Yes, millis() is the time in milliseconds since the Arduino was powered up or reset. So what ? You know when power was detected and when it stopped being detected so you can calculate how long it was on or off by subtracting one time from the other.
Yes, millis() is the time in milliseconds since the Arduino was powered up or reset. So what ? You know when power was detected and when it stopped being detected so you can calculate how long it was on or off by subtracting one time from the other.