Abstract: An automatic control apparatus and method for sprinkling water over a predetermined area includes a control apparatus having first and second sensors disposed underground within the predetermined area, with the first sensor being disposed in a horizontal orientation immediately below the plant root level and the second sensor being disposed in a horizontal position a predetermined distance below the first sensor. The predetermined distance between the first and second sensors is selected to provide a measurement of the wilt-point moisture content of the type of soil found within the predetermined area. The first and second sensors are provided to measure the impedance of the soil therebetween, with the impedance being proportional to the moisture content of the soil. The output of the first and second sensors is compared with a predetermined electrical reference value established for the wilt-point moisture content of the type of soil found within the predetermined area.
November 2, 1981
Date of Patent:
September 15, 1987
Water Sentry, Inc.
Marvin H. Weintraub, Donald R. Bernier, Larry Cameron