In this example I wanted to compare the readings of a DHT11 and a DHt22 (AM2032) temperature sensor. The sensors were positioned side by side with the same length of wire connecting them to my Arduino. Basically i was keeping the conditions as similar as possible.
This also shows how to connect 2 of these types of sensors.
The DHT11 costs about $1 using the links at the bottom, the DHT22 costs $5. So as you can see there is also a price difference that you may consider.
Schematic
Here is a simple schematic showing both devices connected to your Arduino
dhts breadboard
Code
This uses the adafruit DHT library
#include "DHT.h"
//DHT11
#define DHTPIN11 6 // what pin we're connected to
#define DHTTYPE11 DHT11 // DHT 11
DHT dht11(DHTPIN11, DHTTYPE11);
//DHT22
#define DHTPIN22 7 // what pin we're connected to
#define DHTTYPE22 DHT22 // DHT 22
DHT dht22(DHTPIN22, DHTTYPE22);
void setup()
{
Serial.begin(9600);
dht11.begin();
dht22.begin();
}
void loop()
{
// Wait a few seconds between measurements.
delay(2000);
// Read DHT11 temperature as Celsius
float tempDHT11 = dht11.readTemperature();
// Check if readings have failed
if (isnan(tempDHT11))
{
Serial.println("Failed to read from DHT 11 sensor!");
return;
}
Serial.print("DHT11 Temperature: ");
Serial.print(tempDHT11);
Serial.println(" *C ");
// Read DHT22 temperature as Celsius
float tempDHT22 = dht22.readTemperature();
// Check if readings have failed
if (isnan(tempDHT22))
{
Serial.println("Failed to read from DHT 22 sensor!");
return;
}
Serial.print("DHT22 Temperature: ");
Serial.print(tempDHT22);
Serial.println(" *C ");
}
Output
This was the output from the serial monitor, as you can see a slight difference in the readings
DHT11 Temperature: 26.00 *C
DHT22 Temperature: 25.40 *C
DHT11 Temperature: 26.00 *C
DHT22 Temperature: 25.40 *C
DHT11 Temperature: 26.00 *C
DHT22 Temperature: 25.40 *C
DHT11 Temperature: 26.00 *C
DHT22 Temperature: 25.40 *C
DHT11 Temperature: 26.00 *C
DHT22 Temperature: 25.40 *C
Links
1x DHT11 DHT-11 Digital Temperature and Humidity Temperature sensor with Cable for Arduino
DHT22 Digital Humidity AM2302 and Temperature Sensor Module For Arduino
