ESP8266 and DHT11 example in Micropython

In this example we look at a DHT11 example in Micropython for an ESP8266. We will use uPyCraft and again we use a variety of Wemos shields. In this example we will use the original DHT version 1.0.0 shield which was based on the DHT11 . Later versions of the shield use the DHT12.

First of all lets look at DHT11

The DHT11 digital temperature and humidity sensor is a composite Sensor contains a calibrated digital signal output of the temperature and humidity. Application of a dedicated digital modules collection technology and the temperature and humidity sensing technology, to ensure that the product has high reliability and excellent long-term stability. The sensor includes a resistive sense of wet components and an NTC temperature measurement devices, and connected with a high-performance 8-bit microcontroller.

Requirements

Lets take a look a the shields and boards that are required for this example

Image	Summary
	The Wemos mini – ESP8266 based board, it comes with various headers. This is the beauty of it you can create stackable projects with the board and pin compatible shields
	This is the original DHT11 shield – still available from many sellers. The later version uses a DHT12 which is an I2C device
	This is simply a base, you plug the Wemos Mini into one side and you can plug a shield or shields into the other side

Parts List

I connect the Wemos Mini to the dual base and then put the DHT shield along side this, you can connect the Wemos DHT shield directly to the Wemos Mini if you want.

Code

[codesyntax lang=”python”]

from machine import Pin
import dht
import time

while True:
	sensor = dht.DHT11(Pin(2))
	sensor.measure()

	print('Temperature = %.2f' % sensor.temperature())
	print('Humidity = %.2f' % sensor.humidity())
	time.sleep(3)

[/codesyntax]

Output

You should see something like the following in uPyCraft

Ready to download this file,please wait!
..
download ok
exec(open(‘dht.py’).read(),globals())
Temperature = 29.00
Humidity = 16.00
Temperature = 28.00
Humidity = 17.00
Temperature = 28.00
Humidity = 17.00
Temperature = 28.00
Humidity = 17.00

Links

https://akizukidenshi.com/download/ds/aosong/DHT11.pdf