Help me build this circuit!!

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WarDemon666

Platinum Member
Nov 28, 2000
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So far im getting an 800 watt inverter and its going to power a normal powersupply in the car. What im trying to design is a way to shut down the computer automatically when i remove the key. I found some software that will hibernate the computer when 2 pins of the LTP port are touched, with a countdown.... so heres what im thinking....


3 relays...

when the ignition is ON a relay turns on the inverter, and hits the power on the computer, when i remove the key, a relay touches the two ltp pins and the countdown begins, upon shutdown there is no more power and of the hard drive etc cables, so another relay switches off the inverter. when a key is put back the inverter is then turned on and the computer also...


Will this be possible? I drew out the diagram on paper but i have an old scanner and it only works in win98, so i cant scan it.

Can anyone make me a schematic or just tell me if this will work, and if so, what kind of adjustments must I make to my plan..

Thanks!
 
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tRaptor

Golden Member
Jul 31, 2002
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That sounds like a lot of messing with the ignition. What kind of car? Just a scarry thought when you decided to rip it all out. What I would do would be to control the relay based in the car stereo, it usually has some voltage that it outputs from the antenna (not sure if thats it) but that allows you for example to turn your amp off automatically. Idealy it would be a system that could stand to just be switched off.

On the other hand, you could use the voltage being removed from when the stereo turns off to start your shutdown sequence.
 
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WarDemon666

Platinum Member
Nov 28, 2000
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Originally posted by: tRaptor
That sounds like a lot of messing with the ignition. What kind of car? Just a scarry thought when you decided to rip it all out. What I would do would be to control the relay based in the car stereo, it usually has some voltage that it outputs from the antenna (not sure if thats it) but that allows you for example to turn your amp off automatically. Idealy it would be a system that could stand to just be switched off.

On the other hand, you could use the voltage being removed from when the stereo turns off to start your shutdown sequence.
Click to expand...

Well, im using relays so im hardly taking power from the ignition.... I doubt I should run into problems.... I want to be able to hibernate because startup/shutdown will be much faster, and i can continue play from where I left off :)
 
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tRaptor

Golden Member
Jul 31, 2002
1,227
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Originally posted by: WarDemon666
Originally posted by: tRaptor
That sounds like a lot of messing with the ignition. What kind of car? Just a scarry thought when you decided to rip it all out. What I would do would be to control the relay based in the car stereo, it usually has some voltage that it outputs from the antenna (not sure if thats it) but that allows you for example to turn your amp off automatically. Idealy it would be a system that could stand to just be switched off.

On the other hand, you could use the voltage being removed from when the stereo turns off to start your shutdown sequence.
Click to expand...

Well, im using relays so im hardly taking power from the ignition.... I doubt I should run into problems.... I want to be able to hibernate because startup/shutdown will be much faster, and i can continue play from where I left off :)
Click to expand...

Ah, that makes sence. I didnt mean that you where taking power from the ignition. Just ment in the sence that "why rip into the ignition amd cause problems" when you dont need to?
 
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TerryMathews

Lifer
Oct 9, 1999
11,464
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Are you really wanting to shutdown the computer on literally removing the key from the ignition, or just when you turn the car to off? If you're just wanting it to go off when the car does, or at least start shutdown, it's easy. This will also have the added benefit of behaving like a normal radio does.

Wire the inverter to the battery, wire 12v switched from the car to a VRM to step it down to LPT signaling voltage (5V?).
 
Evadman

Evadman

Administrator Emeritus<br>Elite Member
Feb 18, 2001
30,990
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Why turn off the inverter with the ignition? A GOOD inverter (costco has a 1200 watt for ~80) will pull < 1/100 an amp with out a load. When you trun off your car, there is a floating overcharge on the battery that burns off in ~15 minutes or so. That gives you about 5 minutes of "free" power at ~200 watts. Have a normaly closed relay that opens on igniton hot, and when closed, have it send a shutdown command to the computer.

You can also have the computer shutdown the inverter by switching a relay, which is easily done though an interface board. They are sold in kits for < $50.

Just remember, inverters are not designed to be run on a relay. a 1000 watt inverter will pull > 80 amps, which is quite a bit for a relay. They can be had, but they are not cheap. Painless makes a good one that will handle that load.
 
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WarDemon666

Platinum Member
Nov 28, 2000
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Originally posted by: TerryMathews
Are you really wanting to shutdown the computer on literally removing the key from the ignition, or just when you turn the car to off? If you're just wanting it to go off when the car does, or at least start shutdown, it's easy. This will also have the added benefit of behaving like a normal radio does.

Wire the inverter to the battery, wire 12v switched from the car to a VRM to step it down to LPT signaling voltage (5V?).
Click to expand...

dont need any voltage in the LTP. the program reads a ground + status port connection, thus, all i need is a relay, or switch to make the two pins touch...
 
