I apologize for the confusion, note that the recommended WiFi adapters for OpenSprinkler are listed on the product webpage:
http://rayshobby.net/cart/opensprinkler/os-20
as well as the online user manual:
http://rayshobby.net/?page_id=3775#network
Edimax is a USB WiFi dongle. It can’t work with OpenSprinkler (microcontroller version) because it requires a USB host device.