Introduction¶

CircuitPython driver for Dallas 1-Wire temperature sensor.

Dependencies¶

This driver depends on:

Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle.

Usage Example¶

import board
from adafruit_onewire.bus import OneWireBus
from adafruit_ds18x20 import DS18X20
ow_bus = OneWireBus(board.D2)
ds18 = DS18X20(ow_bus, ow_bus.scan()[0])
ds18.temperature

Contributing¶

Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.

Building locally¶

To build this library locally you’ll need to install the circuitpython-build-tools package.

python3 -m venv .env
source .env/bin/activate
pip install circuitpython-build-tools

Once installed, make sure you are in the virtual environment:

source .env/bin/activate

Then run the build:

circuitpython-build-bundles --filename_prefix adafruit-circuitpython-ds18x20 --library_location .

Sphinx documentation¶

Sphinx is used to build the documentation based on rST files and comments in the code. First, install dependencies (feel free to reuse the virtual environment from above):

python3 -m venv .env
source .env/bin/activate
pip install Sphinx sphinx-rtd-theme

Now, once you have the virtual environment activated:

cd docs
sphinx-build -E -W -b html . _build/html

This will output the documentation to docs/_build/html. Open the index.html in your browser to view them. It will also (due to -W) error out on any warning like Travis will. This is a good way to locally verify it will pass.

Table of Contents¶

Simple test¶

Ensure your device works with these simple tests.

examples/ds18x20_simpletest.py¶

# Simple demo of printing the temperature from the first found DS18x20 sensor every second.
# Author: Tony DiCola
import time

import board

from adafruit_onewire.bus import OneWireBus
from adafruit_ds18x20 import DS18X20


# Initialize one-wire bus on board pin D5.
ow_bus = OneWireBus(board.D5)

# Scan for sensors and grab the first one found.
ds18 = DS18X20(ow_bus, ow_bus.scan()[0])

# Main loop to print the temperature every second.
while True:
    print('Temperature: {0:0.3f}C'.format(ds18.temperature))
    time.sleep(1.0)

examples/ds18x20_asynctest.py¶

# Simple demo of printing the temperature from the first found DS18x20 sensor every second.
# Using the asynchronous functions start_temperature_read() and
# read_temperature() to allow the main loop to keep processing while
# the conversion is in progress.
# Author: Louis Bertrand, based on original by Tony DiCola

import time

import board

from adafruit_onewire.bus import OneWireBus
from adafruit_ds18x20 import DS18X20


# Initialize one-wire bus on board pin D1.
ow_bus = OneWireBus(board.D1)

# Scan for sensors and grab the first one found.
ds18 = DS18X20(ow_bus, ow_bus.scan()[0])
ds18.resolution = 12

# Main loop to print the temperature every second.
while True:
    conversion_delay = ds18.start_temperature_read()
    conversion_ready_at = time.monotonic() + conversion_delay
    print("waiting", end="")
    while time.monotonic() < conversion_ready_at:
        print(".", end="")
        time.sleep(0.1)
    print('\nTemperature: {0:0.3f}C\n'.format(ds18.read_temperature()))
    time.sleep(1.0)

`adafruit_ds18x20`¶

Driver for Dallas 1-Wire temperature sensor.

Author(s): Carter Nelson

class adafruit_ds18x20.DS18X20(bus, address)[source]¶

Class which provides interface to DS18X20 temperature sensor.

read_temperature()[source]¶: Read the temperature. No polling of the conversion busy bit (assumes that the conversion has completed).

resolution¶: The programmable resolution. 9, 10, 11, or 12 bits.

start_temperature_read()[source]¶: Start asynchronous conversion, returns immediately. Returns maximum conversion delay [seconds] based on resolution.

temperature¶: The temperature in degrees Celsius.