Thinking about building a car computer system

[CHollman82]

I was going to do this in my old car but it was such a POS that I didn't even bother, but now I am interested in it again. What I was thinking was setting up a very basic mini-itx system and mounting it in the trunk, mounting an lcd display on the underside of the passenger sun visor, putting a keyboard on the inside of the glove box door, and a trackball mouse on the center arm rest.

The computer itself would use a Via-EPIA board, probably the 800mhz or 1000mhz model (the epia boards have processors built onto them), 256mb pc133 sdram, and my old 20gb WD hard drive. I would power it with either a 50-100 watt DC-DC power supply connected direcly to the battery, or a DC-AC inverter plugged into the cigarette lighter and a standard computer power supply. Since my headunit doesn't have any input jacks I would split the speaker cables and wire them to a 1/8" headphone jack that would connect to the line-out on the soundcard. I would use the system for MP3's primarily, but it could also be used to watch divx movies, play games, do homework (yeah right), and maybe even use the internet.

So, what do you think? Any comments, suggestions, or questions are welcome, and if you've done this kind of thing before I would appreciate any advice or help you can give me.

[car audio dave]

[quote]Since my headunit doesn't have any input jacks I would split the speaker cables and wire them to a 1/8" headphone jack that would connect to the line-out on the soundcard.[qutoe/]

thats very creative. just be careful you dont blow your speakers with the distortion. in all likelihood they wont be very loud and youll turn the volume way up to compensate. that can blow speakers.

other than that, it all sounds good. are you gonna link it into your diagnostics on your cars PC? that would be awesome to have a program on there so you can know when anything goes bad on your car.

[CHollman82]

"are you gonna link it into your diagnostics on your cars PC?"

I never thought about that, that would be cool. But diagnostic software is extremely expensive isn't it? The keyword for this whole project is "cheap"

"just be careful you dont blow your speakers with the distortion. in all likelihood they wont be very loud and youll turn the volume way up to compensate. that can blow speakers"

Maybe Ill find a different way to do that then, I wonder if you can buy an adapter like that

[sunrunner_pei]

Originally posted by CHollman82
Since my headunit doesn't have any input jacks I would split the speaker cables and wire them to a 1/8" headphone jack that would connect to the line-out on the soundcard.

The problem with doing that is that the speakers would be un-amplified. Most coputer speakers have a small amplifier built in. Plug a pair of un-amplified computer speakers into your sound card and you'll see what I mean. ;) This will not work as is with your car's speakers.

I'd suggest getting a new HU that has an AUX. input, or pick up a FM Modulator (like for a changer) that has an AUX input to use your current HU.

[sound_xtreme]

Yea, companies make RF modulators specifically for rca in's on HU that dont provide any. I sell some and they work wonderfully, you can do a seach on ebay and come up with a few probably.

I was wondering though. I have never been able to find any good DC-DC power supplies that arent a million a dollars.

I was gonna do the same thing(only I plan on running a Athlon XP) and was gonna get one of those foldable backlit keyboards for up front.

Let me know on the DC-DC power supply if you can find any.

[twitch]

in all actuality guys, you shouldn't need a DC-DC power supply, because all the power supply in a comp does is drop it to 12 volts...so it SHOULD work, but don't quote me on that

Twitch

[CHollman82]

Here is a 60w DC-DC PSU for $50

http://mini-box.com/pw-60.htm.

I wouldn't use an athlon xp, they are great processors and I have the 2800 in my computer, but in a car they run too hot and use too much power. From the research I've done on this the less moving parts the better, the only moving part I plan to have is the HDD, which I will make a seperate enclosure for so that I can better protect it from shock and better cool it. The main things you need to remember if you are going to do this is that you don't have a lot of power to work with, you don't have very many cooling options (can you imagine how hot it gets in the trunk in the summer, even in NY), and the components will be under constant shock and stress.

[CHollman82]

Originally posted by twitch
in all actuality guys, you shouldn't need a DC-DC power supply, because all the power supply in a comp does is drop it to 12 volts...so it SHOULD work, but don't quote me on that
Twitch

Actually, computers need 12v, 5v, and 3.3v rails, and maybe others, so you will need some kind of electronic setup between the battery power and the computer power, and since I am not a great electrician I might as well buy a PSU.

Something else I just realized is that computers constantly draw power even when they are off, so wiring a master kill switch between the battery and the PSU is necessary, I could probably mount it on the side of my center console

[CHollman82]

"I'd suggest getting a new HU that has an AUX. input, or pick up a FM Modulator (like for a changer) that has an AUX input to use your current HU."

But I like my HU :(
How much do FM Modulators cost?

[sound_xtreme]

fm mod's are about 20-30 bucks.

I dont plan to have my computer in the trunk. I am going to have a custom fiberglass center console running from the front to back. And cooling....that is what fans are for(i think fans can handle vibrations and jolts rather well since many amps come with them). The hard drive, thats a different story.

And the reason I want to run something higher in Mhz is beacuse I plan on running mostly DivX on this machine.

[Coolwave]

For a power supply I would suggest one that is made for use in a car. I know http://www.opussolutions.com/ specializes in this area. It does look like a sweet solution.

If you head over to mp3car.com and check out their forums there is a lot of information. In the Powersupply area I found that the Opus power supply retails for $180 and also if you are a member of the mp3car.com forums you can get $10 off or free shipping from Opus.

I think everything you would need to know is listed in those forums, but when you get it all figured out don't forget to post everything you do along with pictures here! :D

[CHollman82]

Thanks for the link, I don't think I will have pictures anytime soon, this is just an idea but right now I don't have enough money to spend on this, and won't be making much more than I need for my car payment anytime in the near future. I was planning on building piece by piece, so that maybe this time next year Ill have a really cool system in their

[JMILLS]

I am going to be working on the same project over the next couple of months, but with a different purpose. I intend to link the system in with a software package that runs diagnostics and soon will be showing HP/Torque. My major slow down right now is video output. Haven't figured out an inexpensive monitor option.

[nadir]

hey, good luck on your project.

I attempted this at once... and you know what? after using it for about a month, it got too complicated and tiring to always updated unles you get really hardcore and set up a wireless networking that would automatically synchronize your music/other media files w/ one on your server machine.

There are GPS units that plug in via USB... all you'd need is a road mapping software.

As for power supply... i just got a 300w. power inverter for my car and it worked like a charm.

I had problems with goin for audio... if you settle for FM modulator, you lose alot of quality. The bose systems that come w/ the maximas are a little bit complicated so I couldn't just splice wires in the harness. I just used a cassette adapter.

As for the LCD screen... you're best bang for the buck is getting a PS1 TFT backlit screen. You know those mini screens (7" i believe) for mobile playstations. You could just remove the screen and make a custom case for it and mount it somewhere. That's what I did... I mounted it on a flex-arm that I bought from crutchfield.com ($20). The LCD screen had a S-video input and my built-in video card on the PC had a s-video out. worked perfect.


If you are still interested in doing this... join this forum ( http://www.mp3car.com/vbulletin/index.php ). They are dedicated to projects such as the one you want to attempt. Also, they have plenty of pics so that you can get an idea of it.