I have 3 MS16A's that are deployed outside my house. 1 is covered from the weather and works fine. The other 2 are on the south side of the house that is exposed to most of the weather that we get. Although X10 claims that these are "fully weather-proof", I have seen fog inside the lenses many times. I just pulled the 2 exposed to weather and opened them up. 1 had standing water in the battery compartment and the batteries had rust on the contact points. The other had a film of condensed water on the batteries. The worse unit had water saturation visible on the edge of the circuit board and some corrosion on the buttons.
Is this normal for these modules? If so, is there a way to improve their not-so-fully weather-proofedness to actually workable? My first thought would be silicone, but that would trap moisture inside without any escape if I miss a spot. I've seen a couple sensors that include some sort of rain cover or hat which seems like a good plan. I may have to move them to see if that will help, but I located them in the optimal location for detection. If I move them, they may last longer, but they won't necessarily function as desired.
An alternative is to use some other system and link it to X10 somehow. I've glanced at the Chamberlain CWA2000 which looks pretty good. But, I don't see that it has a direct way to link it to a PowerFlash like their older system did.