So, another observation… maybe I didn’t realize previously that it does let you view (read-only) the sprinkler without entering a password, but doesn’t allow any changes. Not sure if that is by design, but typically I wouldn’t want someone over the public internet to view the schedule without a password. Perhaps the unit can’t accomodate this. The access from devices that haven’t accessed the local device web page does still seem to be an issue (invalid ip/port).
Some design thoughts…
When I schedule something to go of just once on a day, why not allow the interval to be 0? Based on my experimentation, it requires both that you put a window (say 06:30-07:30) and an interval. Adding an interval has no value, and if you happen to choose an interval short enough, it might run multiple times (you have to think about this when you schedule). Also, perhaps an option is to only require the end time if the interval is zero? That way, if another program pushes the execution/start time beyond the (would-be) end time, it would still run?