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 Notes¶
Of course, you must import the library to use it:
import adafruit_si7021
This driver takes an instantiated and active I2C object (from the busio
or
the bitbangio
library) as an argument to its constructor. The way to create
an I2C object depends on the board you are using. For boards with labeled SCL
and SDA pins, you can:
from busio import I2C
from board import SCL, SDA
i2c = I2C(SCL, SDA)
Once you have created the I2C interface object, you can use it to instantiate the sensor object:
sensor = adafruit_si7021.SI7021(i2c)
And then you can start measuring the temperature and humidity:
print(sensor.temperature)
print(sensor.relative_humidity)
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-si7021 --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 this simple test.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | import time
import board
import busio
import adafruit_si7021
# Create library object using our Bus I2C port
i2c = busio.I2C(board.SCL, board.SDA)
sensor = adafruit_si7021.SI7021(i2c)
while True:
print("\nTemperature: %0.1f C" % sensor.temperature)
print("Humidity: %0.1f %%" % sensor.relative_humidity)
time.sleep(2)
|
adafruit_si7021
¶
This is a CircuitPython driver for the SI7021 temperature and humidity sensor.
- Author(s): Radomir Dopieralski
Implementation Notes¶
Hardware:
- Adafruit Si7021 Temperature & Humidity Sensor Breakout Board (Product ID: 3251)
Software and Dependencies:
- Adafruit CircuitPython firmware for the ESP8622 and M0-based boards: https://github.com/adafruit/circuitpython/releases
- Adafruit’s Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
-
class
adafruit_si7021.
SI7021
(i2c_bus, address=64)[source]¶ A driver for the SI7021 temperature and humidity sensor.
Parameters: -
relative_humidity
¶ The measured relative humidity in percent.
-
start_measurement
(what)[source]¶ Starts a measurement.
Starts a measurement of either
HUMIDITY
orTEMPERATURE
depending on thewhat
argument. Returns immediately, and the result of the measurement can be retrieved with thetemperature
andrelative_humidity
properties. This way it will take much less time.This can be useful if you want to start the measurement, but don’t want the call to block until the measurement is ready – for instance, when you are doing other things at the same time.
-
temperature
¶ The measured temperature in degrees Celcius.
-
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