HD3901 Capacitive Leaf Wetness Sensor thumbnail 1

Senseca

HD3901 Capacitive Leaf Wetness Sensor

Dual-surface leaf wetness sensor with capacitive sensing for agricultural and floricultural monitoring.

Leaf wetness range 0…100% with ±5% accuracy
Two 0.5…3 V analog outputs for upper and lower surfaces
Factory calibrated, IP67 protection and 5 m or 10 m cable options

Quantity

Overview

The Senseca HD3901 is a dual-sensitive surface leaf wetness sensor designed for agricultural and floricultural monitoring. It uses a capacitive measuring principle to detect condensation and small water droplets on its upper and lower sensitive surfaces, accounting for the different drying times of the two sides of a leaf. The sensor measures wetness from 0…100% with ±5% accuracy, while its white sensitive surfaces are designed to simulate the thermal and radiative properties of a real leaf.

The sensor provides two 0.5…3 V analog outputs for separate wetness measurements and operates on a 5…18 Vdc power supply with less than 1 mA consumption. It is factory calibrated and features an IP67-rated sealed enclosure, with treated surfaces resistant to atmospheric agents and chemicals found in pesticides. Available with 5 m or 10 m fixed cables, the HD3901 is suitable for crop monitoring in open fields, greenhouses and meteorological stations.

Typical Applications

Leaf wetness monitoring in agriculture and floriculture
Condensation monitoring for mold and fungal infection prevention
Wetting and drying time monitoring in open fields and greenhouses
Leaf wetness measurement at meteorological monitoring stations

Key Features

Dual-sensitive surface for separate upper and lower wetness measurements
Capacitive sensing principle for detecting small water droplets
Leaf wetness measurement range 0…100%
Measurement accuracy ±5%
Two separate 0.5…3 V analog outputs
White sensitive surfaces designed to simulate real leaf thermal and radiative properties
5…18 Vdc power supply with less than 1 mA consumption
IP67 sealed housing and treated surfaces resistant to atmospheric agents and pesticide chemicals
Fixed 4-pole cable available in 5 m or 10 m lengths
Factory calibrated, with no user calibration required

Benefits

Separate upper and lower wetness measurements from one sensor
Supports timely phytosanitary treatments to reduce mold and fungal infection risks
Leaf-like sensitive surfaces provide realistic condensation monitoring
Ready to use: factory calibrated, no user calibration required
Low power consumption supports continuous monitoring
Weather-resistant construction supports outdoor and greenhouse use
Two analog outputs allow connection to compatible data loggers

Specifications

Measurements
Measuring principle	Capacitive
Measured parameter	Leaf wetness degree
Measuring range	0…100% of sensitive surface area covered by water
Measurement accuracy	±5%
Sensitive surfaces	Dual-sensitive surfaces (upper and lower)
Detection capability	Condensation and small water droplets

Electricals
Power supply	5…18 Vdc
Current consumption	Less than 1 mA
Analog outputs	2 × 0.5…3 V
Upper surface output	0.5…3 V (H-marked surface)
Lower surface output	0.5…3 V (unmarked surface)
Output correspondence	0.5…3 V corresponds to 0…100% wetness
Load resistance	Greater than 10 kΩ

Sensor Construction and Materials
Housing material	Polypropylene (PP)
Sensitive area material	Copper grid on glass epoxy substrate
Sensitive surface colour	White
Surface characteristics	Designed to simulate the thermal and radiative properties of a real leaf
Surface treatment	Resistant to atmospheric agents and chemicals present in pesticides
Electronics protection	Circuit board enclosed in a sealed plastic housing

Environmental
Operating temperature	−30…+60 °C
Protection rating	IP67
Condensation resistance	Sealed housing supports operation in high-condensation environments

Physical
Overall dimensions	61 × 115 × 11 mm (excluding cable)
Weight	Approximately 100 g (including 5 m cable)
Cable type	Fixed 4-pole cable ending with open wires
Cable length options	5 m or 10 m
Mounting arrangement	Two fixing holes in the plastic support

Installation, Calibration and Maintenance
Installation location	Within plant foliage or on a nearby meteorological station mast
Recommended orientation	H-marked sensitive surface preferably facing upward
Installation angle	Approximately 30…45° relative to the ground
Mounting method	Clamp or screws through the fixing holes
Data logger requirement	At least two voltage analog inputs
Calibration	Factory calibrated; no user calibration required
Maintenance	Periodic cleaning of sensitive surfaces with water and normal detergent
Wetting and drying analysis	Measurement recording and analysis using a connected data logger

Models and Ordering Information
HD3901.5	Leaf wetness sensor with 5 m fixed cable
HD3901.10	Leaf wetness sensor with 10 m fixed cable

Drawing

Downloads

HD3901 Family Datasheet	DownloadHD3901 Family Datasheet
HD3901 User Manual	DownloadHD3901 User Manual
HD3901 Family CE Declaration of Conformity	DownloadHD3901 Family CE Declaration of Conformity