HI, I have used dht11 sensors before without problem, but now can't get it to work. I have two of them and same with both of them. Ohh, I'm using 1.5.5 Arduino IDE.
The sensor is this: http://www.ebay.co.uk/itm/400594595597
The library is this: GitHub - adafruit/DHT-sensor-library: Arduino library for DHT11, DHT22, etc Temperature & Humidity Sensors
Output from serial:
DHTxx test!
Read failFailed to read from DHT
Humidity: 0.00 % Temperature: 0.00 *C
Humidity: 0.00 % Temperature: 0.00 *C
Humidity: 0.00 % Temperature: 0.00 *C
Read failFailed to read from DHT
Humidity: 0.00 % Temperature: 0.00 *C
Humidity: 0.00 % Temperature: 0.00 *C
Humidity: 0.00 % Temperature: 0.00 *C
Read failFailed to read from DHT
The code:
// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain
#include "DHT.h"
#define DHTPIN 2 // what pin we're connected to
// Uncomment whatever type you're using!
#define DHTTYPE DHT11 // DHT 11
//#define DHTTYPE DHT22 // DHT 22 (AM2302)
//#define DHTTYPE DHT21 // DHT 21 (AM2301)
// Connect pin 1 (on the left) of the sensor to +5V
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor
DHT dht(DHTPIN, DHTTYPE);
void setup() {
Serial.begin(9600);
Serial.println("DHTxx test!");
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)
float h = dht.readHumidity();
float t = dht.readTemperature();
// check if returns are valid, if they are NaN (not a number) then something went wrong!
if (isnan(t) || isnan(h)) {
Serial.println("Failed to read from DHT");
} else {
Serial.print("Humidity: ");
Serial.print(h);
Serial.print(" %\t");
Serial.print("Temperature: ");
Serial.print(t);
Serial.println(" *C");
}
}
The connection:
(+) to UNO +5V
(OUT) to UNO D2
(-) to UNO GND
Thanks
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