Patent ID: 8565904

Claim:
An add-on irrigation controller for controlling water control valves and for utilizing with an existing controller set with initial start times and initial run-time durations, comprising: a housing, a microcontroller housed within said housing and programmed with a microcontroller program operative to receive and transmit data and to determine said initial start times and said initial run-time durations from said existing controller; a data input system configured to allow data to be imported into said add-on irrigation controller; wherein said data input system comprises a data input receiver operable to receive evapotranspiration data and any regulation data; wherein said evapotranspiration data are obtained from an evapotranspiration local characteristic curve for at least one locality; wherein said any regulation data comprise local mandatory watering restrictions for said at least one locality; wherein said evapotranspiration data and said any regulation data are accessible to said microcontroller program; wherein said microcontroller program is configured to calculate a watering budget and watering schedule based on at least said evapotranspiration data, on said any regulation data, on said initial start times, on said initial run-time durations, and on a minute-based representation of a total water volume as delivered by said existing controller; wherein said representation of said total water volume is calculated by multiplying an initial number of watering days per period of time for a designated zone of said existing controller, by an initial number of watering events per day for said designated zone of said existing controller, and by a number of minutes per watering event for said designated zone of said existing controller; and wherein said representation of said total water volume is allocated to a number of watering days of said period of time; wherein said microcontroller program is capable of utilizing said watering schedule to control said water control valves; at least one non-volatile memory storage medium configured to receive and to store data from said microcontroller; and a real-time clock operatively connected to said microcontroller.