Fix detection range setting

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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Fix detection range setting #3

Closed profi248 closed 5 years ago

profi248 commented 5 years ago

Hi, I've tried to fix a problem with detection range setting on MH-Z19.

If you sent the original byte sequence for changing range to 0-2000ppm or 0-5000ppm to the sensor, range actually got set to 0-1000ppm. For some reason the bytes indicating the range have to be sent in an different order. I found out thaks to this analysis here: https://revspace.nl/MHZ19#Setting_the_measurement_range.

Also, we need someone to test it on MH-Z19B too, I have only tested this with MH-Z19.

UedaTakeyuki commented 5 years ago

Hi, David.

Thank you for your kindly help to test on MH-ZZ19 and fix. Also the page you've indicated is so good informative for me. Thank you!