I'm not sure about the MHZ-19B, but I've been using the SenseAir S8 and the data that comes out of it has been rather noisy when powered by a switching power supply. If you have an oscilloscope, you might want to check whether your 5V rail changes in voltage when taking measurements. For example, mine looked like the picture in the middle of this blog post: https://blog.jean-francois.im/2021/05/08/building-a-simple-a...
If that's the case, I've found that the quality of the measurements fare better when there's a linear regulator supplying the power. I bought some LM7805s off DigiKey and they should arrive sometime soon, ping me if you want to know how that experiment went.
The temperature graph is pretty easy to understand as you see the A/C kick on twice during the day. The CO2 level is maybe not as obvious but I can see when I was in this room and when I closed the window when I was leaving.
I imagine co2 not being perfectly mixed and maybe wafts of it hitting the sensor? The overal trend is clear though. Try transforming the data with a moving hour average or something.
That's great advice and I will definitely look into it. I have a servo and a LCD panel on the same 5V supply as the ESP32, and while I think the USB power supply I have is sufficient, it is definitely worth investigating.
If that's the case, I've found that the quality of the measurements fare better when there's a linear regulator supplying the power. I bought some LM7805s off DigiKey and they should arrive sometime soon, ping me if you want to know how that experiment went.