===== Dallas 1-Wire Support =====
* Support for Dallas 1 Wire is included on Kernel 3.10.67-52 and upwards. Make sure you are updated.
* Will cover an example of a temperature sensor well known **DS1820** other 1 wire IC's are supported too.
You have to edit **/etc/modprobe.d/blacklist-odroid.conf** file to enable the 1-wire driver because the driver exists in the blacklist by default.
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Default GPIO for 1-Wire is **Pin #7 (GPIO83)**
* **Connection: With External-Supply**
{{:en:1-wire-external-power.png?750|}}
Pin 1 (Left): Ground (-)
Pin 2 (Middle): Pin #7 C1
Pin 3 (Right): VCC (3.3V)
You also need to add a resistor from 4.7k to 10k between pin 2.
* **Connection: Supplying the Parasite-Powered**
{{:en:1-wire-parasite-power.png?750|}}
Pin 1 (Left): Ground (-)
Pin 2 (Middle): Pin #7 C1
Pin 3 (Right): Ground (-)
You also need to add a resistor from 4.7k to 10k between pin 2.
* Load the required kernel modules: modprobe w1-gpio && modprobe w1-therm
* Check if your sensor is working: root@odroid:~# cd /sys/bus/w1/devices/
root@odroid:/sys/bus/w1/devices# ls
10-000802f41d67 w1_bus_master1
root@odroid:/sys/bus/w1/devices#
As you can see my sensor is detected as **10-000802f41d67**, each sensor has a different id. So yours will be different.
* Read the temperature:root@odroid:/sys/bus/w1/devices# cd 10-000802f41d67
root@odroid:/sys/bus/w1/devices/10-000802f41d67# cat w1_slave
33 00 4b 46 ff ff 03 10 30 : crc=30 YES
33 00 4b 46 ff ff 03 10 30 t=25562
root@odroid:/sys/bus/w1/devices/10-000802f41d67#
Temperature is t=25562 or 25.562 degree's Celsius.
Multiple sensors can be connected on the same line as the draw below.
{{:en:untitled_sketch_bb2.png?750|}}
root@bigsmall:/sys/bus/w1/devices# ls
10-000802f37119 10-000802f41d67 w1_bus_master1
Two sensors in parallel.