If the photocell is pointed east, weather does make a big difference. For other bearings, less so. And light pollution is more or less the same every night so it can be accounted for. Still, I suggested an LCD alarm clock as a decent compromise between accuracy, feature set, cost and transistor count. An analog one has fewer, closer to a 555, but will use more energy and produce a ticking sound (still less than the computers’ fans). And then there’s a windup one or a rooster…
If you’ve ever woken up to one of these bad boys on a fresh set of batteries, you know the feeling of true terror. Not sure if the windup ones are any gentler…
I used a windup one for the lols. I could barely fall asleep and it would indeed ring very loudly, but only for 20 seconds or so. Of course, the clock spring is wound separately from the ringer spring.
Light pollution on an overcast night might give your photoreceptor a false positive
If the photocell is pointed east, weather does make a big difference. For other bearings, less so. And light pollution is more or less the same every night so it can be accounted for. Still, I suggested an LCD alarm clock as a decent compromise between accuracy, feature set, cost and transistor count. An analog one has fewer, closer to a 555, but will use more energy and produce a ticking sound (still less than the computers’ fans). And then there’s a windup one or a rooster…
If you’ve ever woken up to one of these bad boys on a fresh set of batteries, you know the feeling of true terror. Not sure if the windup ones are any gentler…
I used a windup one for the lols. I could barely fall asleep and it would indeed ring very loudly, but only for 20 seconds or so. Of course, the clock spring is wound separately from the ringer spring.
Battery powered ones don’t tick, or at least the one I had didn’t