Using the DHT11 Temperature Sensor with MicroPython on a NodeMCU

DHT11 Temperature Sensor

• Connect the VCC pin to a 3.3v power pin
• Connect the GND pin to a GND pin.
• Connect the Data pin to pin D4.

• There is a DHT11 module built-in to MicroPython
• Import the dht module.
• Set which data pin on the NodeMCU is connected to the data pin on the DHT11.
• The data pin is the GPIO pin number, not the data name. So pin D4 is (GPIO) pin 2 on the ESP-12:

• Temperature is in Celsius, RH is in %.
• To convert from Celsius to Fahrenheit: F = (C * 1.8 + 32)

import dht
from machine import Pin
import time
## D4 = GPIO2
d = dht.DHT11(Pin(2))

## Can only collect temperature every ~2 seconds, so sleep 5s.
time.sleep(5)
d.measure()
c = d.temperature()
h = d.humidity()

f = (c * 1.8 + 32)
print( "Temp is " + str(c) + "C (" + str(f) + "F) and RH is " + str(h) )

# Temperature is in C, RH is in %.

Bare vs. Shielded DHT11

• A DHT 11 with a shield has 3 pins.
• A bare DHT11 has 4 pins.
• In either case, 3vs4 pins, there are only 3 pins used: Signal, Vcc (+), Ground (-).
• The shielded, or PCB mounted, version includes a 10K Ohm pull up resistor for the signal line.