Soil Temperature and Humidity Sensor – SHT20

Description

Temperature and humidity sensor based on the Sensirion CMOSens® SHT20 4C. The metal housing is weather-resistant and prevents water from penetrating the sensor body and damaging it, but lets air through so it can measure soil humidity. It can also be used to accurately measure the ambient temperature and relative air humidity. The sensor operates with 3.3 V logic and features an I²C interface, particularly suitable for use with Arduino, Fishino, Raspberry Pi, etc. The connection cable is 1 meter long and has four wires: red = VCC (3 to 3.7 VDC), black = GND, yellow = SCL, green = SDA.

Connecting to Arduino

The image below shows a connection with an Arduino running at 5 V logic; since the sensor is 3.3 V logic, a level shifter has been placed in between.

Technical Specifications

• Humidity:
  – Measurement range: 0%RH ~ 100%RH
  – Resolution: 0.7%RH at 8-bit / 0.04%RH at 12-bit
  – Accuracy: ±3%RH
• – Red = VCC (3 to 3.7 VDC)
  – Black = GND
  – Yellow = SCL
  – Green = SDA

Documentation and useful links

• DFRobot Arduino SHT20 library