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.

• Using an UART to Implement a 1-Wire Bus Master
• Book of iButton® Standards (PDF)
• DS18S20 High-Precision 1-Wire Digital Thermometer (PDF)

• DS9097 - COM port adapter which performs RS-232C level conversion.
• Custom 1-wire serial port interface (see below).

• DS1820 / DS18S20 / DS1920 - High-Precision Temperature Sensor.
• DS18B20 - Programmable Resolution Temperature Sensor.
• DS1822 - Econo Temperature Sensor.

Find ROM codes for all connected devices:

from digitemp.master import UART_Adapter
from digitemp.device import AddressableDevice

print(AddressableDevice(UART_Adapter('/dev/ttyS0')).get_connected_ROMs())
# ['108739A80208006F', '10A75CA80208001A']

Get temperature:

from digitemp.master import UART_Adapter
from digitemp.device import DS1820

bus = UART_Adapter('/dev/ttyS0')  # DS9097 connected to COM1

# only one 1-wire device on the bus:
sensor = DS1820(bus)

# specify device's ROM code if more than one 1-wire device on the bus:
sensor = DS1820(bus, rom='10D67E5B02080037')

# display sensor's information
sensor.info()

# get temperature
print(sensor.get_temperature())
# 25.48

Set resolution for DS18B20 and DS1822):

from digitemp.device import DS18B20
sensor = DS18B20(bus)

sensor.set_resolution(DS18B20.RES_9_BIT)

digitemp.device module provides following 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

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.

See Serial Port Temperature Sensors - Hardware Interface for details.

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

• Slavko for SVG schematics and testing.

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.