Archive for July, 2007

Car PC: Part 4 – The Installation

With the hardware set up and all the software systems configured, it was now time to install the whole thing into the car itself. The whole process took a while to do and was split into three main chunks:

Wiring

The first job was to lay down all the wiring. This included power cable, speaker wire and extension leads for the screen.

Wiring Diagram

In the above diagram, what is not shown, is that both the PC and Amp take their power from a thick power lead, fused, put through a distribution block, and run directly from the battery. Additionally, a switched positive connection is required for the M2-ATX to initiate remote startup and shutdown procedures. The easiest place to run this from, I found, was the existing headunit ISO loom.

The black, red and green connectors running to the screen in the diagram are the power supply and USB/VGA connectors. The power was spliced into a connection from the M2-ATX as the screen is designed to run from regulated 12V DC. These cables were run down the centre of the car.

Finally, as shown on the diagram, the audio connections run from the PC to the AMP via a 3.5mm audio jack adapter –> RCA/Phono connectors (blue), and then from the amp, I wired the speaker outputs to the old headunit ISO loom (purple wire pairs). All the speaker cable in the car was replaced with decent quality, shielded stuff. The picture below shows the cables being laid with the centre of the car bare as a work in progress.

Cables

Another note: When running the cables down the car, it is important to physically separate the power and data/speaker lines to prevent inteference which commonly manifests itself as alternator whine coming through the speakers. The easiest way to do this is to run the two sets of cables down either side of the centre console, or run them down either side of the car itself.

Cables cont

The above pic shows the cables running from the car interior, through the ski hatch and into the boot.

The Screen

With all the wiring in place, access to the wiring loom behind the dash was no longer required and so the screen was the next thing to fit. Obviously, prior to the final installation it had been tested for fitment so it was simply a case of refitting the centre console with the screen installed into the dash. The pic below shows what things look like behind the scenes on the dash:

Dash Bare

The PC

And finally the PC was secured in the boot using metal mounting brackets beside the subwoofer and the wiring tidied up. All the USB data leads, VGA connection and the power and switched ignition leads were connected to the PC and Amplifier via the M2-ATX. Just to note that at this point, the amplifier being used is quite a basic one which is why it has not been installed ‘cleanly’. When I get a proper amp, the boot installation will look a lot tidier and I will gain a bit more boot-space.

Boot state

You can see the PC beside the subwoofer and it fits snugly in the gap.

Wiring amp

The ultimate plan is to create a ‘stealth’ panel infront of where the PC is currenty fixed and fit the amplifier behind that as well. That should make things look a lot cleaner and give some more room (not that I use the boot a lot anyway).

The Finished Article

With everything done, here are a few pics of how it looks completed and installed:

Finished

Loading/resuming Windows XP at bootup:

Loading windows

The main frontend view (this is Centrafuse, but I usually use RoadRunner)

Frontend

Sat Nav view

navigation

Media player currently playing Linkin Park

media

GPS and WiFi adapters installed out of the boot for better reception. They are hidden behind the seatbelt and secured to the plastic coving.

gps and wifi

View from the rear seats.

rear view

Overall, the installation looks very OEM (to me at least! and boot excluded obviously lol). There is no evidence of the masses of cabling in the car and having the PC gives me a lot of functionality that I wouldn’t get with a regular headunit or even an all in one headunit costing a lot more.

There is also a lot of room for potential upgrades and further features which I can implement at a later date – and I have hinted at a few plans throughout the course of these posts… so this is basically a never ending project!

I hope it has been a good read and things do make sense. If you have any comments or questions, either post away on any of the posts (parts 1- 4) or just get over to the forums for anything a bit more in-depth.

Cheers.

Car PC: Part 3 – Software

Part three of the Car PC saga :D

Now that the PC itself was up and running and the screen and mount were completed, it was time to work on the insides of the beast, so to speak: the software – the thing that makes everything work!

The Backend

The PC itself was based on an extremely cut down version of Windows XP SP2. I removed unecessary features, slipstreamed hotfixes and drivers, and pre-installed some tweaks making a totally unattended installation that automatically installed everything I needed. This created a small install footprint and made the OS very quick to boot from cold / resume from hibernation.

I did experiment with using a 4GB compact flash card and CF -> IDE adapter as a boot drive mainly for the speed advantage (and solid state advantage), but due to the limited write cycles on CF cards, installing a standard version of XP (dynamically) would severely reduce the lifetime of the card. There are solutions to this (eg, using XP Embedded from Microsoft), but that involves a lot of hassle, so I opted to go for the old fashioned mechanical hard drive.

The entire system was tested indoors using a regular ATX power supply for ease of troubleshooting any problems – especially with the multitude of USB devices being used. Bluetooth partnerships were created with headsets and phones and COM ports configured for the GPS reciever and FM radio. When the system was found to be stable and with everything fully functional in it’s barebones OS state, it was time to install and configure the frontend.

The Frontend

The frontend is essentially what you see when you look at the screen. It is the software that is running and gives the user the functionality required from the PC in the car environment. There are several front ends available for use – some free to use, some not. Which frontend you choose is down to personal preference and before making a decision I tested two of the biggest ones on the system:

RoadRunner

RoadRunner

This front end is free to use and is customisable both in terms of plug-ins and skins. It links to other external applications to handle various functions. Eg. Audio playback is controlled by winamp, GPS navigation can be controlled by Freedrive/Mapmonkey (maps are required from “Destinator” but need to be purchased) and DVD playback could be handled by PowerDVD, for example. It has a large userbase, because it is free and does the job very well.

Centrafuse

Centrafuse

The other frontend I tested out was Centrafuse. This one is not free to use (there is a trial available), and comes in several different versions – the price of each is determined by it’s feature set. Again, very easy to work with – perhaps more so than RoadRunner, and there are a lot of plug ins and a few skins available. Centrafuse handles the majority of functions independently (as far as I can tell) as it doesn’t seem to call on other external programs as much as RoadRunner. One point to note is that Centrafuse does seem a little more resource hungry compared to RR.

Each frontend is very easy to set up and get working for basic functionality but things like phone control and GPS are a little more involved.

Now that system is fully operational, all that remained was to transfer some multimedia (audio and video) onto the hard drive so that there would actually be something to play! When doing this, make sure all files have correct ID3 tags otherwise when the frontend reads them, if you try searching for something by listing albums or artists, it will be a mess…

Transferring material to the PC in my case was simply a case of connecting to the wireless network and accessing network shares containing the albums etc that I wanted. This method will also be used when the PC is installed as the wireless link works from the driveway without any issues.

With everything as I wanted it, the final stage was to install the whole lot in the car. See Part 4!