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Project 31: Soil Humidity Sensor
Introduction
This is a simple soil humidity sensor aims to detect the soil humidity. If the soil is lack of water,
the analog value output by the sensor will decrease; otherwise, it will increase. If you use this
sensor to make an automatic watering device, it can detect whether your botany is thirsty so as to
prevent it from withering when you go out. Using the sensor with Arduino controller makes your
plant more comfortable and your garden smarter.
The soil humidity sensor module is not as complicated as you might think, and if you need to
detect the soil in your project, it will be your best choice.
The sensor is set with two probes inserted into the soil, then with the current go through the soil,
the sensor will get resistance value by reading the current changes between the two probes and
convert such resistance value into moisture content. The higher the moisture (less resistance) is,
the higher conductivity the soil has.
The surface of the sensor have undergone metallization process to prolong its service life. Insert it
into the soil and then use the AD converter to read it. With the help of this sensor, the plant can
remind of you: I need water.
Specification
1. Power Supply Voltage: 3.3V or 5V
2. Working Current: ≤ 20mA
3. Output Voltage: 0-2.3V (When the sensor is totally immersed in water, the voltage will be
2.3V)
4. 5V power supply (the higher humidity, the higher the output voltage)
5. Packaging : Electrostatic bag sealing
6. Sensor Type: Analog output
7. Interface Definition: Pin1- signal, pin2- GND, pin3 - VCC
8. Service Life: about one year (gold-plated surface for enhancing conductivity and
corrosion resistance )
9. Module Size: 20*60mm