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Thread: Turning laptop on/off using a switch and P2140

  1. #1
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    Turning laptop on/off using a switch and P2140

    Hi All,
    I've read up on the P2140 and seen a couple of videos and I think I understand, but I have a couple of questions.

    I'm basically wanting to power my laptop my turning the switch on, and away I go.. Simple as that, no ignition turn on or anything like that.

    Anyway, first question is, on one of the wires on the P2140 it is used for telling the PSU the car ignition is on OR a switch is on - once this is on, it provides power to the laptop - correct?

    However, if I just plug the power into my laptop, it doesn't automatically power on. So I'm going to need to extend the switch from the laptop to the car - correct?

    If I'm right in what I've said so far, if I want a switch to turn the laptop on, then I will need two switches? One for the PSU and one for the laptop? - If this is correct, then how can I use one switch instead!?

    Thank you!

  2. #2
    MySQL Error soundman98's Avatar
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    i'm having trouble understanding what/why you want to do..

    you want to manually turn the laptop on, and you also want the psu to automatically turn the laptop on?

  3. #3
    Neither darque nor pervert DarquePervert's Avatar
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    Quote Originally Posted by AdrianL View Post
    Hi All,
    I've read up on the P2140 and seen a couple of videos and I think I understand, but I have a couple of questions.

    I'm basically wanting to power my laptop my turning the switch on, and away I go.. Simple as that, no ignition turn on or anything like that.

    Anyway, first question is, on one of the wires on the P2140 it is used for telling the PSU the car ignition is on OR a switch is on - once this is on, it provides power to the laptop - correct?
    Correct.

    However, if I just plug the power into my laptop, it doesn't automatically power on. So I'm going to need to extend the switch from the laptop to the car - correct?
    You're correct, I think.
    You make it sound as if the laptop wouldn't be in the car, though.

    If I'm right in what I've said so far, if I want a switch to turn the laptop on, then I will need two switches? One for the PSU and one for the laptop? - If this is correct, then how can I use one switch instead!?
    No.
    You need one switch on the ignition-controlled line that runs to the IGN line of your P2140. It will act as a 'valet switch' of sorts:
    When the switch is off, the PSU will never sense the ignition is on, so it won't trigger bootup of the PC.
    When the switch is on, the ignition can be used to control startup and shutdown of the PC.
    If the PC is on, you can initiate shutdown of the PC by turning your switch off.


    If you want to have startup/shutdown of the laptop by a switch only (regardless of the state of the ignition), then just extend a power switch from the laptop to wherever you want the switch (console, dashboard, gear lever, etc.).
    The P2140 has a "dumb mode" that will allow it to provide power and bypass all the intelligent features.

    However, if you're going that route, why not save a few bucks and get an inexpensive aftermarket car power adapter for your laptop model, extend the switch and be off to the races?

    Thank you!
    You're welcome.
    Last edited by DarquePervert; 05-05-2011 at 08:00 PM.
    Have you looked in the FAQ yet?
    How about the Wiki?



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  4. #4
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    That's great. I think you covered everything there. So yes, basically I don't want anything to do with the state of ignition.. would just like a on/off switch so that it can be used without the keys in.

    The reason I was looking at the P2140 was because both rails offer 12V - I need one for my laptop and the other for the monitor, are there others that can provide this? As the others I looked at tend to only have 12V on one rail (like the P1900).

    Thanks again,
    Adrian

  5. #5
    Neither darque nor pervert DarquePervert's Avatar
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    Why not get an inexpensive car power adapter for the laptop and a monitor that doesn't need regulated 12v.
    You'll save some coin in the long run and achieve exactly what you want.
    Have you looked in the FAQ yet?
    How about the Wiki?



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  6. #6
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    To be powered from the cigar lighter?

    I know I said I'm using a laptop, but I will be disassembling it and mounting it somewhere. Maybe I should have said that originally... haha.

    The monitor I will be buying will be a 7" Lilliput (open frame) that I will be moulding into the dash. Wanting it to look as standard as possible really.

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