Three sensors have ability measuring 20-80% RH with accuracy +/-3%
SHT21 and DHT22 are sensors for measuring humidity and temperature.
BME280 is sensor from well-known maker Bosch, for measuring atmosphere pressure, humid and temperature.
This video will show test result of those 3 sensor to check which one is the best one. However, none of them are correctly. We need to calibrate it with simple things.
After make sensor correctly, then we can use it to measure humid and temperature of room, view via internet by Blynk software
Watch the video for full detail process of checking and calibration