// Smart Irrigation System
#include <DHT.h>
 
#define DHTPIN     7
#define DHTTYPE    DHT11
#define SOIL_PIN   A0
#define RELAY_PIN  8
 
DHT dht(DHTPIN, DHTTYPE);
 
// Thresholds (calibrate for your soil type)
const int DRY_THRESHOLD  = 600; // ADC value — adjust after calibration
const int WET_THRESHOLD  = 300; // ADC value
const float MAX_TEMP_C   = 38.0; // Don't water if too hot (evaporation loss)
 
bool pumpRunning = false;
 
void setup() {
  Serial.begin(9600);
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, HIGH); // Relay is active-LOW; HIGH = pump OFF
  dht.begin();
  Serial.println("Smart Irrigation System Ready");
  Serial.println("Soil\tTemp(C)\tHumidity(%)\tPump");
}
 
void loop() {
  int soilRaw    = analogRead(SOIL_PIN);
  float tempC    = dht.readTemperature();
  float humidity = dht.readHumidity();
 
  if (isnan(tempC) || isnan(humidity)) {
    Serial.println("DHT11 read error — check wiring");
    delay(2000);
    return;
  }
 
  // Decision logic
  bool soilDry    = soilRaw > DRY_THRESHOLD;
  bool tempOk     = tempC < MAX_TEMP_C;
  bool shouldPump = soilDry && tempOk;
 
  // Control relay (active-LOW module)
  digitalWrite(RELAY_PIN, shouldPump ? LOW : HIGH);
  pumpRunning = shouldPump;
 
  // Log to Serial
  Serial.print(soilRaw);
  Serial.print("\t");
  Serial.print(tempC, 1);
  Serial.print("\t");
  Serial.print(humidity, 1);
  Serial.print("\t");
  Serial.println(pumpRunning ? "ON" : "OFF");
 
  delay(5000); // Check every 5 seconds
}