4.1. Sample sketch
#include "DHT.h"
#define DHTPIN 8 // what digital pin DHT11 is connected to
#define DHTTYPE DHT11 // DHT 11
DHT dht(DHTPIN, DHTTYPE);
const int relayPin = 13; // what digital pin relay module is connected to
void setup() {
Serial.begin(9600);
dht.begin();
pinMode(relayPin, OUTPUT);
digitalWrite(relayPin, LOW); // Initialising to 0V as the relay module is high-level trigger
}
void loop() {
delay(2000); // Wait 2 seconds between measurements.
float t = dht.readTemperature(); // Read temperature as Celsius (the default)
if (isnan(t)) { // Check if any reads failed and exit early (to try again).
return;
}
Serial.println(t); // Plot temperature values
Serial.print(" ");
if (t > 32) { // if temperature > 32 degrees Celsius
digitalWrite(relayPin, HIGH); // turn A/C on
delay(500);
}
else {
digitalWrite(relayPin, LOW); // else turn it off
delay(500);
}
}