Someone using reliable OUTDOOR Humidity Sensors?

End Devices (Nodes)
39

Have you looked at the SHT31 and Si7021 sensors with membrane/PTFE filter?
The versions with membrane/PTFE filter are rated for IP67.

SHT31 was previously mentioned in: The WORKBENCH part 1

SHT31

Si7021

Sensor modules based on Si7021 with filter are available on AliExpress:

A possible option to protect the rest of the electronics from moist and water is by covering (painting or spraying) it with (the sensor itself should not be covered of course):

  • Liquid Electrical Tape (LET)
    Manufacturers: Star brite, Permatex, Performix.

  • Plasti DIP
    Similar to LET (but possibly thicker).
    For electronics a thin layer better preserves cooling properties.

    Performix and Plasti DIP also have spray versions.

For reliable measurements you will still need a proper housing that protects the sensor from rain and (direct) sun light and that allows for sufficient ventilation. E.g. something like:

A compact DIY outdoor weather station could be build with a Heltec CubeCell HTCC-AB01 board + Si7021 module + BMP280 module and above plastic outer shield. The CubeCell board supports Li-ion/LiPo batteries and solar panel charging and uses only 8.5 uA in deep sleep when powered by Li-ion or LiPo battery.

Sensor Tests

Some tests with above sensors: http://www.kandrsmith.org/RJS/Misc/hygrometers.html