I just started using the Arduino based OpenSprinkler version and now I am wondering about how to set the rain delay for the rain sensor. I can not set the delay in the sensor itself, it just activates a relay as long as it rains or better as long as the surface is wet. Where in the app can I tell the controller how long it has to wait with watering after the sensor registered any rain?
The rain sensor works by delaying the controller using it’s own analog method and the delay is a function of the drying speed of the material used inside the rain sensor. Basically, they are supposed to dictate the “how long to stay off after rain”.
The app can start a rain delay manually, using “Change Rain Delay” from the main menu however this is unrelated to the rain sensor you have installed.
To second what Samer said: the rain sensor typically has a mechanical delay (which is also adjustable by opening or closing the vent size), so you don’t need to add additional delay in software. I have written a blog post about rain sensor. Check it out here: http://rayshobby.net/using-rainfreeze-sensor-with-opensprinkler/