Description

This module allows the measurement of moisture through analog output pins and it provides a digital output when a threshold of moisture is exceeded. The module is based on the LM393 op amp.

It includes the electronics module and a printed circuit board that “collects” the rain drops.  As rain drops are collected on the circuit board, they create paths of parallel resistance that are measured via the op amp.

The lower the resistance (or the more water), the lower the voltage output.   Conversely, the less water, the greater the output voltage on the analog pin. A completely dry board for example will cause the module to output five volts.

With potentiometer sensitivity adjustment
The output format: digital switch output (0 and 1) and analog AO voltage output;
Small board PCB size: Approx. 3.2 cm x 1.5 cm

Pin, Control, or Indicator

Description

VCC

+5 Volts Power Source

GND

Ground or negative power source

DO

Digital Output. Goes low when moisture exceeds set threshold.

A0

Analog Output – Zero to five volts. The lower the voltage, the greater the moisture.

Power LED

Indicates that power is applied

Output LED

Illuminates when moisture has exceeded threshold set by sensitivity adjustment.

Sensitivity Adjustment

Clockwise is more sensitive. Counterclockwise is less sensitive.