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pydigitemp 1.4.1
Python implementation of 1-Wire protocol.
Originally written to replace digitemp utility in my pet project
and get direct access to 1-wire devices. It was created for reading DS1820 temperature sensor connected
to RS232 serial port through DS9097 adapter.
Documentation used
Using an UART to Implement a 1-Wire Bus Master
Book of iButton® Standards (PDF)
DS18S20 High-Precision 1-Wire Digital Thermometer (PDF)
Supported Hardware
Bus Drivers
DS9097 - COM port adapter which performs RS-232C level conversion.
Custom 1-wire serial port interface (see below).
1-Wire Devices
DS1820 / DS18S20 / DS1920 - High-Precision Temperature Sensor.
DS18B20 - Programmable Resolution Temperature Sensor.
DS1822 - Econo Temperature Sensor.
Usage
Find ROM codes for all connected devices:
from digitemp.master import UART_Adapter
print(UART_Adapter('/dev/ttyS0').get_connected_ROMs())
# ['108739A80208006F', '10A75CA80208001A', '2825EA52050000CE']
Get temperature when there is only one 1-wire device on the bus:
from digitemp.master import UART_Adapter
from digitemp.device import TemperatureSensor
sensor = TemperatureSensor(UART_Adapter('/dev/ttyS0'))
sensor.info()
print(sensor.get_temperature())
Get temperature from specific sensor:
from digitemp.master import UART_Adapter
from digitemp.device import TemperatureSensor
bus = UART_Adapter('/dev/ttyS0')
sensor = TemperatureSensor(bus, rom='108739A80208006F')
sensor.info()
print(sensor.get_temperature())
You can directly instantiate a device class to use its features (e.g.: setting resolution):
from digitemp.device import DS18S20
sensor = DS18S20(bus, precise=False)
or:
from digitemp.device import DS18B20
sensor = DS18B20(bus)
sensor.set_resolution(DS18B20.RES_10_BIT)
digitemp.device module provides following device classes:
DS18S20 - for DS1820, DS18S20 and DS1920 High-Precision Temperature Sensors (family code: 0x10);
DS18B20 - for DS18B20 Programmable Resolution Temperature Sensors (family code: 0x28);
DS1822 - for DS1822 Econo Temperature Sensor (family code: 0x22)
DS1820, DS1920 - are aliases for DS18S20
See more examples in examples directory.
Schematics
IMPORTANT DISCLAIMER: All circuits presented here are collected from different sources on the Internet and thus are
provided on an entirely “as-is and no guarantees” basis. We do not provide a warranty of any kind and cannot be held
responsible in any manner.
1-wire serial port interface
See Serial Port Temperature Sensors - Hardware Interface
for details.
USB/UART adapter
These are tested:
ds18b20-uart.svg
ds18b20-uart-par.svg
ds18b20-uart-dioda.svg
ds18b20-uart-diodapar.svg
Not all schematics work in all cases, depending on adapter and cable length.
These are not tested yet:
ds18b20-uart-mosfet.svg
ds18b20-uart-npn.svg
Thanks
Slavko for SVG schematics and testing.
License
Python license. In short, you can use this product in commercial and non-commercial applications,
modify it, redistribute it. A notification to the author when you use and/or modify it is welcome.
See the LICENSE file for the actual text of the license.
For personal and professional use. You cannot resell or redistribute these repositories in their original state.
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