Is this schematic any good???

**umarth** · 03-10-2005, 02:39 AM

A year ago I bought an old crappy car (87 trans am) to learn mechanics and just have fun fidling with it. On of the things I wanted to do was put in a computer. When I found this site I tought: ****, I'm not the only crazy bastard to think up stupid **** like this!

So any way, this is my first post. After spending a dangerous amount of time reading stuff here, I drew up a schematic of what the 1st phase of my carputer might look like, and I'm hoping some of you guys have the courage to look it over and give your thoughts on it. (see attachement).

For it's intended purpose, I need a moderately strong processor and a half decent 3D video car that supports hardware accelerated T&L. Hence the P4 mobile with a GForce 3. I also whant Very clean sound from this thing (will not have a head unit) so I'll probably use a SB Audigy NX or SB Extigy. And before you ask, no it's not for gaming: custom GPS app by me and some collegues of mine.

Note: the computer, inverter, external sound card and amps will be at the rear of the car. The USB hub will ether go between the two front seets (center concole) or directly into the front dash. The dash will only have the Touch Screen and CD drive.

The only reason why I'm thinking of going with an inverter is for scalability reasons: as the project goes on, I'll be adding more and more junk to it (step motor controlers, sensors, possibly 1 more screen, etc.) And the fact that I'm not sure if the OPUS 150W would suffice for the current config.

Well, long enought for a first post. Comment and advice are please! Good or bad.

ps.: HD will be a 3.5" 7200 RPM of mederate to large capacity (depending on how well we manage to compress all the GIS data -a mix of vector and raster).

**Mad Ad** · 03-13-2005, 11:31 PM

use all your USB sockets before you go to a hub

**WebDog** · 03-13-2005, 11:40 PM

i would also cut the ITPS out of that setup...

**Bugbyte** · 03-14-2005, 12:12 AM

You're using the ITPS to power the Xenarc, right? As long as you're doing that, I don't see a problem although the Xenarc may not work properly when you have the car switched off.

I've been using my Xenarc plugged directly into the cigarette lighter for months with no ill effects. It comes with a lighter adaptor, so I surmise it is designed to deal with voltage fluctuations. If you are worried about it being powered and draining your battery, don't. I leave mine on and it hasn't yet. If I'm away for more than a week or so, I unplug it. Might be better just to get a timed relay that switches on when power is on and off when key is out of ignition.

Otherwise, congrats! Looks like you're planning it out carefully, a key ingredient for success.

**umarth** · 03-14-2005, 08:37 PM

The reason why I'm thinking of puting a USB hub in there is because of the distance between the screen and the motherboard: a good 10-12 feet. And I'm worried that this might be a bit far for a USB cable.

If you take a closer look at the drawing, you'll notice that the hub has a 10 foot cable that goes to the mobo, and that the CD drive and the zenarc are about 1 foot away from the hub.
Now, if 10-12 is no major issue for a USB cable, then I could drop the hub (for now any way)?

As for the ITPS, I've already decided to drop it, as I want the screen to survive the crank and the thing needs 13 and some volts to give 12v. At the moment I dont know where I'll tap the 12v for the screen.

**umarth** · 03-14-2005, 08:48 PM

As Webdog and you suggest, I've decided to scrap the ITPS mainly because it does not survive crank n'or engine off. Useability wise its not a big thing, but I just think that it makes for a better integration look if the CarPuter can behave just like normal HU.

Silly me, I had'nt thought that the screen could simply be plugged directly into the cig. ligther. That could very well do for the first install of this setup.

Thanks for the input.

**Bugbyte** · 03-14-2005, 10:32 PM

Drop the hub. I've got 16 feet of USB with no problem at all. Lots of others have reported the same. If it gives you fits, you can always put one in.

**thanatos106** · 03-14-2005, 10:42 PM

Originally Posted by Bugbyte

You're using the ITPS to power the Xenarc, right? As long as you're doing that, I don't see a problem although the Xenarc may not work properly when you have the car switched off.

I've been using my Xenarc plugged directly into the cigarette lighter for months with no ill effects. It comes with a lighter adaptor, so I surmise it is designed to deal with voltage fluctuations. If you are worried about it being powered and draining your battery, don't. I leave mine on and it hasn't yet. If I'm away for more than a week or so, I unplug it. Might be better just to get a timed relay that switches on when power is on and off when key is out of ignition.

Otherwise, congrats! Looks like you're planning it out carefully, a key ingredient for success.

There is nothing inside the cigarette lighter just a led and a resistor.......

My xenarc is plug to the carputer and goes on and off with the hole setup...

Nice diagram and good luck.......

**maxxell** · 03-14-2005, 11:10 PM

10-12 feet might not be enough to traverse from the trunk to the dash. I spoke with a professional installer before doing my setup and he said 15 is the minimum, so I went with a 16-foot wire to a hub. USB isn't guaranteed to carry beyond 16 feet (see the back of your USB devices boxes). I use a 16-foot USB wire to my hub, then another 2 feet or so of wire from the hub to the lilliput and have never had a problem. It's just one more thing you should be aware of.

MadAd- Why would you use the USB sockets before going with a hub? If you've got a bunch of devices, I would think it better to run one long cable up to the dash, then branch out from there. Am I wrong?

**umarth** · 03-15-2005, 07:21 PM

Your xenarc is plugged to the car puter? in what way? How was the wirering done? I mean the power cable of the zenarx is pluged into what 'plug' of the PSU? And what PSU du you have?

Thanks