Adventures with Arduino Part 21

 

I have now built a plant moisture monitor from project 8 in the Arduino project handbook.

 

I still need to do some finer calibration but it works.

If you have the book, the project is on page 58/59.  The code can be downloaded from

https://arduinohandbook.wordpress.com/projects/8-plant-monitor/

The full code from the book is now on the website for the book. My code is below as it just lights up and LED.

// Soil Moisture Sensor Hygrometer example code
// Code author:  aafent. This code is copy free, if you want please mention the author's name and/or the site
//Interface Description (4-wire)
//VCC: 3.3v-5v
//GND: GND
//DO: Digital output interface (0 and 1) threshold taken from potentiometer
//AO: Analog output interface
const int moistureAO = 0;
 
int AO = 0;
int tmp = 0;
int LED = 13;
 
void setup (){
  Serial.begin(9600);
  Serial.println("Soil moisture sensor");
  pinMode(moistureAO, INPUT);
 
}
void loop ()
{
  tmp=analogRead( moistureAO );
  if ( tmp != AO ) 
  {
    AO=tmp;
    Serial.print("A=");
    Serial.println(AO);
  }
 
  delay (1000);
    {
if(analogRead(0) > 900){ // depends on soil moisture
 
digitalWrite(LED,HIGH);
delay(1000);
digitalWrite(LED,HIGH);
}else{
digitalWrite(LED, LOW);
}
    }
}

This lights up an LED if the sensor reads > 900 (as per code)

There is a trouble shooting guide to the FC-28 which I am using on the Arduino forums