1// Example testing sketch for various DHT humidity/temperature sensors 2// Written by ladyada, public domain 3 4#include "DHT.h" 5 6#define DHTPIN 2 // what digital pin we're connected to 7 8// Uncomment whatever type you're using! 9//#define DHTTYPE DHT11 // DHT 11 10#define DHTTYPE DHT22 // DHT 22 (AM2302), AM2321 11//#define DHTTYPE DHT21 // DHT 21 (AM2301) 12 13// Connect pin 1 (on the left) of the sensor to +5V 14// NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1 15// to 3.3V instead of 5V! 16// Connect pin 2 of the sensor to whatever your DHTPIN is 17// Connect pin 4 (on the right) of the sensor to GROUND 18// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor 19 20// Initialize DHT sensor. 21// Note that older versions of this library took an optional third parameter to 22// tweak the timings for faster processors. This parameter is no longer needed 23// as the current DHT reading algorithm adjusts itself to work on faster procs. 24DHT dht(DHTPIN, DHTTYPE); 25 26void setup() { 27 Serial.begin(9600); 28 Serial.println("DHTxx test!"); 29 30 dht.begin(); 31} 32 33void loop() { 34 // Wait a few seconds between measurements. 35 delay(2000); 36 37 // Reading temperature or humidity takes about 250 milliseconds! 38 // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor) 39 float h = dht.readHumidity(); 40 // Read temperature as Celsius (the default) 41 float t = dht.readTemperature(); 42 // Read temperature as Fahrenheit (isFahrenheit = true) 43 float f = dht.readTemperature(true); 44 45 // Check if any reads failed and exit early (to try again). 46 if (isnan(h) || isnan(t) || isnan(f)) { 47 Serial.println("Failed to read from DHT sensor!"); 48 return; 49 } 50 51 // Compute heat index in Fahrenheit (the default) 52 float hif = dht.computeHeatIndex(f, h); 53 // Compute heat index in Celsius (isFahreheit = false) 54 float hic = dht.computeHeatIndex(t, h, false); 55 56 Serial.print("Humidity: "); 57 Serial.print(h); 58 Serial.print(" %\t"); 59 Serial.print("Temperature: "); 60 Serial.print(t); 61 Serial.print(" *C "); 62 Serial.print(f); 63 Serial.print(" *F\t"); 64 Serial.print("Heat index: "); 65 Serial.print(hic); 66 Serial.print(" *C "); 67 Serial.print(hif); 68 Serial.println(" *F"); 69}