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UedaTakeyuki / mh-z19

Read CO2 concentration from mh-z19 sensor on the Raspberry Pi & handle it. Detect Raspberry Pi model automatically and read the value from an appropriate serial device.
MIT License
182 stars 37 forks source link

Reported co2 level wrong #25

Closed rimeraz closed 3 years ago

rimeraz commented 3 years ago

Hey,

I received my MH-Z19B and connected it to my raspberry.

I ran a pip install mh-z19 and when I execute python -m mh_z19 --all I receive the following output: {"SS": 0, "UhUl": 0, "TT": 50, "co2": 5000, "temperature": 10}

Temperature is reported more or less correctly (compared against thermometer and DHT22). But co2 value can't be correct. Point of measure was outside.

What else can I do for debugging?

rimeraz commented 3 years ago

Nevermind.

Running

python -m mh_z19 --detection_range_5000
python -m mh_z19 --zero_point_calibration

solved the issue. Now it returns: {"SS": 0, "UhUl": 0, "TT": 50, "co2": 401, "temperature": 10}

UedaTakeyuki commented 3 years ago

Hi rimeraz,

Thank you for using this library. According to the datasheet, need a few minutes to preheat time or return the wrong value.

By the way, please don't forget to give Star to this repository if you like this :-) thank you!