Introduction¶

A CircuitPython driver for the Sensirion SGP30 gas sensor with eCO2 and TVOC output. This sensor uses I2C!

Installation and 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.

Installing from PyPI¶

On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally from PyPI. To install for current user:

pip3 install adafruit-circuitpython-sgp30

To install system-wide (this may be required in some cases):

sudo pip3 install adafruit-circuitpython-sgp30

To install in a virtual environment in your current project:

mkdir project-name && cd project-name
python3 -m venv .env
source .env/bin/activate
pip3 install adafruit-circuitpython-sgp30

Usage Notes¶

See the guide for wiring and installation instructions.

First, import the library:

import busio
import adafruit_sgp30

Next, initialize the I2C bus object:

import board
i2c_bus = busio.I2C(board.SCL, board.SDA, frequency=100000)

Since we have the I2C bus object, we can now use it to instantiate the SGP30 object:

sgp30 = adafruit_sgp30.Adafruit_SGP30(i2c_bus)

Reading from the Sensor¶

To read from the sensor:

eCO2, TVOC = sgp30.iaq_measure()
print("eCO2 = %d ppm \t TVOC = %d ppb" % (eCO2, TVOC))

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-sgp30 --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/sgp30_simpletest.py¶

""" Example for using the SGP30 with CircuitPython and the Adafruit library"""

import time
import board
import busio
import adafruit_sgp30

i2c = busio.I2C(board.SCL, board.SDA, frequency=100000)

# Create library object on our I2C port
sgp30 = adafruit_sgp30.Adafruit_SGP30(i2c)

print("SGP30 serial #", [hex(i) for i in sgp30.serial])

sgp30.iaq_init()
sgp30.set_iaq_baseline(0x8973, 0x8aae)

elapsed_sec = 0

while True:
    print("eCO2 = %d ppm \t TVOC = %d ppb" % (sgp30.eCO2, sgp30.TVOC))
    time.sleep(1)
    elapsed_sec += 1
    if elapsed_sec > 10:
        elapsed_sec = 0
        print("**** Baseline values: eCO2 = 0x%x, TVOC = 0x%x"
              % (sgp30.baseline_eCO2, sgp30.baseline_TVOC))

`adafruit_sgp30`¶

I2C driver for SGP30 Sensirion VoC sensor

Author(s): ladyada

Implementation Notes¶

Hardware:

Adafruit SGP30 Air Quality Sensor Breakout - VOC and eCO2 (Product ID: 3709)

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_sgp30.Adafruit_SGP30(i2c, address=88)[source]¶

A driver for the SGP30 gas sensor.

TVOC¶: Total Volatile Organic Compound in parts per billion.

baseline_TVOC¶: Total Volatile Organic Compound baseline value

baseline_eCO2¶: Carbon Dioxide Equivalent baseline value

eCO2¶: Carbon Dioxide Equivalent in parts per million

get_iaq_baseline()[source]¶: Retreive the IAQ algorithm baseline for eCO2 and TVOC

iaq_init()[source]¶: Initialize the IAQ algorithm

iaq_measure()[source]¶: Measure the eCO2 and TVOC

set_iaq_baseline(eCO2, TVOC)[source]¶: Set the previously recorded IAQ algorithm baseline for eCO2 and TVOC

set_iaq_humidity(gramsPM3)[source]¶: Set the humidity in g/m3 for eCO2 and TVOC compensation algorithm