Thermal sensor
OwnerKenneth J. Cuminginventor
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Abstract
A sensor device is shown for detection of soil moisture levels using thermal diffusivity techniques. The sensor device has a porous media in a first zone, a heated temperature sensor arranged within the first zone, a second zone of a thermally conductive dense media containing a second reference temperature sensor, and leads connecting the sensors to a circuit to provide power to the heated temperature sensor and to the second reference temperature sensor. The circuit includes a comparator to compare outputs from the heated temperature sensor to the second reference temperature sensor so as to provide a signal indicative of soil moisture levels when the sensor device is operationally placed to receive soil moisture into the first zone.
Claims18
A soil moisture content sensing device intended in use to be embedded in a soil area to be sensed, said device comprising a porous media forming a first zone, a heated first temperature sensor arranged within said first zone, a second zone of a thermally conductive non-porous media, and a second reference temperature sensor located within said second zone, said sensors being connected to circuit means which includes means to provide power to heat said first temperature sensor, said circuit means including comparator means to compare outputs from said heated first temperature sensor and said second reference temperature sensor.
Dependencies are inferred from the claim text.