Short answer: In humid or rainy weather, an old phone used as a security camera usually fails at the charging port first, not at the camera. Samsung's support page says its phones "will not charge if moisture is present in the charging port," and that the water "will naturally evaporate from the charging port within approximately 1 to 2 hours." Google's Pixel help page describes the same protection with a different message: "Liquid or debris in USB port." For those hours the phone runs on its battery while the cable is still plugged in. If the battery is old, the camera can go dark before the port dries. The fix is mostly about where you put the phone and how the cable reaches it, not about buying anything.

This is a plain-English guide for people using a spare Android phone as an offline security camera at home, in a shop or in a storeroom, often without internet , through a long wet season.…