Page 1 of 3 123 LastLast
Results 1 to 10 of 23

Thread: Cheap GPS (Requires some modding)

  1. #1
    Constant Bitrate SniperXX's Avatar
    Join Date
    Oct 2004
    Location
    Southern California -- Diamond Bar/Walnut Area
    Posts
    122

    Cheap GPS (Requires some modding)

    Well I found this link.

    http://www.hackaday.com/entry/1234000147047359/

    Basically you are modifing one of the GPS units for an old Palm III into a serial GPS. Just posting it if some of you needed a cheap GPS and had one of the Palm ones lying around.

  2. #2
    Calm
    Down
    Or
    Get
    A
    2
    Week
    Vacation
    -Love
    The
    Forum
    Policeman
    Wiredwrx's Avatar
    Join Date
    Jan 2003
    Posts
    3,605
    Quote Originally Posted by SniperXX
    Well I found this link.

    http://www.hackaday.com/entry/1234000147047359/

    Basically you are modifing one of the GPS units for an old Palm III into a serial GPS. Just posting it if some of you needed a cheap GPS and had one of the Palm ones lying around.
    Looks interesting. And since it is serial, you won't have hibernation/resume issues.

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  3. #3
    Newbie
    Join Date
    Jun 2005
    Location
    Madison, WI
    Posts
    40
    I'm trying to do this project, but I'm confused as to how would you get it to interface with the PC? Can you convert it to run with USB?

  4. #4
    Calm
    Down
    Or
    Get
    A
    2
    Week
    Vacation
    -Love
    The
    Forum
    Policeman
    Wiredwrx's Avatar
    Join Date
    Jan 2003
    Posts
    3,605
    Quote Originally Posted by stash182
    I'm trying to do this project, but I'm confused as to how would you get it to interface with the PC? Can you convert it to run with USB?
    http://www.ramelectronics.net/html/usb_serial.htm
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  5. #5
    Newbie
    Join Date
    Jun 2005
    Location
    Madison, WI
    Posts
    40
    so should I solder the serial cable I solder to the GPS receiver onto the serial port nubbies? AFAIK the original recvr was meant to directly plug into the Palm III serial port which isnt a standard PC serial port. Am I wrong?

  6. #6
    Calm
    Down
    Or
    Get
    A
    2
    Week
    Vacation
    -Love
    The
    Forum
    Policeman
    Wiredwrx's Avatar
    Join Date
    Jan 2003
    Posts
    3,605
    Quote Originally Posted by stash182
    serial port nubbies?
    What is a "serial port nubbie"
    AFAIK the original recvr was meant to directly plug into the Palm III serial port which isnt a standard PC serial port. Am I wrong?
    What do you mean by "standard serial port". The signals are the same, they are serial. Your computer "understands" serial, and the Palm Pilot "understands" serial, that is why you can connect it to the computer without additional circuitry and chips and things.

    The connectors are different, Yes.

    Michael

    P.S. I found the thread after the PM.
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  7. #7
    FLAC evandude's Avatar
    Join Date
    Mar 2005
    Location
    Maine
    Posts
    937
    Quote Originally Posted by Wiredwrx
    The signals are the same, they are serial. Your computer "understands" serial, and the Palm Pilot "understands" serial, that is why you can connect it to the computer without additional circuitry and chips and things.

    The connectors are different, Yes.
    how much have you played with serial

    RS232 uses +12v and -12v logic levels, with -12v being a 1, and +12v being a 0. Most modern serial devices just use +/- 5v, because the serial ports still register the logic levels.

    the output of the device is likely to be TTL serial, which is the same data format, but with 0v being a 0 and 5v being a 1, so the logic levels are completely different voltages, as well as inverted.

