A soil moisture sensor can read the amount of moisture present in the soil surrounding it. It is ideal for monitoring garden, or your plant's water level. This is a must have tool for a connected 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).

It will be helpful to remind you to water your indoor plants or to monitor the soil moisture in your garden. The IO Expansion Shield is the perfect shield to connect this senor to Arduino.

The new soil moisture sensor uses Immersion Gold which protects the nickel from oxidation.

Specifications:

• Working voltage: 5V
• Working Current: <20ma
• Interface: Analog
• Output voltage signal: 0~4.2V
• Depth of detection: 37mm
• Working Temperature: 10℃~30℃
• Size: 63×20×8mm
• Arduino compatible interface
• Low power consumption
• High sensitivity
• Surface finish:Immersion Gold

Wiring:

• VCC external 3.3V-5V
  
• GND external
• DO small board digital output interfaces ( 0 and 1 )
  
• AO small board analog output interface