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/*
* TimeGPS.pde
* example code illustrating time synced from a GPS
*
*/
#include <Time.h>
#include <TinyGPS.h> //http://arduiniana.org/libraries/TinyGPS/
#include <NewSoftSerial.h> //http://arduiniana.org/libraries/newsoftserial/
// GPS and NewSoftSerial libraries are the work of Mikal Hart
TinyGPS gps;
NewSoftSerial serial_gps = NewSoftSerial(3, 2); // receive on pin 3
const int offset = 1; // offset hours from gps time (UTC)
time_t prevDisplay = 0; // when the digital clock was displayed
void setup()
{
Serial.begin(9600);
serial_gps.begin(4800);
Serial.println("Waiting for GPS time ... ");
setSyncProvider(gpsTimeSync);
}
void loop()
{
while (serial_gps.available())
{
gps.encode(serial_gps.read()); // process gps messages
}
if(timeStatus()!= timeNotSet)
{
if( now() != prevDisplay) //update the display only if the time has changed
{
prevDisplay = now();
digitalClockDisplay();
}
}
}
void digitalClockDisplay(){
// digital clock display of the time
Serial.print(hour());
printDigits(minute());
printDigits(second());
Serial.print(" ");
Serial.print(day());
Serial.print(" ");
Serial.print(month());
Serial.print(" ");
Serial.print(year());
Serial.println();
}
void printDigits(int digits){
// utility function for digital clock display: prints preceding colon and leading 0
Serial.print(":");
if(digits < 10)
Serial.print('0');
Serial.print(digits);
}
time_t gpsTimeSync(){
// returns time if avail from gps, else returns 0
unsigned long fix_age = 0 ;
gps.get_datetime(NULL,NULL, &fix_age);
unsigned long time_since_last_fix;
if(fix_age < 1000)
return gpsTimeToArduinoTime(); // return time only if updated recently by gps
return 0;
}
time_t gpsTimeToArduinoTime(){
// returns time_t from gps date and time with the given offset hours
tmElements_t tm;
int year;
gps.crack_datetime(&year, &tm.Month, &tm.Day, &tm.Hour, &tm.Minute, &tm.Second, NULL, NULL);
tm.Year = year - 1970;
time_t time = makeTime(tm);
return time + (offset * SECS_PER_HOUR);
}
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