Grove_Temperature_And_Humidity_Sensor/examples/DHTtester/DHTtester.ino

// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain

#include "Grove_Temperature_And_Humidity_Sensor.h"

// Uncomment whatever type you're using!
//#define DHTTYPE DHT11   // DHT 11
#define DHTTYPE DHT22   // DHT 22  (AM2302)
//#define DHTTYPE DHT21   // DHT 21 (AM2301)
//#define DHTTYPE DHT10   // DHT 10
//#define DHTTYPE DHT20   // DHT 20

/*Notice: The DHT10 and DHT20 is different from other DHT* sensor ,it uses i2c interface rather than one wire*/
/*So it doesn't require a pin.*/
#define DHTPIN 2     // what pin we're connected to（DHT10 and DHT20 don't need define it）
DHT dht(DHTPIN, DHTTYPE);   //   DHT11 DHT21 DHT22
//DHT dht(DHTTYPE);         //   DHT10 DHT20 don't need to define Pin

// 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


#if defined(ARDUINO_ARCH_AVR)
    #define debug  Serial

#elif defined(ARDUINO_ARCH_SAMD) ||  defined(ARDUINO_ARCH_SAM)
#ifdef SerialUSB
    #define debug  SerialUSB
#else
    #define debug  Serial
#endif
#else
    #define debug  Serial
#endif

void setup() {

    debug.begin(115200);
    debug.println("DHTxx test!");
    Wire.begin();

    /*if using WIO link,must pull up the power pin.*/
    // pinMode(PIN_GROVE_POWER, OUTPUT);
    // digitalWrite(PIN_GROVE_POWER, 1);

    dht.begin();
}

void loop() {
    float temp_hum_val[2] = {0};
    // Reading temperature or humidity takes about 250 milliseconds!
    // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)


    if (!dht.readTempAndHumidity(temp_hum_val)) {
        debug.print("Humidity: ");
        debug.print(temp_hum_val[0]);
        debug.print(" %\t");
        debug.print("Temperature: ");
        debug.print(temp_hum_val[1]);
        debug.println(" *C");
    } else {
        debug.println("Failed to get temprature and humidity value.");
    }

    delay(1500);
}