Wednesday, September 27, 2017

LEDE Project/OpenWRT DHT11/22 humidity and temperature sensor on Raspberry Pi 3

Using latest developement version of LEDE Project from git

Kernel config rpi3: lede-project-kernel-config-rpi3.txt (rename it to .config and put it in lede main directory)

Differences between DHT11 and DHT22 are in accuracy of returned values. DHT11 works with interger values (example: 23 C) and DHT22 is more precise (23.6 C)

Pins connected (DHT22):
DHT22 - RPI3
=========
Data - GPIO4
Vcc - Vcc
Gnd - Gnd

Boot rpi3 image and then edit /boot/config.txt adding the following line:

dtoverlay=dht11,gpiopin=4

Save and exit and then reboot the rpi3

Under /sys/devices/platform/dht11@0/iio:device0/ you will find two files

in_temp_input
in_humidityrelative_input

By reading them you will get current values of the dht11/22 sensor.