Adding Aftermarket Internal GPS to the CF-28

Discussion in 'Panasonic' started by Toughbook, Nov 19, 2007.

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  1. stan.distortion

    stan.distortion Notebook Guru

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    Quick note on the gps_in pin, in service manual p71 it's going into a general purpose io that looks like it is only used for switching and identification. Its marked as an input so at a guess putting a 3.3 volt supply through a resistor onto it will cause the gps to show up in the bios.
     
  2. Toughbook

    Toughbook Drop and Give Me 20!

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    Just a dumb question... If the resistor doesn't change the voltage... Why do we need to use it? I measured voltage before and after and got the same reading...
     
  3. stan.distortion

    stan.distortion Notebook Guru

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    To keep the magic smoke in :) They don't really do anything on signal lines, more of a 'just in case' thing.
    You got a measurement from the gps_in pin?
    BTW, if it is for switching then its probably responsible for turning off the irda and turning on one of the internal serials
     
  4. stan.distortion

    stan.distortion Notebook Guru

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    Just checked, the GPS_IN pin is a switch to turn on the GPS option in the bios so the internal serial port can be set up to use it. I got it back to front, the pin is at 3.3v when off and needs to be earthed to enable the GPS option/internal serial.
    cheers
     
  5. Toughbook

    Toughbook Drop and Give Me 20!

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    Ok... When I used the main board to hook up the GPS I did get an option in the BIOS... For a Radio Modem I think. I enabled it but still didn't get anything. I didn't use the resistor though. I didn't see where it would make any difference since the voltage reading was the same with and without.

    I used the links I posted earlier to glean a little more info. I have been building laptops all this week so this weekend and next week I can spend some time experimenting with how to make it work. I'd really like to get it working without the main board. I don't really want to be reliant on having to have a main board to make it work all the time. There has to be a way. The main board just makes soldering a little easier.
     
  6. stan.distortion

    stan.distortion Notebook Guru

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    That's the one with the 4 way dip switch to select modules? Switching 4 to on should get the GPS and associated serial port option to show up in the bios.
    If not a direct connection from the GPS_IN pin (37 on cn18) to earth will do it. The 2 pins beside it (38 and 39) are both earths so a spot of solder between them would do the job.
    Not related to this thread but so for I have found out wireless and bluetooth use the same frequency, if that right is it ok to wire them both into the same antenna? Also, is it possible to use the same antenna for GPS signals?
    cheers
     
  7. Modly

    Modly Warranty Voider

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    GPS will require a very different antenna. When I get home I'll get you a link, but google "Jim D Gray", and the first site that comes up has the ones we are using. They are $32 a piece, about 1.25" long total, and are active antennas.

    I'm still working on how to mount them in though, and I'm ripping apart my 12" screen bezel and drilling it all over to find the best place. I'm not sure what the guy on eBay is doing to mount them, but it looks like he has some custom stuff involved. He uses the same antennas though.
     
  8. stan.distortion

    stan.distortion Notebook Guru

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    That the ones with the hummer in the adds and the black lid? Oh, and the price :)
    They look really well put together though. Don't know if Panasonic ever did an antenna on the right but it looks factory made and there is nothing under that side of the standard lid to mount on to.
    Is the lid magnesium on them? They could be making up a heavy fiberglass lid, doubt it would be simple to get magnesium or even aluminium moulded.
    Lashed together an antenna inside the plastic side cover of my one for now. Bit of an improvement but not much, going to have to make up one to go in the lid. Couldn't find out much on what other folks have done, was going to have a go at something retractable instead of screw on as I will only loose the damn thing. Any ideas or any know where to find some photos of others?
    Cheers for the info on the GPS antenna. Think I'll stick a plug somewhere for that as I have always needed an external antenna to get a signal quickly with the one I have here. A lot of folks are mentioning getting a signal indoors, is that stretching the truth a bit? Only time mine ever got a signal indoors it was in something little more than a caravan.
    cheers
     
  9. Modly

    Modly Warranty Voider

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    I think it's possible to get signal indoors if you're near enough windows. Otherwise it's a stretch...

    http://www.jdgastore.com/index.php?act=viewProd&productId=15

    That's the antenna I'm gonna use.

    As for the fiberglass idea, it's possible, but I'd hate to be the guy dropping it. I've done fiberglass work on cars before, and I know a good smack will split it.
     
  10. Toughbook

    Toughbook Drop and Give Me 20!

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    One guy who bought one of the laptops the guy sells on ebay with the GPS bought a laptop from me. The guy lived close enough so I delivered it to him. He offered me the GPS laptop in partial trade for payment. I declined. I wish I hadn't now. But when I saw how it was put together I wasn't impressed at all. This one was the M34s he used to do. It was held together with glue and tape and looked like crap. Plus the screen was way too small for anything useful... Cool looking toy though. I wouldn't mind building one if I could get a deal on one. The ones he is doing now (CF-28s) look much better.

    Anyway.. I am in the shop now working on the GPS. I am rewiring it with a few resistors in place this time. I'll post again when I turn it on and fool around with it.
     
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