@jremington Thanks, I had already read that link, it's great! However it messes with registers and is a lot advanced. I was wondering if there is a known library that provides the "delay with power saving" or something similar... I really think that arduino should already have it built in in the language since any delay does absolutely nothing, just waits... every time a delay is called, Arduino could check if there is any interrupt attached or any code to watchdog attached, otherwise it should disable everything untill the delay has passed since the user explicitly didnt set any interrupt or watchdog that could cause problem disabling.