J

Jamie571

Senior member
Nov 7, 2002
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Here is the system we built

Here is one of the wiring prints

I worked on this for a friend about 5 months ago. We used a DC to DC supply for the computer, much more effiecent than an inverter. You can buy a good one online for about $50. The biggest thing is heat build up. This was a itx pc with a 40GB 2.5"harddrive I had to use 2 fans on the outside of the case which was one big aluminum heatsink. The wireless was for transferring files to the auto. Mounted the antenna to the front bumper, looks damn good. Everyone always ask my friend about it. Cheapest and most kick ass way to veiw movies, music, and have a kick ass nav unit.
 
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WarDemon666

Platinum Member
Nov 28, 2000
2,224
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Originally posted by: Jamie571
Here is the system we built

Here is one of the wiring prints

I worked on this for a friend about 5 months ago. We used a DC to DC supply for the computer, much more effiecent than an inverter. You can buy a good one online for about $50. The biggest thing is heat build up. This was a micro PC with a 40GB 2.5"harddrive I had to use 2 fans on the outside of the case which was one big aluminum heatsink. The wireless was for transferring files to the auto. Mounted the antenna to the front bumper, looks damn good. Everyone always ask my friend about it. Cheapest and most kick ass way to veiw movies, music, and have a kick ass nav unit.
Click to expand...



Thanks for the post. Why are DC-DC inverters more efficient? If I use an inverter with extra power I can plug my xbox in etc :D Nice system though :D
 
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WarDemon666

Platinum Member
Nov 28, 2000
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Originally posted by: QuitBanningMe
Just get a cheap shutdown controller or do it right and get an Opus.
Click to expand...

shutdown controllers are expensive!

I dont wanna spend a lot of money on this, im probably going to end up using and old 750 mhz or something, and just stick it on the inverter...


All i need is a few relays for it to shut off...

But like Evadman said, maybe the inverter is going to pull too much for the relay.. :(
 
Evadman

Evadman

Administrator Emeritus<br>Elite Member
Feb 18, 2001
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Originally posted by: WarDemon666
But like Evadman said, maybe the inverter is going to pull too much for the relay.. :(
Click to expand...
For a cheap relay, yes. I would just leave the inverter hardwired in, and just have the computer turn off and on. But remember, the computer still pulls power while it is plugged in.

Most automakers allow about .025 of an amp as latent amperage draw, stay under that and you will be fine. Any more than that, and you will kill the bettery if left sitting for a while without starting it.

If you are over that, you will need a relay no matter what. As I said, Painless makes one for that load, but it is >$100. You may be tempted to use a starter relay from an old ford, but they are only made for intermittent use, and will overheat and melt if left energized.
 
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NikPreviousAcct

No Lifer
Aug 15, 2000
52,763
1
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Originally posted by: DnaJ
Originally posted by: QuitBanningMe
oh and this isn't the place to ask try

http://www.mp3car.com
Click to expand...

*summons Nik*
Click to expand...

The ground shakes, develops jagged cracks several yards long, and light beams from the cracks. You hear a low groan that rumbles the ground beneath DnaJ's feet as fire explodes from the cracks in the ground. The fire plooms up behind him into a large ominous form with two seemingly glowing eyes as the groan gains intensity until finally evolving intooooOOOOOWWWWWWWRRRONG FORUM!
 
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WarDemon666

Platinum Member
Nov 28, 2000
2,224
0
0
Originally posted by: Evadman
Originally posted by: WarDemon666
But like Evadman said, maybe the inverter is going to pull too much for the relay.. :(
Click to expand...
For a cheap relay, yes. I would just leave the inverter hardwired in, and just have the computer turn off and on. But remember, the computer still pulls power while it is plugged in.

Most automakers allow about .025 of an amp as latent amperage draw, stay under that and you will be fine. Any more than that, and you will kill the bettery if left sitting for a while without starting it.

If you are over that, you will need a relay no matter what. As I said, Painless makes one for that load, but it is >$100. You may be tempted to use a starter relay from an old ford, but they are only made for intermittent use, and will overheat and melt if left energized.
Click to expand...

and doing that you would leave the inverter on all the time? is that a good idea??
 
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NikPreviousAcct

No Lifer
Aug 15, 2000
52,763
1
0
Originally posted by: DnaJ
Lightning Bolt! Lighting Bolt! :Q
Click to expand...

As the fire subsides and rumble fades, the ground returns to peace as Nik's form disappears until Dan calls upon this awesome power once again.
 
Evadman

Evadman

Administrator Emeritus<br>Elite Member
Feb 18, 2001
30,990
5
81
Originally posted by: WarDemon666
and doing that you would leave the inverter on all the time? is that a good idea??
Click to expand...
I have had a 1250 watter hardwired for a little over a year. No problems yet.
 
U

upsciLLion

Diamond Member
Feb 21, 2001
5,947
1
81
Originally posted by: Nik
Originally posted by: DnaJ
Lightning Bolt! Lighting Bolt! :Q
Click to expand...

As the fire subsides and rumble fades, the ground returns to peace as Nik's form disappears until Dan calls upon this awesome power once again.
Click to expand...

lmno
 
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