/* Arduino Projects for Dummies
 * by Brock Craft 
 *
 * Chapter 10: Building and Automated Garden
 * A system that detects soil moisture and 
 * triggers a solenoid valve
 *
 * v0.1 30.04.2013
*/

int sensorPin = A0; // The input pin for the moisture sensor
int valvePin = 9;   // The output pin to actuate the valve

const int dryThreshold = 950;  // Set this threshold based upon your sensor tests
                               // 1023 = bone dry, < 100 totally submerged
const long sampleInterval = 600;  // Sample every 10 minutes
const int irrigationTime = 5000;  // Duration to let the water flow
boolean DEBUG=true;  // Set to true if you want to read output on the Serial port

void setup() {
  if(DEBUG){Serial.begin(9600);}
  
  pinMode(sensorPin, INPUT);   // Declare the sensor pin as an OUTPUT:
  pinMode(valvePin, OUTPUT);   // Declare the valve pin as an OUTPUT:
  digitalWrite(valvePin, LOW); // Make sure the valve is closed.
}

void loop() {

  int sensorValue = analogRead(sensorPin);    // read the value from the sensor:

  if(DEBUG){
    Serial.print("Sensor value: ");  
    Serial.println(sensorValue);
  }
  
  if (sensorValue>dryThreshold){
    digitalWrite(valvePin, HIGH); // Open the water valve
    delay(irrigationTime);        // Keep it open for the irrigation time
    digitalWrite(valvePin, LOW);  // Close the valve
  }
  delay(sampleInterval);  // wait until the next time to take a reading
}