Hello all. I am having some problems interfacing a GPS with an Arduino Board and was looking for some help.
Hardware
Arduino Board: Uno
GPS: Garmin 18x PC
RS232 Shield
So far what I have done is:
- Upload code to Arduino board.
- Place RS232 Shield on top of Arduino board.
- Connect Garmin 18x PC to serial port on RS232 Shield.
- Open Serial terminal.
I downloaded the TinyGPS library and used the example code that was on there with a few changes (which I highlighted):
#include <TinyGPS.h>
#include <NewSoftSerial.h>
/* This sample code demonstrates the normal use of a TinyGPS object.
It requires the use of NewSoftSerial, and assumes that you have a
4800-baud serial GPS device hooked up on pins 2(rx) and 3(tx).
*/
TinyGPS gps;
[glow]NewSoftSerial mySerial = NewSoftSerial(0,1);[/glow]
void gpsdump(TinyGPS &gps);
bool feedgps();
void printFloat(double f, int digits = 2);
void setup()
{
Serial.begin(4800);
mySerial.begin(4800);
Serial.print("Testing TinyGPS library v. "); Serial.println(TinyGPS::library_version());
Serial.println("by Mikal Hart");
Serial.println();
Serial.print("Sizeof(gpsobject) = "); Serial.println(sizeof(TinyGPS));
Serial.println();
}
void loop()
{
bool newdata = false;
unsigned long start = millis();
// Every 5 seconds we print an update
while (millis() - start < 5000)
{
if (feedgps())
newdata = true;
}
if (newdata)
{
Serial.println("Acquired Data");
Serial.println("-------------");
gpsdump(gps);
Serial.println("-------------");
Serial.println();
}
}
void printFloat(double number, int digits)
{
// Handle negative numbers
if (number < 0.0)
{
Serial.print('-');
number = -number;
}
// Round correctly so that print(1.999, 2) prints as "2.00"
double rounding = 0.5;
for (uint8_t i=0; i<digits; ++i)
rounding /= 10.0;
number += rounding;
// Extract the integer part of the number and print it
unsigned long int_part = (unsigned long)number;
double remainder = number - (double)int_part;
Serial.print(int_part);
// Print the decimal point, but only if there are digits beyond
if (digits > 0)
Serial.print(".");
// Extract digits from the remainder one at a time
while (digits-- > 0)
{
remainder *= 10.0;
int toPrint = int(remainder);
Serial.print(toPrint);
remainder -= toPrint;
}
}
void gpsdump(TinyGPS &gps)
{
long lat, lon;
float flat, flon;
unsigned long age, date, time, chars;
int year;
byte month, day, hour, minute, second, hundredths;
unsigned short sentences, failed;
gps.get_position(&lat, &lon, &age);
Serial.print("Lat/Long(10^-5 deg): "); Serial.print(lat); Serial.print(", "); Serial.print(lon);
Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms.");
feedgps(); // If we don't feed the gps during this long routine, we may drop characters and get checksum errors
gps.f_get_position(&flat, &flon, &age);
Serial.print("Lat/Long(float): "); printFloat(flat, 5); Serial.print(", "); printFloat(flon, 5);
Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms.");
feedgps();
gps.get_datetime(&date, &time, &age);
Serial.print("Date(ddmmyy): "); Serial.print(date); Serial.print(" Time(hhmmsscc): "); Serial.print(time);
Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms.");
feedgps();
gps.crack_datetime(&year, &month, &day, &hour, &minute, &second, &hundredths, &age);
Serial.print("Date: "); Serial.print(static_cast<int>(month)); Serial.print("/"); Serial.print(static_cast<int>(day)); Serial.print("/"); Serial.print(year);
Serial.print(" Time: "); Serial.print(static_cast<int>(hour)); Serial.print(":"); Serial.print(static_cast<int>(minute)); Serial.print(":"); Serial.print(static_cast<int>(second)); Serial.print("."); Serial.print(static_cast<int>(hundredths));
Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms.");
feedgps();
Serial.print("Alt(cm): "); Serial.print(gps.altitude()); Serial.print(" Course(10^-2 deg): "); Serial.print(gps.course()); Serial.print(" Speed(10^-2 knots): "); Serial.println(gps.speed());
Serial.print("Alt(float): "); printFloat(gps.f_altitude()); Serial.print(" Course(float): "); printFloat(gps.f_course()); Serial.println();
Serial.print("Speed(knots): "); printFloat(gps.f_speed_knots()); Serial.print(" (mph): "); printFloat(gps.f_speed_mph());
Serial.print(" (mps): "); printFloat(gps.f_speed_mps()); Serial.print(" (kmph): "); printFloat(gps.f_speed_kmph()); Serial.println();
feedgps();
gps.stats(&chars, &sentences, &failed);
Serial.print("Stats: characters: "); Serial.print(chars); Serial.print(" sentences: "); Serial.print(sentences); Serial.print(" failed checksum: "); Serial.println(failed);
}
bool feedgps()
{
while (mySerial.available())
{
char serialchar = mySerial.read();
[glow]Serial.print(serialchar, BYTE);[/glow]
if (gps.encode(serialchar))
return true;
}
[glow]float flat, flon;
unsigned long fix_age;
// returns +- latitude/longitude in degrees
gps.f_get_position(&flat, &flon, &fix_age);
if (fix_age == TinyGPS::GPS_INVALID_AGE)
Serial.println("No fix detected");
else if (fix_age > 5000)
Serial.println("Warning: possible stale data!");
else
Serial.println("Data is current.");[/glow]
return false;
}
The output I get is:
Testing TinyGPS library v. 9
by Mikal Hart
Sizeof(gpsobject) = 103
No fix detected
No fix detected
No fix detected
No fix detected
No fix detected
No fix detected
No fix detected
As a side note, I noticed when I started to remove the shield to the point where the Analog In and Power Pins were not connected I got garbage, yet still no fix.
ÿ¿ïÿÿÿNo fix detected
ÿÿùÿÿÿÿNo fix detected
¿ÿÿNo fix detected
þÿ
ÿÿïÿÿNo fix detected
ÿþÿÿÿNo fix detected
ÿÿþþÿÿÿÿNo fix detected
ÿü
ÿÿ¿No fix detected
ÿöÿÿ·÷¿ÿÿþüNo fix detected
ßø÷ÿÿþÿNo fix detected
ÿÿÿÿóúÿßÿÿÿßÿþþÿÿNo fix detected
ÿúÿ
ÿøÿßÿÿÿßÿþþþNo fix detected
ÿúÿ
ÿúÿßÿÿÿßÿþþNo fix detected
Any help to let me know if I am headed in the right direction or if I'm doing something wrong is greatly appreciated.
