GPS_Logger_v1

Keyword: GPS, SD Card, LCD, Logger, File system, Analog input, RTC

Control Program

  1. GPS_Logger_v1

Reference

  1. GPS_Logger_01

Function

Every one seconds, GPS data (RMC & GAA) and five analog inputs are logged in SD-CARD.
1. File name creates from time (since 1970/1/1) of RTC
2. Condition shows on Text LCD
3. DEBUG infromation sends PC via USB Serial 

Hardware Configlation

------- GPS Receiver --------

SZP950T (only Japanese explanation)   SiRF3 TTL level Interface

------- Pin Assignment -----

I have changed pin assignment from previous projects.
This is new "Pin Assignment".

Software

------- Known BUG ---------
Just after Recorde Switch activation, the program starts a file open action then takes long time. 
In parallel, GPS sends data stream constantly and some data are missing.
You can see the data (PC Com monitor via USB serial for DEBUG) as follows.

---> Measure for this bug

It's not only 1st line of data problem but also seems like buffer overflow problem and affect all of saved data .
I cannot solve the problem itself at this moment and only tentative solution is below program.
Every time, clear the data buffer (MsgBuf_RMC &GGA) before copy from msg buffer. This makes no problem for recorded data.

        if (strncmp(msg, "$GPRMC",6) == 0) {
            for (int i=0; i<BSIZ ; MsgBuf_RMC[i++]=0);  // Clear buffer
            for (int i=0; msg[i] != 0; i++) {           // Copy msg to RMC buffer
                MsgBuf_RMC[i] = msg[i];
            }
            gps_dat = RMC;

How to use recorded data

 Followings are sequence to use the GPS logger.

1.     After data collection into SD card, you can read the text file from SD card to your PC.
2.     Convert the text file to waypoint, tracks and routes information using GPSBabel software.
3.     Just double clicks the converted file then you can see the result on “Google Earth”.

If you have not installed the software, please check following links.

1.     GPSBabel ->Free Download

2.     Google Earth -> Free Download

Revision

April 17th, 2010      Create this page
April 18th, 2010      Updated the infromation

 


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