The MHZ19 is a small and cheap CO2 sensor based on NDIR (non-dispersive infrared) detection from Zhengzhou Winsen Electronics Technology Co., Ltd.
The sensor supports UART, PWM and ADC output. This driver only implements the UART interface.
UART logic levels are 3V3. The power supply of the device must be in the range of 4.9-5.1V, otherwise the CO2 readings will be off. It is highly recommended to add a buck-bust converter between the power supply and the sensor to stabilize the input voltage.
The code of this driver is the CircuitPython port of <https://github.com/fdobrovolny/mh-zxx>. Changes are minor, mainly passing the uart object to the constructor and defining properties and setters.
There are no dependencies: the driver only uses plain busio.UART read and write methods.
Note: currently, the package is not yet available 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 circuitpython-mhz19To install system-wide (this may be required in some cases):
sudo pip3 install circuitpython-mhz19To install in a virtual environment in your current project:
mkdir project-name && cd project-name
python3 -m venv .venv
source .venv/bin/activate
pip3 install circuitpython-mhz19See examples//mhz19_simpletest.py for a basic usage example.
For information on building library documentation, please check out this guide.
Contributions are welcome! This project follows Adafruit's Code of Conduct before contributing to help this project stay welcoming.