GPS device with text LCD display and track logging to GPX file on SD Card

Dependencies:   MODGPS SDFileSystem TextLCD mbed

mbed Pin #mbed Pin FunctionPeripheral Pin
p5SPI MOSI / SDFileSystemSD Card Data In
p6SPI MISO / SDFileSystemSD Card Data Out
p7SPI SCK / SDFileSystemSD Card Clk
p8SPI CS / SDFileSystemSD Card Data CS
p12GPIO / TextLCDLCD RS
p14GPIO / TextLCDLCD EN
p21GPIO / InterruptInButton switch to GND (start/stop logging)
p22GPIO / TextLCDLCD D4
p23GPIO / TextLCDLCD D5
p24GPIO / TextLCDLCD D6
p25GPIO / TextLCDLCD D7
p27UART RX / GPSGPS TX

Files at this revision

API Documentation at this revision

Comitter:
mprinke
Date:
Sun Feb 17 17:37:39 2013 +0000
Child:
1:1b62ee4c7e05
Commit message:
initial version

Changed in this revision

MODGPS.lib Show annotated file Show diff for this revision Revisions of this file
SDFileSystem.lib Show annotated file Show diff for this revision Revisions of this file
TextLCD.lib Show annotated file Show diff for this revision Revisions of this file
main.cpp Show annotated file Show diff for this revision Revisions of this file
mbed.bld Show annotated file Show diff for this revision Revisions of this file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MODGPS.lib	Sun Feb 17 17:37:39 2013 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/AjK/code/MODGPS/#34a9030f27a4
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SDFileSystem.lib	Sun Feb 17 17:37:39 2013 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/SDFileSystem/#c8f66dc765d4
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TextLCD.lib	Sun Feb 17 17:37:39 2013 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/wim/code/TextLCD/#0c32b66b14b8
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Feb 17 17:37:39 2013 +0000
@@ -0,0 +1,248 @@
+/* mbed GPS Logger using SD Card and Text LCD display
+ * 
+ * Copyright (c) 2013 m.prinke, MIT License
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
+ * and associated documentation files (the "Software"), to deal in the Software without restriction, 
+ * including without limitation the rights to use, copy, modify, merge, publish, distribute, 
+ * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is 
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or 
+ * substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING 
+ * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * @file          main.cpp 
+ * @purpose       GPS Logger using SD Card and Text LCD display
+ * @version       0.1
+ * @date          Feb 2013
+ * @author        M. Prinke 
+ */
+/**   
+ * Time and position data from GPS receiver is displayed on a text LCD.
+ * GPS tracks can be written to a logfile (GPX format) on SD Card.
+ * Logging is started/stopped using a toggle button.
+ * Everytime logging is started, a new file with the filename pattern /sd/gpslog<nnnn>.gpx
+ * is created, where <nnnn> is decimal number in the range 0000 to 9999 which is incremented.
+ * Searching for a new unique filename is started from zero. 
+ * 
+ * LED1: GPS status (blinking: fix invalid; on: fix valid)
+ * LED2: Logging status (off: stopped; on: logging)
+ *
+ * To Do:
+ * - Adjustable logging cycle time (read from config file on SD Card?)
+ * - Start new track segment after loss of GPS fix
+ * - Add support for GSA message (2D/3D fix, dilution of precision)
+ */
+
+#include "mbed.h"
+#include "GPS.h"
+#include "TextLCD.h"
+#include "SDFileSystem.h"
+
+#define GPS_BAUDRATE        4800
+#define LOGGING_CYCLE_SEC   5
+
+DigitalOut led_fix(LED1);   // GPS fix (blinking - no data/no fix; on: fix) 
+DigitalOut led_log(LED2);   // logging active
+InterruptIn button(p21);    // button connects pin to GND
+Serial pc(USBTX, USBRX);    // tx, rx
+GPS gps(NC, p27);           // tx, rx
+TextLCD lcd(p12, p14, p22, p23, p24, p25, TextLCD::LCD40x2); // rs, e, d4-d7
+SDFileSystem sd(p5, p6, p7, p8, "sd"); // mosi, miso, sclk, cs
+
+bool g_logging = false;
+bool g_changed = false;
+uint32_t g_trkpt_no = 0;
+
+/**
+ * Function to create a unique filename
+ *
+ * @param fn pointer to a filename buffer
+ * @param number part of filename (returned by reference)
+ * @return 0 on success, -1 if no unused filename could be created.
+ */
+int get_filename(char *fn, uint16_t *number)
+{
+    FILE *fp;
+    
+    for (int n=0; n < 9999; n++) {
+        sprintf(fn, "/sd/gpslog%04d.gpx", n);
+        if ((fp = fopen(fn, "r")) == NULL) {
+            *number = n;
+            // file does not exist yet
+            return 0;
+        } else {
+            fclose(fp);
+        }
+    }
+    
+    // filename pattern exhausted
+    return -1;
+}
+
+/**
+ * Callback function for button interrupt
+ *
+ * Debounce button and set change flag.
+ */
+void change_logging(void)
+{
+        wait_ms(50);        // button debounce
+        while (!button);    // wait until button released
+        g_changed = true;
+}
+
+/**
+ * Write GPX file header (including start of track segment)
+ *
+ * @param fp file pointer
+ * @param t time structure
+ * @param fileno file number
+ * @return result of last file write access
