Factoring in weather would be a great feature. It would be nice if the code could call a webservice (or simple GET URL) passing it the zip code configured. The service would hit another weather web site and get the weather forecast (preferably by RSS). It would take the forecast and convert it to a simple “Water or not” return. It would go something like:
“If the possibility of rain today is >N1% then don’t water”
or
“If the possibility of rain tomorrow is >N2% then don’t water”
or
“If the possibility of rain the day after tomorrow is >N3% then don’t water”
where N1, N2 and N3 could be configured in the call to the webservice.
Once the algorithm is refined, and a reliable source of weather data defined, the code could be ported into OpenSprinkler directly.