I am already really frustrated with this and can't get it work properly, so i would thankful if someone could help me out here!
That you can understand the issue i have with my MH-Z19, i'll describe the steps i did so far:
- I disabled ABC on my ESPEasy instance (version mega-20190305)
- I put the sensor outside for half an hour and powered on the board (incl. sensor)
- To calibrate the sensor, I connected the HD Pin (Pin7) to GND for >7 secs. Then i removed the calibration wire and waited for another 30 mins.
- I rebooted the board -> ESPEasy reports ppm values around 400ppm (good so far!)
- After putting the sensor inside, it shows values like 1500 or 2000 ppm (Ok could be fine..)
- I was curious, so i put the sensor outside again -> ESPEasy shows ppm values around 1000ppm (What?)
- So i did a recalibration as I described from point 3 and everything is working again (values like 400ppm are reported outside)
It seems that the calibration changes somehow, but i can't figure out what it is.
Please give me some advices, i really appreciate any help!
Edit:
I saw in the log, that sometimes i get those messages:
Code: Select all
10714900: MHZ19: Unknown response: ff fd f7 ff ff ff 78 69 e4
10714903: MHZ19: Init OK
Code: Select all
10857958: MHZ19: Calibrated zero point!
10858151: Command: l
10858151: Command unknown: 'l'