Montaje 9 Medición T y H por puerto serie
Programa con DHT11:
Te proponemos este programa:
#include "DHT.h"
#define DHTPIN 2
#define DHTTYPE DHT11 // DHT 11
DHT dht(DHTPIN, DHTTYPE);
void setup() {
Serial.begin(9600);
dht.begin();
}
void loop() {
delay(2000);
float h = dht.readHumidity();
float t = dht.readTemperature();
if (isnan(h) || isnan(t)) {
Serial.println("Fallo al leer el sensor DHT11");
return;
}
Serial.print("Humedad: ");
Serial.print(h);
Serial.print(" \t");
Serial.print("Temperatura: ");
Serial.print(t);
Serial.println(" ºC ");
}
El resultado se puede ver en este vídeo, simplemente soplando nuestro vaho pasamos de 20% de humedad y 22ºC a 93% y 24ºC.
Advertencia: Si lo hacéis con niños, enseguida se les ocurre ponerlo en el sobaco, menos mal que solo son 5V ;)
Programa con DHT12
La librería de este sensor es más potente y nos puede decir la sensación térmica:
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// Example sketch for DHT22 humidity - temperature sensor
// Written by cactus.io, with thanks to Adafruit for bits of their library. public domain
#include "cactus_io_DHT22.h"
#define DHT22_PIN 2 // what pin on the arduino is the DHT22 data line connected to
// For details on how to hookup the DHT22 sensor to the Arduino then checkout this page
// http://cactus.io/hookups/sensors/temperature-humidity/dht22/hookup-arduino-to-dht22-temp-humidity-sensor
// Initialize DHT sensor for normal 16mhz Arduino.
DHT22 dht(DHT22_PIN);
// Note: If you are using a board with a faster processor than 16MHz then you need
// to declare an instance of the DHT22 using
// DHT22 dht(DHT22_DATA_PIN, 30);
// The additional parameter, in this case here is 30 is used to increase the number of
// cycles transitioning between bits on the data and clock lines. For the
// Arduino boards that run at 84MHz the value of 30 should be about right.
void setup() {
Serial.begin(9600);
Serial.println("DHT22 Humidity - Temperature Sensor");
Serial.println("RH\t\tTemp (C)\tTemp (F)\tHeat Index (C)\t Heat Index (F)");
dht.begin();
}
void loop() {
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
dht.readHumidity();
dht.readTemperature();
// Check if any reads failed and exit early (to try again).
if (isnan(dht.humidity) || isnan(dht.temperature_C)) {
Serial.println("DHT sensor read failure!");
return;
}
Serial.print(dht.humidity); Serial.print(" %\t\t");
Serial.print(dht.temperature_C); Serial.print(" *C\t");
Serial.print(dht.temperature_F); Serial.print(" *F\t");
Serial.print(dht.computeHeatIndex_C()); Serial.print(" *C\t");
Serial.print(dht.computeHeatIndex_F()); Serial.println(" *F");
// Wait a few seconds between measurements. The DHT22 should not be read at a higher frequency of
// about once every 2 seconds. So we add a 3 second delay to cover this.
delay(3000);
}
El resultado es:
