초록 ▼

A capacitive soil moisture sensor that is easy to install, does not require complex calibration, can sense moisture at a particular depth, can accommodate soils of different composition, does not alter soil densities, provides fast response to changes in moisture and provides stable long term use. T

A capacitive soil moisture sensor that is easy to install, does not require complex calibration, can sense moisture at a particular depth, can accommodate soils of different composition, does not alter soil densities, provides fast response to changes in moisture and provides stable long term use. The sensor comprising of a body (10) onto which is attached a plurality of first electrode (20) and a plurality of second electrode (30). A plurality of protective layer (50) of low dielectric constant material is applied over the electrodes and against the body (10) to provide a physical barrier to prevent a conduction path from the first electrode (20) to the second electrode (30) and to provide protection against physical damage. The first and second electrodes (20), (30), once inserted into the soil, forms a capacitor with the soil as the dielectric. A change in soil moisture causes the capacitance of the sensor to change.

대표청구항 ▼

The invention claimed is: 1. A capacitive soil moisture sensor having a lower portion adapted to be inserted into the earth comprising of: a sensor carrier comprising; a body having a generally spade shaped with one tapered end, one opposite flat end and two parallel sides, said body being of a thi

The invention claimed is: 1. A capacitive soil moisture sensor having a lower portion adapted to be inserted into the earth comprising of: a sensor carrier comprising; a body having a generally spade shaped with one tapered end, one opposite flat end and two parallel sides, said body being of a thin structurally rigid material with a plurality of narrow ribs parallel to said two parallel sides, a header enclosure having a generally rectangular box shaped with one top face, one opposite bottom face, said header being joined at said bottom face to said body at said flat end such that said header's said bottom face is perpendicular to said body and such that said bottom face over-hangs said body generally equal distance on all sides, a first electrode comprising a plurality of sheets of conductive material, a second electrode comprising a plurality of sheets of conductive material, a protective layer comprising of a plurality of corrosion resistant and abrasive resistant material, said first electrode being joined onto the surface of one face of said sensor carrier's said body, said second electrode being joined onto the surface of said face of said sensor carrier's said body in the same orientation and alignment as said first electrode, said first electrode and said second electrode positioned so they do not touch, said protective layer joined onto the surface of said face of said sensor carrier's said body over said first electrode and said second electrode, said first electrode and said second electrode so positioned on said sensor carrier to be inserted into the earth so forms a planar capacitor with soil as dielectric. 2. The capacitive soil moisture sensor of claim 1 in which the sensor carrier consist of a corrosion resistant and ultra-violet light resistant material said material selected from fiber glass, polyurethane, and ABS. 3. The capacitive soil moisture sensor of claim 1 in which the protective layer consists of a low dielectric constant material relative to water said material selected from fluoropolymers, chloropolymers, chlorofluoropolymers, and polyparaxylene. 4. The capacitive soil moisture sensor of claim 1 in which the first electrode consist of a conductive material said conductive material selected from gold, platinum, copper, bronze, zinc, and nickel.