Irrigation Controller Schematic

I made this drawing in less than a hour. It is a design for a

irrigation controller which checks the soil conductivity and opens

waters the plant if the soil is too dry. The parts listed in the

schematic should cost less than $20 and that includes a printed

circuit board. The big expense outside of the actual controller

circuit is the solenoid valve which I do not include in the

schematic. Another $20 there.

Done