Automatic sprinkler control

Claim 1

An automatic sprinkler control for maintaining soil moisture of the ground area serviced by a lawn sprinkler system at a preset level by controlling the flow of water to said sprinkler system, said automatic sprinkler control being sensitive to the moisture content of the ground and of the aboveground ambient air and comprising: a. a water valve means for controlling water flow to said sprinkler system, b. a humidity chamber means, a humidity sensitive element means and a latch means, said humidity chamber means being positioned within the ground area serviced by said sprinkler system and maintaining an internal humidity level which depends on the soil moisture level of the ground area serviced and on the aboveground ambient humidity, said humidity sensitive element means being positioned inside said humidity chamber means and coupled to said latch means, said humidity sensitive element means responding to changes in soil moisture considered with ambient humidity by causing said latch means to move, c. a spring loaded valve opening mechanism means and a sensitivity adjustment means, said spring loaded opening mechanism means being operatively coupled to said water valve means and having an initial state such that said water valve means is closed, said latch means being operatively coupled to said spring loaded opening mechanism means, said humidity sensitive element means causing said latch means to be positioned so as to prevent motion of said spring loaded opening mechanism means from an initial state when the soil moisture of the ground area serviced considered with ambient humidity is above a desired level, said humidity sensitive element means responding to drops in soil moisture considered with ambient humidity below a desired level by causing said latch means to be positioned so as to permit motion of said spring loaded opening mechanism means, said spring loaded opening mechanism means in turn moving to open said water valve means allowing water to flow to said sprinkler system, said sensitivity adjustment means being coupled to said humidity sensitive element means and controlling the level of internal humidity of said humidity chamber means below which said humidity sensitive element means initiates open states of said water valve means and thereby functioning as a means for selecting a desired level of soil moisture considered with ambient humidity to be maintained by said automatic sprinkler control, d. a valve closing mechanism means, said valve closing mechanism means being coupled to said spring loaded opening mechanism means and including an impeller means, a reduction gear mechanism means and a reset mechanism means, said impeller means being coupled to said reduction gear mechanism means and said reduction gear mechanism means being coupled to said reset mechanism means, said impeller means being actuated by water flowing through said water valve means when said water valve means is in an open state, said reduction gear mechanism means being actuated by said impeller means and facilitating a mechanical advantage for rotation of said impeller means to actuate said reset mechanism means and return said spring loaded opening mechanism means to an initial state closing said water valve means, said water valve means being closed after a fixed number of rotations of said impeller means and thereby being closed after a fixed volume of water has been permitted to flow to said sprinkler system.