This part covers the wiring for DS18B20, the more accurate and waterproof temperature sensor. As stated before, its weakness is that it lacks the power of reading humidity. Otherwise, it is much more accurate, reliable and has no problems with the WordPress plugin, that displays the readings.
modprobe w1-gpio and then
modprobe w1-therm. Change directories with
cd /sys/bus/w1/devices and display the folder contents with
ls command. It should display one folder that starts with 28, in my case it’s 28-000004a78c7f. Go to that directory by
cd 28-********* (replace the * with the correct identifier of the sensor). The temperature is stored in a file, print it out with
cat w1_slave. You should get something like in the picture below. The temperature is displayed in 1/000 degrees C.
Raspberry Pi has changed a few things in January 2015. The latest firmware includes Device Tree support, which breaks readings from some sensors. Solve this issue by typing in nano /boot/config.txt. Scroll down to the bottom and add the following line dtoverlay=w1-gpio-pullup,gpiopin=4. More information is available here.