makeTime function

[BenShen98]

Hi, I had some problem with this function, When I ask to makeTime what is 0day 0month 0year, it return “4294880896”, which is “6:28:16 2-6-2106”. I had been try to find out the reason for last past hours and couldn't tell why. Please help me

Here is my code.

include

void setup() { Serial.begin(9600); }

void loop() { setTime(sync()); Serial.print(now()); Serial.print(" "); Serial.print(hour()); Serial.print(':'); Serial.print(minute()); Serial.print(':'); Serial.print(second()); Serial.print(' '); Serial.print(month()); Serial.print('-'); Serial.print(day()); Serial.print('-'); Serial.println(year()); } time_t sync() { tmElements_t tm; tm.Hour = 0; tm.Minute = 0; tm.Second = 0; tm.Day = 0; tm.Month = 0; tm.Year = 0; return makeTime(tm); }

Thank you

[blackketter]

The tmElements_t data structure you are creating is not valid.

Keep in mind that the years in a tmElements structure are since 1970 and that the months start at 1 (for January) as do the days.

I hope this helps.

[BenShen98]

Thanks for your help. But I don't think this would be a problem as the time_t means how many seconds has passed after 1/1/1970. Also, When I change the day to 1, month to 1, year to 1970, it returns 1322155904 which is 17:31:44 11-24-2011, it just totally doesn't make sense.

[BenShen98]

Would you mind try this or similar code on your Arduino? As it's possible because something wrong with my IDE on the computer. But it didn't help even after I reinstalled this Time library.

[PaulStoffregen]

Indeed your error is use of 0 for tm.Day and tm.Month.

I just tested this code:

#include <Time.h>
void setup() {
  Serial.begin(9600);
}

void loop() {
  setTime(sync());
  Serial.print(now());
  Serial.print(" ");
  Serial.print(hour());
  Serial.print(':');
  Serial.print(minute());
  Serial.print(':');
  Serial.print(second());
  Serial.print(' ');
  Serial.print(month());
  Serial.print('-');
  Serial.print(day());
  Serial.print('-');
  Serial.println(year());
  delay(500);
}
time_t sync() {
  tmElements_t tm;
  tm.Hour = 0;
  tm.Minute = 0;
  tm.Second = 0;
  tm.Day = 1;
  tm.Month = 1;
  tm.Year = 0;
  return makeTime(tm);
}

This is the result in the serial monitor:

0 0:0:0 0-0-1970
0 0:0:0 0-0-1970
0 0:0:0 0-0-1970
0 0:0:0 0-0-1970
0 0:0:0 0-0-1970

Time is working properly. You simply used 0 in those fields which begin at 1.