Originally Posted by benjaf
Well it could work for a short period of time if you account for the time drift of your device.
The main issue with this approach is that everything is reset if you lose power. Then there is the rollover of the counter, can't quite remember how often that is.
Every 50 days. Also, as you mentioned, the drift with the Arduino counter can be significant (a few minutes per day) especially if the temperature changes.
Thanks for the code