Temperature and Humidity (DHT11, DHT22, AM2302)

The DHT11 is a low cost temperature and humidity sensor with a range of 0 to 50 degrees Celsius. The DHT22 is an improved version with better accuracy and a larger detection range of -40 to 125 degrees Celsius. The AM2302 is the wired version of the DHT22.

Pins

This sensor is often sold mounted on a breakout board with only 3 pins (NC is not exposed). The order of the pins on such boards varies, so you'll need to refer to the labels.

Wiring

The above image shows a DHT11 with breakout board, but the wiring is the same for all DHT11, DHT22, and AM2302 devices.

Note that the order of the pins may vary.

Code

This code will display the temperature and humidity once every second.

Blocks

If you are using a DHT22 or AM2302, you'll need to set the sensor type accordingly in the "init" block.

Python

import dht
import machine
import time

dht_device = dht.DHT11(machine.Pin(4))
# Replace the above with the next line if you have a DHT22 or AM2302
# dht_device = dht.DHT22(machine.Pin(4))

while True:
    try:
        dht_device.measure()
    except:
        pass
    print(dht_device.temperature())
    print(dht_device.humidity())
    time.sleep(1)

"measure" may sometimes result in an error, especially if you're reading too fast. Without the try except, the error will cause your program to terminate.

Results

You should see the temperature (Celsius) and relative humidity (percentage) printed in the monitor once every second.

class DHT11 / class DHT22 - control DHT11, DHT22, and AM2302 Temperature and Humidity Sensors