I would like to measure humidity in rooms where the humidity is close to 100%, is there any recommendation how to do this and not damage the core module?
We suggest searching for the term “conformal coating”.
You can use this. We used this on some of our installations and had good results
You have to be careful not to put a coating on the connector contacts.
We tested a lot of units in high-humidity environments, and the most sensitive parts/signals that should be completely coated are areas around MCU and crystals. On the battery modules, you should focus on the voltage dividers.
UPDATE:
You can also use for example Plastik 70, however we have no experience with that