Installing the Leaf Wettness Sensor

The Pessl Instruments Leaf Wetness Sensor is monitoring the resistance or conductivity in a filter paper. This principle is used by the sensors of several producers to simulate the wetness period of all leafs. The sensor used by Pessl Instruments and has been developed in an Apple Scab project in South Africa.

The small electronic in the cable enables iMETOS to detect the leaf wetness sensor. If the sensor is not connected the input for the leaf wetness sensor has an undefined resistance. If the sensor is connected the resistance is defined and if the filter paper is wet the resistance becomes very low.

Two or more leaf wetness sensor can be connected together they will show wet in case one of them shows wet. Alternative several leaf wetness sensors can be connected to specific repeaters in the Pessl Instruments sensor bus.


To mount the leaf wetness sensor in an orchard or in a field use a cable tie or any other type of tie and fix it trough the white plastic part at the bottom of the sensor on a branch or on a part of the iMETOS holder. The stainless steel spring is not for fixing it is to press the filter paper against the electrodes. 

Created by heiner. Last Modification: Wednesday 08 of February, 2012 09:45:36 GMT by Lena.