#include <DHT.h>

#define DHTPIN A0        // A0 used as digital pin for DHT11 data
#define DHTTYPE DHT11

const int relayPin = 3;  // Relay IN pin
const float THRESHOLD_TEMP = 10.0; // °C (change as needed)

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);

  pinMode(relayPin, OUTPUT);

  // Many relay modules are ACTIVE-LOW. We'll start OFF safely:
  digitalWrite(relayPin, HIGH);

  dht.begin();
  Serial.println("DHT11 Temperature Relay Control Started...");
}

void loop() {
  delay(2000); // DHT11 needs slow sampling (about 1-2 sec)

  float temp = dht.readTemperature(); // Celsius

  if (isnan(temp)) {
    Serial.println("Failed to read from DHT11!");
    return;
  }

  Serial.print("Temperature: ");
  Serial.print(temp);
  Serial.println(" °C");

  // Relay control based on threshold
  if (temp <= THRESHOLD_TEMP) {
    // Turn ON relay (ACTIVE-LOW assumed)
    digitalWrite(relayPin, LOW);
    Serial.println("TEMP HIGH -> Relay ON -> LED OFF");
  } else {
    // Turn OFF relay
    digitalWrite(relayPin, HIGH);
    Serial.println("TEMP OK -> Relay OFF -> LED ON");
  }
}