just like all new dad's, we are good at worrying. the topic that has been heavy for me is the in ground pool.
been looking around for a few days about swimming pool alarms.
i am looking to build a DIY pool alarm. problem is i just dont know what detection method would be best. some options are: IR, PIR, and laser. i have a strong background in lasers and can build any electronics just rough on the programming side. ( im working on that)
the pool is 15'x32' and just under 25000 gallons. getting power to the electronics is not an issue. just trying to figure out how to detect a child falling into a pool. any ideas, suggestion, directions or critique is welcomed....
If you are a new dad then this is a very young child. Unfortunately the only answer (and it comes a shock) is constant vigilance. You are on guard 24x7x356.
Physical barriers would be the next line of defense, but they won't work.
For electronic detection look at commercial systems to see how they tackle the problems, but they won't work either.
I have been in a pool on a couple of occasions when healthy teenagers have slipped silently into to trouble, no fuss, no noise, no splashing. Fortunately both times somebody spotted things were wrong i.e. floating face down unconscious on one occasion and just sinking to the bottom on the other.
i realize that this is no full proof idea or an alternative to good parenting and supervision. it is though a secondary or third defense. ive got a good idea for the laser barrier setup and i believe it will work with 2 beams (one beam at ~1.5' and another at ~4.5' to try to cut down on false positives) but will a PIR work better or maybe a IR detector. what do ya'll think. (i can say "ya'll; i'm in Alabama)
If you are going to do this then go for belt and braces. In other words laser curtains plus something like PIR.
Also make everything is fail safe in other words alarm on loss of signal. The system also needs to be self checking.
Best thing to do is look up how to design safety critical systems.
I don't know how well PIR works during the day. My experience of it is that deer enjoy floodlight banquets eating my garden at night, but detection in daylight may be a problem.
one beam at ~1.5' and another at ~4.5' to try to cut down on false positives
Sorry I forgot to add you are thinking about this the wrong way round. False positives are fine in this instance, false negatives are what you want to avoid.
Hate to be another nay sayer but I don't even trust my fish with my electronic competence. Make sure that you keep in mind that anything you make will be a trivial project for fun and should never be considered an actual safety tool.
I agree with the others about trusting the life of a loved one to something you built and don't thoroughly, thoroughly (hundreds or thousands of hours) test. However, I know I was talking to someone who specifically was working on a project to basically do this. There was some form of necklace or bracelet that has a pendant on it that would send out a distress signal if it got submerged in water. I honestly do not remember more details than that, but it was a supposed to be either a commercial or government based project (Real helpful, I know). The person was helping with the development, so it may not be ready yet.
A possible solution, but not one I would implement, would be surrounding your pool with some form of laser (Or some form of beam) gates, such that if anything crossed the beam, it would trigger your alarm. I would set them back from the edge pool and instead in the area around it. However, it would always trigger whenever you wanted to use the pool as well, and good luck if you have outdoor pets.
That would get my vote - with padlocks. I would never trust a warning device to prevent a vulnerable person from drowning, because you can never be certain that the device will work when it's needed, and you can never be certain that there will be somebody close enough to notice and respond in time. (That's why we use stair gates instead of PIR sensors and laser trip wires and so on...)