[Tutorial] Extracting sensor data from temperature&humidity sensor with Arduino Uno

1. Devices

• Arduino Uno R3

• Temperature&humidity sensor

• some jumper wires or four pins cable

2. Arduino Library

https://github.com/Seeed-Studio/Grove_Temperature_And_Humidity_Sensor
http://wiki.seeedstudio.com/Grove-TemperatureAndHumidity_Sensor/

3. Source codes

// Example testing sketch for various DHT humidity/temperature sensors

// Written by ladyada, public domain

#include "DHT.h"

#define DHTPIN 2     // we're connected to D2

// 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");

    }

}

4. Output

5. Issues

This library is not compatible with the ESP8266 and ESP32 board. One potential solution is to modify the source codes.