It's easy to use the CCS811 sensor with Python or CircuitPython, and the Adafruit CircuitPython CCS811 module. This module allows you to easily write Python code that reads the eCO2, TVOC and temperature from the sensor.
You can use this sensor with any CircuitPython microcontroller board or with a computer that has GPIO and Python thanks to Adafruit_Blinka, our CircuitPython-for-Python compatibility library.
CircuitPython Microcontroller Wiring
First wire up a CCS811 to your board exactly as shown on the previous pages for Arduino. Here's an example of wiring a Feather to the sensor with I2C:
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Board 3V to sensor VIN (red wire on STEMMA QT version)
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Board GND to sensor GND (black wire on STEMMA QT version)
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Board SCL to sensor SCL (yellow wire on STEMMA QT version)
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Board SDA to sensor SDA (blue wire on STEMMA QT version)
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Board GND to sensor WAKE (NOT NEEDED ON STEMMA QT VERSION)
Python Computer Wiring
Since there's dozens of Linux computers/boards you can use we will show wiring for Raspberry Pi. For other platforms, please visit the guide for CircuitPython on Linux to see whether your platform is supported.
Here's the Raspberry Pi wired with I2C:
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Pi 3V3 to sensor VIN (red wire on STEMMA QT version)
- Pi GND to sensor GND (black wire on STEMMA QT version)
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Pi SCL to sensor SCL (yellow wire on STEMMA QT version)
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Pi SDA to sensor SDA (blue wire on STEMMA QT version)
- Pi GND to sensor WAKE (NOT NEEDED ON STEMMA QT VERSION)
CircuitPython Installation of CCS811 Library
You'll need to install the Adafruit CircuitPython CCS811 library on your CircuitPython board.
First make sure you are running the latest version of Adafruit CircuitPython for your board.
Next you'll need to install the necessary libraries to use the hardware--carefully follow the steps to find and install these libraries from Adafruit's CircuitPython library bundle. Our CircuitPython starter guide has a great page on how to install the library bundle.
For non-express boards like the Trinket M0 or Gemma M0, you'll need to manually install the necessary libraries from the bundle:
- adafruit_ccs811.mpy
- adafruit_bus_device
Before continuing make sure your board's lib folder or root filesystem has the adafruit_ccs811.mpy, and adafruit_bus_device files and folders copied over.
Next connect to the board's serial REPL so you are at the CircuitPython >>> prompt.
Python Installation of CCS811 Library
You'll need to install the Adafruit_Blinka library that provides the CircuitPython support in Python. This may also require enabling I2C on your platform and verifying you are running Python 3. Since each platform is a little different, and Linux changes often, please visit the CircuitPython on Linux guide to get your computer ready!
Once that's done, from your command line run the following command:
sudo pip3 install adafruit-circuitpython-ccs811
If your default Python is version 3 you may need to run 'pip' instead. Just make sure you aren't trying to use CircuitPython on Python 2.x, it isn't supported!
CircuitPython & Python Usage
To demonstrate the usage of the sensor we'll initialize it and read the eCO2, TVOC, and temperature from the board's Python REPL.
If you're using an I2C connection run the following code to import the necessary modules and initialize the I2C connection with the sensor:
import time import board import busio import adafruit_ccs811 i2c_bus = busio.I2C(board.SCL, board.SDA) ccs811 = adafruit_ccs811.CCS811(i2c_bus)
Then you'll want to calibrate the thermistor:
Now you're ready to read values from the sensor using any of these properties:
- eco2 - Equivalent Carbon Dioxide in parts per million. Clipped to 400 to 8192ppm.
- tvoc - Total Volatile Organic Compound in parts per billion.
- temperature - Temperature based on optional thermistor in Celsius.
For example to print eCO2, TVOC, and temperature:
print("CO2: %1.0f PPM" % ccs811.eco2)
print("TVOC: %1.0f PPM" % ccs811.tvoc)
print("Temp: %0.1f C" % ccs811.temperature)
That's all there is to using CCS811 with Python and CircuitPython!
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
import time
import board
import adafruit_ccs811
i2c = board.I2C() # uses board.SCL and board.SDA
# i2c = board.STEMMA_I2C() # For using the built-in STEMMA QT connector on a microcontroller
ccs811 = adafruit_ccs811.CCS811(i2c)
# Wait for the sensor to be ready
while not ccs811.data_ready:
pass
while True:
print("CO2: {} PPM, TVOC: {} PPB".format(ccs811.eco2, ccs811.tvoc))
time.sleep(0.5)
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