N00b here. Got 2 questions.

**mp5a4** · 09-12-2008, 02:59 PM

Hello! And sorry about asking stupid questions.
First off a little introductory since I am the new guy here. I am from Hong Kong, and i drives an Alfa Romeo 156 GTA. (I sure hope you guys ship internationally haha)
I am very good at doing Desktops and i know how computer works, but carpc is totally different so i got some n00b questions
anyways, i want to ask about PSU and a little about other stuff so here goes!

1. PSU, where do i actually get the electricity from? I mean in a desktop i just plug it into a wall socket, but what about in car? And i dont see any input on the DC DC converters on sale here? I dont really understand how that works and that is my major concern.

2. Then is the Accelerometer. Where is that connected to? i know OBDII and the computer programs work, but how does the Accelerometer work? does it comes with a USB or something that a program, say PCMScan can read and transfer into a graph?

3. There is no 3 for now!

Thanks a lot guys and i hope i can share my project (which i will complete by Christmas) with you guys. Thanks again!

**FusionFanatic** · 09-12-2008, 04:26 PM

Originally Posted by mp5a4

PSU, where do i actually get the electricity from? I mean in a desktop i just plug it into a wall socket, but what about in car? And i dont see any input on the DC DC converters on sale here? I dont really understand how that works and that is my major concern

"intellegent" automotive ATX [DC-DC] power supplies has 3 inputs (power, ground, and ACC/IGN). "power" or "12v constant" should be connected directly to the car battery, amp power cable, etc. "ground" should be connected to a metal chassis/body panel in the car. ACC/IGN should be connected to a +12v source that is switched on/off with your car's ignition key. (IGN is switched on when the key is in the RUN and START positions, ACC is switched on when the key is in the ACC and RUN positions).

you can see the inputs easily, but there is no industry standard input connector like a home AC outlet.

some models, llike the M2-ATX uses blade connectors (top left):

some models, like the OPUS 320w uses a "block" style I/O connector (lower left, next to the fuse):

some models, like the DSATX and M4-ATX use screw terminals:

other models, like the PICO-PSU use wires with blade connectors at the end of them:

welcome to carPC'ing... good luck

**mp5a4** · 09-12-2008, 04:43 PM

Thanks for the quick reply and the information. Cleared a lot of stuff up
But still got some problems on PSU....
So what happens if i turn my car off? Does power cut right away? Anyway to make a delay so i can turn off the computer in time? See my car is manual and if i stalled, restart the car will everything needs to be restarted? (well not like i stall all the time haha)

**the_gooner** · 09-12-2008, 05:36 PM

Shouldnt. the intelligent supplies will notice when the ignition lead goes to 0v at what point its like pushing the power button on your desktop. it will start the shutdown, standby or hibernate.
when you stall the ignition is still live ( well it has been on my last 4 cars )

**FusionFanatic** · 09-12-2008, 05:38 PM

no, an "intelligent" automotive PSU will not just cut power right away. that's what makes them "intelligent"

you can set the delay time before shutdown. for example, I use an M2-ATX-HV which allows you to set the shutdown delay time to 5 seconds, 30 seconds, 30 minutes, or 3 hours.

as for your stalling problem, give it a little more gas when you let off the clutch.

**Punky** · 09-12-2008, 05:40 PM

Thats where the intelligent part of the PSU or also known as start/shutdown controllers, make things work. When you turn off/on your car, the car sends out a signal (known as ignition), High(12V) when car on, LOW(0V) when car off.
The power supply has 3 inputs, battery +12V, battery Ground 0V, and Ignition(+12V or 0V). So the power supply knows when your car is on or off, and it will turn off or on the computer depending ignition signal.

**FusionFanatic** · 09-12-2008, 05:46 PM

Originally Posted by the_gooner

the intelligent supplies will notice when the ignition lead goes to 0v at what point its like pushing the power button on your desktop. it will start the shutdown, standby or hibernate.

when the "ignition lead" goes to 0v, it starts the delay "timer".

it will not "push the power button" until the set time has passed. for example, I have my off-delay set to 5 seconds. so when I turn the key to the "off" position (or in my car, when I open the door), the PSU will wait 5 seconds before it "pushes the power button".

**the_gooner** · 09-12-2008, 05:49 PM

My mistake
thanks for clearing it up

**mp5a4** · 09-13-2008, 03:44 AM

Thanks all for the input.
Finally one more n00b question.
How do you wire V+ V- and IGN to the correct places?
so i run a wre from the car batteries?
Especally the ignition. How do i wire that? anyone got pics of it done?

I am sorry about these questions. I am not excatly a car guy...

**funkyphil** · 09-13-2008, 04:04 AM

I have the M2 as well, the way you wire it up is simple. RED + BLACK - WHITE IGN. Lets say you are installing the computer in the trunk of your car. You will need to run a power wire that is fused from the positive terminal of your batter to the rear of your car.

Next find a really nice ground some where near the power supply and hook that wire to the ground of the power supply (the black wire).

lastly, find a good ign wire, this is any wire that will turn on and off whenever you put the key in or take it out of your ign. (lot of times the cigg lighter will turn on and off like this) this wire connects to the white wire on the power supply.

So that is pretty much all you have to do!

Good Luck!