Power advice needed

navmaxlp · 01-21-2008, 05:31 PM

Ok so, I'm planning out my project and I know I'm going to use a Samsung Q1 ultra UMPC. Most likely running Streetdeck on it and already know I'll be using the SC-C1 sirius receiver and a GPS receiver. I was thinking of using an external sound device as well. I'd like to hook it all up to a USB hub. I'd like the hub so when I get out of the car, all I have to do is unplug the USB and the power cables and take the computer with me.

The advice I need deals with how to power everything. My car has a built in inverter (dodge caliber) and a cigarette lighter. The inverter is under the center armrest out of the way and shuts off with the ignition. The lighter is slightly hidden as well.

I've been stuggling to figure out first what needs external power and second how to supply power to the items that need it.

I assume the hub will supply sufficient power to the GPS receiver and the sirius receiver and that they don't need any DC in to the unit itself. I'm hoping the Sirius to USB adapter won't need any power either but it seems like it does. I know some USB sound cards may need power but, it seems like some don't. I'll be using an FM transmitter to go right into the antenna of my stock radio so the simplest audio out is fine.

If the sirius adapter needs power, that'll be three devices with only two sources. I'd rather not put a power splitter on the inverter but, it seems like that may be a viable option. I would assume it could handle the minimal amperage draw of the devices it'll be powering. That way, I could use the cigarette lighter to power the UMPC itself.

I've been going round and round with this and I'd like to see what other people think. I'm probably making this much harder than it needs to be. Perhaps I've been obsessing too long. Anyone have any thoughts?

Thanks in advance

navmaxlp · 01-21-2008, 05:44 PM

Here are the parts I was thinking of using

UMPC:

http://www.dynamism.com/q1u/main.shtml

FM modulator to get audio to the stock radio:

http://www.circuitcity.com/ssm/Audio...oductDetail.do

Sirius adapter:

http://www.rush2112.net/mkportal/mod...products_id=35

Sirius receiver:

http://www.crutchfield.com/S-fjzpfxp...aspx?I=607SCC1

USB sound:

http://www.newegg.com/Product/Produc...82E16829128002

GPS antenna:

http://store.mp3car.com/BU_353_Weath..._p/gps-002.htm

For the USB hub, it doesn't really matter, there seem to be so many out there and they all seem the same

DarquePervert · 01-21-2008, 06:15 PM

FM modulators are garbage for sound quality.
I wouldn't expect stellar sound quality from that USB sound device, but it could surprise you.

For powering everything, I suggest reading some FAQs on the topic: http://www.mp3car.com/vbulletin/advfaq.php
There are quite a few about powering a computer in the vehicle.
As a general rule, inverters suck. Your OEM unit that's integrated in teh vehicle may be better than most, however. I'd still recommend going with a DC-DC PSU, though and save the inverter for when you need to plug in a blender or something.

moboman · 01-21-2008, 06:46 PM

22 bucks plus shipping for a cheap usb sound card!! Check ebay, I know there are chinese usb sound cards on there cheap!!!! I have even seen them with the FM Modulator built in.

billmee · 01-21-2008, 09:08 PM

First of all what do you know about the built in inverter.
Is it a pure sine wave, what kind of power can it deliver?

As for the USB devices I prefer to power them off of a hub with a seperate 5v source.
Regulating the 12v from your Batt/Alt down to 5v is pretty easy to do for this.

navmaxlp · 01-22-2008, 01:34 AM

Quote: Originally Posted by billmee

First of all what do you know about the built in inverter.
Is it a pure sine wave, what kind of power can it deliver?

As for the USB devices I prefer to power them off of a hub with a seperate 5v source.
Regulating the 12v from your Batt/Alt down to 5v is pretty easy to do for this.

Well, caliber forums have it at 150W peak. I figure it should be able to handle up to about an amp constant. Thing is though there's no ground prong. Any thoughts?

billmee · 01-22-2008, 04:43 AM

Quote: Originally Posted by navmaxlp

Well, caliber forums have it at 150W peak. I figure it should be able to handle up to about an amp constant. Thing is though there's no ground prong. Any thoughts?

You will have to make your own ground.
Prefered spot it the same grounding point as the radio.

RedGTiVR6 · 01-23-2008, 02:26 AM

I'd be weary....a cheap inverter will end up wreaking havoc on computer parts. If the voltage isn't regulated very well your parts will fail quicker than normal.

Just a word of caution.