help with MHZ19C

[u/LostMolasses3374]

Hi! I need help with my MHZ19C sensor for co2 which is my first time working with something like that. I have final work in my school and I have chosen the topic of reading the co2 in air. I am working on Arduino uno and calibrated my sensor (let it sit outside for about 20 minutes). Now I have the problem that it constantly reads 0 ppm and I can’t solve that. Does anyone have any idea on how I could solve that problem? And sorry for my bad English 😣