date from NTP website which provides seconds from UTC (Jan 1, 1900)

[RichardFerraro]

Anyone have an algorithm to calculate the current month-day-year based on the number of seconds since Jan 1, 1970 as provided by time.nist.gov NTP server.

I can correctly calculate the local time (hour-min-second)
secsSince1970 = secsSince1900 - 2208988800; // subtract seconds in seventy years:
hour = (secsSince1970 % SECONDS_IN_DAY) / SECONDS_IN_HOUR); // hour (86400 equals secs per day)
min = (secsSince1970 % SECONDS_IN_DAY) / SECONDS_IN_HOUR;
seconds = (secsSince1970 % SECONDS_IN_HOUR) / SECONDS_IN_MINUTE);

e.g. results,

Seconds since Jan 1 1900 = 3856635732
The UTC time is 23:42:12
The California time is 16:42:16

I can't figure out how to get the date. I have tried two algorithms I found on-line and neither is even close.

thanks,

Richie

Does anyone really know what time it is? (music by Chicago)

 

[shawn]

This might help: https://github.com/ssilverman/QNEthernet/blob/master/examples/SNTPClient/SNTPClient.ino

 

[MarkT]

This might be useful:
https://howardhinnant.github.io/date_algorithms.html#civil_from_days

However its not difficult to just step forward years, then months, first calculate the days, and don't forget leap days. Not the most efficient, but straightforward coding at least.

 

[blackketter]

Paul's TimeLib should help:

https://github.com/PaulStoffregen/Time

 

[BriComp]

the number of seconds since Jan 1, 1970 as provided by time.nist.gov NTP server.

That is the basis of Teensy time t, so all the TimeLib routines will work just fine.