    that's what RS232 level shifters are for... you can build a fancy one with a MAX232 chip, or you can build one out of cheap discrete components with this schematic: (which I recommend)
    http://www.sparkfun.com/datasheets/P...32-Shifter.pdf
    But don't take it from me! here's a quote from a real, live newbie:
    Quote Originally Posted by Viscouse
    I am learning buttloads just by searching on this forum. I've learned 2 big things so far: 1-it's been done before, and 2-if it hasn't, there is a way to do it.
    eegeek.net

  8. #8
    Calm
    Down
    Or
    Get
    A
    2
    Week
    Vacation
    -Love
    The
    Forum
    Policeman
    Wiredwrx's Avatar
    Join Date
    Jan 2003
    Posts
    3,605
    Evan,

    Before I mistakenly "go off" on you, can you tell me why you posted a dissertation about Serial communications. Also, why are you linking him to information that he doesn't need, and is not relevant to the topic of discussion?

    Michael

    Quote Originally Posted by evandude
    how much have you played with serial

    RS232 uses +12v and -12v logic levels, with -12v being a 1, and +12v being a 0. Most modern serial devices just use +/- 5v, because the serial ports still register the logic levels.

    the output of the device is likely to be TTL serial, which is the same data format, but with 0v being a 0 and 5v being a 1, so the logic levels are completely different voltages, as well as inverted.

    that's what RS232 level shifters are for... you can build a fancy one with a MAX232 chip, or you can build one out of cheap discrete components with this schematic: (which I recommend)
    http://www.sparkfun.com/datasheets/P...32-Shifter.pdf
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  9. #9
    FLAC evandude's Avatar
    Join Date
    Mar 2005
    Location
    Maine
    Posts
    937
    Stash182 asked if he can connect the device directly to the serial connector. You said yes. my "dissertation" was an explanation of why the answer may be "no", under the assumption that the output of the GPS receiver does not use RS232 logic levels, in which case the circuit I linked would take care of that.

    Since there weren't any pictures of the unit before disassembly that I could see, I didn't realize it connected to the same connector as the hotsync cradle, in which case it probably does deal with RS232 levels, in which case my explanation, as you put it, is irrelevant.

    I wasn't trying to be a dick, so thank you for giving me a chance before "going off on me". I made a wrong assumption, and I apologize.
    But don't take it from me! here's a quote from a real, live newbie:
    Quote Originally Posted by Viscouse
    I am learning buttloads just by searching on this forum. I've learned 2 big things so far: 1-it's been done before, and 2-if it hasn't, there is a way to do it.
    eegeek.net

  10. #10
    Calm
    Down
    Or
    Get
    A
    2
    Week
    Vacation
    -Love
    The
    Forum
    Policeman
    Wiredwrx's Avatar
    Join Date
    Jan 2003
    Posts
    3,605
    Quote Originally Posted by evandude
    Stash182 asked if he can connect the device directly to the serial connector. You said yes. my "dissertation" was an explanation of why the answer may be "no", under the assumption that the output of the GPS receiver does not use RS232 logic levels, in which case the circuit I linked would take care of that.

    However, my explanation is in fact irrelevant if the palm does deal directly with RS232 logic signals.
    I will assume that it does "directly deal with RS232 logic signals", because every website I found that had instruction on using these units with a computer make no mention of a MAX232 or similar chip. If you would have followed the link in the first post and read the article, you would have known this.

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

Page 1 of 3 123 LastLast

Similar Threads

  1. garmin mapsource and usb gps mouse
    By thecrow in forum GPS
    Replies: 9
    Last Post: 09-26-2006, 02:24 PM
  2. Getting Started with GPS
    By grepzen in forum The FAQ Emporium
    Replies: 12
    Last Post: 09-26-2006, 05:54 AM
  3. Replies: 6
    Last Post: 02-04-2006, 09:22 AM
  4. Newbie's guide
    By EBFoxbat in forum Newbie
    Replies: 6
    Last Post: 02-08-2005, 10:06 AM
  5. Replies: 0
    Last Post: 08-26-2004, 07:23 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •