and its capabilities to tweat the video settings. But I'm not a Linux guy nor do I know any front end for Linux.

    As you can see, there is still a long way to go...
  8. timothyadam New Member

    Hey, there may be a long way to go, but I'm in for the ride 100%. I'll mess with the RGB inputs tonight or tomorrow and see if I can find some sort of solution on the Mac end (it may have to wait for the weekend until I can put some serious time into it) and I'll let you know if I find any results. I have the 1417/1280 in already, so that at least gives me something to compare to.
  9. audihir New Member

    Media Center Edition

    Hey guys...good work so far. I worked a lot with custom resolution issues and Powerstrip, etc...and even after twisting and tweaking forever...once I had a stable resolution that worked, I still couldn't get the text comes Media Center 2005. I would like to work with you guys to get this thing working in the Audi's, but I am telling you, go with the MCE 2005 as a base OS...unless you know Linux of course (which I regrettably do not either). MCE has nice large Icons just for this reason, and with a few tricks you can easily play DVD's from the hard drive and use the catalog displays just like the MP3's. My brother has developed and completed systems for his Hummer H2 and Z06. He was using some other software package on Windows XP...I can't remember the name off hand, but I will talk to him about it. Did anyone get (or have) the actual technical specs for the true supported resolution? I would assume that with the right harness you would be able to connect this directly using VGA, provided you can get Powerstrip setup with the correct resolution and refresh, which is a whole other deal.
  10. timothyadam New Member

    Windows MCE05 = Apple FrontRow

    Thanks for the input, audihir-

    The equivalent of MCE05 for a Mac is called FrontRow, and works very similarly. I can already connect that via Dietz 1417 (S-Video quality sucks) but is very readable despite the very grey background that is supposed to be black and is messed up by the S-Video.

    I plan to have this fixed this weekend via a direct RGB connection through the VGA output from my Powerbook.

    At this point, I think I'll have to settle for using the Griffin PowerMate as my control device, and use SwitchResX (the equivalent of PowerStrip for a Mac) to get an optimal screen resolution.

    The other thing I am toying with is to try and find an aftermarket touchscreen that is the exact same size of the RNS-E screen, and that I can *very carefully* install in its place. If anyone knows of a particular screen that is the exact size and is a touch screen please let me know!
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    AudiA4B6US Super Moderator

    Good to see that there are some others interested in this too. PowerStrip is a nice tool but unfortunately does it only work within Windows. OS X may be better because it's UNIX based and may allow the same tweaking as Linux does - with the right tools of course.

    I took a look at RoadRunner which is nice and has a large community working on skins. I also found a new front end called cPOS that has a growing number of users because it has build-in interface to read data of the CAN-Bus - something that is a must for me because I want to control the PC via RNS-E.

    While I was playing with my CAN2USB adapter I got a couple of IDs that could be used to control a PC from the RNS-E in TV mode:

    461h (while RNS-E is in TV mode):
    37 30 01 01 00 00 prev track
    37 30 01 02 00 00 next track
    37 30 01 40 00 00 MMI upper left
    37 30 01 80 00 00 MMI lower left
    37 30 01 00 10 00 MMI button pressed
    37 30 01 00 20 00 MMI button turned left
    37 30 01 00 40 00 MMI button turned right
    37 30 01 00 02 00 Return pressed
    37 30 01 00 01 00 Setup pressed

    There are also IDs identifying the current audio source:
    81 01 12 A0 00 00 00 00 AM/FM
    81 01 12 2F 00 00 00 00 SAT
    81 01 12 37 00 00 00 00 TV (Video In)
    81 01 12 A4 00 00 00 00 MP3
    81 01 12 A5 00 00 00 00 CD

    This makes me believe that it should be relative easy to control the PC via RNS-E. The main issue remains the VGA to RGB conversion, from POST until the OS has fully loaded.

    There is not much data available on the real resolution of the RGB input but based on what I read so far, it seems to be a standard NTSC/PAL TV range. I tried to find some converter that can convert the VGA RGB H/V signal to a RGB Composite synch signal but those converter are pretty expensive because they need to do the frequency conversion as well. Maybe there is an OEM module (not only Audi/VAG, maybe Lamborghini :lol: ) that converts a VGA signal to RGBC/NTSC? I don't know.

    I got the Aopen Pandora that comes with a RCA video out. I was thinking of using the Pandora but it only has the Intel GMA graphics that is not really supported by PowerStrip. The best I could do was getting it down to 640x480.

    I also have access to a Mac Mini that has the ATI display adapter. Since the ATI supports custom resolutions, maybe SwitchResX can do better than PowerStrip? Might be worth a try.

    The most interesting alternative is this HP thin client. A Transmeta 800MHz CPU should be fast enough for a CarPC and its ATI 7000 does support custom resolutions. It has an internal 256MB (or optional 512MB) Flash disk where it boots XP Embedded from. Pretty nice.

    So I guess there are plenty of way to use a PC with the RNS-E - once we got it connected to the AV in with a usable resolution.
  11. timothyadam New Member


    hey audia4b6us-

    where can i snag one of those CAN2USB adapters? that looks like a really great tool to use for just about any interface needs regarding the RNS-E...
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    AudiA4B6US Super Moderator

    Re: CAN2USB

    I have this one: but you don't want one of those because they are too expensive. There are a couple of alternatives (Google for CANUSB), just make sure that there is some support available. The hardware should at least come with a COM port driver and CAN Monitor to allow easy integration and monitoring.
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    AudiA4B6US Super Moderator

    A minor update for those who are still interested. The video in of the RNS-E is a standard RGB video in. I was finally successful using an old PC to TV adapter I had lying around that supports VGA to s-video, composite video and RGB/YUV video.
    The converter had a 15 pin Sub-D (HD-15) plug for RGB/YUV and it took a while to figure out that the C synch signal is on pin 15 (H/V synch are on 13/14 and usually H synch is used for C synch when using a PC video adapter).

    Anyway, the converter is one of the cheap kind that allows you to adjust the picture but doesn't store the settings so they get lost when you remove power. Nevertheless, after some fine tuning I got a clear but resized 800x600 picture from my Aopen Pandora mini-PC. The good thing when using the VGA to RGB converter is the fact that you can see the picture even during boot up before Windows fully loaded. That was one of the issues using PowerStrip and a video adapter that would support RGB video.

    The next step will be to find a better VGA to RGB converter that stores the settings and also to continue playing with the CANUSB adapter to figure out how to control the PC via RNS-E.

    Stay tuned...

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