CircuitPython and Python
It's easy to use the STCC4 with Python or CircuitPython, and the Adafruit_CircuitPython_STCC4 module. This module allows you to easily write Python code that allows you to read the STCC4 CO2, temperature and humidity 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 an STCC4 to your board exactly as shown below. Here's an example of wiring a Feather RP2040 to the STCC4 with I2C using one of the handy STEMMA QT connectors:
-
Board STEMMA 3V to breakout STEMMA VIN (red wire)
-
Board STEMMA GND to breakout STEMMA GND (black wire)
-
Board STEMMA SCL to breakout STEMMA SCL (yellow wire)
- Board STEMMA SDA to breakout STEMMA SDA (blue wire)
You can also use standard 0.100" pitch headers to wire it up on a breadboard:
-
Board 3V to breakout VIN (red wire)
-
Board GND to breakout GND (black wire)
-
Board SCL to breakout SCL (yellow wire)
- Board SDA to breakout SDA (blue wire)
Python Computer Wiring
Since there's dozens of Linux computers/boards you can use, below shows 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 to the sensor using I2C and a STEMMA QT connector:
-
Pi 3V to breakout STEMMA VIN (red wire)
-
Pi GND to breakout STEMMA GND (black wire)
-
Pi SCL to breakout STEMMA SCL (yellow wire)
- Pi SDA to breakout STEMMA SDA (blue wire)
Finally, here is an example of how to wire up a Raspberry Pi to the sensor using a solderless breadboard:
-
Pi 3V to breakout VIN (red wire)
-
Pi GND to breakout GND (black wire)
-
Pi SCL to breakout SCL (yellow wire)
- Pi SDA to breakout SDA (blue wire)
Python Installation of STCC4 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:
pip3 install adafruit-circuitpython-stcc4
If your default Python is version 3, you may need to run pip instead. Make sure you aren't trying to use CircuitPython on Python 2.x, it isn't supported!
CircuitPython Usage
To use with CircuitPython, you need to first install the STCC4 library and its dependencies into the lib folder on your CIRCUITPY drive. Then you need to update code.py with the example script.
Thankfully, we can do this in one go. In the example below, click the Download Project Bundle button below to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, and copy the entire lib folder and the code.py file to your CIRCUITPY drive.
Your CIRCUITPY/lib folder should contain the following folder and file:
- adafruit_bus_device/
- adafruit_stcc4.mpy
Python Usage
Once you have the library pip3 installed on your computer, copy or download the following example to your computer, and run the following, replacing code.py with whatever you named the file:
python3 code.py
Example Code
If running CircuitPython: Once everything is saved to the CIRCUITPY drive, connect to the serial console to see the data printed out!
If running Python: The console output will appear wherever you are running Python.
# SPDX-FileCopyrightText: Copyright (c) 2026 Liz Clark for Adafruit Industries
#
# SPDX-License-Identifier: MIT
import time
import board
import adafruit_stcc4
i2c = board.I2C()
sensor = adafruit_stcc4.STCC4(i2c)
print("Starting continuous measurement...")
sensor.continuous_measurement = True
while True:
co2 = sensor.CO2
print(
f"CO2: {co2} ppm | "
f"Temperature: {sensor.temperature:.1f} °C | "
f"Humidity: {sensor.relative_humidity:.1f} %"
)
time.sleep(1)
In the example, the STCC4 sensor is instantiated on I2C. Then, in the loop, the CO2, temperature and humidity readings are printed to the serial console every second.
Page last edited March 17, 2026
Text editor powered by tinymce.
