Very long delay() possible? I'm trying to make an opening and closing little door that should open or close every 12 hours. I was wondering if I could just make a small looping script with a delay() for 12 hours, delay(43 200 000 000); I guess? However, I have no idea if that's possible and/or recommendable. Some feedback/alternatives(if needed) would be nice :)
The real time clock method is the most accurate way but otherwise use millis

unsigned long startMillis = millis();
while (millis() - startMillis &lt; LONG_DELAY_MS);


This will delay up to approx. 4294967295ms (2^32-1) or 49 days, after which the timer will catch up to the value of startMillis