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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
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untested zero point calibration command seems to be working as expected #27

Closed richteas75 closed 3 years ago

richteas75 commented 3 years ago

As requested on https://github.com/UedaTakeyuki/mh-z19/blob/master/pypi/README.md, I'd like to report that the zero point calibration function seems to be working as expected. When called e.g. by

sudo python -m mh_z19 --zero_point_calibration

the current CO2 concentration is set to represent 400 ppm CO2. This was checked in the following way:

  1. calling sudo python -m mh_z19 --all showed a reading of more than 800 ppm.
  2. calling
    sudo python -m mh_z19 --zero_point_calibration returned a message saying that ZERO point calibration was carried out.
  3. immediately thereafter, without changing, calling again: sudo python -m mh_z19 --all returned a reading close to 400 ppm.

Tested using a mh_z19b device connected to a Raspberry Pi Zero W, purchased in the fall of 2020.

UedaTakeyuki commented 3 years ago

Hi richteas75,

I really appreciate your report! Thank you!

albielew commented 3 years ago

Did the same thing with Pi3 before calibration it was 1800 after calibration it was 403

UedaTakeyuki commented 3 years ago

Hi albielew, Thank you for your report!