[LeifCarrotson]

Here, try not to drop the ball yourself:

http://spotthedrowningchild.com/

And remember that as you said, pool drownings are exceptionally rare, so instead of knowing there's a drowning child in frame in the first 60 seconds or so, you're watching for 8 hours a day and probably won't see one all summer.

As an industrial controls engineer, I find myself constantly explaining that humans are pretty bad at being robots and robots are pretty bad at being humans. This seems like yet another example. People are really bad at paying extremely close attention to their entire field of view continuously; machine vision does that tirelessly for the price of a few watts of electricity. In this case, the underwater robot is helpless to communicate to other poolgoers and to the suspected drowning victim, and as a mass of propellers and PVC it's probably slower than a skilled swimmer. Others have expressed concern about being trapped in a potentially broken robot's grasp: robot actuators are bad at grasping squishy humans, but humans are good at that.

I think the greatest value in this system is in the cameras. A light and/or sound to notify a nearby human would make lifeguarding hugely more effective and easier. That said, I don't particularly look forward to camera-laden advertising zepplins floating over the local swimming hole.

[klmadfejno]

I used to be a lifeguard. My pools weren't nearly as busy as that website's examples. If they were, I probably wouldn't have done the job, as that looks super stressful. Much to my surprise, however, I did spot the drowning child at around the same time as the lifeguard. Youth employment validated.