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Remote GPS Readout (my very modest first project) — Parallax Forums

Remote GPS Readout (my very modest first project)

George99George99 Posts: 16
edited 2006-10-17 18:18 in Robotics
My goal is to use the BS2 to average my position over a time period for more accurate readings in hopes of improving my luck at finding geocaches. But, I'm starting with an easier programming project, and now I can wear the GPS on my hat up in the clear and look like a total idiot smilewinkgrin.gif

gps.jpg
[img]http://www.egeorgeonline.com/images/bs2/gps 002.jpg[/img]
[img]http://www.egeorgeonline.com/images/bs2/gps 001.jpg[/img]
[img]http://www.egeorgeonline.com/images/bs2/gps 003.jpg[/img]
bs2
bs2
remotegps.bs2
4K

Comments

  • Tricky NekroTricky Nekro Posts: 218
    edited 2006-08-19 21:00
    Neat!!! Very nice man...

    How much did the GPS costed you???



    Keep walking...



    Provas, Greece

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  • George99George99 Posts: 16
    edited 2006-08-21 11:16
    Hi, thanks. I think I paid $145 for the GPS in May 2005.
  • Mike15Mike15 Posts: 109
    edited 2006-08-21 22:32
    I want to use GPS with my rocket payload. And I am curious how you got the Stamp to read the GPS
    I have a deluo GPS unit I figure the output of the GPS can be determined with hyperterminal. But thats
    about as far as I got.
  • BeanBean Posts: 8,129
    edited 2006-08-21 23:17
    George,
    Cool project.
    Where did you find a case that fits the homework board so well ? What is it ?

    P.S. I don't think it's a modest project at all. Nice job.

    Bean.

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  • George99George99 Posts: 16
    edited 2006-08-22 11:57
    Mike: if you can read the GPS serially with hyperterminal, you should have no problem with the BS. Mine's a Garmin, but I set the output to NMEA format in the menus. NMEA is a standard that many units can output. I got my information on the formats here www.gpsinformation.org/dale/nmea.htm

    Look at my BASIC program to see how to use SERIN and WAIT to pick and choose the data you need from the data stream.

    In the case of the Garmin I just had to connect their serial TX and Gnd pins to the BS and it worked.

    Bean: The case was indeed a lucky find! I got it for 99 cents at A. C. Moore, a craft supply shop; I don't know if they're a national chain, though. I bought a few figuring I'd end up destroying a couple trying to cut the hole for the readout (and I did), so I'll see if I can find one with the label still intact and post back here the manufacturer and model.

    The homework board is not fastened in any way. It just sits in there and with the battery thickness, it doesn't wiggle at all with the case shut.

    Post Edited (George99) : 8/22/2006 1:49:13 PM GMT
  • Tricky NekroTricky Nekro Posts: 218
    edited 2006-08-24 07:02
    Thanks for the repply...

    Can you let me know how accurate it is???



    Very nice project again...

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    -Rule your Destiny-
    --Be Good. Be Bad. Be Provas--

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  • George99George99 Posts: 16
    edited 2006-08-25 18:29
    There are 2 issues keeping it from being as accurate as the GPS.

    The first one is that although the bearing to the waypoint shown as a number is correct, the arrow display is limited by the capabilities of the 5x8 character matrix of the LCD display. I did it fairly simply and used custom character loadup and created 8 arrows point to N, NE, E, SE, etc.

    Second, the NMEA output shows the distance in nautical miles accurate to 3 decimal places. This means the distance reading is in multiples a little over 6 feet.

    You can see in the second photo the discrepancy in the arrow and the distance (gps says 105, reading shows 103).

    My next version of the program will compute the distance using the geographic coordinates instead. This has proven tougher than first envisioned. For one thing, having 2 complete sets of points in RAM (lat and lon of position and waypoint) requires more storage than is available.

    The other catch is that although one minute of latitude is almost exactly one nautical mile, one minute of longitude is 1 NM at the equator and gets smaller as you move away from the equator. At my latitude, it's about .7 miles per minute.

    All this in integer arithmetic with trig functions that divide the circle into 256 parts!

    Stay tuned. (but don't hold your breath)
  • SawmillerSawmiller Posts: 276
    edited 2006-08-26 08:52
    sounds like a job for the propeller
  • killervettekillervette Posts: 16
    edited 2006-08-29 13:17
    cool project. i am pretty new to this stuff...what is the circuit board to the left of the homework board?
  • BeanBean Posts: 8,129
    edited 2006-08-29 14:13
    killervette said...
    cool project. i am pretty new to this stuff...what is the circuit board to the left of the homework board?
    That's the LCD display.

    Bean.


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    Low power SD Data Logger www.sddatalogger.com
    SX-Video Display Modules www.sxvm.com

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  • MacGeek117MacGeek117 Posts: 747
    edited 2006-10-15 22:26
    I'm sure that with a lot of work you could make a completely hand-held version using the Propeller and GPS module from Parallax.
    RoboGeek

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  • Kevin WoodKevin Wood Posts: 1,266
    edited 2006-10-17 05:39
    You can get an instant math upgrade for $15 - $20 by getting the uM floating point coprocessor:

    www.parallax.com/detail.asp?product_id=604-00030
    www.parallax.com/detail.asp?product_id=604-00050
  • steve_bsteve_b Posts: 1,563
    edited 2006-10-17 18:18
    Another need add-on would be the compass IC that parallax sells.

    I'm pretty sure that model of GPS didn't have an electronic compass (just a computed one -- you need to move for it to know the direction).

    So, what you could do, is put the compass IC in the pink box and use the stamp to read it and compare it to the reading come from the GPS. Then when you stop, the GPS keeps outputting your last direction based on previous movement. The stamp could read the compass and then compare to the gps reading. So if you were to stand still and rotate, the display would give you direction relative to you, not your last movements (sorry, does this make sense...haha).

    Just a thought....

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    Steve

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