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Initial Trades: Laptop vs. Motherboard

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  • Initial Trades: Laptop vs. Motherboard

    Hello All,

    I've been snooping around this site for about a year now contemplating doing a carputer for my '98 4Runner. One of the members has done a very nice screen install that's got me salivating
    http://www.mp3car.com/vbulletin/showthread.php?t=66278
    Well -- setbacks are sometimes just cleverly disguised opportunites: my car got broken into and the bastards stole my stereo and Riocar EMPEG which has been the staple of my car system for several years.

    As I'm considering carputering my vehicle, my first trade is going to be the laptop vs. motherboard setup. I've searched around and have seen that both are done (although laptops seem to be less common).

    My thought was to get a broken screen laptop off ebay. I was going to install under the seat (and get a battery that doesnt explode . Some things driving me that way are:
    - Seems the Laptop solution simplifies the power conversion problem. I can either use an inverter + ac adapter, or a single supply dc/dc converter. Shutdown would be done with the windows hibernate feature when running on batteries, and if the computer hangs, the worst case is that the local battery gets drained. I would need to build one of the common circuits outlined on the forum for powerup.

    - I do some amount of off-roading, so vibration is a concern. I thought having the laptop under the seat would provide some amount of shock isolation. Futhermore, notebook batteries are intrinsically less sensitive to vibrations.

    - Lastly, temperature extremes are a concern as I do a good amount of skiing and also live in a hot area. I would think the storage range would be -10F to 120F (i.e. when the car is parked and unused).

    I apologize if Im asking things that are posted already (there is a lot of info on the site).

    Thanks & Regards
    -Ted

  • #2
    my 2 cents
    (i have a laptop installed)

    first, i wouldnt worry too much about shock.
    also, the battery in the laptop has never served me any use.

    if you are truly worried about extreme temperatures, you want to look at booting from a CF card. this is an awesome thread about booting from solid state drives. although it's particular focus is on booting faster, it talks about how to set it up.

    Comment


    • #3
      Yep, you'd probably want to just take the battery out unless you plan on taking the laptop in and out, which I doubt since you are looking for a broken screen model.

      I've been researching the same question and want to point out that if you go the laptop route, shutdown is not really the problem, it is automatic startup. I believe some folks have figured out a way to do this by soldering connections onto the laptop motherboard, but otherwise, you are going to have to push the power button each time, which could be a pain if the laptop is not easily accessible. Again, you could relocate the power button, but that requires more soldering.

      FYI, I'm currently investigating a P3 or celeron solution as they seem to be cheaper alternatives to the mini-ITX; however, the decreased hardware costs may be offset by the need for a larger and more expensive PSU.

      Comment


      • #4
        Originally posted by Uther View Post
        Yep, you'd probably want to just take the battery out unless you plan on taking the laptop in and out, which I doubt since you are looking for a broken screen model.

        I've been researching the same question and want to point out that if you go the laptop route, shutdown is not really the problem, it is automatic startup. I believe some folks have figured out a way to do this by soldering connections onto the laptop motherboard, but otherwise, you are going to have to push the power button each time, which could be a pain if the laptop is not easily accessible. Again, you could relocate the power button, but that requires more soldering.

        FYI, I'm currently investigating a P3 or celeron solution as they seem to be cheaper alternatives to the mini-ITX; however, the decreased hardware costs may be offset by the need for a larger and more expensive PSU.

        Why would you want to take the battery out? Thats more or less the beauty of the laptop. Ive read other members and their mobos and they talk of 5-10 second boots(faster is likely possible) my laptop lives in standby and music is on instantly. Its beauty.

        Startup is rather easy, one member sells a complicated setup for doing this with many checks etc. Theres also another circuit on here(i use it) that is simply a relay and wires going to the power button on the front, you do have to get there.
        98 V6 Camry XLE
        Status-Everything is working again!
        No progress while I am in NYC
        Ze Worklog

        Comment


        • #5
          Thanks for the reply folks: There's definitely a lot more research for me to do. That was a good thread on booting from flash. Not sure if that's the path I'll go on, but reading about the "write filters" that inhibit writes to the physical disk would solve the shutdown problem and thus my need for a battery (which I was planning on using in lieu of a powerdown circuit).

          I will solder the on/off switch to somewhere on the dash.

          To power the laptop, I'm thinking of a simple DC/DC converter to the laptop DC voltage, or a power inverter. There seems to be ample information on inverters on the forum, but what i've noticed from experience what that the PSRR (power supply rejection ratio) kind of sucks on laptops. Most inverters output a 60 Hz square wave (as opposed to a sine wave) which induces all sorts of nasty harmonics on the input power. It seems these harmonics tend to couple through right to the audio output -- so when I had a laptop plugged into my car audio system, I could only play audio by removing the power cord. I'm sure that problem has been solved though and I just need some more research.

          Cheers
          -Ted

          Comment


          • #6
            DC-DC is the way to go, not only will it keep the audio noise free, its far more efficent. Plus they arent that expensive, I paid about 70 shipped for mine.
            98 V6 Camry XLE
            Status-Everything is working again!
            No progress while I am in NYC
            Ze Worklog

            Comment


            • #7
              Yes, dc-dc all the way. Inverters seem to me kind of a half-*** job if there are other ways of doing it. Meaning if you are running some beast that not even the DSATX can handle, then inverter. You are not. So therefore, get a dc-dc.
              Fusion Brain Version 6 Released!
              1.9in x 2.9in -- 47mm x 73mm
              30 Digital Outputs -- Directly drive a relay
              15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
              Buy now in the MP3Car.com Store

              Comment


              • #8
                Originally posted by 2k1Toaster View Post
                Yes, dc-dc all the way. Inverters seem to me kind of a half-*** job if there are other ways of doing it. Meaning if you are running some beast that not even the DSATX can handle, then inverter. You are not. So therefore, get a dc-dc.
                Thanks folks.. kinda what I suspected re: the power supply. However, that means I need to get a laptop that is less than 12V on the input to take advantage of a DC/DC.. right? I know some laptops are 13V and 16V DC input.

                Cheers
                -Ted

                Comment


                • #9
                  Originally posted by Tedp View Post
                  Thanks folks.. kinda what I suspected re: the power supply. However, that means I need to get a laptop that is less than 12V on the input to take advantage of a DC/DC.. right? I know some laptops are 13V and 16V DC input.

                  Cheers
                  -Ted
                  No there are units that take the 12v and turn it into anything from 6 to 24 depending on the product. Just like the igo thing that takes 12 and outputs between 16v and 22v depending on what you choose
                  Fusion Brain Version 6 Released!
                  1.9in x 2.9in -- 47mm x 73mm
                  30 Digital Outputs -- Directly drive a relay
                  15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
                  Buy now in the MP3Car.com Store

                  Comment


                  • #10
                    Uther, about your comment on the startup. If I go with a laptop I am going to have the power button routed to my ignition. When the ignition is turned to the point of starting the car it will press the power button. Don't know if it is a viable option for you or the original poster.
                    -------
                    I'm hungry

                    Comment


                    • #11
                      It's viable, I was just pointing out that you will have to open the laptop and solder - a lot of people aren't willing to do this be it because they don't want to solder, or because they still want to remove the laptop from the car.

                      As for my earlier comment on removing the battery, unless you have a startup / shutdown controller as your DC - DC power source, you should remove the battery. Otherwise, the laptop will act just like it does when plugged into an AC outlet and try to charge its internal battery from the car battery. This equals car battery drain.

                      The other question I have is that assuming you get a su / sd controller, how are you going to wire it to power the laptop? Solder directly to the mainboard or is there some sort of adapter you can wire the controller to that will fit the laptop's plug?

                      Comment


                      • #12
                        Originally posted by Uther View Post
                        It's viable, I was just pointing out that you will have to open the laptop and solder - a lot of people aren't willing to do this be it because they don't want to solder, or because they still want to remove the laptop from the car.

                        As for my earlier comment on removing the battery, unless you have a startup / shutdown controller as your DC - DC power source, you should remove the battery. Otherwise, the laptop will act just like it does when plugged into an AC outlet and try to charge its internal battery from the car battery. This equals car battery drain.

                        The other question I have is that assuming you get a su / sd controller, how are you going to wire it to power the laptop? Solder directly to the mainboard or is there some sort of adapter you can wire the controller to that will fit the laptop's plug?
                        first of all, you don't NEED to open up a laptop and solder to the board. i bought a cheap docking station. the unit has an on/off switch which i cut off and relocated. i've never opened my laptop.

                        next, i have left my p4 laptop (although charged) in my car for over a week and have never had a problem starting my car.

                        i doubt charging your laptop battery from your car battery (while the car is off) will drain your battery. where would all the electricity go? the led light?

                        Comment


                        • #13
                          Originally posted by Freelander View Post
                          first of all, you don't NEED to open up a laptop and solder to the board. i bought a cheap docking station. the unit has an on/off switch which i cut off and relocated. i've never opened my laptop.

                          next, i have left my p4 laptop (although charged) in my car for over a week and have never had a problem starting my car.

                          i doubt charging your laptop battery from your car battery (while the car is off) will drain your battery. where would all the electricity go? the led light?
                          My plan was to charge the laptop from an accessory circuit. I agree with Freelander that the car battery drain wouldnt be that bad, but I personally dont feel comfortable adding an always on circuit. My intent was to have the computer go into standby when the power goes away. I was going to do this with the windows power settings. If by some off chance the computer locks up, then the worst that can happen is that the local battery gets drained,but then is charged on the next car powerup.

                          Regards
                          -Ted

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