Arduino Mega 2560 Project 18: Soil Humidity Sensor

Introduction:
This is a simple soil humidity sensor aims to detect the soil humidity. If the soil is in 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 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 moisture (less resistance), 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 you: I need water.

Specification:

• Power Supply Voltage: 3.3V or 5V
• Working Current: ≤ 20mA
• Output Voltage: 0-2.3V (When the sensor is totally immersed in water, the
• voltage will be 2.3V) 5V power supply，the higher humidity, the higher the output voltage
• Packaging : Electrostatic bag sealing
• Sensor type: Analog output
• Interface definition: Pin1- signal, pin2- GND, pin3 - VCC
• Service life: About one year (gold-plated surface for enhancing conductivity and corrosion resistance )
• Module size: 20X60mm

Connection Diagram:

Sample Code:

/*
  # Example code for the moisture sensor
  # Connect the sensor to the A0(Analog 0) pin on the Arduino board
  # the sensor value description
  # 0  ~300     dry soil
  # 300~700     humid soil
  # 700~950     in water
*/ 
void setup(){
  Serial.begin(57600);
}
void loop(){ 
  Serial.print("Moisture Sensor Value:");
  Serial.println(analogRead(0)); 
  delay(100);
}

Project List

• Arduino Mega 2560 Project 1: Piranha LED Module
• Arduino Mega 2560 Project 2:Digital white LED module
• Arduino Mega 2560 Project 3: Passive Buzzer module
• Arduino Mega 2560 Project 4: Hall Magnetic Sensor
• Arduino Mega 2560 Project 5: LM35 Linear Temperature Sensor
• Arduino Mega 2560 Project 6: DS18B20 Temperature Sensor
• Arduino Mega 2560 Project 7: Digital Tilt Sensor
• Arduino Mega 2560 Project 8: Photocell sensor
• Arduino Mega 2560 Project 9: Digital Push Button
• Arduino Mega 2560 Project 10: Capacitive Touch Sensor
• Arduino Mega 2560 Project 11: DHT11 Temperature and Humidity Sensor
• Arduino Mega 2560 Project 12: Analog Sound Sensor
• Arduino Mega 2560 Project 13: Flame Sensor
• Arduino Mega 2560 Project 14: DS3231 Clock Module
• Arduino Mega 2560 Project 15: Analog Gas Sensor
• Arduino Mega 2560 Project 16: Analog Alcohol Sensor
• Arduino Mega 2560 Project 17: Water Sensor
• Arduino Mega 2560 Project 18: Soil Humidity Sensor
• Arduino Mega 2560 Project 19: Infrared Obstacle Avoidance Sensor
• Arduino Mega 2560 Project 20: PIR Motion Sensor
• Arduino Mega 2560 Project 21: Joystick Module
• Arduino Mega 2560 Project 22: Photo interrupter module
• Arduino Mega 2560 Project 23: 5V Relay Module
• Arduino Mega Project 24: ADXL345 Three Axis Acceleration Module
• Arduino Mega 2560 Project 25: Rotary Encoder module
• Arduino Mega 2560 Project 26: Analog Rotation Sensor
• Arduino Mega 2560 Project 27: HC-SR04 Ultrasonic Sensor
• Arduino Mega 2560 Project 28: Pulse Rate Monitor
• Arduino Mega 2560 Project 29: Reed Switch Module
• Arduino Mega 2560 Project 30: TEMT6000 ambient light sensor