I'm looking for ideas on how to sense when a person or animal has entered a swimming pool. There are several devices on the market that claim to do this, but the reviews are all pretty horrible. False positives seem to be a big problem with existing products. I'm thinking that something like an infrared camera would work but it would take considerable effort to set up the detection area (i.e. where the pool is) in the camera's view. Does anyone have an idea that's not prone to false positives (i.e. leaves falling in the pool, wind blown water, etc)?
