> I incorporated the info with a clock application using a 32 kHz
> crystal. Other than the temperature based crystal drift, it worked
> like a champ.

Temperature is going to be an issue with RC because you can't
reliably factor in the time since the last recorded transition. For
example, if the previous sunset was 8pm and you're seeing a light
level higher than that only 4 hours later you know it's not going to
be sunrise. If RC drift is only a few per cent max then waiting eg
10 hours should be before the expected dawn time

Joe
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