I got a new DHT22 sensor recently and it was returning humidity values that are 15-25% lower than they should be. I thought it might be a bad sensor so I got another from a different supplier and it has the same issue.
I have a Photon powered temp/humidity device that’s been working fine for 2 years with a DHT22. If I swap sensors with one of these two I get the bad humidity result. I thought maybe the new ones were more sensitive to the voltage so I setup a Core with just the sensor. I tried both 3.3V and 5V along with 4.7k and 10k resistors. I tried different DHT libraries include PieTech, along with different pins and wires. In all cases data is received fine and temperature agree but 2 of the 3 sensors have abnormally low humidity. The 1 ‘good’ sensor’s humidity reading agrees with all my standalone weather stations around the house which is why I think it’s the good one.
Has anyone else had this issue and/or have an idea what else I should try?