External reed switch / outdoor proofing GS-WDS07

I’m wondering if anyone has mounted the Chinese 433MHz GS-WDS07 reed switch outside? I’m aware I’d need to waterproof the unit some, and also that I’d probably suffer poorer battery performance.

Otherwise any other tips? The end of an alleyway at the back of our house is protected by a municipal security gate shared by the four houses that back onto this alleyway.

My wife is compromising everyone’s security by leaving this gate unlocked at random and I’d like to be notified (or for her to be notified!) when this has happened.

So my use case needs are a) external and b) wireless.

Thanks!