## Arduino drive the temperature and humidity sensor DHT11 ## Available as both a plain component or an Electronic Brick. The photos Electronic Brick: Voltage,Signal, Ground ![dht11][1] ## 10k pullup resistor needed ## Needs 4.7K to 10K pullup resistor from +5V to Signal pin. Connect to Arduino MEGA 2560 Digital pin 3, not Analog pin.: When the connecting cable is shorter than 20 metres, a 5K pull-up resistor is recommended; when the connecting cable is longer than 20 metres, choose a appropriate pull-up resistor as needed. ## DHT11 Specifications: ## Humidity measuring range: 20% ~ 9 0% RH (0-50 ? temperature compensation) Temperature measuring range: 0 ~ +50 ?C ; Humidity measuring accuracy: 5.0% RH Temperature measurement accuracy: 2.0 C Response time: (Updated by Rob Tillaart: now #include dht DHT; #define DHT11_PIN 3 void setup() { Serial.begin(9600); Serial.println("DHT TEST PROGRAM "); Serial.print("LIBRARY VERSION: "); Serial.println(DHT_LIB_VERSION); Serial.println(); Serial.println("Type,\tstatus,\tHumidity (%),\tTemperature (C)"); } void loop() { // READ DATA Serial.print("DHT11, \t"); int chk = DHT.read11(DHT11_PIN); switch (chk) { case DHTLIB_OK: Serial.print("OK,\t"); break; case DHTLIB_ERROR_CHECKSUM: Serial.print("Checksum error,\t"); break; case DHTLIB_ERROR_TIMEOUT: Serial.print("Time out error,\t"); break; case DHTLIB_ERROR_CONNECT: Serial.print("Connect error,\t"); break; case DHTLIB_ERROR_ACK_L: Serial.print("Ack Low error,\t"); break; case DHTLIB_ERROR_ACK_H: Serial.print("Ack High error,\t"); break; default: Serial.print("Unknown error,\t"); break; } // DISPLAY DATA Serial.print(DHT.humidity, 1); Serial.print(",\t"); Serial.println(DHT.temperature, 1); delay(2000); } **The output from this program to the Serial Monitor will be something like this:** ![DGT11 serial][3] [1]: /editor/20151225/567cf1669d5e0.JPG [2]: /editor/20151225/567cf3c71a17a.JPG [3]: /editor/20151225/567cf44137c9e.jpg