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57 lines
2.1 KiB
Markdown
57 lines
2.1 KiB
Markdown
# OneWire GPIO Binding
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This binding reads temperature values from OneWire bus sensors connected to the GPIO bus on Raspberry Pi.
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## Supported Things
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Temperature sensors.
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Tested successfully with DS18B20 sensor on Raspberry Pi 3.
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## Binding Configuration
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The binding requires OneWire sensor to be properly connected to Raspberry Pi GPIO bus,
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"w1_gpio" and "wire" kernel modules should be loaded.
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Configuration is proper when /sys/bus/w1/devices folder is present, and contains sensor's data.
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## Thing Configuration
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The sensors are visible in the system as folders containing files with sensor data.
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By default all OneWire GPIO devices are stored in /sys/bus/w1/devices/DEVICE_ID_FOLDER,
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and the temperature value is available in the file "w1_slave". The Thing needs full path to the w1_slave file.
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Note the values in sysfs are in Celsius.
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Optional parameter precision makes it easier to lower precision of the sensor value, i.e. precision 1 makes sensor value to show only one digit after the floating point, precision 2 - shows 2 digits. It makes precision reduction with round up, i.e. 20.534C with precision 1 will be 20.5C, 20.555 with same precision will be 20.6C. Allowed values are from 0 to 3. Default value of parameter is 3(max precision).
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In the thing file, this looks e.g. like
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```java
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Thing onewiregpio:sensor:livingRoom "Living room" [gpio_bus_file="/sys/bus/w1/devices/28-0000061b587b/w1_slave",refresh_time=30,precision=1]
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```
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## Channels
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The devices supports currently one channel - "temperature" which allows to read temperature from OneWire temperature sensor.
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## Full Example
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sample onewiregpio.things file content:
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```java
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Thing onewiregpio:sensor:livingroom "Living room" [gpio_bus_file="/sys/bus/w1/devices/28-0000061b587b/w1_slave",refresh_time=30]
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```
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sample onewiregpio.items file content (implements QuantityType for unit conversion):
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``` java
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Number:Temperature LivingRoomTemperature "Temperature: [%.2f %unit%]" <temperature> { channel="onewiregpio:sensor:livingroom:temperature" }
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```
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sample demo.sitemap file content:
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```perl
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sitemap demo label="Main Menu"
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{
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Text item=LivingRoomTemperature
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}
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```
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