Request: dateTime.timestamp

[sgtJohnny]

I'm using you NeoGPS in my project. I'm logging date and time to a CSV file. Sadly some CSV importers have problems with dates.

It would be very helpful if there was a function to get the current date as timestamp (seconds since 1/1/1970) from the neo gps library, like:

  uint32_t timestamp = fix_data.dateTime.timestamp;

Could you make this? :)

[SlashDevin]

The class NeoGPS::time_t already supports this. The example NMEAtimezone.INO shows how to convert the fix.dateTime to a seconds count, offset it by the time zone shift (in seconds), then convert that seconds count back to a time structure (time_t). The "seconds count" type is called NeoGPS::clock_t. Casting a time_t to a clock_t does the conversion from a structure to a seconds count.

In your case, just do this:

uint32_t timestamp = (NeoGPS::clock_t) fix_data.dateTime;

You may also need to review NeoTime.h to confirm the EPOCH. It defaults to Y2K, so you can either

• edit NeoTime.h and select the POSIX epoch

• offset the timestamp in your sketch by the difference in seconds between the Y2K and POSIX epochs. timeanddate.com has some handy calculators for this.

[sgtJohnny]

Hi, thanks for this tip, but what exactly is the "Y2K" Epoch? I did not find any nice info in the web...

My main problem is Trace : 3,2018-05-21 12:01:29.00,476691008,89832085,16007,1032,,3,1452,115,74437, Time Stamp 580219289

But when converting the time stamp back, i get the same date but 2019 instead of 2018?

[SlashDevin]

Y2K = Year 2000

3,2018-05-21 12:01:29.00,476691008,89832085,16007,1032,,3,1452,115,74437,
**Time Stamp ** 580219289

That is the correct value for an EPOCH of 01-01-2000 00:00:00 (confirmed here).

But when converting the time stamp back, i get the same date but 2019 instead of 2018?

Lets see the lines of code that convert it back. Or is it a spreadsheet function you are talking about?

This should work:

uint32_t timestamp = (NeoGPS::clock_t) fix_data.dateTime;
NeoGPS::time_t sameDateTime = (NeoGPS::clock_t) timestamp.

Did you offset the timestamp in your sketch (or spreadsheet) to the POSIX epoch? You would have to add 946,684,800 to a Y2K timestamp to get a POSIX timestamp (or subtract it go back).

[sgtJohnny]

Oh, so the Y2K EPOCH is basically exactly the same as UNIX, but with another date? Its basically "Seconds since 2000"?

Now i'm getting it, sorry!

It works now! :)