Pick and integrate sensor chip protection (and techniques) against moisture/condensate

[forGGe]

Condensed water can damage sensor chip. Following ideas should be considered (researched at least):

• Use internal heater to get rid of moisture. Obviously, can f*ck up a temperature sensor readings.
• Use protective sheath (sintered filter?), like here or here
• Seal everything, except humidity hole, with some compound (silica glue? epoxy?)
• Use housing to avoid leakage into the sensor, like here or here
• Use polytetrafluoroethylene cover for sensor?
• Separate temp sensor to use, in case of dew point is reached and internal heater is activated?

Also see:

• Sheath case for sensor, Ali
• Design guide for SHTxx
• Sensor sealing
• Conformal coating guide
• Example of protection, see some kind of filter on top.
• Outdoor usage of BME280

• Good article on measurements, quote:

  State-of-the-Art Sensor Solution The Si7005 temperature and humidity sensor from Silicon Labs addresses many of the design and manufacturing challenges posed by discrete, hybrid, and modular humidity sensor systems. The Si7005 sensor uses a hydrophobic cover material to provide lifelong protection for the sensor underneath. The cover, made from an expanded polytetrafluoroethylene (ePTFE) hydrophobic filter material, protects against dust and most liquids, and its structure allows water vapor to pass through it, ensuring that the filter does not affect sensor response time. Since the optional cover on the Si7005 sensor (shown in Figure 4) is installed at the factory, no time or labor is spent adding and removing protective tape during PCB assembly, and the cover does not have to be engineered into the product design.

  Key here:

  polytetrafluoroethylene (ePTFE) hydrophobic filter material, protects against dust and most liquids, and its structure allows water vapor to pass through it

[forGGe]

Approach to be tested:

Make a PCB to fit into 1/2 inch pneumatic silencer that acts like a rough filter: https://www.aliexpress.com/item/32964297763.html?spm=a2g0o.cart.0.0.2cfb3c00IL2trj

PCB will contain a sensor, covered with https://www.sensirion.com/en/environmental-sensors/humidity-sensors/filter-cap-sf2/ , to make sure nothing will be leaked inside a sensor and to prevent moisture aggregation.

Finally, all other parts of PCB must be covered with compound, not sure which one yet.

Fittings for cables that are going out of PCB and enclosure with a thread must be selected. Some kind of nut with proper thread and a kind of sealing should work fine.

[forGGe]

The sensor board is protected according to https://github.com/forGGe/HappySnail-THSensor/issues/9#issuecomment-539531196

Verification is in progress