Need a way to start a daily timer.

Hey guys, i have a little experience with programming arduinos, not too advanced.

but now ive hit a brick wall, this is it:

i need my Arduino to run an I/O code that i wrote, between 8 am and 4:30 pm every day,

how can i go about this?? i dont want to use a physical timer, as it takes too much space/weight in my application, therefore id like Arduino to do it, is it possible??

thank you for any help :D

You need a way for the Arduino to get the current time after it lost power. Once you have that, the rest is covered by the Time-library.


The arduino can be connected to a battery 24/7, thats not a problem, i just need it to stay in standby mode until 8 am, then run the program ( loop) until 4:30 pm, then go back into standby mode,

sorry if i wasnt so clear :S

i dont want to use a physical timer,

Not sure exactly what you mean here. You can bodge something up with a timer and maintain your own time of day by waking every ?mS, incrementing a counter, then going back to sleep, but really you should use an RTC chip.