I am unable to get a valid fix using this module. Using c language on a Propeller Activity Board and downloaded the GPS example, gps_example_c.side from Parallax. The module indicates it has a good fix (solid blue light). I am using the GND, 3.3v and TXD pins.

The output is below.

GPS Fix: Not Valid
Altitude (meters): 0.00
Num Satellites: 0
Compass Heading: 0.00
Velocity (knots): 0.00

Latitude Longitude
0.000000 0.0000000000

Any thoughts??


  • The code sample might be waiting for a 3d fix, wheres the module might be at 2d fix. This could be resolved by code, or try moving outside (as a test) to get a better lock.

    could you attach a link to the code you downloaded? or attach it here?
  • I think the problem is that you are not using the correct pins and therefore not receiving any data.

  • iseries wrote: »
    I think the problem is that you are not using the correct pins and therefore not receiving any data.


    Good point. Make sure you've adjusted the code so that the code RX pin is assigned/connected to the GPS TXD pin.

    If the code also needs a pin number for TX, you could set that to an unused pin.
  • @tombutler Hi Tom !

    I think I spotted a different "gotcha" that might be causing trouble here...

    The latest GPS library with compatibility for the new Parallax GPS module is only in the Blockly branch.

    If you have downloaded your SimpleIDE workspace from the main branch (which would be the logical thing to do, and all the instructions also say to do that), then you will run into problems in some conditions (depending on the satellite type being received).

    I'd recommend updating your gps library to the latest one like this:

    1. Open your local SimpleIDE folder; probably here: "My Documents/Simple IDE/Learn/Simple Libraries/Sensor"

    2. Delete the folder called "libgps", or move it somewhere else. Perhaps to your desktop for now. Make sure it's gone from the SimpleIDE folder.

    3. Download Blockly branch of simplelibs from here:
    Click the green "Clone or Download" button, and choose the zip file format.

    4. Open the zip file and go to the subfolder : "Learn/Simple Libraries/Sensor"

    5. Copy the entire folder called "libgps"

    6. Paste the libgps folder that you copied in step 5 into the local SimpleIDE folder you found in step 1.

    Now give it a test! Re-compile and run your SimpleIDE gps code, and you should see the correct data once the GPS module blue fix LED is lit.

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