+ */
+int write_gpx_header(FILE *fp, GPS_Time t, uint16_t fileno)
+{
+    g_trkpt_no = 0; //< reset trackpoint number
+    
+    fprintf(fp, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
+    fprintf(fp, "<gpx\n");
+    fprintf(fp, "  version=\"1.0\"\n");
+    fprintf(fp, "  creator=\"mbed GPS Logger\"\n");
+    fprintf(fp, "  xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n");
+    fprintf(fp, "  xmlns=\"http://www.topografix.com/GPX/1/0\"\n");
+    fprintf(fp, "  xsi:schemaLocation=\"http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd\">\n");
+    fprintf(fp, "<time>%04d-%02d-%02dT%02d:%02d:%02dZ</time>\n", t.year, t.month, t.day, t.hour, t.minute, t.second);
+    fprintf(fp, "<trk>\n");
+    fprintf(fp, "  <name>track%04d</name>\n", fileno);
+    return fprintf(fp, "<trkseg>\n");
+}
+
+/**
+ * Write GPX trackpoint - add your geo-referenced data here
+ *
+ * @param fp file pointer
+ * @param t time structure
+ * @return result of last file write access
+ */
+int write_gpx_trkpt(FILE *fp, GPS_Time t)
+{   
+    fprintf(fp, "  <trkpt lat=\"%.4f\" lon=\"%.4f\">\n", gps.latitude(), gps.longitude());
+    fprintf(fp, "    <ele>%.1f</ele>\n", gps.altitude() * 1000.0);
+    fprintf(fp, "    <time>%04d-%02d-%02dT%02d:%02d:%02dZ</time>\n", t.year, t.month, t.day, t.hour, t.minute, t.second);
+    fprintf(fp, "    <name>TP%06d</name>\n", g_trkpt_no++);
+    return fprintf(fp, "  </trkpt>\n");
+}
+
+/**
+ * Write GPX file footer (including end of track segment)
+ *
+ * @param fp file pointer
+ * @return result of last file write access
+ */
+int write_gpx_footer(FILE *fp)
+{
+    fprintf(fp, "</trkseg>\n");
+    fprintf(fp, "</trk>\n");
+    return fprintf(fp, "</gpx>\n");
+}
+
+
+int main() {
+    GPS_Time t;
+    char filename[30];
+    uint16_t fileno;
+    FILE *fp = NULL;
+    uint16_t log_wait = 0;
+    
+    button.mode(PullUp);        
+    button.fall(&change_logging);
+    gps.baud(GPS_BAUDRATE);
+    lcd.cls();
+
+    while (1) {
+        // Wait for the GPS NMEA data to become valid.
+        // (Status flag in RMC message)
+        while (!gps.isTimeValid()) {
+            led_fix = !led_fix;
+            lcd.locate(21, 0);
+            lcd.printf("[no fix]");
+            wait(1);
+        }
+
+        gps.timeNow(&t);
+#if defined(DEBUG)
+        pc.printf("The time/date is %02d:%02d:%02d %02d/%02d/%04d\r\n",
+            t.hour, t.minute, t.second, t.day, t.month, t.year);
+#endif
+        lcd.locate(0, 0);
+        lcd.printf("%02d:%02d:%02d %02d/%02d/%04d %9s %10s",
+            t.hour, t.minute, t.second, t.day, t.month, t.year, 
+            (gps.getGPSquality() > 0 ? "[fix]   " : "[no fix]"),
+            (g_logging ? "[logging]" : "[stopped]"));
+        
+        // Check if at least four satellites produce a position fix and a valid quality.
+        if (gps.numOfSats() < 4 && gps.getGPSquality() != 0) {
+            // No fix or poor quality
+            led_fix = !led_fix;
+        } else {
+            // Fix valid and good quality
+            led_fix = 1;
+#if defined(DEBUG)
+            pc.printf("Lat = %.4f Lon = %.4f Alt = %.1fkm\r\n", 
+                gps.latitude(), gps.longitude(), gps.altitude());
+#endif
+            lcd.locate(0, 1);
+            lcd.printf("Lat: %07.4f Lon: %08.4f Alt: %.0fm   ",
+                gps.latitude(), gps.longitude(), gps.altitude() * 1000.0);
+                
+            if (g_logging) {
+                if (log_wait-- == 0) {
+                    log_wait = LOGGING_CYCLE_SEC - 1;
+                    if (write_gpx_trkpt(fp, t) < 0) {
+                        // write error
+                        fclose(fp);
+                        g_logging = false;
+                        led_log = 0;
+                    }
+                }
+            }
+        }
+        wait(1);
+        
+        // Logging state changed
+        if (g_changed) {
+            if (!g_logging) {
+                // Start logging
+                if (get_filename(filename, &fileno) != 0) {
+                    error("Could not create file with unique name\n");
+                } else {
+                    // open file for writing
+                    fp = fopen(filename, "w");
+                    if (fp == NULL) {
+                        error("Could not open file for write\n");
+                    } else {
+                        if (write_gpx_header(fp, t, fileno)) {
+                            g_logging = true;
+                            led_log = 1;
+                        }
+                    }
+                }
+            } else {
+                // Stop logging 
+                write_gpx_footer(fp);
+                // close file
+                fclose(fp);
+                g_logging = false;
+                led_log = 0;
+            }
+            g_changed = false;
+        } // if (changed)
+        
+    } // while (1)
+}
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Sun Feb 17 17:37:39 2013 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/0954ebd79f59
\ No newline at end of file