Does anybody know a list of clock commands?

[Meladi Catalino]

Hi,
Does any of you know a list of clock functions of something? I have this Language Reference for arduino: arduino.cc/reference/en But there's nothing about time & date, so if any of you know where i can find such functions and commands it would be really nice.

My goal is to make a very simple arduino code, so a LED strip will turn on when the clock is for example 23:25 and turn off again at 04:14 and so the code will repeat that every time the clock becomes e.g. 23:25 again.
I also want to be able to make the LED light fade slowly in and out. (so it takes e.g. 5 min to fade into full brightness, and out again when it's suppose to turn off)
I am not a very good programmor so i really hope you guys can help me out, especially because i can't find any code with a time stamp that i can edit INSIDE the code.

If you write any code, can you then please make a comment next to the code that explains what every line of code does? That helps me understand how it works.

Thanks

[John Matthews]

Hi - googling "c time functions" took me here:
https://www.tutorialspoint.com/c_standard_library/time_h.htm
which is quite a handy summary, and is this the sort of thing you could use? (If you want the time as a string eg. "HH:MM:SS" rather than hours/minutes/seconds values then you probably want to use the strftime() function.)

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(void)
{
    // Get current calendar time as a time_t value.
    time_t rawTime;

    time(&rawTime);

    // Convert the time_t value into a structure including hours and
    // minutes values, and display them.
    struct tm tmInfo;

    localtime_r(&rawTime, &tmInfo);

    printf("hour = %d\n", tmInfo.tm_hour);
    printf("mins = %d\n", tmInfo.tm_min);

    exit(EXIT_SUCCESS);
}

Output:

hour = 12
mins = 1

[John Matthews]

...although doing a bit of research, I don't think any of those functions are available on an arduino? If that's the case then apologies; you'll need something arduino-specific.

[John Matthews]

Looking at this:
https://www.electronicwings.com/arduino/basic-functions-related-to-time-and-interrupts-in-arduino
implies there isn't anything that will give you the current time, only time since the program started.

Do you have some way of inputting an absolute time value which your code could add the millis() value to to get the current time?

[Meladi Catalino]

John Matthews wrote:Looking at this:
https://www.electronicwings.com/arduino/basic-functions-related-to-time-and-interrupts-in-arduino
implies there isn't anything that will give you the current time, only time since the program started.

Do you have some way of inputting an absolute time value which your code could add the millis() value to to get the current time?

-Oh, does that mean that everytime you start the Arduino you have to physically change a number/time that the mills() function adds itself to?
I'll just use a DS1307 or a DS3231... So it keep track of the time every day for me... instead of typing a new number/time in every time i start the arduino

[John Matthews]

Meladi Catalino wrote:does that mean that everytime you start the Arduino you have to physically change a number/time that the mills() function adds itself to?

I know next to nothing about the adruino, but that's what it looks like just based on that article.

I'll just use a DS1307 or a DS3231... So it keep track of the time every day for me... instead of typing a new number/time in every time i start the arduino

Sounds like a good plan

[John Matthews]

John Matthews wrote:I know next to nothing about the adruino

Can't even spell it

[Ron McLeod]

Meladi Catalino wrote:[Oh, does that mean that everytime you start the Arduino you have to physically change a number/time that the mills() function adds itself to?
I'll just use a DS1307 or a DS3231... So it keep track of the time every day for me... instead of typing a new number/time in every time i start the arduino

Either use a hardware RTC like the DS3231 that you mentioned, or if you have WiFi or some other connectivity, grab the time from a network resource.