Were you able to get accurate CO2 readings from the AliExpress Zigbee sensors? I got two of them and the CO2 values from each were wildly wrong. I'm curious if I'm missing a calibration step.
I'm not sure how accurate it is but the values seem reasonable. It hovers around 360ppm for fresh air. I can see it creep up if I'm in my office with the windows and door closed, and it spikes up if I breathe onto it.