This is a simple water sensor that can be used to detect soil moisture when the water deficit module emits a high level, and the low backwards output. Use this sensor produced an automatic waterer device, so that the plants in your garden, without people to manage. Blue adjustable sensitivity digital potentiometer adjustment () 3.3V-5V operating voltage Dual output module mode, digital output, more analog output. Interface (4 wires) VCC: 0.3 V-5V GND: GND DO: digital output interface (0 and 1) AO: Analog Output Interface Instructions for Use: Moisture module of the soil is more sensitive to environmental humidity generally used to detect soil moisture content. Module to reach the value is set the rate of soil moisture, DO port high output, when the ground humidity exceeds a set value, the low D0 output module; The D0 digital output can be connected directly to the microcontroller to detect high and low from the microcontroller to detect the humidity of the ground; The digital outputs DO module rele can directly drive the buzzer module, which can form a soil moisture alarm device; AO and AD analog output module connected through the AD converter can obtain more precise values of soil moisture; Dimension: 5 * 3 * 1cm / 1.97 * 1.18 * 0.39 inch Material: Metal, Plastic color: blue Package includes: 5pcs soil moisture module 5pcs soil moisture sensor 5pcs 2 Lines Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.