Can anyone explain the readings of the MH-Z19 sensor?

Question

Arduino

Hello! I purchased the MH-Z19 sensor, but instead of joy, only doubts. His testimony does not inspire confidence, and the point is not even in absolute values, but in dynamics. There is no one in the apartment (except for cats) CO2 at the level of 900-1000, I come home from work and ventilate the apartment by opening the windows and even the door to the vestibule - the readings begin to grow and quite sharply exceed 2000. What could be the reason? The sensor is located near the window. Maybe from the influx of cold air it is so sausage? But the temperature in the room is somehow positive.

Answer 1

The indications are specifically delusional. 2000 and more is absolutely nothing to breathe. So there are two options - the sensor is dead or you are using it somehow wrong. I once had one. I found the connection instructions somewhere on the gyktimes. Received data via uart. The indications were quite reasonable.

Answer 2

Read the article
https://geektimes.ru/post/285572/

Answer 3

My sensor lies directly next to the window, I don’t know about absolute numbers, but it shows relative numbers normally - when the window is open it drops to 350 ppm, when it is closed it rises to 2000 ppm. There is a battery under the window, the sensor does not react in any way to its opening and closing.