The Leaf Wetness sensor detects the presence of surface moisture. The sensor is an artificial-leaf electrical- resistance type. It consists of a sensing grid, low-voltage bi-polar excitation circuit, and conductivity-sensing circuit. The GroWeather console measures the conductivity across the grid and displays the result as a moisture level, scaled from 0 to 15. The user may select the threshold level at and above which moisture-hour totals are accumulated.
The sensing grid is a gold-plated etched circuit on an epoxy-glass substrate; the excitation and sense circuits are encapsulated in black epoxy. The included mounting bracket holds the sensor at a 45 angle to simulate a typical leaf position and to permit runoff of excess moisture; it may be mounted on a vertical post, pipe, or stake, or on the Sensor Mounting Arm.
Two Leaf Wetness sensors may be connected in parallel by splicing their cables together. When this is done, the reported moisture level will be twice as high as that of an individual sensor, and complete wetness will be reported whenever either sensor is wet.