next topic »

[on:]

I'm a beginner so please excuse my ignorance.

If I want to program an 8 hr. delay do I program 480000ms or is there an "hour, minute, second" command in the programming language?  Also can someone recommend a method of energy conservation to minimize the electrical consumption during a lengthy delay?  Thanks.

[Reply #1 on:]

As far as I know, millis is the only game in town unless you add hardware such as a real time clock. Don't forget to declare any variables you use to store millis as unsigned long and any constants you use will need a UL suffix e.g. 60000UL. For power consumption help, search the forum for watchdog timer.

Edit: BTW - 480000ms is eight minutes.

[Reply #2 on:]

Have a look at the TimeAlarms library.
Set an alarm to go off in 8 hours and run a function that you specify.
Job done.

[Reply #3 on:]

Thanks wildbill.  Oops, I meant 28800000ms - see what I mean?  Dealing with ms for lengthy timing gets somewhat unwieldy.

Have a look at the TimeAlarms library.  Set an alarm to go off in 8 hours and run a function that you specify.  Job done.

Where would you suggest I look for TimeAlarms library info?

[Reply #4 on:]

Have a look at the TimeAlarms library.
Set an alarm to go off in 8 hours and run a function that you specify.
Job done.

D'oh! of course!

[Reply #5 on:]

Which Arduino board?  There is no way to shutdown the USB chip on boards such as Uno and Mega AFAIK,
so putting the microcontroller into a sleep mode won't drastically reduce current consumption.  Usually you'd
need an real-time-clock chip if going that route as running the microcontroller's 16MHz clock is a large part
of the current consumption.

Its worth searching these forums carefully there have been several lengthy threads on this sort of thing.

[Reply #6 on:]

Where would you suggest I look for TimeAlarms library info?

Google? 

TimeAlarms is included in the Time library:

Code:

http://playground.arduino.cc/Code/time

Unfortunately the playground does not include documentation for it though.  But see the example sketch--and the readme file in the library folder that you install.

And google.  http://www.lmgtfy.com/?q=arduino+timealarms

Cheers,
John

[Reply #7 on:]

I meant 28800000ms - see what I mean?  Dealing with ms for lengthy timing gets somewhat unwieldy.

so, don't do it. Let the compiler take the strain

Code:

8UL * 60UL * 60UL * 1000UL

.
Of course, you could also name the constants.

[Reply #8 on:]

  Also can someone recommend a method of energy conservation to minimize the electrical consumption during a lengthy delay? 

See this for tips on saving power:  http://www.gammon.com.au/power