In progress car PC install.

Arathranar · 10-20-2004, 01:37 AM

So some more bits for my car PC turned up today and I thought I'd start documenting what I'm doing for posterity (and in case it helps anyone in the future!). Since the hardest part of the job will be fabricating the case to fit under the seat and the in-dash mounting solution for the LCD, I thought this was the most appropriate forum.

In this first post, I'll list the pieces I'm building it from (and I'll periodically come back and update this list as things change.

What I've got so far:
$5 - Soyo K7-VME AMD m/b (very cheap - both in price and quality!).
$67 - AMD Barton XP 2500+ (currently I'm planning on underclocking - probably to 1900+)
$25 - 2x256Mb Crucial PC2100. I bought these 2nd hand but one was faulty and only reporting 192Mb (so Pc say 448Mb). I didn't realize at first since I'd reserved 64Mb for the onboard video and thought that was the cause of the discrepancy. When the DIMM dropped to 128Mb (PC says 384Mb) I noticed. I saw the PC say 512Mb once - today. The PC occasionally hangs on resume from hibernate - presumably when the memory reported has changed (need to verify) and occasionally reboots randomly (probably the same). So a memory change/reduction looks to be required.
$5 - Metal enclosure - Steel : 3" high x 12" wide x 10" deep. Will house the m/b, 3.5" hdd and dc-dc psu in here.
$10 - 7.2Ah sealed lead acid battery. I'm going to try and build a tank circuit with this to help the cheaper DC-DC psu I intend to get to survive the crank and have time to get the PC to hibernate after turning off the car.
$10 - 10.4" Daylight readable 800x600 lcd with 2 CFLs.
$60 - Raised din mounting console to replace the center glove box in my 2000 Subaru Impreza Outback Sport.
$0 - Powered USB hub I may use to reduce number of USB cables.
$60 - S&T 2005 + USB GPS
$0 - USB array microphone (already had)
$69 - Seagate 160gB 7200rpm Barracuda
$6 - Miniature trackball (0.9"x1.7"x1.7")
$1 - P/S touch pad
----
$319

Unexpected costs:
$20 - Unexpected replacement of my radio when I blew it up trying to create a custom cable to allow aux in. Turns out just because it's the same socket, the same manufacter and the same purpose (cd-changer) does not mean it has the same pin-out. D'oh! Got the same model in the hope I could work it out but I now believe I cannot do this with this model (still I now have the factory hud to put back in when I sell at least!).
----
$20

To get:
$50 - Mini box 200W DC-DC psu (12V is unregulated but has enough amps to drive an AMD/P4 m/b.
$6 - 10" ATX extension cable
$4 - P4-ATX cable to add to the above DC-DC psu.
$? - Electronic bits & cables to build the tank circuit / power the DC-DC psu.
$? - Controller and inverter for the LCD. I know some of the details and it looks like I can get these pieces. I just need to get in touch with a company in Europe and see how much it costs.
$? - Build a sliding/double-rotating mechanism for the LCD so it will slide out of the center raised din in portrait and rotate to landscape.
$? - Simple circuit to trigger startup/shutdown of the PC based on the accessory voltage line.
$? - Low profile AMD heat sink (current one is 3" high and will not fit in the metal case once I have the m/b mounted on the spacers.
$? - New hud with aux-in on back (preferably cassette since I will use the PC for ripped CDs).
or
$? - Tape adapter to get the PC audio into the hud.

Optional:
~$80 - Slim-line slot loading DVD drive (Pioneer off newegg I believe) I may not bother since mostly I want to be playing all my ripped CDs from the computer in WMA format. The in-dash DVD would be used once in a blue moon for DVDs and CD playback if I'd just bought the CD and was driving back from the shop.
~$20 - IDE->USB adapter or have a go at a *long* custom IDE cable using cat6 twisted pair to see if it works (some people have succeeded). This will be needed for the DVD.

Arathranar · 10-20-2004, 01:49 AM

Ok, so we've got a summary of the pieces. What's my plan of attack?

1. Find a controller and inverter for the LCD. Buy it.
2. Come up with the mechanism for the in-dash housing. The LCD is currently 7.25" wide (portrait) and the din opening is 6.75". I'll have to make a bigger slot. I have 10"-10.25" of depth from the front of the new din housing and the LCD is 10.5". But I need a little sticking out! However, building a housing for the LCD is clearly going to be very difficult. The LCD is in a fairly sturdy and not too ugly case already so perhaps I don't worry about it and just use it as it. I still need to attach it to the sliding/rotating mechanism.
3. Use the hud-mounting frame that came with the new DIN solution as a template for the mounting for the LCD sliding mechanism.
3.5. Maybe - mount the USB array microphone in the raised din socket. Just realized the LCD may get in between me and the mic.

3.6. Maybe - mount the slot loader DVD drive above/below the LCD slot.
4. Use sheet metal or plexiglass to build a 'neat' front for the din unit with just a slot for the LCD. LCD will probably be poking out a bit to be grabbble. Otherwise, cut out thumb/finger recesses so it can be pulled out.
5. Do all the wiring. Not sure how the LCD/potential USB hub will be powered from yet.
6. See if my tank circuit works. The high power requirements of this m/b have me worried the 7.2Ah battery just won't cut it - too much voltage drop as it provides the (up to) 16A that is needed for the full 200W the dc-dc psu can provide.
7. Cut holes and stuff in the metal case and mount the m/b inside using the hacked up mounting plate from the cheap case that came with my cheap Soyo m/b. Mount the m/b right at the front of the case because the front/back space under my passenger seat is very limited - 10" is just about bearable if there are back seat passengers but that leaves no room for the VGA plugs etc to stick outside the case. So I'll have them 2" inside by moving the m/b 2" towards the front of the case (i.e. as far as it will go). Possibly use plexiglass to make a nice little enclosure for the cable ends so the m/b isn't "exposed" in any way. Probably won't get round to that though!
8. Route the cables. Build a 15 or 20A switched power circuit powering the tank circuit + dc-dc psu.
9. Hook up the PS/2 trackball. Route the cable through a removed coin holder slot in the center console.
10. At some point - experiment with the PS/2 track pad I'll also be getting ad nd see which I prefer

.
11. When I have some spare time, write some speech control software for AutoTouch and any other things I want to control (used to do this for a job so I have a head start here

).

Will post some pictures of my bits shortly and hopefully things will make a lot more sense then. The long arm of this install is clearly the LCD controller and the mounting mechanism.

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