I have an arduino mega, raspberry pi, relay shield, solenoid valves and 24Vac transformer. i am pretty sure these are the components i require to run OSPI. I have downloaded the sd image and it appears to be working fully, and the opensprinkler app appears to be working. What i want to know is whether it possible to use the arduino instead of purchasing the controller board from rays hobbies?? I just dont see the point in buying one if it is based on arduino programming and therefore can use the board i already have. If i can, how do i go about connecting it? And where do i change the code to get it to run the arduino, the pins that control the relay shield are 4,5,6 and 7. I hope someone can help!