Engineer Develops Sonar Alarm System To Monitor Kids In the Pool (newatlas.com)

British electrical engineer John Barstead created a sonar alarm system that will warn parents or nearby sunbathers if a small child has accidentally fallen into a pool. The Dolphin Alarm, as it is called, is currently raising production funds on Kickstarter. New Atlas explains how it works: When small children who have no business going into the pool on their own are out playing near it, they wear a special wristband. If they should fall in, the wristband will generate a three-tone sonar signal as soon as it's immersed in the water. That signal will be detected by a hydrophone contained within a receiver unit that floats in the pool. When that happens, the unit will emit a 131-decibel alarm. It will also transmit an alert to an indoor remote unit located up to 150 m away (170 ft), which will likewise sound an alarm of its own. While there are other child-in-the-pool alarms, most of them are wave-activated and have to be shut off when other people are using the pool.

Comments

What if they aren't wearing the wristband?

[mveloso]

The wristband is the flaw. A kid who isn't supposed to go into the pool isn't going to wear their special wristband, especially if it isn't their pool.

Wave-activated sounds superior, actually

[93 Escort Wagon]

I would think a wave-activated device, coupled with a security camera and some sort of mobile or web app, would be great (if I had a pool, which I don’t). It would work for neighborhood kids, which this wouldn’t. And, if I were away from the house, I could still call for emergency responders were it warranted.

This new “invention” seems like something we could’ve had in the 1960s. The only reason it’s even here is probably the word “KickStarter”. Hey, @whipslash, please consider adding the ability to filter out KickStarter stories, the way we can other subjects.

Cheaper Solution

[bobstreo]

Shock Collars and invisible fencing should protect your children quite nicely. And provide a handy guide for your robotic mower, which totally would never kill people instead of cutting grass. /s

Existing products do much better

[heldal]

Interesting idea, but pool guarding systems based only on video is pretty common. Like PoolView, SwimEye, AngelEye among others. It has existed for many years. As a matter of fact, my brother used to code for one of these systems. It's all underwater video monitoring with pattern detection and works fairly well.

The only scenario where I could see this sonar-version would be practical is in Hotel resorts or other closed areas where visiting kids are given this wristband and then left to roam the premises unattended. Going for private households might be the angle required for Kickstarter, but all in all this seems like a product more suited for the business market, IMHO.