DS18B20 – is a digital thermometer that works through the 1-Wire interface. On one 1-Wire interface, potentially you can connect over 20 devices! In this article short review how to connect DS18B20 to Onion Omega 2 and read data.
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For example, connect 2 sensors DS18B20 pins DQ (Data pin) were connected to 19 GPIO on Omega with pull-up resistor 4.7 kOm.
Next, run the command:
insmod w1-gpio-custom bus0=0,19,0 where 19 – is a pin that uses for DS18B20. This command initiates to load kernel w1 module for enabling 1-Wire bus in Linux.
After, go to /sys/devices/w1_bus_master1/ and run ls -lh
It’s a devices ids. For each DS18B20 it must be unique. In sample it 2 devices with 2 unique ids. In Linux, these are folders with devices ids names. Next step – read data from the sensor.
Go to on one of sensor folder (for example, cd 28-0213137b4baa) and run cat w1_slave
If DS18B20 is valid, you must see data similar that data on the screenshot on top. In the sample, t=21000 – is a 21.0 degree in Celsius. That’s all)