pymh-z19b-serial 1.2.3

MH-Z19B CO2 sensor communication via serial port

This package is ment to be used to read data from MH_Z19B CO2 Sensor via serial. Sensor can be bought on AliExpress for around 18€ (Jan 2019)

It is recommended to disable Auto calibration and set measuring range to 5000 to get adequate readings after first day of use.

Requirements:

You need a USB to TTL adapter to read data from the sensor. I use Prolific Technology PL2303 adapter plugged into my router. Router runs a python script with this library that reads metrics periodically and sends it via MQTT.

Python 3.5+

Installation:

pip3 install pymh-z19b-serial

Library Usage examples:

It is possible to use sync and async way to read from the sensor

Sync

Uses pyserial

from mh_z19b.sync import Sensor

sensor = Sensor(port='/dev/cu.usbserial', baudrate=9600)
print(sensor.read_metric())

Async

Uses asyncio and pyserial-asyncio

import asyncio

from mh_z19b.async import Sensor

async def run(loop):
    sensor = Sensor(loop)
    await sensor.open_serial(url='/dev/cu.usbserial', baudrate=9600)
    data = await sensor.read_metric()
    print(data)

loop = asyncio.get_event_loop()
loop.set_debug(True)
loop.run_until_complete(run(loop))
loop.close()