Adafruit Feather M0 and DHT11 humidity & temperature sensor circuitpython example

In this example we connect a DHT11 humidity & temperature sensor to an Adafruit Feather M0 running Circuitpython

First lets look at some information about the chip from the manufacturer

DHT11 output calibrated digital signal. It utilizes exclusive digital-signal-collecting-technique and humidity sensing technology, assuring its reliability and stability.

Its sensing elements is connected with 8-bit single-chip computer.Every sensor of this model is temperature compensated and calibrated in accurate calibration chamber and the calibration-coefficient is saved in OTP memory.

Small size & low consumption & long transmission distance(20m) enable DHT11 to be suited in all kinds of harsh application occasions. Single-row packaged with four pins, making the connection very convenient.

Feature

Full range temperature compensated
Relative humidity and temperature measurement
Calibrated digital signal
Outstanding long-term stability
Extra components not needed
Long transmission distance
Low power consumption

Specification:

Model : DHT11
Power supply : 3-5.5V DC
Output signal : digital signal via single-bus
Sensing element : Polymer resistor
Measuring range humidity 20-90%RH temperature 0 – 50 Celsius
Accuracy : humidity +-4%RH(Max +-5%RH); temperature +-2.0Celsius
Resolution or sensitivity humidity : 1%RH temperature 0.1 Celsius
Repeatability : humidity +-1%RH; temperature +-1Celsius
Humidity hysteresis : +-1%RH
Long-term Stability : +-0.5%RH/year
Sensing period : Average: 2s

This is an example of the sensor/module, there are many different options.

Parts Required

Name	Link
Adafruit Feather M0 Express	Adafruit (PID 3403) Feather M0 Express – Designed for CircuitPython – ATSAMD21 Cortex M0
DHT11	DHT11 Temperature and Relative Humidity Sensor Module
Connecting cables	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Schematic/Connection

This is not the exact same module but the wiring is the same

feather and DHT11 layout

Code Example

I used Mu for development

The following is based on a library , I copied the adafruit_dht library for this device to the lib folder on my Feather M0 Express – https://circuitpython.org/libraries

This is the basic example which comes with the library – a little bit tweaked

[codesyntax lang=”python”]

import time
 
import adafruit_dht
import board
 
dht = adafruit_dht.DHT11(board.D6)
 
while True:
    try:
        temperature = dht.temperature
        humidity = dht.humidity
        # Print what we got to the REPL
        print("Temp: {:.1f} *C \t Humidity: {}%".format(temperature, humidity))
    except RuntimeError as e:
        # Reading doesn't always work! Just print error and we'll try again
        print("Reading from DHT failure: ", e.args)
 
    time.sleep(1)

[/codesyntax]

Output

Here is what I saw in Mu REPL window

Temp: 31.0 *C Humidity: 53%
Temp: 31.0 *C Humidity: 61%
Temp: 31.0 *C Humidity: 61%
Temp: 32.0 *C Humidity: 64%
Temp: 32.0 *C Humidity: 64%

Links