How It Works
The Leaf Wetness Sensor approximates the thermal mass and radiative properties of leaves to closely mimic the wetness state of a real leaf. The way it works is simple: if the canopy is wet, the sensor is wet; if the canopy is dry, the sensor is dry. The Leaf Wetness Sensor measures the dielectric constant of the top of the sensor. The dielectric constants of water (80) and ice (5) are higher than air (1), so the sensor can determine the presence or absence of wetness using this method. Measurements can be logged at user-defined intervals to determine the duration of wetness on the canopy.
Sensor Benefits
Because the Leaf Wetness Sensor measures the dielectric constant, moisture does not need to bridge electrical traces for the sensor to detect moisture; the presence of water or ice anywhere on the sensor surface will be detected. Unlike common resistance-based sensors, it requires no painting or user calibration, and it can detect ice presence. The low power requirement and long battery life (2+ years with Em50 Datalogger) enable effective long-term leaf wetness monitoring.
SPECIFICATIONS
Measurement time: 10 ms
Power: 2.5VDC @ 2mA to 5VDC @ 7mA
Output: 250to 1500 mV
Operating Environment: -10C to 60C
Expected Lifetime: 2+ years continuous use
Probe Dimensions: 11.2cm x 5.8cm x 0.075cm
Cable Length: 5m standard, extension cables available
Connector type: 3.5mm plug
Datalogger Compatibility (not exclusive): Decagon Em5b, Em50, Em50R Campbell Scientific CR10,10X, 21X, 23X, 1000, 3000, 5000
leaf-wetness-spec-sheet-2007