Moteino freezes at high humidity

[MPParsley]

Hello,

I have Moteino R4s with either the weathershield or htu21d attached. They are crashing whenever humidity rises to about 80% (eg in bathroom or in refrigirator).

Any tips are welcome.

[TomWS]

Hello,

I have Moteino R4s with either the weathershield or htu21d attached. They are crashing whenever humidity rises to about 80% (eg in bathroom or in refrigirator).

Any tips are welcome.

Have these motes been deployed for some time or are these all new?

I have had a couple of failures due to condensation and/or corrosion on some outdoor motes.

If your motes have been deployed for a while (9 months or more) and then this just started I'd say your boards need a good cleaning with Isopropyl alcohol, dry thoroughly, and then apply treatment to 'immunize' them from high humidity (see next).

If these are new (or you've just cleaned them)  then you may need to coat the boards with a corrosion or water resistance material to prevent condensation from shorting key signals on the Moteino board.  There have been numerous postings regarding corrosion on the forum.  One of the postings suggested a material call CorrosionX.  I've gotten some of this to use on my next deployment.  It's messy stuff but looks very promising.   I'm less confident in using a hard sealer as these will crack and breakdown over time.  CorrosionX is very thick and should remain a continuous film - even if scratched, it will probably self-heal.

Tom

[Felix]

"Freezing" can be power/circuit related or code related, I would think it's the first like Tom said clean the boards with IPA (avoid flooding the BME280 sensor!).
In general I would try to keep the electronics away from humidity as much as possible. Folks have discussed all kinds of weather proofing options and even enclosing the boards in epoxy and things like that to protect them from the elements. You would have to expose the BME sensor obviously, but start from the simple things like Tom suggested.
Also if you had a chance to do more investigation to try to figure out what's failing that would help in targeting the actual problem rather than trying everything we can think of.

[syrinxtech]

I have one outdoor unit with several sensors attached and outside of what Tom said, airflow really helps.  It routinely hits 100% humidity here where I live and it's thick enough to cut with a knife.  Cleaning and treating all boards, combined with good airflow really helps.  There are several nice vents you can install that allow air flow and pressure equalization that will definitely help.