sleep mode timer interrupt

Hi there, I am going to be running an arduino diecemilia from batteries and I need it to last for as long as possible. I have seen that you can put the arduino into sleep mode which should save power. I want to basically have a program that will wake up just once a day and send a quick digital HIGH signal out and then go back to sleep. I have two questions: 1: Is it possible to wake the arduino with an internal timer (possibly timer2?) and has anyone got any code. 2: Has anyone got any info on the accuracy of any timer?

Thanks in advance, Pete Rogers

Hi Pete,

I think only an external interrupt or a reset will wake a sleeping Arduino. You could search google or check the ATmega168 datasheet to see if the watch dog timer will do a reset if the chip is in sleep mode. If so then you should be able to find code for doing that.

Good luck