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Thread: ATX auto startup circuit

  1. #1
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    Post ATX auto startup circuit

    Hi,

    A number of people have asked for some way to have their carputer startup when they start their car. The usual answer is to switch on 'AC Power Recovery' in the BIOS or run a button to the front of the car.

    I didn't want to do either since I don't have the appropriate BIOS option and a button is ugly. So one of my friends designed this very simple circuit.

    It relies on the fact that you'll have a 5v standby pin from your power supply and that this is available when you turn on the ignition. My sproggy-based power supply from Mastero had one.

    In practise, about a second after I turn on the ignition, the computer starts up. Very cool. This also works in conjunction with moahdib/Jeff Mucha's shutdown controller, so my carputer starts up and shutdown cleanly with the car's ignition.

    Circuit follows, can be built for about a dollar :-)



    Spud.
    VIA C3 800Mhz, 192Mb RAM, 10Gb 2.5" HDD, built-in video & audio, 7" Redant widescreen LCD, Win98Lite, Girder, GPS & street maps of Sydney & Melbourne.
    Spud's Carputer 3PM

  2. #2
    Variable Bitrate
    Join Date
    Jul 2000
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    Jackson, MS, USA
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    233
    So let me understand it correctly,

    I connect the ground on the BC548 to the ground wire on the ATX power supply or the car chassis?

    How many volts should the capacitor be?

    Can I get a BC548 at radio shack?
    24 y/o w/ Silver/Red
    2000 Honda S2000

    http://www.squeezer.net

  3. #3
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    I connect the ground on the BC548 to the ground wire on the ATX power supply or the car chassis?

    How many volts should the capacitor be?

    Can I get a BC548 at radio shack?
    Yes, ground the transistor to your powersupply. I put the circuit in the same case as the powersupply, so that was easy.

    Capacitor should be 16 or 35 volts, doesn't really matter, it only ever sees 5v.

    I would imagine you could get a BC548 anywhere, they're very common. Failing that, get any small signal NPN transistor.

    Spud.
    VIA C3 800Mhz, 192Mb RAM, 10Gb 2.5" HDD, built-in video & audio, 7" Redant widescreen LCD, Win98Lite, Girder, GPS & street maps of Sydney & Melbourne.
    Spud's Carputer 3PM

  4. #4
    Variable Bitrate
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    Jul 2000
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    Jackson, MS, USA
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    My computer boots up when I turn on my car, but it usually trips my inverter. So if I put your circuit into my power supply, will it cause a delay between when the car is started and the computer is turned on, even though my computer comes on when the inverter turns on.

    What I am asking is:

    I leave my inverter on so that when I start the car the inverter automatically comes on. Will you circuit give a slight delay between the time the inverter receives power from the car and when the computer starts, or am I missing something? Do I need to do anything to my settings in the bios even tho my computer turns on when I start the car?
    24 y/o w/ Silver/Red
    2000 Honda S2000

    http://www.squeezer.net

  5. #5
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    Originally posted by Squeezer
    My computer boots up when I turn on my car, but it usually trips my inverter. So if I put your circuit into my power supply, will it cause a delay between when the car is started and the computer is turned on, even though my computer comes on when the inverter turns on.

    What I am asking is:

    I leave my inverter on so that when I start the car the inverter automatically comes on. Will you circuit give a slight delay between the time the inverter receives power from the car and when the computer starts, or am I missing something? Do I need to do anything to my settings in the bios even tho my computer turns on when I start the car?
    The circuit will have a delay of a second or two. I'm not sure what you mean by "trips the inverter" but I assume you need a small delay from when the inverter starts up and when the computer starts up. The circuit should work ok, either way it's only about $1 to build to find out

    BTW, the circuit isn't my design so don't blame me

    Spud.
    VIA C3 800Mhz, 192Mb RAM, 10Gb 2.5" HDD, built-in video & audio, 7" Redant widescreen LCD, Win98Lite, Girder, GPS & street maps of Sydney & Melbourne.
    Spud's Carputer 3PM

  6. #6
    Variable Bitrate
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    Jackson, MS, USA
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    Thanks Spud! I'm going to be on vacation for a few days but I'm going to build this circuit when I get back. I'll let you know how it goes.
    24 y/o w/ Silver/Red
    2000 Honda S2000

    http://www.squeezer.net

  7. #7
    Variable Bitrate
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    Jackson, MS, USA
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    If I wanted to make the delay longer like 3 or 5 seconds what would be the new values of the resistors that I would need?
    24 y/o w/ Silver/Red
    2000 Honda S2000

    http://www.squeezer.net

  8. #8
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    Originally posted by Squeezer
    If I wanted to make the delay longer like 3 or 5 seconds what would be the new values of the resistors that I would need?
    That's all to do with the RC timing constant, I can't remember it from my Uni days

    Doubling either the capacitor value or the resistor value will double the time required to charge though.

    Maybe you should try a 470uF cap and see how you go.

    Cheers, Spud.
    VIA C3 800Mhz, 192Mb RAM, 10Gb 2.5" HDD, built-in video & audio, 7" Redant widescreen LCD, Win98Lite, Girder, GPS & street maps of Sydney & Melbourne.
    Spud's Carputer 3PM

  9. #9
    Maximum Bitrate none's Avatar
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    Is anyone able to repost this circuit? I need it now and it's gone.


    Quote Originally Posted by spud
    Hi,

    A number of people have asked for some way to have their carputer startup when they start their car. The usual answer is to switch on 'AC Power Recovery' in the BIOS or run a button to the front of the car.

    I didn't want to do either since I don't have the appropriate BIOS option and a button is ugly. So one of my friends designed this very simple circuit.

    It relies on the fact that you'll have a 5v standby pin from your power supply and that this is available when you turn on the ignition. My sproggy-based power supply from Mastero had one.

    In practise, about a second after I turn on the ignition, the computer starts up. Very cool. This also works in conjunction with moahdib/Jeff Mucha's shutdown controller, so my carputer starts up and shutdown cleanly with the car's ignition.

    Circuit follows, can be built for about a dollar :-)



    Spud.

  10. #10
    Constant Bitrate
    Join Date
    Sep 2003
    Location
    LA, CA
    Posts
    140
    is it only me having problem with jeff mucha shutdown controller?
    mine does not start the computer nor shutdown autumatically...
    manual says it sends a signal to mobo after ignition goes low...
    does it mean when i crank to start the engene?
    still nothing happens even i wait a long time...
    please soneone help me...
    thanks...

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