40 PCS Soil Moisture Meter Probe

Description:
With the help of a soil moisture metering module which is also known as the hygrometer, you can tell when your plants need watering by how moist the soil is in your pot, garden or yard. Soil moisture is the presense of water in the soil. There are two types of moisture meters: Pin-type and pinless moisture meters. Pin-type moisture meters use the Ohm's law. Therefore, electrical current travels down one electrode, through the material being tested, and into another electrode. The amount of soil resistance and the passing current through the probe is used to measure how much moisture is present in the soil. Since moisture is a conductor, the less resistance means the higher the moisture content of the material being tested. Pinless moisture meters use an electromagnetic frequency to “scan” a specific area for the quantity of moisture. 
It's not a high tech sensor, but ideal for monitoring an urban garden, or your pet water level. This sensor can be used in a variety of DIY projects. This is a necessary tool for a connected IoT garden. This sensor uses the two probes to pass current through the soil, and then it reads that resistance to get the moisture level. More water makes the soil conduct electricity more easily (less resistance), while dry soil conducts electricity poorly (more resistance). The IO Expansion Shield is the perfect shield to connect this sensor to Arduino.

Features: 
VCC: 3.3V-5V
DO: Digital output interface (0 and 1)
AO: Analog Output Interface

Package Include:
40 x Soil Moisture Meter Probe