| 摘要 |
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.
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