Introduction¶

CircuitPython module for the MPL3115A2 barometric pressure & 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¶

See examples/simpletest.py for a demo of the usage.

Contributing¶

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

Building locally¶

Zip release files¶

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-mpl3115a2 --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.

examples/mpl3115a2_simpletest.py¶

# Simple demo of the MPL3115A2 sensor.
# Will read the pressure and temperature and print them out every second.
# Author: Tony DiCola
import time

import board
import busio

import adafruit_mpl3115a2


# Initialize the I2C bus.
i2c = busio.I2C(board.SCL, board.SDA)

# Initialize the MPL3115A2.
sensor = adafruit_mpl3115a2.MPL3115A2(i2c)
# Alternatively you can specify a different I2C address for the device:
#sensor = adafruit_mpl3115a2.MPL3115A2(i2c, address=0x10)

# You can configure the pressure at sealevel to get better altitude estimates.
# This value has to be looked up from your local weather forecast or meteorlogical
# reports.  It will change day by day and even hour by hour with weather
# changes.  Remember altitude estimation from barometric pressure is not exact!
# Set this to a value in pascals:
sensor.sealevel_pressure = 102250

# Main loop to read the sensor values and print them every second.
while True:
    pressure = sensor.pressure
    print('Pressure: {0:0.3f} pascals'.format(pressure))
    altitude = sensor.altitude
    print('Altitude: {0:0.3f} meters'.format(altitude))
    temperature = sensor.temperature
    print('Temperature: {0:0.3f} degrees Celsius'.format(temperature))
    time.sleep(1.0)

`adafruit_mpl3115a2`¶

CircuitPython module for the MPL3115A2 barometric pressure & temperature sensor. See examples/simpletest.py for a demo of the usage.

Author(s): Tony DiCola

class adafruit_mpl3115a2.MPL3115A2(i2c, *, address=96)¶

Instance of the MPL3115A2 sensor. Must specify the following parameters when creating an instance of this device: - i2c: The I2C bus connected to the sensor.

In addition you can specify the following optional keyword arguments: - address: The I2C address of the device if it’s different from the default.

altitude¶: Read the altitude as calculated based on the sensor pressure and previously configured pressure at sea-level. This will return a value in meters. Set the sea-level pressure by updating the sealevel_pressure property first to get a more accurate altitude value.

pressure¶: Read the barometric pressure detected by the sensor in Pascals.

sealevel_pressure¶: Read and write the pressure at sea-level used to calculate altitude. You must look this up from a local weather or meteorlogical report for the best accuracy. This is a value in Pascals.

temperature¶: Read the temperature as measured by the sensor in degrees Celsius.