Arduino ESP8266 driver for DHT22 temperature and humidity sensor

A simple driver for the DHT22.

To use:

1. Create an instance of the DHT22 class
2. In setup(), call the begin() class method with the GPIO pin number to which the DHT22 is attached as argument
3. In loop(), call the read() class method with two float arguments, one each for temperature and humidity. A return value of 0 indicates a successful measurement, and a negative value indicates an error.

Example:

#define DHT22_GPIO_PIN      14      // (esp8266 "D5")

DHT22 dht;

void setup()
{
    dht.begin(DHT22_GPIO_PIN);
}

void loop()
{
    float temp, humidity;
    if (dht.read(&temp, &humidity) == 0) {
        // Success
    } else {
        // Error
    }
    ...
}

NOTE:

• the above example uses a global instance of the DHT22 class - you can also use new DHT22() if required.
• this driver was developed for the DHT22 and not the DHT11.