This is a simple water sensor can be used to detect soil moisture when the soil moisture deficit module plant waterer device so that the plants in your garden without people to manage; Adjustable sensitivity adjust the digital potentiometer (shown in blue) Operating Voltage 3.3V-5V; Module Dual Output mode a simple digital output analog output more accurate; with fixed bolt hole for easy installation; small PCB board size: 3cm * 1.6cm; power indicator (red) and the digital switch output indicator (green); using LM393 comparator chip stable; Small plate interface specification (4-wire): VCC external 3.3V-5V; GND External GND ;DO small board digital output interfaces (0 and 1) ;AO small board analog output interface; Soil moisture module is most sensitive to the ambient humidity is generally used to detect the moisture content of the soil; Module in the soil humidity less than a set threshold value when the DO port output high when the when soil humidity exceeds the threshold value is set the module D0 output low; Small plates digital outputs D0 can be directly connected with the microcontroller microcontroller to detect high and low and thus to detect soil moisture; Small plates digital output DO shop relay module can directly drive the buzzer module and which can form a soil moisture alarm equipment; Small plates analog output AO and AD module connected through the AD converter you can get more accurate values of soil moisture